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1995 Jeep Wrangler YJ ODB1. No Crank-No Fuel Pump and Pressure-No Spark
We purchased a 95 YJ 4.0 HO with a blown engine. The engine would crank but blew the dipstick out of the engine. The Engine was bad. So we got an 4.0 out of an 1995 Cherokee. we have done an engine swap and all the YJ parts are on the new engine except for the Intake and throttle body. So the steps so far.
1. New Battery Showing 12.5 volts
2. All Belt components replace but AC
3. Tried to Start and the Key will go to the start position and will not crank.
4. Jumped the starter and it will spin. Touching 12v Battery terminal to the key start terminal. Key in the On Position. No Start.
5. Checked for Spark. Jumped starter. Jeep Cranked (Starter Fluid) and #6 off showed spark and tried to fire up.
6. Jumped starter again and now No Spark.
7. Have swapped the Relays for the horn and checked the horn. No Spark.
8. 0PSI Fuel pressure
9. When I turn the switch the Heater Fan will turn off.
10. Power to the Fues box in the Engine Compartment.
11. All Engine Fuses and Relays are good.
12. All the Grounds look good
13. Cleaned the Battery Connections.
14. All Fire Wall Fuses are good.
15. Has gas.
16. Tested the relay Key Run Power to the 12 V to ASD, Fuel Pump and Coil.
17. Key in the Start Position 12V to starter Relay.
Thinking we have a Grounding Issue with the ASD System but not sure.
It is a 5 speed Stick shift.
We have the Cherokee ECM 3/15/1995 (YJ 7/15/1995)
Does the 95 YJ have a Clutch Safety Switch?
ASD and fuel pump relay coils share a common switched B+ and are both grounded by the ECM terminal. So depending on when you tested that could look like a bad ground. PCM also monitors that the ASD output has switched on, so the fuel pump relay socket would be the better place to test relay control. Test light across terminals 85 and 86 should light up when you turn the key to run.
On the stick shift starter relay coil should be permanently grounded. On automatic it's switched by the park/neutral switch. Did you transfer the engine harness from your old engine to the new one?
BillyJack wrote: if the ECM is bad or died would it keep the starter from cranking with the key?
No. Based on what you've said you've already checked I'd be going after the starter relay coil ground. Looking at the wiring diagram it runs thru' a connector on the transmission which might not be grounding it if you've used the harness from the XJ. Or maybe you forgot to plug it back in.
Do you have a FSM for the Jeep? They're pretty easy to find with google;)
Neutral safety switch is part of the clutch pedal up under the dash for manual trans. Did you use the original harness for your jeep or the one that came with the replacement engine?
We used the YJ Harness and eternal components from the YJ. We did by accident use the Intake from the Cherokee. I have been unable to find a Switch anywhere on the clutch pedal.
Hardtopdr2 wrote: My mistake the jeeps have it mounted on left side of trans by linkage. It's a 6 pin connector.
Yeah that's the connector I mentioned earlier that might be different on an a XJ harness or could've been left unplugged. Does the wiring diagram you've got show a neutral switch on the M/T? Factory one just shows the ground making a loop at the connector then on out to a body ground.
My bad, it's actually an engine ground. G104 on right side of engine towards the back. It also provides ground to 3 pins on the PCM so if it's bad that could cause a problem with both the starter and ASD relays.
Have Made Progress. The Black with orange Stripe wire was cut/broken off in the wiring harness. We now have Starter Cranking and fuel Pressure, but no spark. We found the ground the connector and reattached it. There are two wires on the ground connector it looks to be solid black. I have not been able to find a broken wire anywhere else.
the fuel pump is running and priming
the coil has pulse signal
the power side of the coil will only have power when the fuel pump does the 2-3 second prime.
I have not been able to find one of the missing Ground wire from the block above the starter. I connected the Black with orange, but the solid black wire is still missing the rest of it.
You mentioned earlier that you replaced ecu with cherokee did you have it programed for the wrangler? If not that might be why theres no spark. The other thing is if you have a anti theft key? Pats/vats or just a regular key (no plastic square in middle of key or buttons on key). If you have a pats/vats key anti theft system it will need programmed to start car.
