1986 L98 weird stuff
Le Mans Master
Joined: May 2007
Posts: 8,448
Likes: 27
From: Valparaiso
but if your spark has fuel there,the sparks are not firing that fuel....
ok lets do this tests :
Spark test:
- try to see if you have spark,take each spark plug cable out (one at a time) and connect a spare spark plug ,see if you have spark (start the engine and watch the little spark firing) ...if you have spark there is no ignition problem.
Injector test :
- take off the injector wire (one at a time) and put a spare injector on the wire,if the injector sound "tick tick tick" then you have good signal from the ECM... (you have to touch it to feel it)
It might be that all of your rh injectors are bad ! i had 2 bad injectors in the past
and i catched em doing the tests im telling you,then Jon at ficinjectors sold me a nice set of his injectors and problem solved !!!
Let me know the outcome of the tests
ok lets do this tests :
Spark test:
- try to see if you have spark,take each spark plug cable out (one at a time) and connect a spare spark plug ,see if you have spark (start the engine and watch the little spark firing) ...if you have spark there is no ignition problem.
Injector test :
- take off the injector wire (one at a time) and put a spare injector on the wire,if the injector sound "tick tick tick" then you have good signal from the ECM... (you have to touch it to feel it)
It might be that all of your rh injectors are bad ! i had 2 bad injectors in the past
and i catched em doing the tests im telling you,then Jon at ficinjectors sold me a nice set of his injectors and problem solved !!!
Let me know the outcome of the tests
Last edited by Calderone; Apr 25, 2009 at 12:28 PM.
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Joined: Apr 2009
Posts: 77
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From: Canisteo NY
but if your spark has fuel there,the sparks are not firing that fuel....
ok lets do this tests :
Spark test:
- try to see if you have spark,take each spark plug cable out (one at a time) and connect a spare spark plug ,see if you have spark (start the engine and watch the little spark firing) ...if you have spark there is no ignition problem.
Injector test :
- take off the injector wire (one at a time) and put a spare injector on the wire,if the injector sound "tick tick tick" then you have good signal from the ECM... (you have to touch it to feel it)
It might be that all of your rh injectors are bad ! i had 2 bad injectors in the past
and i catched em doing the tests im telling you,then Jon at ficinjectors sold me a nice set of his injectors and problem solved !!!
Let me know the outcome of the tests
ok lets do this tests :
Spark test:
- try to see if you have spark,take each spark plug cable out (one at a time) and connect a spare spark plug ,see if you have spark (start the engine and watch the little spark firing) ...if you have spark there is no ignition problem.
Injector test :
- take off the injector wire (one at a time) and put a spare injector on the wire,if the injector sound "tick tick tick" then you have good signal from the ECM... (you have to touch it to feel it)
It might be that all of your rh injectors are bad ! i had 2 bad injectors in the past
and i catched em doing the tests im telling you,then Jon at ficinjectors sold me a nice set of his injectors and problem solved !!!
Let me know the outcome of the tests
I'm going to check these after i get some lunch for my son. I will let you know how I make out. I don't have a spare injector though
Thread Starter
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Joined: Apr 2009
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From: Canisteo NY
Ok has spark on all 8 cyl. Can't check injector plug as I don't have a spare injector. I did unplug the wires and all 4 injectors on that side the rh side aren't firing. I'm not sure if they are getting a signal to them though.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
The ECM has drivers for the injectors. You did check the fuses in the passenger side dash fuse panel, right?
Do you know anyone near you who has the same ECM and can loan you their ECM just for testing? That's how I solved the ECM problem on my 86 and it won't cost you any $$.
Jake
West Point ROCKS!
Do you know anyone near you who has the same ECM and can loan you their ECM just for testing? That's how I solved the ECM problem on my 86 and it won't cost you any $$.
Jake
West Point ROCKS!
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Joined: Apr 2009
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From: Canisteo NY
The ECM has drivers for the injectors. You did check the fuses in the passenger side dash fuse panel, right?
Do you know anyone near you who has the same ECM and can loan you their ECM just for testing? That's how I solved the ECM problem on my 86 and it won't cost you any $$.
Jake
West Point ROCKS!
Do you know anyone near you who has the same ECM and can loan you their ECM just for testing? That's how I solved the ECM problem on my 86 and it won't cost you any $$.
Jake
West Point ROCKS!
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Thread Starter
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Joined: Apr 2009
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From: Canisteo NY
Is the prom the same in those computers also? I have an interchange but wasn't sure if the prom was the same. Or do I just put my prom in there.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
When the ECM on my 86 failed (wouldn't take over ignition timing) I swapped in a friend's ECM. I then knew it was my ECM that was causing my problem. So I bought a remanufactured ECM from O'Reilly's for $100 and installed my old PROM. Engine ran fine from then on.
AutoZone probably sells them too.
You could hit the wrecking yard for one, too. I bought a MAF at my local wrecking yard for $50 off a Camaro. My yard let me install and try it before I headed back home.
Jake
West Point ROCKS!
AutoZone probably sells them too.
You could hit the wrecking yard for one, too. I bought a MAF at my local wrecking yard for $50 off a Camaro. My yard let me install and try it before I headed back home.
Jake
West Point ROCKS!
Drifting
Joined: May 2006
Posts: 1,428
Likes: 7
From: Chewelah Wa
If you can get the thing to run, try listening to the injectors on the side you think is bad with a long screwdriver against your ear, you should hear them ticking as they activate, compare the noise to the other side. If the fuses are good, you might have a wiring problem or the ECM is really bad.
Burning Brakes
Joined: Jun 2005
Posts: 1,189
Likes: 13
From: Wallingford Vermont
Injector signals can be checked with a Noid light. Alot of mechanics have them, should be a quick and easy check. Maybe one of your ECM drivers is crapped.
Way back when, I had a engine low RPM vibration. An ohms check didn't look bad (cold anyway). I went so far as to do a pressure balance test, which they all passed. Out of fustration, I replaced them anyway with another used set of injectors. Voila! engine vibe gone. I surmized that even though the (bad) injectors where passing the correct amount of fuel, they weren't spraying fuel at all, rather squirting fuel at manifold wall.
My bet is your injectors are giving you a problem. If they're original '86 they're junk by now. Even the warranty replacements (multec) are ancient. Injector cleaners and alcohol additives beat the hell out of these old injectors.
Way back when, I had a engine low RPM vibration. An ohms check didn't look bad (cold anyway). I went so far as to do a pressure balance test, which they all passed. Out of fustration, I replaced them anyway with another used set of injectors. Voila! engine vibe gone. I surmized that even though the (bad) injectors where passing the correct amount of fuel, they weren't spraying fuel at all, rather squirting fuel at manifold wall.
My bet is your injectors are giving you a problem. If they're original '86 they're junk by now. Even the warranty replacements (multec) are ancient. Injector cleaners and alcohol additives beat the hell out of these old injectors.
Burning Brakes
Joined: Aug 2004
Posts: 1,174
Likes: 125
From: Dunstable MA
St. Jude Donor '05
If you are getting into the ECM and PROM, and the PO said he replaced something there, check the part number on the PROM to make sure it is the correct one. It took awhile (and a few $) after I got my '87 to find out it was running rough because it had an '88 PROM installed.
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From: Canisteo NY
Got the ECM fr another store today. One nearby had it. Put it in and wam runnng awesome. Took it out for it's first spin running and OMG! I'm impressed. I've had a 5.0 HO Mustang before and this thing would eat it alive!!!! All I have to say is WOW!!!
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From: Canisteo NY
