let play the diagnose my EFI game!

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let play the diagnose my EFI game! #1036074 10/14/11 09:20 PM

Joined: Dec 2010

Posts: 16

Roseville, MN U.S.

McAdam

Need a Spot

I have an 89 montero, v6 5 speed. engine is tired, but still runs. kind of. It starts off running on all 6, then at some point, just stops firing on #2. no spark coming from the dist cap or the wires.

I have tried diff ECUs, wires, spark plugs, coils, distributors, everything I can think of ignition related, but it just wont fire on #2 after it gets warmed up. and the spark when cold is super weak when cold.

If I had all the money I've ever spent on cars, I'd spend it all on cars.

Re: let play the diagnose my EFI game! [Re: McAdam] #1036075 10/14/11 10:43 PM

Joined: Sep 2011

Posts: 628

Castle Rock WA, US

geocrasher Offline

Rock Warrior

I don't know, but keep in mind that resistance goes UP with temperature. So, nothing is really changing except that you've got a weak spark. Its so weak, in fact, that a minor temperature change (increase in resistance) causes complete loss of spark.

1987 Raider, 346K miles and going strong -31" tires, otherwise stock.
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Re: let play the diagnose my EFI game! [Re: McAdam] #1036076 10/14/11 11:33 PM

Joined: Apr 2006

Posts: 228

SF Bay Area

Chief

Wheeler

If its misfiring on one cylinder only and only at certain times not the rest, then it has to be something with that particular cylinder or path of spark travel.

1) You didn't mention repalcing the distributor cap?
2) You could have low compression.
3) One of the valves could be sticking open.
4) Are somehow fouling that spark plug i.e. fuel injector staying open. Any gas or oil on the plug?
5) Or the oposite where injector is staying closed and no fuel is getting into the cylinder.

Good luck <img src="/forums/images/graemlins/patriot.gif" alt="" />

'89 Raider V6, AT, SAS'ed, Dana 44 front & rear, 5:38 gears, NP 231 T-case.
'97 Montero SR, cold weather package, 4.90 R&P, BATTLEZ suspension w/ 2" lift, JAOS grill guard & under body protection, custom rock sliders.

Re: let play the diagnose my EFI game! [Re: Chief] #1036077 10/16/11 09:50 PM

Joined: Jan 2001

Posts: 13,649

Helen , GA

fasteddy

Web Wheeler

Have you checked the spark while it's cold? Have you checked for contstant spark from the coil?

Open the ecu case and check for fishy smells and leaking capacitors.

I also suspect a heat conditional failure of an electrical component, like an injector driver or ignition driver in the ecu. I would also check for trash in the dizzy optical wheel area.

Not responsible for advice not taken...

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