It Never Fails Part II

[ol' yeller]

I am starting a new thread as the old one was too long and getting kinda hard to follow. To recap, '90 coupe with 152,000 miles. Fires and dies or runs weakly for a few moments and dies. So far I have cleaned all 8 ground connections and the positive junction behind the battery. The battery cables have been inspected, cleaned and I verified a good connection at the battery. The alternator has been tested as good. I have checked all the vacuum hoses and connectors I could find. I have replaced the CPS, MAF, O2, and IAC with new. I have pulled the ECM connections and replaced them. I have also replaced all the sparkplugs as the old plugs were gas fouled.

When I replaced the MAF due to a MAF fault code, I cleared the codes. Now it won't set a new code at all. I did have sooty build-up in the throttle body and in the old MAF. After all this, there is still no change in the engine running.

Today I checked the fuel pressure at the rail. When I activated the key (on, not start), it immediately pressurized to 40 pounds. I heard a couple of injectors click and the pressure dropped to just under 20. Upon attempting to fire the engine the pressure immediately jumped to 40 and held. After about 6 attempts (fire & die), it did run, very poorly, for about 30 seconds and then died. Fuel pressure remained at 40 the entire time, even as it stalled.

In my mind this leaves either a bad ECM, a bad ignition module, or a loose timing chain. I am leaning towards the timing chain. I did not pull the Cam position sensor to see if I could detect looseness as the chain tensioner would probably adjust enough of the slack out so it would be hard to see.

With no codes I am shooting in the dark but that can get expensive fast. I am thinking of going to a wrecking yard next week and picking up a used Delco ICM and coil pack to replace the Motorola unit that is currently on there now. I assume any "C" code 3.8 would work. What cars (and years) should I be looking for? A rebuilt ECM can be bought at the local Carquest for around $130 exchange. There are no Advance Parts houses in my area. It just behaves like a timing issue which is why I am leaning towards the timing chain. Thoughts?

Edited February 7, 2010 by ol' yeller (see edit history)

[Guest dpannell]

Greg, most of this sounds similar to my sons Regal problems I experienced last summer.....It turned out to be injectors. Have you checked the resistance on any of them? Dave

[padgett]

Grab a Delco ignition at a U-Pull-It first. You will want one regardless.

What you are experiencing is not consistant with a loose timing chain, they do not heal. May be a good idea anyway but doubt that is the current problem.

40 psi even when stalling is good news, other modules are much easier to swap than a fuel pump.

Do you have access to an injector noid ?

How to Test Voltage to Fuel Injectors With Noid Light | eHow.com

Amazon.com: Alltrade 940580 Kit 73 Fuel Injection Test Noid Light Tool Set: Home Improvement (buy two and get free shipping...

[Guest dpannell]

Also....Goofy as it may sound, when we unplugged the alternator the car ran MUCH better....The dealership mechanic said "it allows more amperage to pass to the injectors...allowing them to fire" THis was however an 88 2.8l efi. Dave

[ol' yeller]

Greg, most of this sounds similar to my sons Regal problems I experienced last summer.....It turned out to be injectors. Have you checked the resistance on any of them? Dave

I have not checked resistance at the injectors. I assume the service manual outlines the way to do it and what readings to expect. I will check there first. If an injector is plugged or worn, how would that show up on a rsistance test? Sorry, on the previous posting I explained that I am an old school car guy (1965 Skylarks). EFI and this computer control stuff is new to me but I am willing to learn as evidenced in what I have picked up on this problem so far. I hope LOL.

[ol' yeller]

Grab a Delco ignition at a U-Pull-It first. You will want one regardless.

What you are experiencing is not consistant with a loose timing chain, they do not heal. May be a good idea anyway but doubt that is the current problem.

40 psi even when stalling is good news, other modules are much easier to swap than a fuel pump.

Do you have access to an injector noid ?

How to Test Voltage to Fuel Injectors With Noid Light | eHow.com

Amazon.com: Alltrade 940580 Kit 73 Fuel Injection Test Noid Light Tool Set: Home Improvement (buy two and get free shipping...

I do not but I will check and see if I can find one either at a local parts house or at Amazon as you suggest. Worn injectors are very possible at 152K especially considering the slightly erratic idle I was experiencing before. Wouldn't worn injectors cause rough running prior to complete failure? The IAC helped but didn't completely cure it.

[sfair]

Two things:

1. When you had your alternator tested, did they check the "ripple"? If it has any ripple, it can cause you all kinds of grief with the ECM.

2. The fuel pressure...what is the "exact" specification for this engine? Going by my memory, which is fading fast, it should be 36 pounds. Also, it should drop when the engine starts, not stay at 40lbs. There should be a key on pressure and an idle pressure specified. Pull vacuum line off of regulator and see if any fuel comes out.

If the pressure is too high at all times, the engine will start but then will blubber its way to stalling as it slowly floods itself out. Might be bad fuel pressure regulator.

[Guest mongeonman]

I d ont think it is the timming chain,if it where loose you would ear it rattle,the one on my 88 was ratteling and the car ran fine,i then pulled the oil pan and the spring from the tensioner had fallen in the bottom of the pan,i was lucky and mannaged to put it back at its place by the oil pan openning,i had alot of fun....

[Guest NEMO]

Replace crankshaft position sender ????

[ol' yeller]

Two things:

1. When you had your alternator tested, did they check the "ripple"? If it has any ripple, it can cause you all kinds of grief with the ECM.

2. The fuel pressure...what is the "exact" specification for this engine? Going by my memory, which is fading fast, it should be 36 pounds. Also, it should drop when the engine starts, not stay at 40lbs. There should be a key on pressure and an idle pressure specified. Pull vacuum line off of regulator and see if any fuel comes out.

If the pressure is too high at all times, the engine will start but then will blubber its way to stalling as it slowly floods itself out. Might be bad fuel pressure regulator.

It was about a month ago when I had the alternator tested. I remember there were 3 tests. One of them was testing the rectifier bridge which was what my main concern was at that time. It passed all 3 tests but I don't remember what the other 2 tests were. I have never heard of a "ripple" test and I don't know if it was one of the 3 tests.

As I work on my cars alone, I was reading the pressure gauge upside down through the windshield as the car would sputter along. My readings were a close approximation at best but there was little fluctuation of the needle when the car was running (poorly). Feathering the throttle made little to no difference in the engine's RPM or smoothness. You make some good suggestions that are easy to do and don't cost anything. When I pulled the sparkplugs that were in the engine, they were very gas fouled so it could be an oversupply of fuel. I will try what you suggest this afternoon and report back this evening.

[ol' yeller]

Replace crankshaft position sender ????

Replaced the CPS. Original looked fine but I replaced it with a new one anyway. No difference.

[Ronnie]

Were all the plugs gas fouled or just some of them. IF it is all of them you might be able to rule out bad injectors as the problem. I doubt they would all go bad at once.

Try starting the car with the accelerator pedal on the floor. That tells the ecm to go into "flood" mode and will not add extra fuel at startup. Once started keep it reved up to about 2500 rpm for a while and see if it runs any better. See if doing that make a difference.

[ol' yeller]

I d ont think it is the timming chain,if it where loose you would ear it rattle,the one on my 88 was ratteling and the car ran fine,i then pulled the oil pan and the spring from the tensioner had fallen in the bottom of the pan,i was lucky and mannaged to put it back at its place by the oil pan openning,i had alot of fun....

I am hoping it isn't the timing chain. With as many miles as the car has on it, if I do replace the timing chain, I'll probably rebuild the engine as well or replace it with a supercharged version of the 3.8. Don't want to go there until I have to.

I'm going to spend some quality time this morning with my service manual checking out the fuel section. When the car dies, it does seem to make a spitting, or puff noise as it dies. Not sure if it is coming out the throttle body. It sure acts like what a way off timing issues was like on my old 300 V8s. I know there are many components that could affect timing including sensors, control modules, and even worn physical components all that weren't on my 40 year old V8s. I'm just trying to be smart about troubleshooting this problem rather than shooting in the dark. I'd love to be able to tell if this is a fuel problem or a spark problem. That would help me target my efforts. Not having an error code is making this a lot more difficult than I'd like. After spending some more time reading this morning, I am dedicating this afternoon to trying to find the problem. I do have access to parts houses but not wrecking yards today. It is a good day not to be a big football fan.

Greg

[ol' yeller]

Ronnie,

All 6 plugs were very dark and smelled of gas. I would think a bad injector would cause a stumble or hard start prior to failing and causing an almost non running condition. I assumed that the gas fouling was caused by the EFI supplying fuel while something was not allowing spark which was why I began replacing sensors like the CPS, the MAF and the O2 as well. I also had no idea how old the old plugs were. They did need changing and the skin on the back of my hands (after changing the rear bank) benifited from the aeration anyways.

This afternoon I will try starting the car with the throttle fully depressed but I sincerely doubt I can get the engine to rev to 2500 RPM. The throttle has little to no effect on the eninge at this point, except to hasten the stalling.

I am determined to find and fix this, whatever it takes. I miss driving my Reatta and its been well over a month now.

Greg

[Ronnie]

I'd love to be able to tell if this is a fuel problem or a spark problem. That would help me target my efforts.

Connect a timing light to one of the spark plugs. Pull the trigger on the timing light (if it has one) and tie it down with a plastic wire tie so the light will flash all the time. When you start the car look at the flashing light (point it toward you instead of the engine) and observe if the light stops flashing when the engine starts dying. If the light stops flashing the spark has stopped as well. Maybe that will tell you something about the problem being an electrical problem or not.

[padgett]

Bad coolant sensor could cause poor running and over-rich stalling. Any smoke coming out the tailpipe ? On a 90 you have to go into diagnostics to see the exact coolant temperature reading.

[Guest dpannell]

Greg, The way my injector issue was explained to me is...... "When the coils in the injectors require too many amperes to fire them it actually shuts them down" Its not the mechanical portion of the injector thats gone bad...its the coil . Again, this was an 88 2.8 efi...but a real similar setup. Dave

[ol' yeller]

OK, I'm getting somewhere. Today prior to doing anything I checked again for codes. Surprise, it came up with 041 & 042. They were both history codes as they had an "h" after the code and the diagnostics said No "e" codes. 041 is a Cam Sensor code and 042 is an electronic spark timing code. A Cam sensor was only $25 so I replaced it with a new one and cleared the codes. No improvement in running but no more codes set.

I then began following the flow chart in FSM until it got to the part where I had to check voltages at the ECM connection. I am 56 years old somewhat overweight and have an inflamed ACL in my left shoulder. Getting a test probe into the correct connection was difficult to near impossible. At this point I decided to replace the ECM as I figured the power issues I had (reported in the prior thread) probably did bad things to the ECM. $89 later, I had the new ECM. I have read other posts about how tight the fit was but after unplugging the connections and dissassembling half the dash behind the glovebox, I slid it out, pulled the Prom from the old ECM, installed it in the new ECM and slid it back into place. It went in a whole lot easier than it came out. I fired up the car and it does run better, still rough, but better. Now, feathering the throttle actually makes a difference and I can keep the engine running at about 2500 RPM by feathering the throttle. If I let off the throttle, it runs roughly for about 30 seconds and dies. It will not idle for more than 30 seconds. No new codes set other than the battery disconnect code (552?) which I cleared.

I then remembered that I had the old IAC installed so I pulled it out and replaced it with the new one. No difference. I dropped one of the IAC screws onto the rag I placed under it but it went south when I tried to retrieve it. After pulling the cruise control diaphragm I gave up trying to find the stupid screw and went to the store and got several new ones. I hope I don't lose points when a judge sees one of the screws is slotted rather than phillips!

I then hooked up my inductive timing light to each of the plug wires and pointed it at the drivers seat to watch it. On each plug wire it would strobe flash as the engine ran. Then just prior to stalling it would go dark for a flash and then flash but not as fast as it did previously until the engine died. I would get a flash or two directly as the engine died.

As I haven't been able to locate an "injector noid" ( I think the local parts houses suspects I was sent on a Snipe hunt), I then disconnected the injector electrical connection, one at a time to see if it made a difference in the running of the engine. It didn't, it would start fine, idle up then begin to miss and then die. There was no fuel leaking when I pulled the vacuum connection on the throttle control.

To recap, I've replaced the plugs, the Crank Position Sensor, the Cam Position Sensor, the O2 Sensor, The MAF sensor, and now the ECM. I think I had multiple problems some of which caused the ECM to fail. Those were probably grounding issues. I really don't want to spend over $200 for a new ICM and as I understand, probably wouldn't fit anyway. Hopefully tomorrow I'll have some time to stop at a wrecking yard and pick up a good working Delco module rather than the Motorola unit I now have. Failing that I guess I could remove the injectors, take them to the local Dr Injector and have them tested. I am also considering replacing the plug wires as a precaution. The ones in there look OK but are probably pretty old.

Padgett, My reading of ED04 (which is the coolant temperature) was 25 That should be OK.

Here are the diagnostic codes currently;

ED01 .44

ED04 25

ED06 23.9

ED 07 45

ED08 70

ED10 12.3

ED11 20

ED12 0

ED16 0

ED17 0

ED18 0

ED19 128

ED20 128

ED21 4.7

ED22 105

ED23 14

ED98 1

ED99 9044

Greg

Edited February 8, 2010 by ol' yeller (see edit history)

[DAVES89]

Just go on Car-Part.com--Used Auto Parts Market and key in a 1992 Pontiac Transport [ that's the vehicle Padgett used] and you will have the unit you need.

I think you are on the right track.

Now go back and watch the last of the Super Bowl...

[sfair]

Timing light will stop flashing if plugs foul out, so......

Try this:

1. Pull 3 of the easiest plugs to get at and clean up to look like new.

2. Replace plugs.

3. Start engine and run until it dies.

4. Immediately pull those plugs and post what you see.

The best way is to troubleshoot this problem and not throw parts at it. Can make you poor in a hurry!

[2seater]

You mentioned pulling the hose from the throttle control. Was this the one connected to the fuel pressure regulator? Is the pcv valve in position and the rubber grommets in place? Do you have a vacuum gauge to connect to the intake? I know the engine doesn't run well, but should have around 18" Hg vacuum at warm idle. The standard rating for the fuel pressure regulator is 3 bar or 43.5 psi and should drop approximately one psi for every two inches Hg of manifold vacuum with engine running. The coolant temperature @ 25 deg.C will have the O2 sensor locked out and it won't be close to running closed loop. Can you get it warm enough to go closed loop so the O2 starts controlling the fuel system? I know you mentioned replacing the MAF but you might try disconnecting it and start the engine. In a good running system, the engine will start and idle okay with it disconnected, although it will set a code. It will generally die if disconnected while running. That injector pulse width looks very, very high. That looks like what I have seen at WOT and high rpm. IAC reading is high too, probably trying to keep the engine running. For some reason the spark advance is pinned at the max. value? Should be in the low 20's for warm idle. That all points to a control system problem or it is trying to cover for a vacuum leak or mechanical problem. The comment about the Central Power Supply causing odd problems was something I had not seen or heard of before, but our cars certainly have one.

Edited February 8, 2010 by 2seater
additional comment (see edit history)

[padgett]

25C is 77F so engine must never have run long enough to get warm, correct ? That is still in the "cold enrichment" range.

[ol' yeller]

You mentioned pulling the hose from the throttle control. Was this the one connected to the fuel pressure regulator? YES

Is the pcv valve in position and the rubber grommets in place? YES

Do you have a vacuum gauge to connect to the intake?

No, but I can get one

I know the engine doesn't run well, but should have around 18" Hg vacuum at warm idle. The standard rating for the fuel pressure regulator is 3 bar or 43.5 psi and should drop approximately one psi for every two inches Hg of manifold vacuum with engine running. The coolant temperature @ 25 deg.C will have the O2 sensor locked out and it won't be close to running closed loop. Can you get it warm enough to go closed loop so the O2 starts controlling the fuel system?

I can try

I know you mentioned replacing the MAF but you might try disconnecting it and start the engine. In a good running system, the engine will start and idle okay with it disconnected, although it will set a code. It will generally die if disconnected while running.

What will disconnecting the MAF show me? What am I looking for?

That injector pulse width looks very, very high. That looks like what I have seen at WOT and high rpm. IAC reading is high too, probably trying to keep the engine running. For some reason the spark advance is pinned at the max. value? Should be in the low 20's for warm idle. That all points to a control system problem or it is trying to cover for a vacuum leak or mechanical problem. The comment about the Central Power Supply causing odd problems was something I had not seen or heard of before, but our cars certainly have one.

I added my answers in your text.

Edited February 8, 2010 by ol' yeller (see edit history)

[ol' yeller]

25C is 77F so engine must never have run long enough to get warm, correct ? That is still in the "cold enrichment" range.

Correct, It only ran for a few minutes.

[2seater]

The MAF probably isn't the problem, but if they act up, it can cause all sorts of driveability issues. The purpose for disconnecting it is simply take it out of the equation. The engine will run in a default mode. It will run with MAF, TPS, O2 and Cam sensor disconnected and perhaps others, although I have only tried the ones mentioned. Sometimes a bad signal is worse than no signal. Your MAF air flow reading looked within reason. I understand what Padgett mentioned about cold enrichment, and I haven't watched injector pulse width during warm up, but that's about 20% duty cycle @ a moderate idle. Is the engine rpm reading a typo? I just noticed it is 20??

[rick60]

This is a long shot, but did you ever consider a restricted exhaust? A rich condition caused by a failed component can damage the catalytic converter. You may have replaced the defective part and corrected the original problem. The damaged converter will not allow the car to run properly. You can loosen the exhaust flange ( between the engine and converter ) to create an exhaust leak. This will eliminate back pressure and allow the car to run if restricted exhaust is the problem. If the flange it rusted you can remove the front oxygen sensor and run the engine. Loosening the flange is the safest method. It is very important to remember that the exhaust gasses are extremely hot and charged with fuel. It can easily cause a fire. Don't run the engine for a long time. Good luck.

[Guest NEMO]

What is in the fuel tank. At this point I would drain it and fill with new clean gas. Look at what comes out ?

[ol' yeller]

Today I went looking for the Padgett upgrade in Ignition modules. I used a '92 Pontiac Transport as the reference vehicle. Evidently GM used several different ICMs over the years and across product lines for the 3.8L If I get the Delco with the round coils, will it bolt to my existing bracket or will I need the bracket from the donor engine? Does it use the same electrical connection? Are the plug wires on opposite sides as my Motorola unit has? The yard is pulling it for me today and I'll pick it up this afternoon.

I also decided to have the injectors rebuilt. With 152K miles on them it certainly wouldn't hurt. I may be able to pick them up later this afternoon as well. They will bench flow test them prior to rebuilding them. If this doesn't work I am considering picking up an '89 3.8L engine that I have found locally for $75. It only has around 70K miles and has good oil pressure.

I don't think it is the Catalytic converter. But who knows? Thanks.

Greg

[padgett]

See the web page . There is a illustration showing exactly what parts you need to convert.

The usit should be the same from 1991-1995, after that the base plate changed - you need the flat one with three mounting bolts - it will swap exactly with the Magnavox. Just be careful not to get one from a 3.3, the ICM is keyed differently, it must be from a 3800.

[Guest Mc_Reatta]

The Magnovox ICM and coil pack was a two part assembly. You removed and attached it to the engine bracket via three studs that were part of the bottom of the ICM.

The Delco is a three part assembly. The sandwich is held onto the engine bracket with the same three studs, however they are not part of the base of the ICM itself, but rather a metal plate that is at the base of the sandwich. The ICM sits on top of this plate, and the three round coils plug onto the top of the ICM, and the whole sandwich is held together with six screws that go thru the coils (two each) thru the ICM and screw into threaded holes in the base plate.

When you pick up the unit at the yard, make sure you see the three studs sticking out the bottom. Then you have the whole sandwich. If the bottom is flat with no studs and the coils seem kind of loose, then they have just pulled the ICM and coils. Then ask them to pull you the mounting plate as well. Make sure you also get the six screws that run thru the coils and ICM and thread into the mounting plate. Wouldn't hurt to try to get some extras in case you suffer from the dropsies like I do.

You will only have to pull the three nuts off the studs of your old ICM one time, and then mount the new assembly to the engine bracket just as the old one was. From then on out, you only have to pull the six screws from the three coils, and the the ICM and coils are easy to change out from above.

The electrical connector is the same for both unless you got the Delco from the wrong engine or year. That's why the 92 transport lookup.

The plug wires are all on the inboard side of the coil packs on the Delco, so a little rerouting is in order. Each of the three coil packs are numbered with the plug wires that should be attached to them. Unless someone has done some swapping of the coils, they are from the front to the rear, 1/4, 5/2, and 3/6.

The numbers marked on the coil packs are irrelvant, they are all the same and can be mixed and matched at will. The firing sequence and therefore which terminal the proper plug wire has to be connected to is controled by the ICM. If you take the coils off, you will see those numbers marked on the ICM in that sequence in case you need to put the coils back in the proper order or have to replace one sometime with an unmarked or incorrectly marked one.

I think if you were to get an ICM out of a newer 3.8, (2000 or newer), the sequence is different from the ICM you need in the Reatta, and while the electrical connector looks the same, the plug in your car will not plug into this ICM as it is pinned differently, just in case.

Good luck, Padgett did us all a big favor by coming up with this easy upgrade.

[sfair]

After it stalls, connect one of those spark testers ($10) to GROUND, not to the plug and check for spark.

I do not think that the exact problem has been determined yet...fuel or spark.

No need to change the motor just yet!

[padgett]

but for $75...oy

[ol' yeller]

but for $75...oy

My thought exactly!

[ol' yeller]

Today I took the ICM to the yard and they did come up with one. One of the mounting studs was hacksawed off but they did line up with the Motorola unit. Then he told me he wanted $100 for it. I passed as I seem to remember $40 being closer to what I read in the past. I'll call around on Wednesday and see if his price is in the ballpark. I will do the Padgett upgrade, I just didn't want to overpay.

I did pull the injectors and took them to a local Dr. Injector shop. They have a great reputation. They flow tested them first and found one was only flowing at 65%. That could do it. The rest were all within spec. They only charged $35 each to rebuild them and warrantee them for a year. I'm going to try and install them after dinner tonight.

Further bulletins as events warrent.

[Ronnie]

They were trying to take you for a ride with that price on the ICM. I gave $30.00 for mine at the local yard.

They flow tested them first and found one was only flowing at 65%.

My guess is that the injectors are not the problem if only one is flowing LESS than normal. Less flow does not flood the engine. The ICM is a better bet for solving your problems.

[sfair]

My thought exactly!

But will you be ticked if you change the motor and it STILL does not run????

[ol' yeller]

Thanks Ronnie, You were right. The injectors made absolutely no difference. I will call around and see if I can get a better price on a used ICM. This is really frustrating. How does the car know the order in which I replace parts and keep the bad one until after I replace everything else? How do it know???

For some of the other suggestions I really don't think there is bad gas. I had already used over half of the current tank and the car isn't in a place during the day that sketchy people would have acess to it.

Padgett, and others, thank you for the webpage and information. It really helps a novice like me. If the ICM doesn't fix it, I'm out of ideas.

Greg

[Guest NEMO]

The only way to see if gas is bad is to check.

[DAVES89]

Why call around?

Car-Part.com--Used Auto Parts Market will do all the work for you. Just key in 1992 Pontiac Transport and it will tell you who has it, how much, and their phone #. [i always buy the newest year that works]If you click on the distance icon at the top of the column it will reset for who is closest.

I have bought mine for $20.00 but $30.00- $40.00 seems to be the going rate...

[sfair]

Just one more idea... be sure and drop the exhaust pipe from the exhaust manifold as previously suggested. A restricted catalytic converter will cause low manifold vacuum which in turn would result in the "no-drop" of the idle fuel pressure plus fuel fouled plugs. If the engine had run rich, for some other reason, it kills the converter in double-quick time, and because of the problems you have had, may be a dead duck, anyways.

That fuel pressure bothered me from the git-go.

Throwing parts at a problem is like shooting ducks in the dark. You spend a lot of money on shells, make lots of noise and your dog gets wet, but the ducks still all fly away!