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4.0 Not Starting After Swap


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Hey all I had a running 4.0 out of a 92 cherokee I pulled to put into my Comanche. I've finally got everything buttoned up at least so I think, and when I try to crank it over to start it all it does is just crank, not even a thought of starting.

 

so far what I've done to try and remedy this is.

 

Checked Ignition coil for Spark, Got it

Checked Spark plugs for Spark, Got it

Checked Fuel Rail for Fuel, Got it

Replaced Spark plug wires

Replaced Spark plugs

Battery Charged up

 

 

 

 

Now this was my first swap and I've looked at vacuum diagrams and believe I have everything in the right place,  Although I do have one wire on my passenger side thats quite long and doesn't have a home..

 

So far what I'm going to check is

 

Compression test

leak down? if I can figure out how.

 

And what I'm thinking of replacing is

 

new Distributor cap

New CPS

 

 

 

Does anyone have any ideas what else I can do to try and remedy this? Also my fuel gauge isn't reading after I swapped from Idiot lights to a new real gauge Any ideas on that and if it can be leading to my problem? I still have two wires to connect on my HO harness to Rear MJ harness, one is for my brake lights and the other is connecting to my Ebrake.

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If you have spark you don't need a distributor cap or a CPS.

 

Did you have the distributor out? If so, are you certain you reinstalled it in the correct orientation?

 

What year is your MJ? The CPS and flywheel changed in 1991 to go with the HO's Chrysler ignition and injection. If you use an HO flywheel and CPS with a Renix ignition and injection, it won't work. Do you have a noid light? Do you know if the injectors are squirting? Have you tried starting it by dribbling gasoline directly into the throttle body?

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If you have spark you don't need a distributor cap or a CPS.

 

Did you have the distributor out? If so, are you certain you reinstalled it in the correct orientation?

 

What year is your MJ? The CPS and flywheel changed in 1991 to go with the HO's Chrysler ignition and injection. If you use an HO flywheel and CPS with a Renix ignition and injection, it won't work. Do you have a noid light? Do you know if the injectors are squirting? Have you tried starting it by dribbling gasoline directly into the throttle body?

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Thanks for the replies, My comanche is an 89, But the Motor, Flywheel are from a 92, and the ax15 is from ~95-96, Injection system is 92, and by ignition system I'm assuming you mean the Coil? Which is also from 92.

 

When I swapped my  cherokee over I took Everything I possibly could, I changed the messy renix wiring system to the 92 fusebox, and inside the cab I took the steering column, inside fusebox everything except the main dash piece.

 

So if I have spark that means my CPS is working correctly right? Had a thought last night that I might have used the wrong CPS(renix) on the new(er) engine.

 

Distributor was never taken off either, I don't have a noid light (the electrical tool correct?) , I know my fuel rail has fuel and pressure, but not sure if the injectors are injecting it, and I haven't tried putting gas or starter fluid in the throttle body. I'll attempt to check the injectors and put some fluid in the throttle tonight! hopefully something works.

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so good news! well maybe.. 

 

After using starting fluid in my throttle body it fires up pretty easy, but only until the fluid is burnt off then it dies. So what does that mean? Injectors aren't injecting fluid? bad injectors? They worked fine about 4-6 months ago when I pulled the engine can they go bad for just sitting there?

 

 

 

 

Ballast resisitor is connected, but does it need to be screwed down? does that ground anything?

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Ballast resistor is an inline voltage dropping resistor used to quiet the pump. It grounds nothing.

 

Checked Fuel Rail for Fuel, Got it

 

How? Rent a fuel pressure gauge at Autozone or elsewhere and check the fuel pressure at the rail.

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Ballast resistor is an inline voltage dropping resistor used to quiet the pump. It grounds nothing.

 

Checked Fuel Rail for Fuel, Got it

 

How? Rent a fuel pressure gauge at Autozone or elsewhere and check the fuel pressure at the rail.

 

 

I pushed down on the Schrader valve and fuel came out, and also I had my fuel lines switched and when I went to pull the fuel line off it had quite the pressure, and fuel, and it made a decent mess! But I can still check for pressure just have to go buy a gauge.

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She's Alive! I don't know what happened to make it start running all of a sudden, but I had a Noid light hooked up and a fuel rail pressure tester on, rail read at 40 psi cranking, and it just started trying to fire up.

 

 

But I'll be damned if the jeep gods won't keep me from driving, but now my Clutch won't disengage, UGH

 

Brand new Throwout bearing, fork, master and slave (pre bled), pressure plate, and clutch all new! and torqued down to spec. 

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