Retired w/Reatta

starts, then stalls

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I just went to a specialty tool shop and learned some interesting things.  The oil pressure sender is indeed a 1 1/16" using a six-point deep-well socket; with a twelve-point it just spins.  Problem is the six-point socket is 5" deep and won't fit in the space, and it cost $45, non-returnable.

Open-end 1 1/16" wrench is too sloppy; box wrench in that size only comes as twelve-point, also too sloppy.  Story may well be the same with a 26mm but the shop had none to try.

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Think I've used a socket from the top and a pair of water pump pliers through the fenderwell.

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I just reread Padgett's post #23, so I went and tested the car again.

With the key on my DVM showed 11.90 volts.

With the car running it showed about 9.0 volts.

When the car stalled, the DVM read 12.45 volts.

If the oil pressure sender was good, the fuel pump volts would have gone to zero, right?

If the OPS is bad, it wouldn't make the car stall, right?

Sometimes the universe works in strange ways.

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At this point I'd also monitor the fuel pressure on the rail. Spec is around 40 psi but anything over 20 should idle.That said it could be an ICM heating up and failing. I've seen that before. I always keep a couple of spark plug testers around to check. (embedded HTML seems broke had to embed manually).

There is nothing like having the right tools around particularly if you like oddballs and orphans. Now that I am becoming auld and frail I have enough to outfit a three bay garage including a lft ('vert needs freeze plugs, is there a way to take things loose, remove the rad and just move the engine enough to get to the backside plugs ?)

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Stanley,

Try this test to determine if the fuel pump is causing your engine to stall.

 

Below are instructions for powering the fuel pump directly from the battery to make it run continuously as long as the wire is connected. Powering the pump directly from the battery will eliminate all the fuel pump controls, (OPS, BCM, ECM, fuel pump relay) from being the cause of the engine stalling

 

If you have a fuel pressure gauge connect it so you will be able to monitor the fuel pressure while the pump is running.

 

With the jumper wire connected, start the engine and watch the fuel pressure gauge to see if the pressure drops when the engine stalls.

 

- If the fuel pressure drops when the engine stalls replace the fuel pump.

- If the engine stalls and the fuel pump maintains pressure the fuel pump is not the problem.

- If the engine continues to run and does not stall, you are one step closer to determining the cause of your problem.

 

Once you have ruled out the fuel pump as causing the engine to stall you can move on to doing other tests to determining what is causing your engine to stall.

 

_______________________________________________________________________

How to power the fuel pump directly from the battery:

 

1. Make certain the ignition key is in the off position.

 

2. Use a length of wire, 14 gauge or larger, to connect the green fuel pump prime/test connector to the positive side of the battery to supply the fuel pump with 12 volts. The pump should begin to run.

 

Having the connectors on the length of wire is is helpful but not necessary as long as you can connect a wire between the green connector and the positive terminal of the battery safely.

 

fuel_pump_test-6.jpg

 

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I was down with a bad (are they ever good?) cold the last few days so I just got around to testing the fuel pump today.

I made a hot wire of 12G speaker wire with an electrical connector at one end for the green connector, and an alligator clip at the other end for the battery connection.  Thank you Ronnie for promoting safety.

I connected the fuel pressure gauge.

I hooked up the wires with the key off:  Fuel pressure read 42 PSI.

Karen-not-a-collector started up the car:  Fuel pressure went to 35, held there steady until car stalled, then went back up to 42 PSI.

So I take the results to mean the fuel pump is not the problem.

From whence do I wander?

S.

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Yes, your test proved the fuel pump is capable of maintaining proper fuel pressure for the engine to run without stalling.

 

Just to rule out a fuel pressure problem completely - I would perform the same fuel pressure test again without using the jumper wire.

 If the test results are the same you will have proved the fuel pump and fuel pump controls aren't causing the stalling problem.

 If the fuel pressure drops while doing this test the fuel pump is losing power and we will have to figure out why.

 

Assuming the fuel pressure remains good...

Next, as TexasJohn said, connect a spark tester to one of the plug wires so you can watch it to see if the ignition system loses spark when the engine stalls.

 

Below is a photo if the spark tester I use. Anything similar should work. They are inexpensive at the parts stores.

 

post-95476-0-66656100-1443570570_thumb.j

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I performed the same fuel pressure test without using the jumper wire.  Started car up, PSI went to 38.  Car stalled, PSI went to 42.

I checked the spark plug wires with a spark tester.  With the car running the light went on for all 6 wires (some brighter than others).  I held the tester to one wire and when the car stalled the light stayed on.

The wires and plugs have not been changed for a long time.

S.

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I think you have ruled out fuel pressure as the cause of the engine stalling.

 

If I understand you correctly you have a strong spark at the plugs when the engine stalls. Correct? If you still have a strong spark as the engine stalls that should rule out the ignition system as causing the engine to stall. Usually bad spark plugs and wires won't cause an engine to stop running. They can cause the engine to miss under load but I don't think they would cause the engine to die..

 

The fuel control system is the next thing that should be checked. It was saved for last because it is the most complicated. A few question need to be answered before you start troubleshooting the fuel injection system.

 

1. Are there any ECM codes being displayed in the on-board diagnostics?

 

2. Does the engine start right back up every time after it stalls?

 

3. If you start the engine and hold the gas pedal down to keep it running at 2000 rpm will the engine still stall or will it continue to run as long as you keep it at 2000 rpm?

 

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1)  The on-board diagnostics show; e026h, b552h and no r codes.

 

2)  The engine starts right up every time after it stalls.

 

3)  I started the engine and kept the RPM near 2000.  The engine hesitated a few times but kept running for over 3 minutes; then the RPM gauge went bonkers, bouncing between 500-5000 RPM, went back to 2000 RPM for a few seconds, then the engine died.  This is the longest I've been able to keep the engine running.

Answer to #3 is that it still stalls even with RPM kept at 2000.

S.

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Wow! That wasn't the result I was expecting from holding the RPM at 2000. I was hoping the engine would run smoothly. Then all you would have to do is clean or replace the Idle Air Controller and it would fix your problem. What you described is more than just a fuel control problem. The fuel injection components and sensors shouldn't effect the tachometer with the exception of the Crankshaft Position Sensor. It could be causing your stalling problem as well as the other problems you describe.

 

The engine hesitation, the erratic tachometer and the code B552 (BCM memory reset) while the engine is running leads me to think you may have a problem with the grounds behind the battery or a bad connection somewhere effecting the electronics. The grounds behind the battery could be loose or dirty. They are isolated grounds for the computers, and other electronic components.

 

I hate to send you on a wild goose chase but I would not continue with trouble shooting this problem or throwing expensive parts at it until you know for certain all the grounds around the battery are clean and tight.

 

After you have the grounds clean, clear all codes and try running the engine again at 2000 RPM, see what happens and then let us know..

Edited by Ronnie (see edit history)

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I began the parent of this thread on 14 may 2015 under the heading Dash Electrical Problem.

At that time I disconnected, cleaned, sanded, checked for cracks, reconnected tight with electrical grease the battery, the ground junction block, the ground terminals and the fusible links; all were originally clean and tight.  I checked the vacuum lines for cracks or rotting (I found one end of a T that was rotted but even when repaired had no effect on problem). 

Yesterday I again visually checked all of those connections, all fine.

So I clear the e026h and b552h codes; start the engine.  It stalls immediately.  I try again, manage to get the RPM at ~2000.  Engine runs very rough for almost 2 minutes, then it smooths out and runs sweet for about 10 minutes.  I took my foot off the accelerator and the idle went to1100 RPM, then to about 800 RPM, still smooth.  After about 3 minutes the tach starts flipping from ~500 to ~3500 RPM.  It alternated between the bonkers mode and idling at ~800 RPM for the next 5 minutes and never stalled.  Engine ran for another 5 minutes and then I turned it off.  Checked codes, e026h appeared; I cleared it and went to bed.

Today started up car, stalled immediately.  Started again and tried to keep RPM at ~2000.  Engine ran very rough for about 2 minutes, smoothed out, I took my foot off the accelerator, RPM bounced from ~500 to ~3500 for about a minute, then stalled.

S.

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Stanley,

Is the tach reporting correct engine speed? That is to say, is engine speed actually spiking up when the tach does or is the tach not synchronized with the engine speed when it goes way up momentarily and showing a reading much higher than actual? Should be pretty obvious by the sound of the engine. That 3.8 starts "screaming" at about 4000 Rpms.

I ask because I had an ECM fail on my scrub 88 coupe a while back. Engine wanted to stall out all the time and the tach (when on screen, this is a CRT car remember) would spike to 6500 RPMS and back down repeatedly to "actual" engine speed though the engine never actually went up to 6500 (which is the the top end incidentally).

Given the history of electrical malfunction you've had with this car now (BCM/EEPROM failure) I'm starting to wonder if your ECM got smoked also. That said, being a 90 I presume it still has Magnavox iginition on it. These ignition modules are failure prone - more so than the Delco setup used in 91 - so it may be suspect also. Typical failure mode is leaking of the green slime which causes the module to overheat and self destruct the electonics

New replacements for both versions and their associated coil packs are still readily available and if you are near a you-pick yard they are plentiful on many GM's equipped with the 380p from 88-90 (for the Magnavox type). Whether they are any good is the issue, if you can get one cheap with an exchange warranty then buy a used one to try.

This is all just a suggestion. If you happen to have a spare ECM you might try swapping it in to see what you get. Unfortunately, the diagnostics on these cars misses a lot of powertrain faults and then fails to set any useful codes leaving us to do seat of the pants troubleshooting.

KDirk

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Kevin,

The tach is not reporting the true engine speed.  On the low end, ~500 RPM and up to ~2000 RPM it sounds true; over that it's just the gauge going bonkers, not the engine.

Yes, being a '90 it has a Magnavox ignition; which is clean and dry.

I do have a couple of spare ECMs and Magnavox ignitions (I may even have a Delco out of a '91) that I've collected from u-picks over the years (look good but not tested).

I will try replacing the ECM and see if it has any effect.

S.

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... Given the history of electrical malfunction you've had with this car now (BCM/EEPROM failure) I'm starting to wonder if your ECM got smoked also. That said, being a 90 I presume it still has Magnavox iginition on it. These ignition modules are failure prone - more so than the Delco setup used in 91 - so it may be suspect also. Typical failure mode is leaking of the green slime which causes the module to overheat and self destruct the electonics

New replacements for both versions and their associated coil packs are still readily available and if you are near a you-pick yard they are plentiful on many GM's equipped with the 380p from 88-90 (for the Magnavox type). Whether they are any good is the issue, if you can get one cheap with an exchange warranty then buy a used one to try.

This is all just a suggestion. If you happen to have a spare ECM you might try swapping it in to see what you get. Unfortunately, the diagnostics on these cars misses a lot of powertrain faults and then fails to set any useful codes leaving us to do seat of the pants troubleshooting...

 

Stanley,

 

I agree with Kevin. It is probably time to start swapping parts until you find the one that is causing the problem. I was trying to lead you down a path that would - through a process of elimination - keep narrowing down the list of components that could cause the engine to stall until you found the problem. Although that isn't the fastest or easiest way to troubleshoot a problem like yours it is the cheapest because randomly swapping parts can get expensive. However, after you described what is going on when you try to keep the engine running at 2000 RPM, there is no clear path to follow from here.

 

If it were me I would start with swapping out the Crankshaft Position Sensor because it is a cheap part that (in my mind) might be the most likely to cause the erratic fluctuation in the tachometer reading but swapping out the crankshaft sensor isn't any more logical than Kevin's suggestion to swap out the ECM and it will take more time to change out the crankshaft sensor.

Edited by Ronnie (see edit history)

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a) I have seen ICMs fail in almost any way possible.

B) Secondary ignition issues (ICM, coils, plug wires, plugs can do almost anything but do not set codes.

c) Just for S&G, disconnect the alternator and just run on battery for a while. Enough noise coming from the alternator could make the tach (and ECM) go wonkey

d) You don't have a battery charger conected do you ?

e) E026 is the quad driver and should not kill an engine.

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Kevin, Ronnie, Padgett, et al,

SUCCESS!  I pulled the wiring harnesses from my ECM and attached them to a spare, but untested, ECM I had aquired from a U-Pull.  I started up the engine, it fired up right away, RPM went to 1100.  Engine ran smooth for a few minutes, RPM went to ~ 800, I put it into gear and went fo a drive for the first time in over 4 months!

After about 10 miles of driving around the neighborhood, stopping occasionally, shutting engine off, starting and driving again, car ran flawlessly.  Every time I shut it off I checked for codes.  Sometimes e026h and b440h showed, but car continued to run smoothly.

I am now in the process of putting everything back together.  I won't mention on a public forum what I think of the engineer who designed the access for the ECM, but would it still be fun if it was easy?

A very grateful thank you to everyone who gave advice and encouragement along the way.  I truly appreciate the help I received from people whom I have never met yet we have bonded through a shared appreciation of an automobile. 

Many of us come from different everthings ( age, race, geographic distribution, politics, etc.) but this incredible vehicle, the Buick Reatta, makes us all best friends.

Thank you again,

Stanley

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Padgett,

I didn't see your post before I posted my response.

When the car was just sitting idle for a long time I did connect a solar batter maintainer.  I don't remember the voltage it collected but it was quite low.

Thanks, S.

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So basically, amidst all the testing, I replaced the BCM with a good used unit, had a spare 1990 Reatta eeprom reprogrammed for my specific vehicle and replaced the ECM with a good used unit.

I still don't know what made the BCM to abandon all reason but right now life is good.

S.

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Glad you found it and makes sense just rarely fails that way. Why it is good to have spare modules, somethines when intelligence fails, swapping is what is left. Did the EO26 clear also ?

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OK. That is the Quad Driver. The diagnostice will let you exercise the fans and other devices. Should be able to hear if they work. What ever does not work is what needs checking out but can be reasonably sure it is not the ECM.

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I got into diagnostics today for ECM Output.  It appears as if EO07, canister purge solenoid, is my demon.

I found references to this in past posts on this Forum but nothing actually in how to remove the canister and check the solenoid.

Should I start a new thread since the car is no longer stalling?

Thanks,

S.

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