Calling all electrical/ignition geniuses???

[GTJAMMER]

Howdy,
I've got a wierd one for ya. 95GT, stock, cruisin' down the highway pretty as you please and then she dies. Engine quits running for three to five seconds. Then starts right back and keeps going. Check engine light comes on, but no codes. Here's the wierd thing. All the gauges stay at normal indication, except the tach, which drops to zero. So I assume I'm losing ignition, because the tach is run by ignition pulses, right? What would cause ignition to drop for a few seconds. I have a twenty minute commute, and it happens about ten minutes into the drive, drops out one or two times, then no problems. Driving home, about ten minutes in, bam, drops out a few times then is fine for the rest of the drive. I don't get it. Plugs, wires, cap and rotor, and all the obvious things ok. Let me know if you have run into this before.


Thanks, Gtjammin

 

[AznStanger3v]

the only time that happened to me was when i actually had the governor on my car (no longer ) i was topping my car out and the tach dropped to zero and i had to wait for the car to slow down and it kicked back on. i laughed my ass off on that one. i dont think you are laughing about yours though

 

[mo_dingo]

The CEL comes on because the car stalled. It's just like when you turn the key to the acc position. All of the sensor lights will come on, telling you that the bulbs are in working order.

The tach runs off of the pip module (sensor on the dist.) The tach is dropping because your motor is shut off (i.e. not making any revolutions). Does the speedometer still work?

My guess is that something is shutting down temporarily. Like the fuel pump, or the coil. So you ran the codes, and nothing came up? I guess that is a good sign the emmisions stuff is in working order.

I would test the fuel pressure first. Then hook up a vacuum gauge and see if it remains steady at the correct reading range. When was the last time you did a tune-up? If the wires/dist cap haven't been replaced in a while, you might think about that.

Remember, it's probably not one of the emmisions sensors (i.e. MAF, IAT, ECT, EGR, smog pump, O2's, ...etc). A code would have likely been thrown if it was.

My guess is look at the simple things. If the fuel pump isn't 100%, it could be failing temporarily, causing the motor to stall. A sudden stall like this is most definately something serious; integral to the car running properly. Ingition coil maybe. You can disconnect the MAF/ECT/IAT/O2 stuff, and the car should still run. Albeit not very well, but it should still run.

My truck sort of did the same your car was doing when the fuel pump went bad. But mine wasn't so consistent. Also, look to your distributor, as it could be the cause.
Scott

 

[Hef5.0weisen]

Ironically I was about to run an airplane earlier tonight at work, but #3 engine wouldn't start, bad ignition exciter. Guy I work with, started talking about how his truck (302 F-150) use to cut off like your car, wound up being an ignition module. I may be wrong but I belieive its under the air intake ducting on our cars, little metallic box with cooling fins, good luck

 

[tmoss]

I would suspect the TFI module, the distributor pickup coil, or the coil in that order. The tach gets it's signal from the TFI module which is controlled for ignition by the pickup coil and the computer.

 

[The Hitman]

Funny my car is doing the same thing (SEE POST "COULD THIS BE AN INGNITION OR COMPUTER PROBLEM")! So it could be the TFI, the PIP or the Coil.. hmm..

I was figuring these things earlier..
there's no way it could be the computer itself could it?

 

[tmoss]

It's not impossible that it's the computer, but most likely one of the other things.

 

[madams74]

Go for the pickup in the distributor and then the ignition module. The ignition modules seem to be pretty bullet proof in our cars. ALSO while the engine is running, try moving some of the wiring around the distributor by hand and tap on the module. It may be a broken wire or a cold solder joint.

 

[The Hitman]

That's the first thing I did. I wiggled every wire in that car. Nothing. So I'm guessing it's the part itself. I also tapped the module and nothing happened.

 

[The Hitman]

How are the MSD distributors for our cars?