DFI and ECMDiscuss all aspects of DFI (Digital Fuel Injection), ECMs (Electronic Control Module), scanners, and diagnostic equipment. Fine tune your Third Gen computer system for top performance.
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I have a 1990 Pontiac Firebird Trans Am GTA, with the 5.7 liter V8 (tuned port injection), automatic transmission, and 44,000 miles on it.
The car does not idle properly. It varies from idling too fast, sometimes up to 2000 RPM's when sitting in the driveway, or when I drive it, it can stall out at every stop sign and red light. At other times, as when I drove it for its emissions test, it acted perfectly, with no idling problems or stalling out.
This problem started when the battery, while connected to the car's cables, got wet with a bucket of water. About an hour after this happened, the car would not start, unless I put my foot on the gas pedal and gave it gas. When I took my foot off, the car stalled out. The above listed behavior started as well. Before the water, there was no sign of this problem at all.
I think that the computer was damaged, or shorted-out, somehow. I've heard that if you reverse battery cable clamps when jump-starting a car, that you can damage the computer.
Since water can conduct electricity, I thought that somehow the water caused the current to jump improperly. The car did not have this problem until the water spilled on the battery. Some people have told me it could be a "bad ground", but how could a "bad ground" cause a problem so fast?
I have had the car checked, and had parts replaced, but the problem continues. The idle air control valve, coolant temperature sensor, throttle position sensor have been changed. No luck. The car shows no problem codes, but it does show Code 12 when the ALDL is grounded.
The "Check Engine" light has NOT come on while I have been driving or running the car, but the light does work, appearing, then disappearing, when I first start the car like it is supposed to.
They've told me it could be a vacuum hose problem, but no problems were found.
Mechanics have told me that water can't damage a computer, because they wash dirty terminals with water. They also tell me that there is NO WAY that a car can have a damaged or defective computer, WITHOUT SHOWING A TROUBLE CODE. Other mechanics have told me that a computer CAN BE defected or damaged, and yet NOT show a trouble code.
I am running out of mechanics and ideas. I don't know who's right or wrong. I am reluctant to go to the Pontiac dealership, for fear I'll be ripped off, and still have the same problem with the car when I leave. I have had a couple of bad experiences at dealerships, with another car I have.
If my computer has been damaged, do I install a new computer and new PROM together? If the original computer has been damaged, how do I know whether the original PROM is damaged or not?
Does anyone have any suggestions?
Thanks in advance!
Tony:confused
well i would vote no for water touching the batter causing a dead ECM. i spray down my whole engine bay quite often to wash it and that includes the battery getting a good direct spray to wash away any acid that may leak.
i can see a dead ecm would not put out trouble codes, i mean if it fried, how can it say so?
its like a dead guy telling us all he is officially dead.
