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'86 MJ 2.5L Starting Issues

sureshot007

NAXJA Forum User
Location
Kenmore, NY
1986 MJ Longbed
2.5L TBI

Car has been torn apart by previous owner for racing. So anything is possible...

Issue: Will not start by itself. If you squirt a shot of starting fluid in the throttle body while cranking, it fires right up and runs just fine.

Troubleshooting performed:
1) Checked resistance across the injector, injector harness, diagnostic connector and ecu plug and all is within spec according to the FSM.
2) Replaced fuel pump anyway
3) Replaced ECU anyway

There is fuel coming out of the inject while it's running, you can see it. Spark plugs and wires have a few hundred miles on them. Battery is less than a year old, and holds a charge just fine. Also tried jumping it as well, just in case. It was starting fine before the head came off. Bad head gasket was replaced, and the head was taken to NAPA for them to freshen up. Reinstalled, and here we are.

Does anyone have any ideas what else I should check?
 
There must be a temperature sensor (likely on the intake manifold) to tell the computer to richen up the mixture when cold. This is the same as a choke on carburetter engine. Your FSM should tell you what the resistance should be at a given temperature. Often systems will have two of these sensors, one in the intake for air temp and one (maybe in the block?) for coolant temperature. You might even be able to swap these to get it to start up without spray start, but testing with your meter is the best.

It could even be the connection to that sensor or the wires to it.
 
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