leecarr

This vehicle sat for a while but ran fine when parked. Put it in the shop to change oil and it wouldn't start. I have 2 and the other one had a similar problem, after a lot of playing with it, it ended up being the CPS. I replaced it in the other one (along with the plugs and coil) and it still won't start. 1 out 25 times it will start and run fine, but shut it off and it won't start again. I swapped the ECM and other sensors off of the running vehicle and nothing happens. There is fuel to the engine, starting fluid or dumping gas in the throttle body doesn't even make it cough. I am stumped, what could it be?
Thanks in advance.

Ant.

WHat Year? What Engine?
Whats the PSI at the rail?
If you are getting the fuel you need at the rail I would check the spark..

Ant...

leecarr

The year and engine are in the subject line of the post, I don't have a fuel pressure gauge so I'm not sure on that and I know I have no spark, that is the problem. I do believe it is a wiring problem but I'm running out of places to look.

4.slow95

coil? plugs? wires? distributor cap and rotor? the cam sensor inside the distributor? gotta start with the basics!

leecarr

All are new or swapped out from a running vehicle that ran fine when the parts from the non running vehicle were put in it. It is very intermittent, started fine twice in a row then would not start again and runs perfect when it is running. All the relays and fuses under the hood have been checked. The fuel pump is running, I have not checked the fuel pressure but ordered a gauge so I can do that. It almost seems like a loose wire or bad connection but I can't find it. I have been doing this for a long time so I know all the basics and then some but this electronic stuff is always a pain.
Still stumped but thanks for the input.

98redjeep

Could it be the ignition key switch?

97xjbrian

Just throwing in the basics did you check all your fuses? If so then ignore me lol

leecarr

Checked all the fuses and relays, it could possibly be the key switch but it turns over fine and starts sometimes and everything else turns on with the key. The way it acts makes absolutely no sense at all, it's almost like it starts when it feels like it.

Hek

I have exactly the same problem myself. I bought 1998 Jeep Cherokee Classic 4.0 liter last month. It runs just fine until I checked the oil dipstick and its on "add" range so I added one quart. Now it won't start, belt moves a bit but not spinning. I decided to change the oil myself, found it dirty and extremely old. Okay, as we all expected, once the filter is removed the oil comes gushing, right? Nope! There was barely a cup of oil that came out. I put in the new filter and added 5 quarts to start. Nope. Another quart. Nope. What? Oil is supposed to be the one that get the engine running not the other way around. I felt like it was my fault yet it was not. Or was it?

It was running just fine til I added the oil. I certainly did not overfill it as there was barely any to begin with. Another thing, I added one quart yesterday and none of it come out today and checked the ground under and there's tiny oil leak puddle, probably 20 drops worth. Certainly nothing from that quart I added and less than a cup came out. Where did the oil go?

98redjeep

I would check foe power at the starter. If you have power to the starter but it doesn't crank hit it with a hammer. If it starts you buy a new starter.

Hek

I tried hammering the starter to no avail. I asked a couple of mechanic friends and they are equally as stumped. I wonder about the person who posted this forum has found the problem yet? I'm getting desperate when no one can find what caused this problem.

MonacaYankee

Try cleaning up the ground next to the battery.

leecarr

I cleaned all the grounds already, I had that problem with another Cherokee and that fixed it. The battery is fully charged and it spins over fine, it's almost like you're plugging and unplugging the coil wire at random. I have had problems with these before that I would swair was a spark problem but ended up being a fuel problem. I ordered a fuel pressure gauge so I can check the pressure. Pouring gas in the throttle body or using starting fluid makes no difference. The really strange thing is that when it does start it starts right up and runs perfect. I miss the days when if you had one hot wire and fuel you could make an engine run.

Ant.

When I first got my jeep cherokee 99.

The wire that connects to the coil had a bad plug.. If I moved that wire around in a certain way it would fire right up, Move it another way and it would get no spark.. You might wanna check there..

Ant...

cpttuna

RE-connect the wire from B+ to the starter. Redo your grounds.