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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Today I have made no progress. I started by checking my P/N switch. I know that this wouldn't have cause my problem but I have an intermittent reverse light problem and I wanted to check its function anyway.
I decided to do a few signal checks and and the engine wouldn't turn over. I trouble shot it to a starter relay. Must have failed because of the repeated abuse of checking signals. I went and grabbed one from the store and replaced it. Not a big deal but it did take up a large chunk of my time.
Next i I checked my sensor grounds. As I said in an earlier post it was at about 40 ohms. Not to much and I have just refreshed the dipstick ground a couple of days ago so I didn't mess with it again.
I found a new signal to check, B+, although I don't know what it does. Somebody in some forum said it could cause my symptoms. It was 10 volts DC.
And now now I sit and wait on my battery to charge because I left the key on while I ate dinner.
My current situation.
Last edited by Cjjcalhoun; 07-04-2017 at 12:42 AM.
Looks like you have some serious electronic equipment. 40 OHM is way too high for a ground connection. I think some attention is needed there. I ran a new cable to the dipstick ground from the battery -ve to make sure it was grounded. There's another ground on the driver's side near the hood release that you could check.
Always make sure you have a fully charged battery before proceeding. It won't crank fast enough to fire up on a weak battery. These XJs are fussy that way needs to hit around 300 RPM or it won't fire the injectors. According to manual, only four inputs read during cranking: CPS, Crank signal, Sync signal, Battery +.
If it doesn't get the crank signal, it won't fire injectors. See page 76 of that RENIX manual. Also, if TPS is sending a WOT (Wide open throttle), it won't let the injectors fire (thinks it's flooding and your putting your foot on accelerator to clear the condition). Did you calibrate your TPS recently? Good sensor ground needed there too!
Looks like you have some serious electronic equipment. 40 OHM is way too high for a ground connection. I think some attention is needed there. I ran a new cable to the dipstick ground from the battery -ve to make sure it was grounded. There's another ground on the driver's side near the hood release that you could check.
Always make sure you have a fully charged battery before proceeding. It won't crank fast enough to fire up on a weak battery. These XJs are fussy that way needs to hit around 300 RPM or it won't fire the injectors. According to manual, only four inputs read during cranking: CPS, Crank signal, Sync signal, Battery +.
If it doesn't get the crank signal, it won't fire injectors. See page 76 of that RENIX manual. Also, if TPS is sending a WOT (Wide open throttle), it won't let the injectors fire (thinks it's flooding and your putting your foot on accelerator to clear the condition). Did you calibrate your TPS recently? Good sensor ground needed there too!
The electronic equipment is from my work. I am a 20+ year verteran Electronics Technician. I agree that 40 ohm is way too high for a ground connection but I don't believe it to be high enough to cause a no spark condition. I know this to be true from doing prior maintenance. I once had over 70 ohms and a good running jeep. I reduced it to 40 ohms when I removed the C101 connector. I will go further and try to get it lower but I want to get the jeep running first.
My my battery charger allows for a 50 amp charge just for starting. I believe this gets me to the 300 rpm but I am not sure. I left it on a trickle charge over night. Should be fully charged today.
As as far as the four signals required. I know I have CPS at the computer 12v battery, and the sync signal. I know I looked at the crank signal but not sure if it was good or not. Should I be looking for a voltage or a square wave? I will look in that manual, to see if it says.
I do have fuel pressure and I do hear the pump turn on when I turn the key on. You're right about the P/N switch. It sounded good when I thought about it but it doesn't affect spark.
The map map sensor is plugged in and functioning properly. I put a vaccuum in it just to see if it was in range and it was.
It tested correctly voltage wise.It is only part not replaced on your list ?
Yes, but I didn't see where he said he checked the pulse only the 5v signal. It pulses while cranking correct? And if the air gap from it and the flexplate are off or it is broke. I have had this problem a couple of times and it's always been the crank sensor. Not saying that's his problem. But I would change it and at the very least now you have a spare and know it's good. Lol!
Ok. I had one with th signal and still no spark I changed it and it was alive. But I do not remember the year, I have had many jeeps and can't remember what one it was.
Ok. I had one with th signal and still no spark I changed it and it was alive. But I do not remember the year, I have had many jeeps and can't remember what one it was.
07-03-2017, 08:15 PM
