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i have a 4 cyl. 1992 merc topaz. it would turn over but, not start. i have had it at a garage for 3 weeks. i was told the mechanic replaced and or checked everything possible. they called me and told me to come and pick it up. they are giving up and cannot fix the problem. does anyone have any ideas that could be a solution ?????
they supposedly checked fuel pump, changed control module and plugs and distributor
Glad to be of help. I seriously doubt the mechanic replaced or checked everything. You need a new mechanic. Here is what you need to check: First check compression. This will tell you if you need a timing belt. Compression should be 125 or better and not have more than 20psi difference between best cylinder and worst cylinder. If compression is below 75psi, replace timing belt. Next, Check for spark at plugs. If you have spark at plugs your electrical having to do with spark is all fine and no need to check any other component. However if there is no spark, check with test light to make sure you have 12 volts at coil+ and if so, check at coil- while cranking and look for pulse flash on-off-on-off. If test light flashes, your coil is bad. If test light does not flash the problem is coil pick up, cranksensor and or ignition module. If you have spark at plugs all those things are ok. Next check fuel pressure. If fuel pressure is within specs, check with noid light at injectors. If you have pulse flash while cranking this is ok as well. If no pulse flash, the problem is cam sensor, or ECM.
Check for codes.
Let me know what you find out and I will continue to help you.
I'm switching to Q&A format to be notified of your reponse.
Let me know if you have spark at plugs, fuel pressure and compression and codes if any. If everything mentioned is ok, the problem could be your MAF sensor. Here are some links for testing and cleaning MAF sensor.
Ford MAF Sensor Testing-videos
Cleaning Ford MAF sensor
thanks for the help. I am not very tech savy with autos. this is an ongoing process as i am trying to keep my college student son with something to drive. i will try to check the spark at the plugs as soon as possible. i hope i can continue our conversation then.
a little background. i had it at a local garage for over 3 weeks. the owner finally called me and told me that they did not know why it would not start and to just come and get it. it is like i said a 1992 topaz but, only had about 70,000 miles on it when my sons grandmother gave it to him. it was a good vehicle for about 6 months when one day he drove it from work to lunch. it sat about an hour and when he got back in it to drive back to work it would not start. it would turn over but, not start. he let is set there over night and when he got in it the next day it started right up. he drove about another month. then one day it did the same thing and now will not start at all.
again, thanks for the help. i hope i can get back to you after i check for spark at the plugs.
Be sure to check codes and check compression. We can continue until problem is solved. Let me know what you find. What sub model Topaz is it? GS,LTS,sport,XR5? Is this engine vin x? It sounds more like an intermittent problem with MAF sensor. Checking codes will help to narrow it down.
thanks, XXXXX XXXXX get back to you
just thought you might like to know that i took the car to a different mechanic. he fixed it in 2 days. said that it was an issue with the distributor and timing mechanism. thanks for your help