1990 Olds Stalls/Bogs on acceleration

Looks like you changed/tested everything, except one of the first things you shoulda done. Change the fuel filter.

I had an 89 Celbrity with 4 cyl engine had the same symptom...it would run fine but once in a while when you step on the gas after a red light, it would bog and stall.. It would re-start and run fine..

I never did find the problem...

At one point I was thinking maybe a throttle position sensor problem.. I replaced it and that did not fix it...

Let us know if you figure it out...

Mark

I forgot to add , in my case it seems it would never happen twice in a row..you had to be stopped and idling at a light for a minute or so before it would happen.. just a quick stop and it would never happen, and it would never happen after a re-start, you had to sit idling in drive for a minute or two before it would happen...

very tough to troubleshoot... you would really need to instrument the car to determine if it was a spark or fuel problem or what...

to the other poster, i don't see how this could be a fuel filter problem...

please let us know if you ever figure it out

Think the 4's had throttle body, but my '88 Celebrity 2.8 with MFI had similar symptoms. Stalled leaving a stop light, but not always. Progressed a couple weeks later to stumbling while accelerating, but not always. My mechanic replaced 2 injectors and that fixed it.

--Vic

No trouble codes?

there are 3 possibilities. Too much fuel - too little fuel - not enough spark. It would help if you figured out which. Your description suggests not enough fuel as the most likely.

Doesn't this engine have a vacuum controlled pressure regulator that controls fuel pressure to the rail? If so the pressure should drop when idling and increase when you step on the gas. The vacuum hose to the regulator can collapses after idling for a while and that might cause the symptoms. Or I suppose the regulator could just be sticky, but those are just wild guesses based on the assumption it is not getting enough gas which could be wrong.

-jim

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thanks for the replys, I forgot to add I did also change the fuel filter... it was actually the first thing i did. And it did nothing. When i check the fuel pressure it reads high 30s at idle and when i step on the gas it does increase. It seems like it is not getting enough fuel to me, when it starts to bog if i spray a little carb cleaner in the hole for the air dam it picks it back up instead of killing it like it normally would. But my pressure looks good and I tried injectors out of another car that has been working just fine... So i don't know how it would not get enough fuel?

Good test. And was your fuel pressure test also while the problem was occurring? I mean one would expect all tests to tell you nothing when the problem isn't there. If you are testing the right function when the problem occurs you should see what it is. The MAP sensor would have a vacuum signal also that could be faulty due to bad tubing. Throttle position can have dirty electrical connections. You said you changed that right?

-jim

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if you can get the problem to happen in the garage while you are troubleshooting it, then you may have a chance. Mine would only happen when i was actually driving it...

So if the problem is a lack of fuel problem and you have changed the injector(s) and the fuel supply pressure is good,.... can you monitor the electrical signals feeding to the injectors with an o'scope if you can or at least a voltmeter. If the voltage (or pulse width actually) drops or does not increase when it should, then we know the computer is not telling the injector to inject more gas for some reason when it should be when you step on the gas...

i.e.

is the computer not telling the injector to spray more gas?

or

is the computer telling the injector to spray more, but the injector does not or cannot obey?

Mark

ok all good stuff.... and I was checking the fuel pressure while it was having the bogging issue. The problem is random and only happens some of the time, but it will happen with the car parked or me driving it. I would by hand move the throttle linkage with the gauge attached and watch the gauge. As the car started to bog the pressure would actually stay the same or climb it would never drop.... Is it possible for the pressure to be at spec but still have too low volume? As far as the map sensor and tps sensor, the map sensor i replaced with a known good one and did not change. I hooked my meter up to it and it read correctly, with and without me jiggling the wires around and tugging on them. the tps sensor pretty much the same deal except i didn't put on another sensor, i just test it similar to the map. It shows smooth operation from closed to wot. Does anyone know where the ecm is at on this beast, I want to check the wires going directly into it?

Because the ECU isn't giving it enough. It's time to get a scanner and start looking at the inputs and outputs.

--scott

I wish winaldl would work with this motor!!!!!!

I tried listening to the injectors with my long screwdriver. and it sounds as if all of them are clicking and not missing a click when the engine is bogging...

connect a volt meter to them..

when you open the throttle, there has to be an increase in gas flow, in the old days the accelerator pump did this,,,

you will not be able to tell by hearing the clicks if more or less gas is being injected... the clicking will tell you that some gas is being injected...

looking at the meter you should be able to see the voltage or pulse width increase when you open the throttle..like a dwell meter used to work..

Do you have the service manual?

Mark

also in my Celebrity which was single injector throttle body by the way... the problem would not persist for long enough to set a code....I had no codes or check engine light..

Mark

I had an 89 Regal with the 2.8 that did the same thing. It was the injectors.

was it the injectors themselves bad or the wiring to them?

Could he simulate the load from acceleration by putting it in drive and chocking the wheels and putting on the parking brake, then giving it some gas? It might not look the same to the computer, but it produces some of the same conditions.

I'll contribute a probably-dumb idea. I haven't seen anybody mention the spark advance. Does the car have a vacuum advance? Maybe those went out with carburetors ...

Yea this car has no vacuum advance, the computer does it all. It doesn't even have a distributor