Engine Won't fire.

[dracosix9]

I need a little help here. I purchased an 86 Ranger not to long ago. Ran fine for about a week then I notice it would miss every once and a while when Idling whether hot or cold resulting in a little engine rock. Then about two weeks after this started I was coasting down the ally behind my house when I went through a puddle and hit a pot hole that was hidden by the puddle. About three seconds later the engine just died outright, no sputtering or ruff idle nothing just stopped firing like I had turned it off. Now I can't get her to fire no mater what I try, and I've tried a lot.

I've checked for fuel pressure. OK
Injectors are Firing.
No Spark at Plugs when turned over.
No Spark at Coil when turned over.
12V on both sides of Coil with key on.
Coil Resistances are good.
Harness rings out good from coil to ICM.

And today I pulled the ICM off the distributor and measured the resistances as per the diagnostics page. All resistances are slightly higher/lower than what is listed as Min/Max. The only thing that Didn't ring out was the backplate to any terminal, (not sure if it is only for heat sinking purposes or to provide grounding), reads as an open.

I'm pretty sure it's the ICM but I'm not sure as the one I got at the reckers is ringing out almost identically to the old one. Any help you can give will be greatly appreciated.

 

[IMenriched]

I need a little help here. I purchased an 86 Ranger not to long ago. Ran fine for about a week then I notice it would miss every once and a while when Idling whether hot or cold resulting in a little engine rock. Then about two weeks after this started I was coasting down the ally behind my house when I went through a puddle and hit a pot hole that was hidden by the puddle. About three seconds later the engine just died outright, no sputtering or ruff idle nothing just stopped firing like I had turned it off. Now I can't get her to fire no mater what I try, and I've tried a lot.

I've checked for fuel pressure. OK
Injectors are Firing.
No Spark at Plugs when turned over.
No Spark at Coil when turned over.
12V on both sides of Coil with key on.
Coil Resistances are good.
Harness rings out good from coil to ICM.

And today I pulled the ICM off the distributor and measured the resistances as per the diagnostics page. All resistances are slightly higher/lower than what is listed as Min/Max. The only thing that Didn't ring out was the backplate to any terminal, (not sure if it is only for heat sinking purposes or to provide grounding), reads as an open.

I'm pretty sure it's the ICM but I'm not sure as the one I got at the reckers is ringing out almost identically to the old one. Any help you can give will be greatly appreciated.

take to your favorite parts store (ICM) test there...test min of 3times

look over connections really well don't forget the grounds everywhere
there should be a inline resistor to/from the coil

 

[450rwhp]

i had a problem similar to this. turned out to be the ground wire on the side of the coil was badly corroded.

 

[dracosix9]

Well I had the old ICM and the replacement from the wreckers tested three time each. Both passed, *hangs head low* now I'm going to have to find the poor hot/cold connection that is causing all these problems.

Could the bad connection have caused the intermittent missing at idle also? Again any help is welcomed and appreciated.

 

[kimcrwbr1]

Yea especially intermittent problems like was said go throught and check all the wires and connectors especially the grounds take the grounds apart and clean/sand them and put them back together. You can try starting it after each one to determine which one is bad for us or future reference if in fact that is what the problem is. start there and be complete it dont cost nothing and your eliminating a possible variable to another condition.

 

[dracosix9]

Anyone have a factory wiring diagram or at least one that's half decent? I have the Haynes tear down book but the electrical draws are the shits. Any help would be awesome.

 

[IMenriched]

Anyone have a factory wiring diagram or at least one that's half decent? I have the Haynes tear down book but the electrical draws are the shits. Any help would be awesome.

Its right here at TRS in the tech Library
http://www.therangerstation.com/tech_library/EDiagrams/index.htm