I have a 1991 Geo Tracker which dies on a random basis. I have replaced the main relay, the fuel pump relay, distributer cap and rotor and finally the ECM. It still dies on a random basis. Any one have any ideas?
When it dies you need to at least narrow the cause down to fuel or spark. My WAG would be fuel pump if its not getting fuel.
My first thought is electrical
shake the wiring harness while it’s running, maybe you’ll find a broken wire somewhere.
I did not go into all the detail of what I had already done. I removed the fuel pump and tested it and it was working fine. The problem was not fuel and when it dies the tack drops immediately. I have also replaced the fuel pump relay and the main relay.
Does it shut off suddenly or does it sputter and die? Is it hard to restart?
I had problems with a car that would cut out for a second or two and then go as if nothing had happened, or if it happened at a stoplight, it would die but easily restart. Sometimes went weeks without missing a beat, then would drive me crazy for a day.
Adding Heet fuel drier to the fuel tank appears to have solved the problem.
Although I’m not familiar with the Tracker, the problem you describe is common to many vehicles and is most often a cam and/or crank position sensor. When one of these sensors drops out, the engine quits. Some cars will throw a code but others do not. These sensors cause random stalling and performance lag.
A fuel pump can certainly die on a random basis so the act of removing it and checking it may not mean anything.
Without knowing if the problem is lack of fuel or spark and if the assumption is made the problem is not the fuel pump then a faulty ignition switch could be considered.
Often, but not always, if it sputters a few times before dying it’s related to a fuel (or lack thereof) problem. If it shuts off instantly with no hiccup at all then it point to a lack of spark, as in ignition module, ign. switch, etc.
The car does not sputter at all. It simply dies and the tack drops like a rock. I have subsequently attempted to replace the crank position sensor. It is in the distributor in this car and I could not find one available so I have replaced the entire distributor. I am in the process of setting the timing back up.
I have had a couple of mechanics here who came to the same conclusion. So I tried to prlace the crank position sensor but found none available from my resources so I purchased a rebuilt distributor and have installed that. I am still in the process of setting the timing. If this solves the problem I will let you know. Thanks for the input.