So my 89 t cab is running fine. Last week, I go WOT in 1st, shift to 2nd at redline, get into 2nd at 5200, full on and... (discontinuity) ...and now we're at 4000 climbing back up. It was if the ignition failed for 100 millis. Dashboard lights up like at startup, and the ABS light stays on. Startled, I drove her around for a while not at WOT and everything was perfectly normal. I tried again on the West Side Highway. This time, the discontinuity occurred at WOT between 2nd and 3rd. Kinda shook the poor girl, too. Today, I disconnected the battery and went the through the ECU reset process -- start cold, touch nothing for 10 mins, etc. Took her out and sure enough, a very brief but complete loss of power at WOT at high RPM in 2nd. Motronic issue? First time she's done this.
I don't know much about the t as of yet so I will be watching this thread to see how it turns out. Could it have something to do with the voltage regulator? Or a bad ground somewhere? I doubt it is an ECU as they are completely independent of each other, with the exception of the crank sensor. Good Luck, dave
Hey Buzz & Dave, First off, Happy New Year. Second off, check both coils. It happened to me............ Cheers, Hank
sounds like a power or ground issue.... check all the basics, most likely somthing loose. also, note these cars are known for fusebox faults. regards, Jim
Did it feel like a complete shutoff? If so look at spark, fuel is a more 'gentle' misfire. Hard to tell though without; A) using an oscilloscope to capture the various input and output signals B) being able to re-create the misfire Remeber that that vehicle has 2 crank sensors and 1 cam phasor. The cam phasor times the fuel delivery and is not related to the the spark timing.
Thanks man. My next step was to go over the basic electrical connections on the wiring loom back there. How would the fusebox factor in here? The problem seems to be high-load-RPM transient. A fusebox problem would seem less transient. Under less than WOT and high RPM, she runs beautifully.
First round of probing and examinations yields no obvious problems. Fusebox and major grounds look good. Moving on to coils and sensors to the ECU. The problem is completely reproducable with the engine under load, and it seems less of an RPM issue, perhaps. I pulled away from a stop light and got off the clutch a little too fast, started to bog down, applied the throttle and blip! Discontinuity, dashboard lights up, ABS light stays on. Steve Arena was able to reproduce the problem at the higher RPMs original cited. The event is very transient -- not more than 100 millis -- and really smacks of an ECU reset of some kind.
For those tracking this thread -- she's still got the problem. No clear solution. I suspect it will end up being something depressingly obvious in retrospect.
Not the ECU. A wire going up into the dashboard was slightly loose. Under acceleration, it would shift a bit -- and the problem would occur. It was not RPM, it was simple force dynamics. Chances are if I had hit the brakes hard, the same thing would have happened. All connectors were checked and the terminals cleaned. The recent motor-out service was a red herring in all of this. I don't know exactly which wire it was (confession: I didn't do the work). But the important thing to know is that beyond the obvious ignition leads, ECU leads, and fusebox connections, the Mondi t has a bunch of important terminations and gangings just behind the dashboard.
Glad you found the trouble. I was under the dash recently and saw all kinds of wires, busses, and fuse/relay blocks. All I could think of was that if anything ever goes wrong under here, I'll never find the problem. Dave
