Issue with new fuel injectors

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01-19-2019, 11:14 PM

Tom Jackowski Jr.

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Year: 1992

Model: Cherokee (XJ)

Engine: 4.0

Issue with new fuel injectors

Hey guys, I installed the 703s in my 92 XJ today and I’m having an issue. On my first startup it was running rough so I disconnected the battery and let it sit for an hour to reset the pcm. When I tried again it ran a bit better but still not great. When I rev it, it shakes pretty bad. Also when I put it in drive it sounds like a bit of a knock now. Never had this problem before with the old injectors. Anyone know what could be going on? I know the injector wires are in the right places I lableled them

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01-20-2019, 07:34 AM

Cummins93

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Year: 1995

Model: Cherokee

Engine: Turbo 4.0

Make sure all injectors are firing. With a screw driver to your ear listen to each injector click. If they are disconnect the coil, pull the rail off and visually check that all injectors are firing. Be absolutely certain the right plug is on the right inj.

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01-20-2019, 08:03 AM

cruiser54

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Year: 1990

Model: Cherokee (XJ)

Engine: 4.0

And make sure you didn't booger up the line from the intake manifold to MAP sensor.

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01-20-2019, 08:14 AM

Tom Jackowski Jr.

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Year: 1992

Model: Cherokee (XJ)

Engine: 4.0

Quote:

Originally Posted by Cummins93

Okay I’ll give that a shot this morning thanks.

Quote:

Originally Posted by cruiser54

And make sure you didn't booger up the line from the intake manifold to MAP sensor.

Yeah that was the first thing I thought of when it happened but the line is good

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02-09-2019, 09:07 AM

XRs&XJs

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Model: Cherokee (XJ)

What was it? Did it just need to go through the 50 starts for pcm to re learn? I seen you have a 92 not sure if obd1s do that.

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02-09-2019, 09:47 AM

Tom Jackowski Jr.

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Year: 1992

Model: Cherokee (XJ)

Engine: 4.0

I think the ECU had to relearn. Throttle response is great now and drives great, but my idle is a little choppy. Truck shakes a bit at idle. But I think that might have more to do with the cracks in my exhaust manifold causing a bad idle

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