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running like.......


Rbenh

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1 hour ago, Rbenh said:

whats next? still runs bad, not as bad but still bad. backfires, misfires, RPMs jumping up, ...... BCM?

It's not likely that the BCM is causing those symptoms. Possibly the ECM but most of it's job is to control fuel delivery even though it does control spark advance. I'm guessing the reason the RPM is erratic is the IAC is going crazy trying to compensate for the engine running poorly. The backfiring is a little unusual for a 3800 that doesn't have a distributor.  Can you tell if it is backfiring through the intake or the exhaust?

 

If I was working on your car I would take another look at the ICM and spark plug wires.  Check closely to be sure that you didn't get a couple of plug wires crossed. Crossed plug wires would account for backfiring and misfiring.  After you rule out the ignition system, replacing the ECM might be your next step.

 

2seater knows the 3800 engines really well and has experimented with them a lot. Maybe he has some other ideas on what could be causing your problems.

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  • 2 weeks later...
On 9/14/2019 at 1:39 PM, Bobnewbie said:

This was interesting to follow. Did you get it running right?

Bob, I would like to know too. Sometimes when we try to help people they just disappear and we never know the outcome.  Looks like that is the case this time.  It's a shame because knowing what was done to fix the problem might help someone in the future with similar issues.

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  • 4 months later...

Still not running, I have set up an appointment to have it checked out. I will left notice of what it was if it gets resolved.

It better be something significant after replacing the parts, checking the sensor voltages, fuel pressure, and etc.

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There is one thing I am looking for. I broke the fitting to the fuel regulator hose where it connects to the vacuum bolt mounted on the throttle body. Does anyone where what is part name/number is and where to get one. So far I am calling it the "vacuum connection block"  but that does not lead to a part number.

1990-buick-reatta-base-coupe-2-door-38lbeautiful-little-carnot-many-1990s-12.jpg

Vacuum.png

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No idea on the part number but the salvage yard will have lots of them. Just be sure it comes from the same engine. GM used a similar part for lots of years but there are small differences in the actual dimensions. Always good to have spares since it does get brittle from solid aluminum 30 years of heat cycles. I make my own from solid aluminum or nylon.

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  • 1 year later...

I am back, it has been a while. I took the car to a shop and they got it running. it is still not right though. I replaced the MAS assembly, the timing chain, and a a few relays along with all other sensors. It runs using the old MAS with a missing resistor and broken housing. With the new sensor on it, it stalls out pretty quick. tried the battery disconnecting the battery for 24 hours, the reset the ECM connection to the MAS and there was no change. Is the ECM bad? Or is there another way to reset the data between the 2?

While i am here what size hose do i need for the sun roof? Mine it split a few places so i have water leaking onto the floor.

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I'm dealing with an EGR issue. Maybe you have the same issue.

Regarding the hose, if yours is bad remove it and take it to a parts house and have them match it up.

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I put on a new EGR yesterday.

Good thought for the hose, why did I not think of that.

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Did the EGR do the trick? If not, I'd review Ronnie's post on 8/31/19 and check the ICM and plug wires again. I've heard that replacement ICM/Coil packs can be defective even if new. So worth another check. 

 

I posted the following under a different topic, but cut and pasted below since it seems to put a final touch on most of my issues. Still have issues with the Cruise Control servo, but that's another page......

 

The MAF was replaced (due to code (E034) and then I got a code for the Cam Sensor (E041). Replaced both which were of no help. I then got a code for the Ignition System (E042) and after checking and finding that two cylinders were not getting spark, I then replaced the Ignition coil and ignition control module. The car now runs great (at least for the 25-30 miles that I've driven since). Turns out, I suspect, that the ICM was probably the original culprit all along in spite of the E034 and E041 codes.  Funny thing is that the codes popped up one at a time and not all at once. Had the E042 code shown up first, a replacement ICM and coil pack may have cured the poor performance right off the bat. As it is, I spent way too much on trouble shooting, especially with the replacement MAF (and also the catalytic converter) before checking the ignition coils. I'd suggest that anyone encountering extremely poor performance start off by testing the ignition coil and ICM

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