Hi all,
My E30 threw a CEL and died on the way to work today. Luckily, it was just a mile short so I could walk here. I'm hoping for a little help diagnosing so I don't have to call a tow truck, pay a shop to diagnose & fix, etc.
The car is a 1991 318i chassis with an M52/S52 cams, OBD1, Conforti intake with 540i 3.5"MAF, and M50 computer with Chuck Stickley software.
Background:
A couple of times recently, I'd be driving along happily (usually on the freeway or after some time at higher speed/RPM), the CEL would spontaneously come on and the car would begin running very unevenly @ anything below 3500RPM. Poor, uneven idle, no power at all until 3500RPM or so, then pretty strong in upper rev range. Then after a short time driving, it would clear itself up, CEL would turn off, and it would be back to normal.
Today:
Same behavior on the way to work. Car drove great all the way through the freeway portion of the drive, then threw a CEL and began running poorly after exiting the freeway. Then suddenly one mile from work, it began to bog down in gear and I knew it was time to park it. After stopping, the car would repeatedly turn over and catch, then die again. If I tried to give it gas when it caught (even if I left the starter engaged), it died as if flooded, but I wasn't smelling excess gas.
The real bad news is that I just ordered a Peake Research R5 FCX-III Fault Code Reader yesterday, and it's not here yet - the problem beat me to the punch
I'm thinking it's the used 540iMAF I put on the thing, intermittently failing. Can a bad MAF cause this problem? Doesn't the car have a default fuel/air map it can run if the MAF fails? What if I just unplug the MAF entirely - won't the computer detect that it's not receiving a reference voltage and go into closed loop? Then it would run poorly (and quite lean I surmise), but at least run. Could the temp sensor for the DME cause such a severe problem? What else?
BTW, I can't believe that it's a spark issue, because the car only intermittently has the problem. The plugs are new NGK's, gapped correctly. Also, the fuel pump & filter are new, done at the swap (besides, it's behaving like it has too much fuel - not the other way around).
What do you experts think? Thanks in advance for any help.
My E30 threw a CEL and died on the way to work today. Luckily, it was just a mile short so I could walk here. I'm hoping for a little help diagnosing so I don't have to call a tow truck, pay a shop to diagnose & fix, etc.
The car is a 1991 318i chassis with an M52/S52 cams, OBD1, Conforti intake with 540i 3.5"MAF, and M50 computer with Chuck Stickley software.
Background:
A couple of times recently, I'd be driving along happily (usually on the freeway or after some time at higher speed/RPM), the CEL would spontaneously come on and the car would begin running very unevenly @ anything below 3500RPM. Poor, uneven idle, no power at all until 3500RPM or so, then pretty strong in upper rev range. Then after a short time driving, it would clear itself up, CEL would turn off, and it would be back to normal.
Today:
Same behavior on the way to work. Car drove great all the way through the freeway portion of the drive, then threw a CEL and began running poorly after exiting the freeway. Then suddenly one mile from work, it began to bog down in gear and I knew it was time to park it. After stopping, the car would repeatedly turn over and catch, then die again. If I tried to give it gas when it caught (even if I left the starter engaged), it died as if flooded, but I wasn't smelling excess gas.
The real bad news is that I just ordered a Peake Research R5 FCX-III Fault Code Reader yesterday, and it's not here yet - the problem beat me to the punch
I'm thinking it's the used 540iMAF I put on the thing, intermittently failing. Can a bad MAF cause this problem? Doesn't the car have a default fuel/air map it can run if the MAF fails? What if I just unplug the MAF entirely - won't the computer detect that it's not receiving a reference voltage and go into closed loop? Then it would run poorly (and quite lean I surmise), but at least run. Could the temp sensor for the DME cause such a severe problem? What else?
BTW, I can't believe that it's a spark issue, because the car only intermittently has the problem. The plugs are new NGK's, gapped correctly. Also, the fuel pump & filter are new, done at the swap (besides, it's behaving like it has too much fuel - not the other way around).
What do you experts think? Thanks in advance for any help.
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