TwiztedAgony

This is my 1999 Jeep Cherokee with a 4.0L/AW4/np231!!

OK .. my fuel pump went out, so I replaced it and it ran fine for a few days to a week, then it started dying randomly or felt randomly, well it died at the gas station here in Union so I towed it home (6 blocks) .. hasn't started since!!

OK .. so I redo the fuel pump still won't start, I check if I am getting fuel at the rail and I AM plenty of fuel probably 3x more then my 97 Grand Cherokee with same engine!! (I have no way to test PSI on the fuel rail) and I can hear the fuel injectors firing!! Just to make sure its still not fuel I have sprayed starting fluid in the throttle body and still won't start .. so fuel is out I am thinking!!

I move on to spark.. I know its not the ASD (auto shut down relay) because the Fuel pump IS coming on and the fuel injectors are firing .. I check the MAP sensor, supposedly you can unplug it and it will start if its bad, doesn't start, so I move on .. I replaced the cap/rotor/wires .. still won't start!!

This is where I am at .. wtf can it be?

Will the CPS kill the spark if it went out and doesn't see the flywheel spinning?

Only other thing I can think of is the distributor anyone ever here of one going out like that?

Some relay I am not thinking about?

Ideas??

Thx in advance

bsmith97xj

any 3 wire 5 volt sensor can kill spark if it shorts the 5 volt to ground. cam sensor crank sensor oil pressure sensor map sensor and throttle position sensor. Does ur volt meter guage in cluster work? when this 5 volt short to ground occurs most of the guages are stuck at zero even with key on.

TwiztedAgony

Yea my volt meter, fuel, and oil pressure gauge move when I turn the key.

bsmith97xj

thats good just got to find out where u are losing spark. Coil to dist. dist to spark plugs. or if there is no spark at all!

TwiztedAgony

None at all.

Turbo X_J

Do you have a scanner?

TwiztedAgony

Nope, no scanner .. but the Check Engine Light never came on .. will it still throw codes with it off?

SirLasVegas

is the starter engaging? Does it still make a cranking sound like its trying to turn over?

TwiztedAgony

Yes, cranks fine with no unusual noises.

Turbo X_J

"This is where I am at .. wtf can it be? "

Any one of a thousand things of course. Yes if you have a scanner for instance a defective crankshaft position sensor will set a code (P0320 ask me how I know). Though it may not come a up as a generic. If you can access a scanner with manufactuer specific codes then it should be a piece of cake.

But first of all are you sure you have fuel? Have you pulled a plug and it is soaked with gas? That's the first thing to check.

ogmeme

Had problem with 2001 Cherokee working find one day, then wouldn't start anymore the next morning. Would crank fine, and never got any engine light or codes. Replacing crankshaft position sensor was the solution, started right up. I had 165,000miles and have read that they usually go out at around 140,000 without warning

tiwvr1

if u have a tach does it move at all when u crank? If not it is most likely the crank sensor.

TwiztedAgony

This got me excited cause it doesn't move when I crank but tried the same trick on my 97 Grand Cherokee by pulling the coil wire and the tach on it never moved either, are Cherokees wired different then their bigger brothers? Or maybe it doesn't work on newer models?

Turbo X_J,
You happen to know a brand or have a link to a decently priced OBD2 scanner that will work on both my 97 ZJ and my 99 XJ (and maybe on a future TJ with a 4.0L also) .. Did a search and I get bombarded with all sorts of ones from cheap POS ones that just spit a number to hella spendy ones that tell you step by step what bolt to pull first! .. Just want one that will spit a code and give me a part to replace, that is decent in price .. Looks like I will be grabbing a CPS on the 1st or 3rd when I get my SS check might pick up a scanner before hand if I can find one cheap enough

mhickm

I got my jeep running. I replaced the Cam Shaft Positioning Sensor and the Crank Shaft Sensor and it started right up.

The Crank Shaft on this jeep is a nightmare if you have 4x4. The drive line is in the way. I had to get my 13 year old step son to put it in because no one else could get their arm up in there. A complete NIGHTMARE.

I no longer have any codes and the transmission is shifting better.



I have a 1999 Grand Cherokee, inline 6, 162,000 and it won't start. It has been sitting for a few months.


When I replaced the camshaft positioning sensor it started up and ran fine. Then it wouldn't start again so I replaced the fuel pump.


Ran the codes and it still said cam shaft so I replaced it again. Nothing! I cleared the codes and now I'm getting the following codes:

P1388 - shutdown relay control circuit - the relay is working
P0320 - cam shaft positioning sensor
P1495 - EVAP
P0743 - transmission
P0753 - transmission


The relays under the hood seem to be working. There seems to be no power to the injectors. I'm at a lose. I don't want to replace the computer so I am hoping someone has some answers.