Today I got help and did some fuel pressure tests. When the fuel pump prime I got 28 psi for three seconds, then it drops and after 10 seconds I have 6-4 psi. When I did the test by myself it took some seconds for me to get to the gauge, therefore the post about 10 psi, sorry for that. When I crank the pressure drops 4 psi to 24 psi, when the engine starts running it have 28 psi. I pinch the rubber return line at the wheelhouse as the picture below, but no difference in pressure.
Droped my tank today and looked at the fuel pump, see pictures below:
Could you see anything wrong?
Haven't changed rubber hose from fuel tank to fuel rail, if it's bad or can’t handle the increased psi would it expand or shrink?
/Johan
Change out those plastic quick clamps for metal clamps that can apply appreciable hose clamp pressure. I've never seen plastic hose clamps used for a fuel pump connection. I just recently learned a lesson with a factory pinch style radiator hose clamp on a Nissan that has the little lock open tabs for easier install. It snapped when I pinched it with pliers making me think it had unlocked and clamped down when the tabs had actually over bit and eclipsed only allowing partial clamping pressure. The clamp in a blind spot on the lower hose felt tight but leaked under operating pressure, half a gallon of coolant in 150 miles at about 25% of the pressure a fuel pump will produce.
[This message has been edited by Joseph Upson (edited 07-27-2016).]
Change your pump, throw that airtex in the garbage and purchase a better delco/Delphi pump. It will include the correct submersible fuel hose, better clamps. Your current pump has a bad check valve which holds pressure in the line. Usually gives symptoms of long crank times, and weak running because the pump has to reprime every startup, and has to fight the falling fuel while running. Recheck your base timing by using the mark on the harmonic balancer in the picture shown above. I verify by removing the spark plug, inserting a wooden dowel into the hole that is long enough to touch the top of the piston and not fall in. Rotate clockwise and watch to see where TDC is on #1. This verifies the mark on the harmonic, the TDC of #1 (incase the chain has jumped) ans hopefully your distributor rotor is on 1 at the same time.
Now I have 40 psi after 3 seconds of prime. My problem now is that one of the threads on the distributor are gone so i can't screw the cap on one side, I miss a tach-filter as well.
Now I have 40 psi after 3 seconds of prime. My problem now is that one of the threads on the distributor are gone so i can't screw the cap on one side, I miss a tach-filter as well.
/Johan
So get a longer screw and use a nut under it, or replace it, and get a tach filter.
Have ordered a new tach-filter but haven’t received it yet.
I can start the engine now, but its still retarded, the same as before. If I set 10 degrees, the engine runs for ten seconds, after that it automatically add 10 degrees, and revs up. If I have 0 degrees and little less retarded ignition the engine starts and run for 10 seconds and then just dies. If I have rotor lined up vid #1 it won’t start. Looking at plugs after engine has run, they are black of soot. Since I have 40psi in pressure and it’s not dropping I guess I don’t have leaking injectors, in fact I have 30 psi after 30 minutes, could that be correct? Why does it run only retarded? Bad ICM? Bad plugs? No tach-filter?
Over the years here, I've seen so much confusion relating to setting the static timing.
First of all, the cap position can be anywhere you wish to orient it... as long as the rotor is pointing to the terminal used for #1... and the piston is at the top of the compression stroke for cylinder #1.
The only thing restricting where the distributor can actually be positioned is the wiring harness. Obviously the connection for the ICM can't be pointed away from the coil if you expect to connect the harness etc.
Below is the 2.8 in my Formula. To do the initial static timing, I have the timing mark for cylinders #1 and #4 (the wider mark on a known good harmonic balancer) set to 0° with #1 piston on the compression stroke. If I'm installing the distributor, I drop it down so that when fully seated, the rotor is pointing at the indicated bolt on the upper intake. I then rotate the outer distributor so that the terminal I'm using as #1 (as it could be any which one you want) is lined up with the rotor. The terminal I've selected seems to work best in regards to orienting the distributor towards the coil. The engine is now timed well enough to start, and dynamic timing can now be set with a timing light (or for the old guys like me, by ear). Nothing to it.
Humor me and do this !!! if you do this you will be amazed!! its not hard and is a basic timing procedure, works with every motor that uses a distributor
I have tried this but when I'm about to adjust to 10 degrees before TDC I always end up turning the dist counter clockwise so my timing gets retarded. If I want my engine to run the rotor has to pass 1 prong on dist. If I line up rotor to #1, find tdc by using a screwdriver and set big groove on harmonic at 0, the engine runs really bad and the big groove on harmonic balancer pass 0 degrees when I get the flash from timinggun. I thought that I should turn dist clockwise to set timing before 10 ¤ tdc, but I guess I’m wrong there.
Now I also got the problem that I get chocks whenever I touch the top of the dist to turn it. The engine also dies after 12-13 seconds of running. I’m a little bit tired of this, feels like I’m going backwards on this one.
When I did a search I found this thread and it says the other way, so I'm confused
You've somehow stumbled across the one thread on this which is wrong. The rotor turns clockwise.
I don't understand how this wouldn't be apparent to you when you're timing the engine. You're using a timing light, right? Can you not see for yourself which way the timing moves when you turn the distributor?
[This message has been edited by Patrick (edited 09-05-2016).]
It was the only relevant thread I found when I searched for counter wise.
Yes I use a timinglight when I set timing Yes, I turn the dist, counter clockwise so the timing marks on the balncer go from passed 0 degrees to 10 degrees advanced (before tdc) and my distributor ends up like the picture below and I don't understand why it ends up there. The arrow is where I point the rotor.
Last post about timing, will leaved to a shop during winter. But i just want to clarify how i do it, so it’s no misunderstanding about my explanation. Sorry about bad picture quality.
With negative cable unhooked, I position big groove at 0, feel the piston at TDC with a screwdriver and drop dist, shaft as picture below. Where the rotor points don’t matter, I chose this position and put a white mark at upper intake.
Step 2 Put cap on as picture and starts engine. Place paperclip to short A and B. At this position the engine runs rough and it dies after 5 seconds of running, I get a flash when engine passed 0. So i turn cap counter clockwise to advance timing.
Step 3 When I turned the cap so it is like picture below the advance is 10 degrees. Now the engine runs for 5 seconds, then suddenly the advance is 20 degrees and i have 2500rpm on the tach.
Thanks for your time and answers, hope the shop can fix this.
Got my car back from shop with dist in right position, no more glowing manifold and got some Power. Unfortunately they couldn't fix my idle, so I need some help.
Engine fires up, start idle around 1600-1800, sometimes its hunting down to under 1000, revs up to 2000. But after a minute the problems start it’s suddenly revs up to 3000 and stay there, until I turn it off. If I change from P to R or D idle drops perfectly down to 1100. I can drive the car and last time I drove it, the idle was okay when the engine was hot. CTS/ÉTC have 4000 ohm MAT have 3580 ohm MAP return 4,95 Engine off and 1,17 at idle. EGR Tube is new and I have sprayed it with start gas with no increase in rpm.
Have center console out and easy access to ECM, is it possible to measure resistance and volt at the cables at the ecm or do i need ecm scan tool? I’m curious to see if the sudden increase to 3000rpm is in relation to sensor information.
You can back probe the signal wires at the sensor or computer for voltage readings. can you measure the vacuum at the intake? Possible an intake leak causing un-metered air to enter in. Best way to check is with flammable brake cleaner along all intake gaskets, still may not find it so a vacuum reading may be needed.
Unfortunately I can't measure vacuum don't have any tools for that, but will try brake cleaner around intake. I back probe some cables at the Ecm O2 sensor D7, have 0,15 v engine off ignition on, when engine idle around 1700 rpm it drops to 0.08, after a minute when idle speed increase to 3000 rpm it's starts to change from 0.23 to 0.69, new value for every second. Don't knew that's normal or a result of wrong fuel mixture or causing wrong fuel mixture. cts have 2.37v at Ecm, and Mat 3.49, shouldn't they be 5v? Tps have 0.71 v
Originally posted by Johan: ... O2 sensor D7, have 0,15 v engine off ignition on, when engine idle around 1700 rpm it drops to 0.08, after a minute when idle speed increase to 3000 rpm it's starts to change from 0.23 to 0.69, new value for every second. Don't knew that's normal or a result of wrong fuel mixture or causing wrong fuel mixture. ...
It is normal for the O2 sensor reading to jump around. "Nominal" is ~.445 volts, but it should transition rapidly between ~.2 volts and ~.8 volts if everything is working correctly. (This won't happen until the engine is warm. When it's cold, you will probably see .00 volts, if you're using a volt meter. If you're using a scan tool, it will likely "plug in" a reading of .445 volts, until the O2 sensor warms up and starts working.)
[This message has been edited by Raydar (edited 07-15-2017).]
The IAT controls the idle speed. Sounds like it is stuck, usually by crap building up in the hole the IAT inserts into. Unscrew the IAT and clean out the carbon.
Try placing your hand over the throttle body and see if the RPM's increase, that will confirm a reasonable vacuum leak , perhaps the throttle body gasket is leaking or it could be the EGR valve diaphragm is bad. Your IAC valve might be choked up with carbon/sludge too. it could be the intake gaskets are leaking underneath the intake. I would imagine the later would also contribute to oil consumption as well. Hope this helps! Ben Smith
------------------ "Persistence is the Twin Sister of Excellence- One is a matter of quality, the other, a Matter of Time"
Don't know that you mean about 'placing your hand over the throttle body and see if the RPM's increase', but if I place my thumb over the iac valve the engine dies immediately. Have clean IAC valve a twice. Retighten the bolts holding the TB, but no change. Can't say that I have oil consumption, but I have odor from ex that I will look in to. Tomorrow I will leave the car to a shop specialist in American cars; they will start looking at valve lash adjustment, then the bad idle.
I set my timing by ear. Advance the distributor a degree or two, each time you try it. When it starts to ping, under a heavy load, retard the distributor slightly, until it doesn't ping.
I set my 4.9's timing this way. It appears the ring had slipped, since I had an "additional" ten degrees of advance, from where the timing light said was "correct".
This is the most reliable way. Specs cover the average cars. Every car has its own little quirks. You can use the 'pinging' as a sign of too much advance, but I also use a hot engine test. If it cranks too slow after setting a min or two hot, retard it slightly till it cranks normally. Both together is best. Id also suspect a leak in the tube too as causing the high idle. Ive had a few cars that would barely run set on spec, so ive learned to not trust that factory specs are the best. Found that with timing, spark plugs and even wheel alignment.
I replaced the lower intake gasket so i had to remove two push rods, while doing that I felted on the other ones and i thought they were loose so I adjusted them, have read your thread Patrick about it. Since I never have done valve lash adjustment before and that one fiero owner here in Sweden think i should look in to it in order to fix my idle problem, i have decided to let a shop look in to the valve lash.
Here's a video of a start-up of my car. In the end of the video the engine revs up to 2800 rpm, right after I stoped filming it went down to 2400 rpm https://www.youtube.com/wat...45o&feature=youtu.be
/Johan
[This message has been edited by Johan (edited 08-20-2017).]
Since I never have done valve lash adjustment before and that one fiero owner here in Sweden think i should look in to it in order to fix my idle problem, i have decided to let a shop look in to the valve lash.
IMO, your idle speed issue has nothing to do with valve lash.
quote
Originally posted by Johan:
Here's a video of a start-up of my car. In the end of the video the engine revs up to 2800 rpm, right after I stoped filming it went down to 2400 rpm
It seems to me that your idle speed increases on its own just about when the ECU would be going into closed-loop operation.
Has the idle stop screw ever been tampered with on the throttle body?
Without re-reading this whole thread, here's what I think potentially might be going on....
Possibly the ignition timing was done without the ALDL jumper in place. The timing would then be too retarded, and the idle quality/speed would suffer. So the idle stop screw was tampered with to increase the idle speed. When the ECU goes into closed-loop operation, the ignition timing is advanced. This allows the engine to run better, which increases the idle speed. But because the idle stop screw has been tampered with, the IAC valve cannot bring the idle speed down to where the ECU wants it to be.
[EDIT] It also occurred to me that even if the ALDL jumper was in place during the ignition timing... if the outer hub of the harmonic balancer has spun (which is not uncommon with the age of these engines), the ignition timing will also be too far retarded... and what I stated above conceivably could still occur.
Neither of these two scenarios may apply here, but I felt it was worthwhile mentioning... just in case.
[This message has been edited by Patrick (edited 08-20-2017).]
I think you're right about closed-loop, Patrick, that's why I want to plug in a scanner to see what sensor values the ECU receives. If i shift into D or R the idle drops immediately to 1200 rpm from 2400rpm don't know why.
I have tampered with the idle screw, I waited as long as possible not to, but in the end it was my last hope. I used this method:
(warm Engine) I just reposted this in another thread... To set idle: -Ground out terminals in ADL connector -Put key in RUN -Let sit for a minute to allow the IAC to screw in. -Unplug IAC, turn off key -Unground ADL(???I forget, but pretty sure) -Start car and adjust the Idle screw to get it to run at like 500-600rpm. -Turn off car and plug IAC back in and you should be good to go
I also unplug the battery before I started the Engine.
I have a jumper in the ALDL when I set timinig, but as you say the harmonic balancer can be off, that's why I will leave it to a shop so they can set it by ear.
I have tampered with the idle screw, I waited as long as possible not to, but in the end it was my last hope.
...
And all that accomplished was to create other problems. The idle stop screw needs to be returned to the factory setting. Basically, it only needs to be turned in far enough so as to prevent the butterfly from binding when closed.
quote
Originally posted by Johan:
If i shift into D or R the idle drops immediately to 1200 rpm from 2400rpm don't know why.
There's no mystery here. The IAC valve can do nothing regarding idle speed because the tampered-with idle stop screw is now holding the butterfly valve in the throttle body open too far. When the transmission is put into gear, the idle speed slows down simply because there is a load being put on the engine.
[This message has been edited by Patrick (edited 03-02-2024).]
