JHowell37

Believe it or not, the POS in my avatar has had a lot of cash dumped into it. Since I acquired it in August I have replaced the following items.
1. Everything in the intake manifold refresh kit from 928 specialists.
2. Did one of their timing belt kits as well
3. temp-2 sensor
4. spark plugs
5. spark plug wires
6. rotors and distributor caps
7. throttle position switch
8. new Ford Racing fuel injectors (24lb/hr)
9. rebuilt air meter from 928 International
10. new O2 sensor
11. Rebuilt ECU

Why is my car running like ****?

To be more specific, we'll toss items 1-7 on my list into the maintenance category. After replacing the aforementioned items, my car was idling at 1600RPM and increasing as the engine got warmer. This issue came to light possibly due to some stupidity and a can of ether which resulted in one end of the intake being blown off and denting the door on the refrigerator in my garage. I figured I might have damaged the delicate wire in the air meter so I ordered a rebuilt air meter from 928 International. Installed it and the problem was still present. Found a used ECU on e-bay and it didn't seem to want to start my car. Took that ECU along with the one from my car and tried both in another member's car. The ECU that that caused my idle to run at 1600RPM caused his to run at 1600 as well. The ECU that wouldn't start my car, did start his, but it ran poorly, excessively rich, etc. So it was obvious that both were bad. I sent out the e-bay ECU because it seemed to be in better overall condition and had it rebuilt/repaired by ProgramaInc. I get it back, plug it in the car and the car starts up with some difficulty but it does start and run. It runs very rich and is belching out black smoke. I've got and air/fuel ratio guage hooked up and it was reading right in the middle. So I decide to have a look at the O2 sensor. The signal wire on the O2 sensor looked like it had been severed about 10 years ago so I put in the new one I had. The problem is still present.

I should mention the idle adjuster screw on the side of the throttle body is all the way in. It has been this way since I bought the car and I'm sure it's incorrect because there wouldn't be a screw there if it were meant to be all the way in. Turning it does nothing. Jumping the B and C terminals on the service port cause the engine to stall. With the new O2 sensor, the air/fuel guage reads rich. I removed the XXV relay and put in a jumper and got voltage on terminals 2 and 4 on the air meter. I left the air meter unplugged and started the car. It runs better in "safe" mode then it does with the air meter plugged in. It seems to me that the "rebuilt" air meter is sending bad info to the ECU. Or perhaps the ECU isn't properly interpreting the info from the air meter. Any suggestions?

Mike Frye

Hey J,

Don't know about the MAF, but you said the idler adjust screw was all the way in and

My manual says you're only supposed to adjust the idler adjust screw with these jumped, so have you tried the combination of backing off the screw and jumping BC to see if it will run? Mine idles down about 70 rpms when it's jumped (IIRC). Those two need to be handled in combination though.

The fact that when you got the car it was all the way in, and the 02 sensor was disco-ed means that it was all changed to 'fix' whatever was going on (which you may have already fixed or which may still be a problem somewhere). Replacing the O2, adding a good temp ll sensor etc. may have made it so the idle and other settings are now overcompensating.


Also, no offense intended, but could anything else have been damaged in the explosion?

JHowell37

Anything is possible in terms of other damage from the ether incident. But everything seems to work fine and give the proper readings with one exception. I put the ohm meter on terminals 2 and 5 of the air meter. This has a fairly small range of operation and should register between 3.6 and 4.1 ohms. Mine is showing 4.4. So that is well out of range. I'm not sure how to test for voltage with the plug connected.

I'm not too worried about the stalling issue with the terminals jumped because I can tell that the ISV is working. I've actually shut off the engine, disconnected the battery, and then backed off the screw and again, it seems to make little difference.

What I find most interesting is the fact that when I unplug the air meter, the overall running condition of the engine seems to improve drastically. It idles very smooth, without any black smoke. With that said, we know the ECU can tell the difference between having the air meter and not having it. I'm going to see if I can plug my ECU into a car that I know for certain is working properly and make sure it was properly repaired. But I'm still thinking the problem is in the air meter.

tomcat

Don't know how much you used, but not good for the mass flow sensor (hot wire).

How did it run when you got it?

JHowell37

I've replaced it since the ether incident with a rebuilt one from 928 International. I suspect this is where the problem is because the car runs better with it unplugged which is apparently a tell-tale sign of a bad MAF.

Mike Frye

JHowell,

The part from 928 intl. has a warranty, right? I know you want to get it figured out ASAP, but I'm sure they'll exchange it if it's bad, or at least bench check to confirm whether or not it is.

MD is a bit of a drive or else I'd swing by and let you try mine. I only have the one though, and I'm using it.

Also, mine is working but probably hasn't been serviced since new, so I don't know how close it is to being 'the weakest link'.

I would recommend calling 928 intl, I'm sure they can talk you through a few tests to verify whether or not sending it back is an option, or if it could be something else.

JHowell37

As mentioned on the JDSporsche site having the engine run better but not perfect when the MAF is removed almost guarantees a MAF failure. Trust me I've done all of the checks prescribed everywhere, but there is something you could do for me and I'll send you a PM.