cuts out @ 3000 rpm

[sector6]

I'm at a loss on this...90 325ix - When I bought it, the original owner stated the car most likely had a bad fuel pump causing a "bogging" issue starting at 3000 rpms or so (as he put it).

Here's what happens...

Motor runs smooth/strong through the rpms when the motor is NOT at peak temperature. Once the engine is up to peak temp, throttle will cut out starting around 3000rpms sputtering and dying w/ almost total loss of power until you let off, then returns to a perfect idle.

If you stomp the gas, the motor instantly falls on it's face with the sputtering/power loss. If you slowly press the gas, it will climb smoothly through the rpms till you hit 3k and then start with the sputtering/power loss.
NO CEL (and yes, bulb is good:))

I'm no mechanic, but it seems to me, a bad fuel pump would act the same no matter if the motor was hot or cold.
Maybe a sensor somewhere??
Only thing I tried was swapping the AFM off my 89is. But the AFM is not the prob. No intake leaks that I could see either. Car does have a NEW 02 sensor.

Like I said, I'm not much of a mechanic, and any help would be much appreciated. Any ideas?

Thanks
Paul

[jlevie]

I think what I'd try in an effort to fix this would be a new DME temp sensor and a smoke test of the intake. It could also be a bad crank position sensor. It would also be a good idea to run the suite of fuel system tests in the Bentley right after running the car long enough for the problem to be present.

[Sagaris]

I agree with your thoughts about the fuel pump.

I feel that it could be the oxygen sensor .

Here is why:
(You say you aren't much of a mechanic so forgive me if I am insulting your intelligence by dumbing things down and possibly telling you things you already know. )

When your engine is cold, the ECU runs in open-loop. The engine ignores certain inputs such as the oxygen sensor and runs the engine on pre-programmed parameters. Once the engine is up to operating temperature it switches to closed loop and takes readings from the oxygen sensor. This explains the crappy running when it warms up.

If your oxygen sensor is bad (sending the ECU false or slow signals) it will show its ugly face as soon as it switches to closed loop when you are up to operating temp. I am not 100% sure if it works like this with e30's but on some cars if you unplug the oxygen sensor while the car is at operating temperature and it starts running better, then thats your sign.

Give this a try, its free and easy to do. Let us know what you find.

[sector6]

Thanks for the replies guys.

I suspected the 02 sensor, but like I said, it's new (perhaps faulty).
I searched bavauto for a "DME temp sensor" but didn't find anything listed. Do they go by another name?
I'll try replacing the mentioned sensors and see how it goes as well as test the 02 as mentioned to start with.

I'll let you guys know what I find.
Thanks again,
Paul

[Sagaris]

DOH! I thought I had read your post thoroughly, apparently not thoroughly enough. It still seems like an O2 sensor related issue but if nothing changed with the new sensor then its probably safe to say the O2 isnt it unless there is some resistance buildup in the O2 sensor wiring /harness.

As for the DME temp sensor. Just search for a coolant temp. sensor (the one that feeds a signal to the ECU not the gauge).

[sector6]

...is this the temp sensor I'm looking for? Found at bavauto.com
Part # : 0 280 130 026

Another quick one, the sensor from my 89is should work right? It would be nice to test that before I spend $$ on parts I may not need.

Thanks again!

[sector6]

Guys, think I figured it out. There was a vacuum leak lurking in there after all (a big one). I'll try and snap a pic as I'm not sure how to explain it.

[sector6]

Guys, think I figured it out. There was a vacuum leak lurking in there after all (a big one)...

WRONG!! Wasn't the problem. :D
I am now getting a 1222 code. So I'm trouble shooting that in hopes to resolve this.

Slowly I'm finding time to work on this.

Check list so far:

No further air leaks detected - Have not run a smoke test yet though!
Cleaned AFM with MAF cleaner spray (was very dirty - lots of black residue came out) - no change
Replaced much needed air filter - no change
Swapped AFM from my IS - no change
Replaced spark plugs - no change
Replaced O2 sensor - no change
Cleaned various electrical connections - no change
*Removed improperly installed crank position sensor. Found the wire has been damaged by rubbing against the alternator belt. Have NOT been able to replace this yet.

It's now snowing and freezing balls outside so I'm calling quits for now. This is as far as I've got.

Note on 1222 code: makes mention of potential valve issue. If there was a valve issue, wouldn't it be apparent if the engine cold, and not just after it warmed up?

So, Still not up and running yet. Just a quick status update! ;)

[jlevie]

No further air leaks detected - Have not run a smoke test yet though!

In that case, there is a real possibility that there are still intake leaks. The only reliable method of
locating intake leaks is to have a smoke test run on the intake and crank case
and to test the brake booster with a gage and vacuum pump. The complete list
of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hose and valve
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

Since several small leaks that can be difficult to find w/o a smoke test add up to a large leak, you can either have a smoke test run or go for the grand solution and replace every hose, seal and gasket that could result in an intake leak,

[bcrdukes]

Check the hose that is ATTACHED to underneath the throttle body and is connected to your charcoal canister. Some people here have found that hose to be a huge and popular vacuum leak culprit. It looks like an elephant trunk.

[sector6]

In that case, there is a real possibility that there are still intake leaks. The only reliable method of
locating intake leaks is to have a smoke test run on the intake and crank case
and to test the brake booster with a gage and vacuum pump. The complete list
of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hose and valve
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

Since several small leaks that can be difficult to find w/o a smoke test add up to a large leak, you can either have a smoke test run or go for the grand solution and replace every hose, seal and gasket that could result in an intake leak,

Thanks again for the reply,
...aside from the potential intake leaks, what are your thoughts on the damaged crank position sensor wire? How likely is that to be the cause?

[Hallen]

Thanks again for the reply,
...aside from the potential intake leaks, what are your thoughts on the damaged crank position sensor wire? How likely is that to be the cause?

Pretty much zip. If it were shorted or broken, you wouldn't run at all. If it was just broken enough were it made vibrating contact, maybe, but I seriously doubt it. The outer case on that set of wires gets chafed or cracked pretty easily because of the heat and it's location. Usually just taping it up is OK as long as it hasn't cut into the actual wires that are inside the bundle..

[BlUe E30]

my friends had your EXACT problem and it was the vacuum line under the throttle body that you can barely see its the 90 degree angle one dry rotted and broke off completely

[StereoInstaller1]

My wifes car had a similar issue..not as severe as you are describing, but along similar lines.

I took apart the fuel injector harness under the intake manifold and cleaned all the corrosion out, shot some dialectic grease in there and all has been well every since.

GL!
Luke

[BigSam]

Paul, I realize that you arent going to do shit tonight because it's 12 degrees outside, but serious look at the big tube under the intake manifold. It almost caused me to lose my mind after I put the 2.7i into my car.