Long story short, bought this 1990 bronco. Wouldnt start when i was looking at buying it. (helped me on the firm price he had) but it had spark. So rebuilt the upper end cuz head gaskit was leaking. Post rebuild still no start but had spark. Replaced all the relays, map senc. stator and computer. It started, ran for 10 mins(just had time to set timing) and just shut off like someone turned the key off. Checked for spark no spark. replaced coil and ICM. Started run for 10 mins and was running damn good an then shut down again. Checked for spark, No spark. Im out of ideas, please help me start to sleep at night again!
Before doing anything stupid and expensive, like replacing the distributor, start with the simple things, you already pointed at something, the key-switch, then, since you say you have spark, you might be missing fuel, have you checked the fuel pressure?, have you checked the fuses?. Anyway, as the usual procedure with our trucks, get the codes first to see what does the ECU have to say.
Pull codes then check grounds by disassembling and seeing if the ground stud is loose in the fender at the battery pigtail and by the code checking connector. I am not sure but suspect the 92+ uses the black ICM.
i rebuilt the distributor, had to when i changed the pickup when it wouldnt start after the rebuild. I thought the pickup was bad so replaced it. At the same time i replaced the relays and the pigtails, the ICM (gray). Still no start, pull computer and it was fried(burnt fried) so replaceing the EEC it started. Thats when it started with the 10 min and stall. Replaced coil, and another ICM, ran and then 10 mins click stopped. I dont have a obd1 tester, so jumped plug and got no codes, but a buddy is loaning me one this wekkend ...just to double check ..b4hntn ill check thoughs grounds. Thanx guys, any ideas is one step closer to helping me at least getting to drive this BEAR..
This is warm up , heat related then no spark. Rules out the ACT and ECT because they would just run badly.
Wild guess 1. I believe the 1990 had a push start, (grey ICM) circuit which means there is a resistor between the ICM and the computer somewhere.
Wild guess 2. PCM. If you replaced the computer with anything other than the same number it may cause problems. If you replaced it with a used one I may have the same time, temperature and vibration issues the original one had. See ECMTOGO.com for details. They might test yours free. I have had repaired or replaced my ECM, air bag, and overhead module temp/compass boards and mine is only a 94 and 17 years old. What electronics do you own that old that still work?
yep, gray one. tested resistor it seem to be in specs. I did replace the comp. Its a reman., i made sure the numbers were the same. I think im going to pull the distributor and replace the pickup again. I think i grabed the cheapest one i could at the time, hope thats not bitting me in the tailgate
Might be a feedback circuit that is causing the pickup to repeat fail due to the incompetence of some part that is not being replace during dist rebuild, see post #2, indicating to replace all parts of dist that are electrical.
Hey. Try testing the Fuel Relay. It has to have power run through it to feed the EEC. Which will then feed the ICM
Power if your ignition is working. There are some great write ups here to help http://easyautodiagnostics.com/index_ford_4.9L_5.0L_5.8L/index_of_articles_1.php.
To me it sounds like a component or a connection should be getting hot, check wiring on the fender after it dies, at the coil connection and on the distributor. It's not likely but maybe the resistor is failing, test ohms after it shuts down maybe? You did use a dielectric grease on the TFI module when you installed it right? I seen something similar because ASE mechanic didn't. The TFI failed within the week.
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