KA24E Engine Problem... Help Please...

[rocksteady_racer]

Here's the symptoms: Running too rich (up to 3000 it's rough but once you pass 4k it's definately running way too rich cause it smokes gas out (thick black smoke). It does hit 5000 rpm but hard to get there especially before it's warmed up. Also the idle seems to bounce a lot.

Before it's warmed up it seems like it's hitting hte speed limiter at 3K for some reason but the ecu says the VSS is working fine. I tried rewiring the MAF. I also swapped out my coolant temp sensor thinking that might fix it. I checked the ECU codes and all I get is 55 (no code).

I checked all my sensors and injectors with a Multimeter and they all looked good. I even installed my aeromotive FPR thinking it was the fpr blowing out from the walbro 255. Also I checked the compression on the block and it looks fine to me (all cylinders are pretty much the same at 155). I realized that my TPS sensor was not a manual one (automatic ecu that I got from advanced auto cause they are stupid LoL) so I swapped that out with a new one.

And none of those fixed the problem.

I ran seafoam through the IACV and the brake vaccuum hose and that didn't make it any better either. Any other ideas? I can put a video of my motor up if you guys want to see. It's running rich across all cylinders based on my spark plug readings. I even got a new cat because my old one was clogged from all the rich gas geting pumped through it by the motor.

I'm running out of ideas here? I don't see how the distributor timing could have changed unless the chain jumped because I didn't touch it. And I even removed the valve cover to check and nothing looks bent or broken.

I checked my intake manifold when I was trying to clean it and it was covered in black soot. The head does make an odd ticking noise though which also confuses me because I took the metal chain guide off the top of it. The only things I can think could possibly be it would be an exhaust manifold leak, vacuum leak (which I don't hear but the seafoam leads me to believe the bpt valve is leaking because it was smoking), or it needs a new timing chain.

But it seems like the motor problem is constant. And if it was a timing problem I don't see why the motor would run really bad when it's cold and horribly slow but a little better when it's warmed up. Any help would be greatly appreciated. Thanks in advance.


Modified by rocksteady_racer at 11:05 AM 6/25/2009

[phuz]

Swap your ECU with a known working unit.

[breadbox]

And break up the text next time. That bish is hard to read. I second the ecu.

Also I am guessing its a 89-90 with a 5spd and 5spd ecu?

[Vegascorbin]

Couple of things. The walbro 255 will blow right through stock fuel pressure regulator. Stock pressure is around 40 PSI and the Wllbro can put out upto about 90. Be sure your FPR can handle up to 90 PSI and dial it back to factory pressure. Check the Manual or search for the proper setting.

Sounds to me like you either are just forcing fuel through the injectors at all times, or as others have said the ECU is shot.

Check your fuel pressure and if posable swap in a known good ECU.

[rocksteady_racer]

I swapped the ECU out too. Sorry about the msg length. Was trying to make sure no one was going to say something I already tried. I have an aeromotive FPR and I set it to the stock setting. But everytime I set it, it changes which is why I thought it was a vaccuum leak somewhere. It is an 90 5spd with 5 spd ecu.

[Vegascorbin]

Do you have an inline Fuel pressure gauge? If so what is it showing. If the pressure is changeing then that will mess things up.

I did not re-read the original post. Longshot thought but did you change the fuel filter before setting the pressure?

[rocksteady_racer]

I swapped the fuel filter about 3000 miles ago. The pressure gauge is on the aeromotive FPR. I set it and it stays steady but as soon as I check again later the pressure seems to slowly creep up by itself (like the vaccuum is decreasing but the line is fine). That's why I figured a vaccuum leak but then I think the motor's running condition might be causing the change of pressure too. Maybe a head problem?

[rocksteady_racer]

Any ideas?

[dirty240]

i had the same problem and ended up unplugging my iacv... its worked fine ever since

[CJR04]

I am working on my brother's car and it has exactly the same symptoms. It is running too rich (11.5 or less, read using a wideband O2 sensor) and it iddles rough.

I suspected the computer, after checking almost all the sensors and them checking OK. I have troubleshoot and found the same results as you.

The car had originally burnt a computer and a mechanic swapped it twice. I am using the ALL Data program to help me troubleshoot. I checked the computer #'s on the list that they provide for when you need to replace it and it corresponds to a 1991 car and my brother's car is a 1990 (2-90 production date)

I just got another computer that supposely is for 89-90 and swapped it but now the car runs worst. No codes. I will play with the throttle cable and the IAC as I had adjusted it before to try to solve the issue with the first computer.

With first computer and MAF disconnected, it ran better on iddle but still rich. With new computer as soon as I disconnect the MAF, the car shuts off.

Also, I could not extract codes from first computer as it had an LED missing and I could not even make the one left blink.

[Wc240]

have you tried running the proper idle mixture adjustment, base timing adjustment?

[CJR04]

I adjusted the timing to 15 degrees.

On the mixture, you mean at the back of the intake at the side screw? That is my next move. It has been moved so much that I don't even know of a starting point.