Pressure just means the pump is working, not that fuel is getting to the cylinders (which is needed to run). Pull a vacuum line, spray brake clean, carb cleaner, or starting fluid into the vacuum port for about 10 seconds, then try it again.
Pressure just means the pump is working, not that fuel is getting to the cylinders (which is needed to run). Pull a vacuum line, spray brake clean, carb cleaner, or starting fluid into the vacuum port for about 10 seconds, then try it again.
100% correct, and that is the next step. I will try starter fluid tomorrow and see if she tries to run.
EDIT: I could not chance the car just starting tomorrow, and losing the chance to trouble shoot this. I just went out at 2:00am (to my neighbors delight I am sure) and sprayed carb cleaner into the throttle body and it ran a couple seconds till the carb cleaner was gone. Just to make sure, I cranked it over again a couple more times and nothing. I sprayed more carb cleaner into the throttle body, and again it ran for a couple seconds.
CaptainDean was over here tonight, the car fired right up and idled perfectly. He noticed the negative terminal was not looking so good, and I said I had been meaning to change it, as I had a new replacement. It was really more cosmetic, as the rubber boot on the terminal was just gone. The contacts were shiny and clean, and a brand new battery. Anyhow, I put the new cable on, and when we tried to start the car again, it would not start. The ONLY thing I did was replace the ground cable from the back of the engine to the battery, and the small lead that goes down to the metal close to the strut tower. Before I attached the small wire, I took a Dremel with a wire wheel to make sure it had a good clean contact, free of paint.
Again, NOTHING else was touched, but just in case checked the ground 20 more times, the ECM orange power wire, the C500 connector and everything in that area.
That the ground wire was replaced I am sure has NOTHING to do with this ongoing problem, just an example of how random this problem is. This has happened exactly like this before, start the car, come out the next day and it will not start. All while never even opening the decklid. Wait a day, 2, 3, a week and randomly one day the car will start and run perfectly again. All that being said, we still spent an hour checking wires, connections, wiggling anything even remotely close to where I changed the grounding cable. All while attempting to start the car to no avail.
This is what is known: Fuel pressure is Ok, and spark is solid.
Now on to some logical troubleshooting, thought trains and processes, from my point of view, and what I have learned at least.
Here is a peek into my head and the thought processes I am going through
I am getting good solid spark, and fuel pressure. I can therefore rule out 95% of electrical, such as fuel pump, fuel pump relay, coil, pick-up coil, cap, rotor, ICM, ICM wire to coil, ICM wire to ECM.
Knowing that the car will fire now with carb cleaner sprayed into the throttle body, I can also rule out the distributor, Plugs, Cap, Wires and rotor.
Ok, everything above ruled out, It now comes down to the fact that the fuel pump is working, and there is pressure, but why is fuel not getting to the cylinders? For all 6 injectors to ALL stop working, and then randomly start working 100% perfectly is statistically just NOT possible. So, lets just rule out that the physical injectors themselves are bad... whats next.... What is left is the signal pulse to the injectors. What would cause that pulse not to work? I replaced the ECM a few weeks back and that has not solved this issue. I can understand one wire shorting out, and an injector failing, but all 6 injector wires at the same time? Is there ONE wire somewhere that can cause all 6 injectors to not receive a pulse. I know this is controlled from the ECM, but again, I already swapped it.
Logically following the symptoms, it sounds like it can possibly be the ECM. But the section of the ECM that controls the injectors, to work, and randomly start to work again, and not to over and over again, highly unlikely. To make it even more statistically improbable, this is a swapped out ECM already, and the same exact problem persists.
So this is now where I am at.
Question: How can I check the signal to the injectors so see if the pulse is there? Can it be done with a multimeter? I do realize I need to pull the upper plenum to get to the fuel rail and get those pesky plugs loose.
Question: How can I check the signal to the injectors so see if the pulse is there?
I've never used one, but here's some info on using a Noid Light.
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A fuel injector Noid Light will help you to troubleshoot a misfire or a No Start Condition or a BAD fuel injector and is one of those MUST HAVE tools to diagnose the majority of fuel injected vehicles on the road today.
[This message has been edited by Patrick (edited 03-09-2015).]
I know what the issue is but I need you to do more testing for me to tell you exactly what it is. Use a multi meter and go test the fuel injector harness, with the key on, test the PINK wire and the PINK/WHITE STIPE wire for 12Volts, (ground to the engine) then report back.
Another thing see if your TPS is stuck at WOT, if you happen to have another one swap it out, (but don't go buy one just yet) and/or check voltage on the dark blue wire on the TPS and report what it is, (key on)
Edit to add; being in a no start condition is where you want to be, you don't want it to just start with out knowing and fixing the problem.
[This message has been edited by sardonyx247 (edited 03-09-2015).]
Since it runs by manually adding fuel to the intake, the no-start issue likely stems from the injector pulsing which narrows things down to +12V power feed to injectors, driver pulsing from ECM on both drivers (if only one was working, it would run on 3cyl), ECM ground connection, or sticking injector (slim chance as nearly all would have to stick at the same time).
Pull the injector harness connector and verify 12V on the pink wires with the key in the run position. Back probe the ground wires for the ECM at the ECM connectors - does the ecm have proper ground. Back probe the injector ground wires (2) at the ECM connectors - use lighter outlet for 12V power feed - does the light flash when you crank the engine. At the injector harness connection, locate both +12 power feeds and both Injector ground wires, pull the connector apart - use test light to see if the light flashes on both sets during crank. Pull one of the injector clips and run a test light between the two terminals. When the engine cranks, the light should flash.
My $$$ is on a bad wire that intermittently loses connection or a bad connection at the injector harness connector.
[This message has been edited by fieroguru (edited 03-09-2015).]
Someone correct me if I am wrong, but the V-6 Fieros use batch fire fuel injection, which means that all three injectors in each bank of cylinders open and close together. That being the case, if it is a loose wire, or two, hopefully that will narrow things down for you.
I agree on the bad wire theory. There must be an injector power wire that either has a bad connection at the plug in or has a break in it that loses contact intermittently based on position and temperature. I would check the injector power wire for continuity when its in a no start condition, that would tell you.
Another thing see if your TPS is stuck at WOT, if you happen to have another one swap it out, (but don't go buy one just yet) and/or check voltage on the dark blue wire on the TPS and report what it is, (key on)
The TPS is new, and was installed around 50 miles ago. With my test light to ground & connected to the blue wire inside the plug (Center on the plug) , with the key on, nothing. (should it be over 6v? If so my test light will show it. If it is lower that 6v I will have to dig around for a multimeter.
quote
Originally posted by fieroguru: Back probe the ground wires for the ECM at the ECM connectors - does the ecm have proper ground.
Sorry, I am not too versed with electrical stuff.... when you say backprobe at the ECM, I am not sure what you mean exactly. I did verify that the ground strap is securely connected and cleanly on the ECM. I also tested with a test probe with power from cigarette lighter, and grounded to the case of ECM shows continuity, so that shows the ECM is grounded.
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Originally posted by fieroguru: Back probe the injector ground wires (2) at the ECM connectors - use lighter outlet for 12V power feed - does the light flash when you crank the engine.
Sorry, again not following.... connect the test probe / light to the cig lighter, and to ground and see if it flashes? I thought the ground was constant, Does the ground to the fuel rail pulse on and off?
quote
Originally posted by fieroguru: At the injector harness connection, locate both +12 power feeds and both Injector ground wires, pull the connector apart - use test light to see if the light flashes on both sets during crank. Pull one of the injector clips and run a test light between the two terminals. When the engine cranks, the light should flash.
Just to verify, the 12v and or ground is not constant? I thought the "pulse" was a computer generated pulse on another wire other than the power and ground wires. If not, why is a noid light needed to test, as a standard test light will work, correct? I am NOT questioning your skill in any way, I am just trying to follow, absorb & understand all of this.
Ok, I tested the plug. When I unplugged it, the connectors were all very clean, no corrosion, dirt ect. Just for good measure I sprayed electrical connector cleaner in the plug before putting it back together.
The first thing I did was try to start the car, and it will not start, that's a good thing n this case!
I unplugged the main fuel rail connector, and tested each wire, here are the results: (The 2 wires on the right were shown as continuity on my tester AKA: direct ground with the battery)
The 2nd and 3rd wires were showing nothing, are these the 2 wires that carry the injector pulse to the front and rear banks? (If the above statement, a few posts back is true, and on the Fiero an entire bank of 3 fires at the same time). If this is the case, can I just hook a noid light here to test for signal, instead of pulling the plenum to check directly at the injector?
After spraying the cleaner, and insuring the connector was tightly put back together, the car will still not start. This makes it doubtful that there is a bad connection in this plug.
[This message has been edited by JohnWPB (edited 03-09-2015).]
Injector "pulse" may not be the best term. The injectors see 12v with the key on, the ecu injector control grounds the injector to allow the injector circuit to be completed, thus opening the injector(s).
Injector "pulse" may not be the best term. The injectors see 12v with the key on, the ecu injector control grounds the injector to allow the injector circuit to be completed, thus opening the injector(s).
So, if I understand correctly, the injectors have a constant 12v. The ground is pulsed on and off to control firing of the injectors. This being the case, a standard test light can be used to check for a pulse?
Lastly, in my photo above, there are 2 constant grounds on that plug when I tested it, so those are probably not the pulse wires. If those grounds are the pulse wires, my injectors are being told to stay on / open constantly, as they show constant ground. This leaves me to think that the center 2 wires, that I was getting nothing from, are the ground wires that are turned on and off?
Man what a saga ..... this is when I really appreciate my carbed V8 383 ..... John dont give up I'm positiveyou allwill finally solve this regards Daneyl
The professional way would be to hook up an oscilloscope to the injectors and look at the signal. It is also safe for the driver because of the very high input impedance (around 1 million ohms). A good shop should know how to do this. Connecting a bulb _might_ fry the transistor drivers because bulbs have very low resistance and therefore draw a lot of current.
...or maybe you could pull the injectors out and turn over the engine to see if they spray fuel. You can begin with something simple as this:
... go on to do something like this:
[This message has been edited by cebix (edited 03-09-2015).]
Engine side of plug Pin B - light green Pin C - light blue Are the leads to the ECU that ground the injectors.
Ok, see if I have this right, before I go blow something up
Injectors receive +12v constant power when the key is on. The Pin B (light green) & Pin C (light blue) are the "pulsed grounds" from the ECM, I can connect a Noid Light to +12v power on one side of it, and then connect the other side to Pin B and then to Pin C to check for pulses to each bank of injectors. I hope this is the case, as this would be far easier than removing the entire upper plenum to test an individual injectors power. Especially when there is a VERY low chance I have bad injectors. Yes, it is possible to have a bad wire under the plenum, but this would be worth checking first. If I have no signal to the plug, then I know its is BEFORE the wiring goes underneath the plenum.
I am going to HF to pick up a Noid Light. ALl I can do is pray that the car will not start when I get back! How crazy is that to say, that I do NOT want the car to start! LOL
[This message has been edited by JohnWPB (edited 03-09-2015).]
Could this also be a loose or bad connection at the ECM connector?
Possible, but unlikely at this point. I have checked and rechecked that plug, and it looks like the day the car was manufactured as far as ho clean the pins are. Also, after replacing the ECM I still have the exact problem. I have the center console out, so I have wiggled and rocked that connector, and nada.....
Injectors receive +12v constant power when the key is on. The Pin B (light green) & Pin C (light blue) are the "pulsed grounds" from the ECM, I can connect a Noid Light to +12v power on one side of it, and then connect the other side to Pin B and then to Pin C to check for pulses to each bank of injectors.
Originally posted by JohnWPB: Sorry, I am not too versed with electrical stuff.... when you say backprobe at the ECM, I am not sure what you mean exactly.
Front side of the connector goes into the ECM, the backside has the wires sticking through. Back probe means to shove a multi-meter, test light, or thinner paper paper along the wire and into the connection. The purpose is to see verify what signal (ground, 5V, 12V or some other value) is at the connection.
Why this is important... The ECM has 2 ground wires. A12 and D1 (and D6 for the O2 sensor). D1 goes to the same ground eyelet as the fuel pump relay. The relay works (pump kicks on), so the eyelet has a good ground, but you don't know that the section of wire from the eyelet to the ECM provides the ECM with a good ground w/o back probing.
HF was out of the Noid lights by me. The closest HF other than that one is in Delray Beach, FL. I will be there tomorrow for work, so instead of the 40 round trip today, I will just pick it up while I am down there.
Again, I just hope the car does not decide to start tomorrow before I get a chance to test. I will test the ECM ground pulses to the injectors of the ECM harness front side of the plug. If I get pulses, then I will back probe to see if the signal is getting through to the other side of the plug. Wow, that almost sounds like I know what I am talking about! LOL!
I have Daytona coming up in 2.5 weeks, and REALLY would like to get this resolved before then.....
I am not sure if you read my post from before.... But you shouldn't be losing fuel pressure as fast as you are after turning off your car. Have you looked into this? Also have you checked the ignition switch? One time I had one that was wore just right that it would cause the car to die going down the road. Sometimes the car wouldn't turn back on, other times it would. Something else that you can test.
I am not sure if you read my post from before.... But you shouldn't be losing fuel pressure as fast as you are after turning off your car. Have you looked into this? Also have you checked the ignition switch? One time I had one that was wore just right that it would cause the car to die going down the road. Sometimes the car wouldn't turn back on, other times it would. Something else that you can test.
Yes, I read it, sorry I did not acknowledge it, so many items to check, cross check and test. The fuel pressure is dropping a tiny bit faster than it should. It is something I am going to certainly look into. At the same time, with 45 PSI present at key on, that is almost double what it needs to start and run, and more than likely not part of this problem.
The ignition switch is possible, but again remote. Wiggling it, pushing / pulling has done nothing when the car will not start. Also, I am getting power to all circuits that the ignition switch controls, the computer, the starter, dash warning lights and such, fuel pump and fans. That should cover it, unless there is one particular wire from the ignition switch to power something I am not aware of, which, believe me, is quite possible.
I am off to bed, and will pick up that Noid test light tomorrow.... and to think at one time we were all told to "Avoid the Noid.....".
Ok, it is down to a bad ground(or shorted wire) from the ECM, a bad ECM, or a sensor telling the ECM not to fire.(ie bad wire, bad sensor, or bad ICM) I would say it is not a bad wire from the injectors to the ECM as more than one wire would have to fail. (but possible)
So the tests,
First make sure you have "check engine light" and any time it does not start, key in run, but not on position(bulb test) To explain, no check engine light means either no power to the ecm or no ground.
Test the wires on the ECM harness to see if they are a good ground. Your ECM grounds are A12 Ground D1 Ground Mainly the first 2 but check the next anyway and log the details. D6 O2 Ground to explain: The injectors are getting power, the ECM grounds the other side to open(fire) the injector, but the ECM itself is not a ground so it has to ground it out somehow, thus a bad ground wire would take out the whole bank of injectors.
Next test the TPS circuit. Key on Black should have ground (ground) Gray should have 5 volts (5 volt reference) Dark Blue should be under 2.5 volts. to explain: a TPS with too high of voltage(over 2.5 volts) will make the ECM think it is clear flood mode, thus not fire the injectors
Ground the ALDL and make sure it flashes code 12, also if any other codes are stored make notes. To explain: I need this info on which direction to go. IE figuring out if the ECM is the problem
I want to take ownership of the problem and fix it like I tried a few pages back, you do need a noide light, as useing a test light can short out the ECM. Or I can load you up with all the info and tools to fix it your self. You have to be methodical on this, not skip anything, and your problem will be solved. Too many cooks in the kitchen.
Right now you are at the point you can take out the ECM and the car will run on starting fluid, it will spark, but not run the injectors without an ECM. Just FYI.
Do you have a laptop you can scan with? IE ALDL cable and the works? I have noticed during this thread you have had/caused other problems, but we CAN fix this. No guessing, no hunches, just get it fixed. I am really leaning to a wireing problem as it is intermintent.
[This message has been edited by sardonyx247 (edited 03-10-2015).]
They say a picture is worth a thousand words.........This wire in this picture cost almost a $1,000 dollars! (FAR more with labor involved!)
CaptnDean was over here today and found this. It was in the main wiring harness, between the engine and the firewall. It was also in a well wrapped and normal looking, clean wire loom. When I examined the wire here closely, it does not look melted as it may in the picture, but crushed instead. All of those slices in the wire casing match perfectly with the wire loom. As if, when the mechanic helped me install the engine, it was sat down on that wiring harness, and the loom worked like a cookie cutter on the wire! When I bend the wire, I can actually see where the only thing holding it together is the casing, and the copper wire actually has a break in it. If I bend the wire back again, just EVER so slightly, I can see the wires inside the casing touch and make contact. AKA Intermittent connection.
Dear GOD I hope this was it! I can really not take much more than this. This problem has been on again, off again. Replace something and it runs beautiful till it dies over and over, and over again.
Now, a good little prank to make everyone laugh a bit......
Dean was so proud that he found the wire, and the car started right up. I was ecstatic! He was by the drivers door, and I asked him to go ahead and fire it up, as I just want to hear it run! As he reached ink, I pulled the coil wire. (I couldn't resist!). He cranked it for a second, 2 seconds, and after 5 or six seconds he let off the key, leaned back out, banged his foot on the ground and in a VERY stern voice said "You have GOT TO BE KIDDING ME! ! !" I said Dean, it may be.... he cut me off.... No Dean right...... cut off again... Dean look here! And I showed him the coil wire as I plugged it back in. He opened palmed me in the chest and knocked me back a step while shaking his head and starting to crack a smile. LOL! I looked at him and said, Dean, you know that feeling you just had, that frustration, ANGER, and total disbelief you had for that ever so brief moment? well "Welcome to my world!" . We laughed it off, and later I told him, I am serious, how you felt earlier, immagine that over and over, and when you think it is fixed, over again. Then you get a glimpse on how I have felt trying to track this down.
Now a big thank you to those that have helped in this thread. You all put me right on the track to narrowing it down to a small bit of things to diagnose. A bigger thank you to Lou for coming over and helping to diagnose, and what we thought was fix it a couple weeks ago
finally.... A HUGE THANK YOU TO DEAN for helping me time and time again, and actually finding the problem.
Fantastic! That wire is green like a ground wire. I can imagine that a repair shop would have charged you hundreds of dollars to diagnose your problem. Some years ago I paid a repair shop over a thousand dollars to fix a driveability problem on a 90's Olds that I had bought for my daughter.
Just a word of caution, I wouldn't celebrate that the issue is resolved until you know exactly what that wire went to and that it could have caused this no start issue.
Just by the color and proximity it "could be" one of the two main wires from the ECM to the Injectors, but that "should" only impact the injectors on a single bank, not both banks. That would mean the engine should have ran on 3 cylinders vs. not at all unless there is something else at play.
It clearly was a bad wire, but if it went to the MAP, IAC, A/C or some other unrelated system, its wasn't contributing to the no start issue where fuel isn't getting into the cylinders. The reason the engine started once the wire was wiggled or repaired might just be coincidence. It has restarted many, many times before w/o the issue being fixed, so this could just be another one of those instances.
Just a word of caution, I wouldn't celebrate that the issue is resolved until you know exactly what that wire went to and that it could have caused this no start issue. [.....] It clearly was a bad wire, but if it went to the MAP, IAC, A/C or some other unrelated system, its wasn't contributing to the no start issue where fuel isn't getting into the cylinders. The reason the engine started once the wire was wiggled or repaired might just be coincidence. It has restarted many, many times before w/o the issue being fixed, so this could just be another one of those instances.
Ok, I have to admit I have been thinking the exact same thing.... TRUST ME!
This wire came out of the ECM wiring harness, and grounds to the engine / transmission. Where the wire came out of the loom, it looked good, and was connected to the engine / transmission in what looked to be visually correct. It was after it went into the loom is where the problem was. How Dean found that is just awesome!
Dean seems to think that particular ground wire is what goes to the ECM and is then pulsed to the injectors. Basically cutting off both banks of injectors when it would intermittently stop providing ground to the ECM.
Dean seems to think that particular ground wire is what goes to the ECM and is then pulsed to the injectors. Basically cutting off both banks of injectors when it would intermittently stop providing ground to the ECM.
quote
Originally posted by sardonyx247:
Ok, it is down to a bad ground(or shorted wire) from the ECM, a bad ECM, or a sensor telling the ECM not to fire.(ie bad wire, bad sensor, or bad ICM)
to explain: The injectors are getting power, the ECM grounds the other side to open(fire) the injector, but the ECM itself is not a ground so it has to ground it out somehow, thus a bad ground wire would take out the whole bank of injectors.
I am really leaning to a wireing problem as it is intermintent.
So John...... is it official ?? No more issue?? Danyel
I do not want to jinx anything...........
Talking to Dean the other day, he said "I think your car is fixed now", I QUICKLY had to tell him that I had him on speaker phone, and my car could hear him!
I will say however, I have been driving the car more in the past 3 days than I have the 4 years that I have owned it. 2-3 times a day. Before, I would only take it out when I knew I did not have to be somewhere at a certain time. It was terrible having a car that I continually had to worry about not when, but where it would happen next. I tried cooking the engine here for a week, start, up to temperature, turn off, start and run for a half hour, and it would still restart. I could never reproduce the problem in the driveway. The ONLY time I could get it to act up is randomly driving, and just waiting for it to quit. This was the ONLY way to diagnose and trouble shoot it. When it was running, it was impossible to trouble shoot.
Anyhow, tonight I went to a car meet, hung out for a half hour, and then took the car to the island, and drove south along the beach about 5 miles, then turned around and drove north along the beach about 15 miles and then back west to come home. It was such a pleasure to just take a leisurely drive, with the thought that it may be fixed. Only time will tell. I have a car show 20 miles to the North of me Sunday, then 3.5 hours North to Daytona if all goes well up to that point.
..... John dont give up I'm positiveyou allwill finally solve this
