Theres been tons of idle problems on the forum , I`m after the loping or surging idle problem solution once and for all. The engine/car is a 86GT 2.8 automatic.

Symptoms:
1. Car sits over night, on first start in the morning , the engine will run up to 1500rpms.
2. Then with-in 30 seconds or less, it will drop to 500rpms (but won`t stall)
3. Then its back up to 1500rpms, then down to 500rpms, it does this for 1-2 minutes .
4. If I tap the gas , during this time, it will keep flucuating back-n-forth, allmost --but not stall.
5. If I shut the car off, during this 1-2 minute time, then re-start the engine, it will go up to 1750-1900rpms and stay there for 4-6 minutes, then slowly (step down) and drop to 950rpms where it belongs.
6. If it let it go threw this --shut it off and walk away for 4-5 hrs, it will start and go strait to 1500rpms like its supposed to , not loping or hunting, then idle down to 950rpms the way its supposed to.
7. If I let it sit overnight or longer than 8 hrs or so, it`s back to the surging--/--hunting again.
8. Ran it for 5 minutes last night until it straitend out.
9. It`s been 12 hrs, just started it this morning, it went strait to 1500rpms , then stalled (thats a first for the stalling issue) re-started it right away, it went threw the 1500 to 500rpms senario--BUT only after 30 seconds of strait running time at 1500rpms, tapped the gas and it did the hunting, but not down as far as 500, each time I tap the pedal during the first minute it won`t drop all the way to the 500rpms, it keeps getting higher in rpms on the low side, it works its way from 500rpms up to 1000rpms, then will idle fine, like its supposed to .
10. After the 3rd time of re-starting this morning in a row --all with in a 3 minute time period, the 2nd & 3rd starts it will run up to 1750-1900rpms and stay there and bounce back to there, whether I tap the gas or not. (no dropping down as far as 500rpms)
11. Then it will idle down from 1750-1900rpms to 1500rpms to 1200rpms to 1050rpms to 950rpms and stay at 950rpms.
12. Just went back out--and started it (15 minutes have passed) it went up to 1900rpms and stayed there for 5 minutes.Then dropped to the normal 950rpms --no stepping down or flucuation.
13. If I drive the car right away or anytime mentioned above --it`s ok --at first start it will want to climb up or drop down in idle for a minute , (while in drive/gear) after a 1/4 mile run and or first stop sign, it`s fine.
14. The car runs like a top.

As mentioned the car runs like a top, no codes, ran winaldl on it, dodgerunner and I both read the logs and compared them with his logs and it seems fine in all aspects.
Has anyone every fixed this type of problem ? If so what did it take or what did you do, I have replaced most if not everything I can think of, I don`t want to name everything , I`d much rather hear what you folks did to fix yours.
Any and all info/help will be appreciated --even if you had to kick the the door 3 times and pop the sun-roof up and down before you started the car....Sorry for the long post , I know others have posted this in the past, and got answers , then I see them post again, trying to help someone else with this problem, and still say they have been fighting it for a year or so and gave up--well I`m not going to give up, I want to put a end to this thing--even if I have to take the car apart one bolt at a time, that way we`ll have it on record for the next or exsisting members that has or still have this problem. Guessing is also welcome.......Thank You for your time and expertise.

The last time I had a problem wear the car wasn't throwing any codes,I couldn't figure out what was wrong a friend finally came over and pulled the data,nothing abnormal!Finally I baught a fuel pressure tester,turned out to be low fuel pressure on a new pump that only had 30,000 miles on it.After checking the fuel pressure,you might want to replace the fuel filter too (could be one of three things, after testing the fuel pressure,fuel pump,fuel filter or fuel pressure regulater) .It wouldn't hurt to clean your grounds.Have you tried removeing the IAC and cleaning the tip,(yea,I know no codes).Allso there is a port on the inside base of the throttle body that should be cleaned.Some times the EGR will buildup a carbon like washer at the end of the EGR tube that attaches to the intake manifold,you can attempt to clear this washer through the butterfly of the intake,(with a thick curved piece of wire).

James , I installed a new fuel pump & filter, has about 500miles or less on it, checked the fuel pressure a couple days ago, it`s perfect..But how did you check for your pressure regulator? I installed a new iac and cleaned the passage before I did that. The port on the inside base of t.b.--is this the one that runs over to the lower intake, its a small black tube coming off the back of it? I installed a new egr tube--when I had the plentum off and new egr gaskets on the egr vavle and plentum sides of the tube and cleaned that stuff out of there (wasn`t much though) This is good --keep them coming...Thanks for replying

On cold start the ECM is in open loop right? What does the ECM "see" in terms of sensors? I ask this to clarify and narrow down what to look for in terms of sensors.

How is your battery? Have you tested the charging system and had it load tested recently? Did you switch out the battery for a battery that you know is good? Any unusual items putting a drain on the battery overnight? I allways think electrical on cold start fluctations because the sensors and ECM "see" voltage, someone chime in here and correct me if I am wrong, ok? Did you take a couple of hours and clean all of your grounds down to bare metal, check for good battery connections. Have you checked the output terminal wiring on the alternator up to the main power terminal and then to the battery? See where I'm going on this for you 3800? I'd even check the battery acid levels in the batttery too. Hope this helps you out.

------------------
jetman
Silver 86 SE 2M6 4-speed, with "check wallet light"

quote Originally posted by 3800superfast: James , I installed a new fuel pump & filter, has about 500miles or less on it, checked the fuel pressure a couple days ago, it`s perfect..But how did you check for your pressure regulator? I installed a new iac and cleaned the passage before I did that. The port on the inside base of t.b.--is this the one that runs over to the lower intake, its a small black tube coming off the back of it? I installed a new egr tube--when I had the plentum off and new egr gaskets on the egr vavle and plentum sides of the tube and cleaned that stuff out of there (wasn`t much though) This is good --keep them coming...Thanks for replying

I dont think the Fiero fuel pressure regulater is acesable without pulling the intake manifold,when mine went bad it was leaking fuel out of the intake (I wondered were my gas was going,major tear in the diaphram).Allso if you were able to remove the vacume line off the fuel pressure regulater and if there was a hole in the ruber diaphram,fuel would come out of this vacume line.That was on a Camaro and was much easer to access (a fuel test should show if it's fuel related). The port in the pic below that says IAC Port,should be cleaned.If you have a vacume leak,I know some people will spray started fluid on the motor and see if that causes it to idle up (caution can melt paint)Possible a bad gasket somewear.
I never had good luck with that method.Allso look for broken or missing vacume lines (the plastic can become brittle with age).

I know you have a list for people who post this problem, and I know you went thru the list. I would check the torque on the intake manifold to head bolts. vacuum leaks under the manifold are a biatch to find, an aluminum to cast iron interfaces seem to be a weak spot, as aluminum expands much faster and more than iron. most people never re torque those, and the should at least be checked. not a pleasant thought. the plenums are like materials, and are not as prone to developing leaks.

for troubleshooting I would also consider blocking the egr port off under the manifold, to rule out an sticking egr valve.
swap your map sensor out, it could be going flakey, at the least check the connection and that silly rubber T on the lines.
I think this sounds like a vacuum leak issue, more than any sensor, as the ecm is not looking at o2 yet, but it is looking at coolant temp, iat, and map and tps. and if any of those were flakey, it would likely show up in drive issues or warmed issues, but may be more subtle.

I have hunted this problem for several years and have not really found the answer. I can start my engine after sitting all night and it fires right up but goes from 1500 to around 600 back and forth. I can cut the switch off and restart and it works perfect. I changed the mat and ecm temp sensors and that really helped. I got to where I just start the car and cut the switch off and restart. It runs perfect. There is something about the two sensors that is just not exactly right. If you find the problem please let me know. I keep thinking that there may be a problem with the cold start injector, but I have checked it out also.
Don

Jetman, I have a new alt ( 500miles tops) and it puts out about 14.8 or so. The values on the ecm while running winaldl seem to be what the service manual is calling for ,or better. One problem with winaldl --is when you start the car, to try to find the problem, the winaldl program raises the rpms by a couple hundred and puts the ecm in the field service mode, which won`t allow for the car to actually do the loping/hunting. I cleaned all the grounds except the ones over by the bellhousing, I did clean them real well, before the engine was re-installed about 500miles ago . I will go threw and do them again. I know what your saying with the sensors going flakey because of voltage being low or erratic. Thats why I put in a new battery and alternator...I`ll go threw the electrical again as mentioned and check connectors and all....Thanks for replying keep em coming..

quote Originally posted by 3800superfast: Another interesting thing I found was if you stop power the the ecm either by disconecting battery or unpluging that little fuse looking thing back by the battery C-500 block, the car won`t hunt idle on first start up, this only works once, you would have to re-set ecm each morning, which we all know, wouldn`t be to good of an idea.... Thanks for replying keep em coming.

Same exact senario on my car, resetting the ECM will give me a fast "step down idle" but only on the first start.
The ECM is trying to learn something right? But what?

quote Originally posted by jetman: Same exact senario on my car, resetting the ECM will give me a fast "step down idle" but only on the first start. The ECM is trying to learn something right? But what?

Good question, I think it has the iac, tps, cts, mat, map, bpw to deal with at idle. Last night I added a ground from my distributor, (thinking electric here) to a solid on the bell-housing, cleaned all the grounds again, pulled the ignition modual, cleaned it and added new white heat sink compound, plugged in and re-plugged in all the connectors, to make sure they where all clean, switched the mat and map , started the car (cold) its starts hunting for 30-45 seconds or so, tapped the gas, it got worse, so I shut it off. The waited a second or so , started right back up with no hunting idle--went right to 1500rpms, stayed there for 30 seconds, then started raising until it got to 1750rpms, then stayed there for all most 5 minutes , I kept tapping the gas , and it would get a tad lower each time, then raise a hair, then I un-hooked the T vac line, that is used for the map , did one at a time, I could here it suck air and the idle lowered, un-hooked the electrical connector to the map, it idled lower again, then when I plugged them back in real quick , the idle went back up to where it was, then just left it alone, it took another 5-6 minutes and went strait to 950rpms. Total of 11 minutes from cold start to get down to normal 950rpms---seems like a long time, it does do the step down deal during this also.
I`m guesing everyone that has had or still has this--has had at least the top part of the engine off ? If so post what all you did and how far down you went--mine was down to the block replacing head gasket.
It allmost feels like its starving for gas--when the fuel gauge is hooked up , it stays right where its supposed to . Iv`e been threw the vac lines so many times its crazy anymore.
I know from reading for the past couple of years --most everyone has been threw replacing all the sensors too--and that didn`t work.
What could be the difference in a matter of a couple seconds between starts to make this happen?
I thought I `ll try pressuring up the fuel lines by keying on a few times before starting for the first time, and it makes no difference.
The worse part is --you only have a couple (if that ) minutes to fool with it--and as crazy as this sounds --then your good to go for the rest of the day--as its allready done its first start ?
If everyone has had the top end off, lets figure out --if they got down as far as the lower intake, and try to work from there. Just throw in anything you tried at one time of the other that may jog something here --I hope...Thanks again guys keep em coming Can anyone find **Hunting Idle** info on the internet that doesn`t deal with Fieros, just cars in general, maybe something there..?

Superfast sounds like you are determined to find the cause and I sure hope so. It will be some little something. I have played with this for several years and I just can;t pin point it. The extra grounds that I installed helped a bunch and I cleaned all connectors. Also new battery and alternator. The only sensor that I have not changed is the map sensor and I don't think that is it. It sure is strange two starts and it is perfect. That is why I was thinking fuel as the second start gives it another shot of gas. Can the cold start injector be adjusted so that it will give more fuel at start up. Strange problem and as many of us has this problem, I would have thought someone would figured it out by now.
Don

he has a valid point, BUT he is working with a big cam and tuning his custom ecm. the ecm is very capable of a smooth idle at anytime, something is whacking it out. yes it could be lean, or rich or timing glitches, but what is causeing the ecm to do that??
either a sensor or something directly effecting a sensor.
if you want to have some fun with trouble shooting this, start fooling the ecm.
I would start with fooling the temp sensors. go out when it has sat and you know the problem will start. get out your handy dandy digital meter. measure the resistance of the IAT and the CTS. note the value, go to r/s and pickup a couple of variable resistors that will pickup that value, I thinmk 5k or 10k ohm ones are good. set one to each of the sensor measured value with the meter. jump them into the 2 circuits. now the ecm will never see any temp increase, and in theory, should work to hold the fialure longer.
before you start the car, get a vacuum guage on the manifold on the map line. now start it, and record the vacuum levels and note how it is acting, vibration, dips etc.
do your tricks to make it go away. if it does go away, it is NOT a temp sensor pushing an ecm mode change, as the ecm sitll thinks it;s the same old cold motor. if it does go away, note the vacuum guage and how it is acting. shut it off. reconnect the temp sensors. restart and warm til the motor is ok at idle. shut off, and remeasure the sensors. (just for another attack strategy)

now, assume you cannot make it work right with your 'temperature never changes' workarounds. that would suggest that the ecm is noticing a slight change in temp and is acting differrently. now you have to wait again. let everything cool off to known failure mode. tweak your temp sensors to a warm motor range, as noted above. install them and start the motor cold with the sensors sayig it;s wam and note the vac and if it is acting the same. (it won;t be a great idle to begin with as it is not really warm, but it should run ok).
see if that poinst anything out. post the results and lets go over them.
(and before you ask, yes, I am insane in some of my trouble shooting techniques, but this is a strange problem)
I would prefer to go the "clean hands" route of hunting this down before the wrenches start flying!

Hey, superfast glad to see your determined to solve this problem. I have a different idle problem but am following this topic with interest. One question I have is how much vacumm should be present say at the map sensor at idle? And what are the chances that that big line that goes to the brake booster is leaking? How much vacumm should be present at the booster? I have hooked up a vacumm gage to my car but don't know what the normal reading should be. Good luck

18-22 inches at idle, steady. depends on how good a condition the motor is in as to the actual value. blipping the throttle should cause it to drop to neqr 0 if you hit it wide open, and will hit 30+ when slammed shut from a wot blip.

tjm4fun, Ok just to double check, I should put the resistors in the connections that plug on to the map & mat ? Thats what you meant by iat ==idle air temp? Whats the best setting on digi-multimeter to set to measure that type resistence ? I want to use the measurement with the omega sign ? All I have done in the past , with the CTS is make sure its getting the 5 volts to it. And it does. One of my downfalls is reading meters so bear with me on this part--I need all the help I can get... I will learn the correct way to read them , if it means fixing this idle problem for everyone, once and for all.. Just for the hell of it , until I read this --tonight I was going to try the old ecm ( I have 3 that work for this car) and install an ads superchip that another forum member was nice enough to send to me --as everyone says it makes their engine runs rich, adding gas---was thinking what Don was above, fuel, on that first start. I will however try the resistors after I figure out what I`m reading at both sensors, I have 1 --10k maybe 2 here from the winaldl cable, but can get whats needed from radio shack, if anyone happens to allready know, please post. I should have payed more attention in school to electronic devices and how they work......Thanks Guys keep em coming .......

ok, yes the omega sign is ohms. Scales vary depending on meter types, I would start with the 10000 (10k) range. the IAT is the one on the air cleaner, input air temp, also called mat, but I switch the 2 alot. the 2 sensors on a sitting motor should agree fairly close, at least initally!
here is a chart of the resistive values, so you should get a 10k ohm potentiometer (variable resistor)


the iat/mat is a 2 wire sensor, so that is easy, just put the resistor across the 2 wires. the cts, you need to be sure you are across the right 2 wires, should be the yellow and black wires. I would be very interested if the 2 sensors match. if the car has been sitting overnite, the 2 sensors should be at the same temp, and have the same resistance, at least within 100 ohms!
saying it's in your shop I would guess it is around 60 or so degrees, from that chart, I would say that would be roughly 4000 ohms. the value does not appear to be linear, so that's a SWAG (scientific wild-assed quess). for practical purposes, if you had 2 of the 3.9k ohm factory test mode resistores, that would be close enough for ambient temps now. (verify that with the meter)
the 10k ones would put you around 30 degrees, probably ok for testing too.

now one thing, when you measure the existing sensors, have the plug off, and go right on the sensor pins, you don;t want to back feed voltage to the ecm,as that will alter the reading. the cts is the biggest pain there as far as which of the pins is which.

Now if you go with one of the on hand resistors, realize this is only valid for a few minutes of testing, as the motor is warming up, there are other factors, it will run richer this way, as it will still be in the fuel map for that cooler temp range. of course on the plus side of that, if the hunting continues with the motor warmed up, and the ecm still running in cold mode, then that narrows the search area to the ecm, or map and the egr system (at least according to the fsm egr is a factor even at idle) I expect codes may pop tho, temp related.
one other thing, do a winaldl before you start anything, and check the iat and cts temp, see if they match, then followup with the resistance check right at the sensor. that should verify wiring. and also send up a red flag if they are radically different, as the ecm won't be using the correct areas of the fuel maps.

Now that I've thoroughly confused you...... you have a PM (from a while ago)

edit: as I may not have been clear on this, if you hook up a resistor, the sensor will NOT be connected. you will just be connecting across the plug. the resistor is taking the place of your sensor.

[This message has been edited by tjm4fun (edited 10-02-2006).]

Pm sent...

tjm4fun, Got pm Thanks for the above info --sent another pm....

email sent!!

Email recieved will work on the first issue asap , then report findings.

now before everyone starts re-inventing the sensors... have you checked to see if the throttle stop screw has been tampered with?

------------------
Former West Coast Fiero Employee

New and Pre-Owned Auto Sales Consultant
Power Ford Valencia

Yep, Checked to make sure the cap was still there a year ago----its there... No tampering.. Thanks for the reply--keep em coming....

whats the condition of the O2? Is there any fluctation on the scan tool?

just for a shot in the dark, try disconnecting the cold start switch.....

My next step is to jump the fuel pump so it will run all the time and then start the cold engine and see what happens. I still believe there is a fuel problem or the sensors have a very long delay action to the ECM. I know that you can turn on the switch key and then offf and back on three or four times and then when you start it, everything works properly which leads me to fuel.
Don

Chicken McNizzle, 02 sensor is fine, found a discepency in the data showing in winaldl .

We've been checking some things via email, as some of the details are rather long. I think what 3800superfast is trying to come up with is a logical way to approach this problem without throwing a ton of parts at it.
We did find something with his sensors, and I tried to duplicate this surge condition, but it was way too warm here today, and the motor was in closed loop in under a minute. I did manage to get a short bit of surging tho and an abnormally high start idle by fooling my ecm .
The biggest issue is that there are probably quite a few root causes for this, and not everyone will have the same cause, but if we can come up with a logical checklist and approach that most people can do with some simple tools, then we may save alto of folks time and $$$ and frustration.
This is usually an open loop failure, and the o2 sensor is not used. most people say everything is fine when it warms up. the ones that see no or little change on warmup would be a differrent failure mode.

quote Originally posted by ka4nkf: My next step is to jump the fuel pump so it will run all the time and then start the cold engine and see what happens. I still believe there is a fuel problem or the sensors have a very long delay action to the ECM. I know that you can turn on the switch key and then offf and back on three or four times and then when you start it, everything works properly which leads me to fuel. Don

Don Hold tight right now---I`m 99% sure I have found the problem, just need another 24-36hrs to prove my theory is correct. Late yesterday with kind of a un-conventional method (which will be explained soon) I got the car to start with no loping , tried again after 24hrs and it worked again....This car has done this pretty much as long as your has Don , so I know it will be the same solution for you and the other members with this hunt idle problem...

quote Originally posted by 3800superfast: Don Hold tight right now---I`m 99% sure I have found the problem, just need another 24-36hrs to prove my theory is correct. Late yesterday with kind of a un-conventional method (which will be explained soon) I got the car to start with no loping , tried again after 24hrs and it worked again....This car has done this pretty much as long as your has Don , so I know it will be the same solution for you and the other members with this hunt idle problem...

I sure hope you have found the answer. If so, then you will be the Best Forum member for sometime. Thanks again
Don

I've posted this info before, but will re-post for those reading this thread.

I bought my '88 GT new, and when it was about 8 months old it started having the exact same symptoms. The dealer found that the car was running lean during initial startup until it went into closed-loop mode. They replaced almost all of the fuel injection system and most sensors under warranty before I asked for the zone manager for help. A GM engineer from the Milford Proving Grounds picked up my car and took it to work, and they found that my engine had severe intake valve deposits. I was told it was caused by some impurities in the gas that was distributed mostly to the midwest, and was a big problem in Michigan, Ohio and the surrounding states. The engineer said the deposits act like a sponge on cold start and soak up enough of the fuel sprayed by the injectors that it causes the engine to run lean until it goes into closed loop mode, when the O2 sensor can compensate for it. If the valves are warm, the fuel will not be absorbed by the deposits, so the only time it happens is first start after the engine is fully cooled. It usually takes sitting overnight.

GM cleaned off the intake valves with a "walnut shell" blaster without pulling the heads, and this fixed the problem. My car ran fine for probably 10 years afterward, but then it starting to show signs of the same symptoms coming back. Since the problem seems to be caused by a lean condition at cold start, which is controlled by the base calibration tables, a friend of mine burned a modified calibration for me a few years ago that richens up the air/fuel ratio for open loop at cold start only. This seemed to fix the problem (more like masked it), but now my car is starting to have the same symptoms again. This winter while my car is sitting, I plan to pull the intake and check the valves for deposits, unless someone else comes up with an alternate solution.

What I can say with confidence, is that the engine runs lean in open loop mode after sitting overnight. That's been confirmed on my car by multiple technicians. Any sensor problem that causes the ECM to command a leaner than ideal A/F ratio during cold start will probably cause the same symptoms. One possible fix would be to change the O2 sensor to a heated type, and modify the calibration to allow closed loop operation sooner after startup. I've heard that heated sensors can be operational in only a few seconds after start, so the engine would probably still surge for a few seconds, but then stop when it enters closed loop mode. Just an idea. Still a bandaid to the real problem, but it's a fairly simple retrofit.

John

quote Originally posted by Johns88GT T-Top: I've posted this info before, but will re-post for those reading this thread. I bought my '88 GT new, and when it was about 8 months old it started having the exact same symptoms. The dealer found that the car was running lean during initial startup until it went into closed-loop mode. They replaced almost all of the fuel injection system and most sensors under warranty before I asked for the zone manager for help. A GM engineer from the Milford Proving Grounds picked up my car and took it to work, and they found that my engine had severe intake valve deposits. I was told it was caused by some impurities in the gas that was distributed mostly to the midwest, and was a big problem in Michigan, Ohio and the surrounding states. The engineer said the deposits act like a sponge on cold start and soak up enough of the fuel sprayed by the injectors that it causes the engine to run lean until it goes into closed loop mode, when the O2 sensor can compensate for it. If the valves are warm, the fuel will not be absorbed by the deposits, so the only time it happens is first start after the engine is fully cooled. It usually takes sitting overnight. GM cleaned off the intake valves with a "walnut shell" blaster without pulling the heads, and this fixed the problem. My car ran fine for probably 10 years afterward, but then it starting to show signs of the same symptoms coming back. Since the problem seems to be caused by a lean condition at cold start, which is controlled by the base calibration tables, a friend of mine burned a modified calibration for me a few years ago that richens up the air/fuel ratio for open loop at cold start only. This seemed to fix the problem (more like masked it), but now my car is starting to have the same symptoms again. This winter while my car is sitting, I plan to pull the intake and check the valves for deposits, unless someone else comes up with an alternate solution. What I can say with confidence, is that the engine runs lean in open loop mode after sitting overnight. That's been confirmed on my car by multiple technicians. Any sensor problem that causes the ECM to command a leaner than ideal A/F ratio during cold start will probably cause the same symptoms. One possible fix would be to change the O2 sensor to a heated type, and modify the calibration to allow closed loop operation sooner after startup. I've heard that heated sensors can be operational in only a few seconds after start, so the engine would probably still surge for a few seconds, but then stop when it enters closed loop mode. Just an idea. Still a bandaid to the real problem, but it's a fairly simple retrofit. John

I understand everything you say and you have some good thoughts. I have always thought it to be fuel related. Now if we could get another cold start fuel injector that would shoot twice the amount of fuel, then I think the problem would be solved.
Don

no, the cold start won;t fix it. it only is energized while the starter is engaged. even if you rigged it to run 2x as long, which would be 16 seconds it will not fix it.
Johns88 is correct it is rooted in the lean condition, and honestly, I think those GM engineers were full of shyt about intake valve deposits. if that were the case every car in your area would have had the same issue, and you would have heard of this form all the car owners. likely they found your motor may have had some casting defects in the heads, or some other crud, but cleaning the intake valves???? come on, the next tank or 2 of gas and the problem would be back. Had that been me I would have called them on that line right there. cleaning the heads on the car?????, ok, fine, if they could do that it would be a common place maintenance item. I don;t doubt what you say they told you, I am saying they fed you a line of crap. and believe me, they do that, having assisted a few people in buybacks of their cars with lemon law fights. There you find out how stupid they think the car buying public is.

I think your remapped chip is more along the lines of a correct solution, that was applying thought to the problem. the cold start maps are crippled to meet emmisions standards, and those old slow ecm's do not have the resources to correct properly. fixing the map is one of the best overall solutions.

ps...
and so many people say Fuel Injection is better. my carbed cars never did any of this, and my boat idles at 575 rpm in gear without missing a beat. and those are 1976 350 sbc blocks, last carb rebuild was 12 years ago. even in december in the damp and 30's, they start faster than most cars do.

quote Originally posted by tjm4fun: no, the cold start won;t fix it. it only is energized while the starter is engaged. even if you rigged it to run 2x as long, which would be 16 seconds it will not fix it. Johns88 is correct it is rooted in the lean condition, and honestly, I think those GM engineers were full of shyt about intake valve deposits. if that were the case every car in your area would have had the same issue, and you would have heard of this form all the car owners. likely they found your motor may have had some casting defects in the heads, or some other crud, but cleaning the intake valves???? come on, the next tank or 2 of gas and the problem would be back. Had that been me I would have called them on that line right there. cleaning the heads on the car?????, ok, fine, if they could do that it would be a common place maintenance item. I don;t doubt what you say they told you, I am saying they fed you a line of crap. and believe me, they do that, having assisted a few people in buybacks of their cars with lemon law fights. There you find out how stupid they think the car buying public is. I think your remapped chip is more along the lines of a correct solution, that was applying thought to the problem. the cold start maps are crippled to meet emmisions standards, and those old slow ecm's do not have the resources to correct properly. fixing the map is one of the best overall solutions. ps... and so many people say Fuel Injection is better. my carbed cars never did any of this, and my boat idles at 575 rpm in gear without missing a beat. and those are 1976 350 sbc blocks, last carb rebuild was 12 years ago. even in december in the damp and 30's, they start faster than most cars do.

I agree with you. I have yet to see a Nascar with fuel injection. Although I still like the fuel injection over the Carb.
Don

quote Originally posted by 3800superfast: Don Hold tight right now---I`m 99% sure I have found the problem, just need another 24-36hrs to prove my theory is correct. Late yesterday with kind of a un-conventional method (which will be explained soon) I got the car to start with no loping , tried again after 24hrs and it worked again....This car has done this pretty much as long as your has Don , so I know it will be the same solution for you and the other members with this hunt idle problem...

Holding breath waiting for an update, turning blue, hint please?

I haven`t forgot the thread, I`m working away at this, tjm4fun has been nice enough to help/advise/work with all this , even though his engine isn`t plauged by the hunt idle syndrome, it is sensor related jetman, your getting close with the mat & cts. I`m not trying to delay anything, but it is taking time and different test to get this to a point that *hopefully* we will be able to say--ok --heres what you need to do to fix the issue in most cases. What we are doing at this point is stimulating the sensors, I can get mine to stop the hunt idle, and tjm4fun has been getting his engine to hunt idle. Wer`e at the root cause, but now need to go a little further to make it a permanent fix. Some engines may vary as mentioned above, but the fact , that the root cause is opened up , is a great start . I`m not going to quit until its resolved--which hopefully will be very soon .

ok, I'm back form my last hoorah social trip on the boat. Now it is switched back to all fish all the time. lots of sharp knives hooks, gaffs, and other instruments of offshore/nearshore fishing. It may take a day or so for my alcohol/food daze to pass.
I'm curious what has happened with the last pass of tests.....

tjm4fun , All test sent to your reg email this morning, email yet tonight if you can. I found 1 way of bring that idle to where its suppoed to be and no hunting..lol.. you`ll see it in the tests, lmk asap (tonight) I have a little down time...