swapped stroker into new truck....no fire

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BIGWOODY

NAXJA Forum User

Location

Greensboro, NC

• Jul 26, 2004

• #1

I put a new CPS on it, but I'm still only getting an ac volt reading of 2 or 3 millivolts. The coil isn't firing, the injectors aren't firing. I thought mybe due to the amount of welding, I shorted out the control unit for the injection system, tried another one, still no luck. The motor ran and fire fine in my XJ, now it's in the MJ and of course now that I've finished eveything else on it the damn thing won't start.....any ideas? The injectors and coil have power to them , just no pulse....

 

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MrShoeBoy

NAXJA Forum User

Location

Cincinnati, OH

• Jul 26, 2004

• #2

Do you have voltage going to the computer? Also have you checked the wiring to and from the computer? Maybe theres a short somewhere.

AARON

 

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BIGWOODY

NAXJA Forum User

Location

Greensboro, NC

• Jul 26, 2004

• #3

computer has voltage, coil has voltage, injectors have voltage, made sure all ground straps were go to go(battery to motor, motor to chassis). New coil, CPS, computer(known good one), no fire........

 

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Dr. Dyno

NAXJA Forum User

Location

Al Ain, UAE

• Jul 26, 2004

• #4

Perhaps the pick up in the distributor (cam position sensor) has packed up. This sensor is essential so that the injector firing pulse is synchronized with the spark. If it's bad, the injectors won't fire and the engine won't start.
Check your PCM for fault codes. It may reveal something.

 

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rsalemi

NAXJA Forum User

• Jul 27, 2004

• #5

You don't mention years? 87 to 90 is Renix and 91+ has a different distributor - are yours compatible? Also flywheels are different in those years.

 

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BIGWOODY

NAXJA Forum User

Location

Greensboro, NC

• Jul 27, 2004

• #6

this is an 87' renix motor going into an 88' all the reasearch I've done tells me there are no major differences in the wiring or parts. I have checked the wiring from the CPS back to the computer, its getting a good signal, swapped two other computers in, no change. Everything has power, there is just no pulse to the coil or injectors, therefore ,no spark or injector fire. Is there anything I'm over looking here?WTF? I've put in two coils, two CPS, ?two computers and have run seperate ground straps to engine and chassis...ANYONE?

 

old_man

NAXJA Forum User

Location

Loveland, Colorado

• Jul 27, 2004

• #7

Like Dr. Dyno said, it sounds like the cam timing sensor in the distributor.

 

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BIGWOODY

NAXJA Forum User

Location

Greensboro, NC

• Jul 27, 2004

• #8

I've replaced the distributor twice, put the motor on TDC compression stroke, even pulled the #1 plug out to make sure it was on compression stroke. The one thats one it now we took off a running jeep, no luck.

 

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rsalemi

NAXJA Forum User

• Jul 28, 2004

• #9

Ground wire for the cam sensor - to the block at dipstick?

 

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BIGWOODY

NAXJA Forum User

Location

Greensboro, NC

• Jul 28, 2004

• #10

Joy the SOB runs, ran a seperate ground wire from the chassis ,spliced into the ground wires for the computer. Next question, anybody know where the main ground junction is on this thing? I'm would rather repair the complete problem then leave it sorta rigged...

 

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CW

NAXJA Forum User

Location

Coeur d'Alene, Idaho

• Jul 28, 2004

• #11

I had the same problem, then I realized I didn't have the ground wire that bolts to the block near the dip stick hooked up. I would make sure all your wireing is correct.

 

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triple 4

NAXJA Forum User

Location

Cache Vally Utah

• Jul 30, 2004

• #12

When we did our swap xj motor, trany, computer and wire harness into a mj
it would not start . We finally put the coil from the xj into the mj and she fired right up. Go figure.