car dying for no apparent reason

caninelver · 05-29-06, 10:25 PM

Last week I put a new battery in since the old one was dead most of the time over the winter. Yesterday I drove it to work as a test prior to B.G. I have a 105 mile commute and figured that would give it a good workout. About 20 miles from home it died but the check engine message never came on. It started right up and a couple miles later did it again. I had to crank it several times but it started and the pedal went to the floor by itself and the engine was racing. Before I could turn the key off it went back to a normal idle. I'm thinking I might have water in the gas because if it was an electrical problem it would have thrown a code. After that it drove fine for the rest of the trip. The battery checks out ok. Now I'm a little nervous about the trip to B.G. Other than bad gas I don't know what else to check. Anyone have any thoughts on this?

LT4man · 05-29-06, 10:31 PM

Denny, that's a good one.

Very puzzling. Sounds like a glitch. Might not be anything at all. I have seen stranger things happen.

SAVE THE WAVE!

caninelver · 05-29-06, 11:33 PM

Yeah, I am not going to worry too much at this point. If it lets me sit Thursday, I'll hitchhike the rest of the way. Got to eat at Roscoe's.

6speeder · 05-29-06, 11:48 PM

I think you can rule out contaminated fuel as your problem. Fuel symptoms would be random missing, hesitation, loss of power, etc., not a complete shut-down. It sounds more electrical, even though the SYS light was not displayed. As a test, turn your ignition to 'on', and notice if the SYS light flashes. It is possible the bulb may be burned out.

Since all worked well after the first two engine failures, it will be difficult to diagnose your problem, unless there are some history codes.

John Robinson · 05-30-06, 07:10 AM

You might want to look at this information and do a test of the TPS. Stranger things have happened and even though the TPS is supposed to code it may not.

Throttle Position Sensor

The scan tool displays throttle position in volts. The voltage should display between .23 - .59, with throttle closed and ignition “ON,” or at idle. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT) about 4.6 volts.

The ECM has the ability to Auto-Zero the TP sensor voltage if it is between .23 and .59 volt. This means that any closed throttle voltage between .23 and .59 volt will be determined by the ECM to be 0% throttle angle, and should display 0% when the throttle is closed. A failure in the TP sensor circuit should (MY OPINION MAY NOT )set a DTC 21 or 23.

Copied from the service manual for a 93 model
I just spent $600.00 bucks finding out the TPS was bad and not coding. By the way the sensor I had was an after market sensor I went with the good old AC Delco OEM part this time. The symptoms I had just before failure were when I started the car the idle was up around 2k and I got a ASR service code on the display. The next time I went to start the car it cranked but would not start. It finally caught and ran on high idle until I got to a garage to have a diagnostic run. After shutting down the car it would not restart and DID NOT have any codes at all. The garage immediately said the opti was bad. Had car taken to another garage and they determined the ECM was bad. New ECM car still would not start I asked mechanic if the car had spark he said yes and also fuel. We sprayed choke cleaner into the throat of the throttle body and it backfired and then started to run. The TPS was telling the injectors to shut down because it thought the engine was flooded and needed to crank at WOT without fuel to clear itself. AT this time it was running with a high idle. Mechanic immediately crabbed a new TPS and put on car it it settled right down and has run perfect since. Your problem may not be the same as mine but I love to tell the story just in case someone else gets caught in the box like I did.

caninelver · 05-30-06, 03:52 PM

Thanks for the input. I'm kind of doubting that its the gas myself. A guy I work with has been building hot rods in his spare time for about 40 yrs is telling me that he thinks it is my coil starting to go bad. He's got me so worried about it that I'm going to put a new one in tomorrow just to be safe. I called chevy, they want $75. Napa wants $47 for the same thing. Napa wins.
John-what the heck are you doing on here at 7:10am. You are a dedicated CACer!

John Robinson · 05-31-06, 06:28 AM

In 1956 I had a 55 Oldsmobile. I had it tuned up with new plugs, wires, distributor cap, condenser, and coil , and timing. I had the garage put all the old stuff in a bag in the trunk and left Detroit for Parkersburg West Virginia. When the car got warmed up it would not run over 55 MPH and would hardly pull the hills down south. Got to Parkersburg found a garage with a new sun machine and we spent about 4 hours trying to find the problem. Finally out of desperation we started to put back the old parts to see if we could find the problem. The first thing we changed back was the coil and bingo the problem was solved. That's when I learned that new is not always better and the old saying it either works or it quits did not hold true for coils. Put the new coil on but keep the old coil with you with the tools to change it back if necessary. I vote for the old guys idea.

Yes it is early in the morning but I have not been able to break the habit of getting up for work since I Retired in 92. Some day I may sleep in until 8.

WhalePirot · 05-31-06, 09:06 PM

My '72 ran/shutdown totally, due to a clogged fuel filter. It restarted, after a rest then ran for a shorter period. While this may not be your issue, I would pack a fuel pressure gauge until I knew for sure.

kenwa · 05-31-06, 09:16 PM

Quote:

Originally Posted by caninelver

Last week I put a new battery in since the old one was dead most of the time over the winter. Yesterday I drove it to work as a test prior to B.G. I have a 105 mile commute and figured that would give it a good workout. About 20 miles from home it died but the check engine message never came on. It started right up and a couple miles later did it again. I had to crank it several times but it started and the pedal went to the floor by itself and the engine was racing. Before I could turn the key off it went back to a normal idle. I'm thinking I might have water in the gas because if it was an electrical problem it would have thrown a code. After that it drove fine for the rest of the trip. The battery checks out ok. Now I'm a little nervous about the trip to B.G. Other than bad gas I don't know what else to check. Anyone have any thoughts on this?

The coroner would call that "Natural Causes".

Sorry, couldn't resist...

MoeJr · 06-03-06, 12:15 AM

Disconnect the cruise control from the throttle body. My Grandmothers 88 Turbo New Yorker gas pedal would go to the floor on its own once in a while. Ended up being the crusie control was activating on its own.