Hello,
Thank you all in advance for any help you're able to give. I have recently acquired 1997 TJ with the 2.5. I've been working on Jeeps for the better part of two decades now, and don't come across much I can't solve myself, especially with the help of forums like this.
The guy I bought it from sold it cheap because it wouldn't start. I figured worst case scenario, I've been really wanting to TDI swap a TJ, so I picked it up.
I'd like to get it going so that I can putz around in the meantime and know that I have a running Jeep before I repower.
So far the steps I have taken are as follows:
Ensured it was getting fuel. No trouble with the pump priming or pressure at the rail.
Checked, and there is no spark coming off the coil.
Replaced the coil. Both old and new ones read in spec with a meter.
Checked the ASD relay. Everything works out fine and probed everything from the back as well to make sure it's putting out the correct ground/power. I jumped the terminals just to make sure, but still nothing.
Changed crank and cam sensors with Mopar ones.
Ensured both the 5v inputs to the sensors is good.
New plugs, wires, distributor cap, and rotor. (I know this is downwind of my problem, but the old one was worn anyways and it's something I usually do when I buy a vehicle.)
At this point I was still seeing no change so I started some diagnostics.
I have 12v at the dark green and black wire going into my coil as I should. With a test light hooked up to my positive battery terminal, I was not getting the pulsed ground through the grey wire that should trigger the coil.
There is continuity all the way from the plug on the coil to A7 on the PCM on the grey wire, and I visually inspected and couldn't find any chafing.
When I manually short the trigger wire from the CPS, I wasn't getting any relays closing or activity whatsoever. This pointed me to the PCM.
I bought a PCM programmed to my VIN from Ares Technologies on eBay. When it's plugged in I get the relay triggering with the CPS ground.
However, when I try to start it, I get the same crank no spark condition. Additionally, my gauges go crazy with the new PCM attached. If I leave my ignition on I keep getting relays resetting and the fuel pump going like it's gaining and losing power constantly.
I feel like I might have just gotten a bad PCM, but I wanted to check and see if there's anything I might have missed along the way that might point to something else?
I'm borrowing an oscilloscope this weekend to make sure my trigger signals from the CPS and Cam positioning sensor are where they should be.
Thank you all in advance for any help you're able to give. I have recently acquired 1997 TJ with the 2.5. I've been working on Jeeps for the better part of two decades now, and don't come across much I can't solve myself, especially with the help of forums like this.
The guy I bought it from sold it cheap because it wouldn't start. I figured worst case scenario, I've been really wanting to TDI swap a TJ, so I picked it up.
I'd like to get it going so that I can putz around in the meantime and know that I have a running Jeep before I repower.
So far the steps I have taken are as follows:
Ensured it was getting fuel. No trouble with the pump priming or pressure at the rail.
Checked, and there is no spark coming off the coil.
Replaced the coil. Both old and new ones read in spec with a meter.
Checked the ASD relay. Everything works out fine and probed everything from the back as well to make sure it's putting out the correct ground/power. I jumped the terminals just to make sure, but still nothing.
Changed crank and cam sensors with Mopar ones.
Ensured both the 5v inputs to the sensors is good.
New plugs, wires, distributor cap, and rotor. (I know this is downwind of my problem, but the old one was worn anyways and it's something I usually do when I buy a vehicle.)
At this point I was still seeing no change so I started some diagnostics.
I have 12v at the dark green and black wire going into my coil as I should. With a test light hooked up to my positive battery terminal, I was not getting the pulsed ground through the grey wire that should trigger the coil.
There is continuity all the way from the plug on the coil to A7 on the PCM on the grey wire, and I visually inspected and couldn't find any chafing.
When I manually short the trigger wire from the CPS, I wasn't getting any relays closing or activity whatsoever. This pointed me to the PCM.
I bought a PCM programmed to my VIN from Ares Technologies on eBay. When it's plugged in I get the relay triggering with the CPS ground.
However, when I try to start it, I get the same crank no spark condition. Additionally, my gauges go crazy with the new PCM attached. If I leave my ignition on I keep getting relays resetting and the fuel pump going like it's gaining and losing power constantly.
I feel like I might have just gotten a bad PCM, but I wanted to check and see if there's anything I might have missed along the way that might point to something else?
I'm borrowing an oscilloscope this weekend to make sure my trigger signals from the CPS and Cam positioning sensor are where they should be.
