two cranks...???

I recently bought a 1994, XJ 4.0 which has been sitting unused for about a year.

The maintenance I have done so far:

- Changed the motor oil
- New battery
- flushed radiator
- cleaned out the throttle body
- air filter
- added a bottle of Redline fuel injector cleaner
- replace driver side motor mount

It runs pretty well but needs two cranks before she will start if she has been sitting around for more than an hour.

What do you guys think? CPS?, PLugs?, Wires?

What else do I need to do?

2 cranks is good, even for a new vehicle. I have a 99 Ford that cranks 3 or 4 times before it starts, everytime. Not sure why you think you have a problem...

It depends a little on what you mean when you say "two cranks." If you mean two revolutions of the engine, then as oogabooga says, this is good for a 4.0, whose computer withholds spark until the crank position sensor has registered the timing. Newer ones seem to do it in a couple of cranks. Renix-equipped (pre-91) ones will always do 4 revolutions when cold.

If you mean two cranking attempts, this is not so good, and I would suspect the check valve in the fuel pump, if it varies with the time it has been off. To test this theory, try turning on the ignition without cranking - you should hear the fuel pump start and then shut off. As soon as it shuts off, start it. If it starts more quickly then, it is symptomatic of pressure drop caused by a bad check valve. You can replace the fuel pump of live with it.

I just had a similar problem with 2000 Grand Cherokee, it was the gasket at the fuel pump.

What I really meant it is with two cranking attempts, the first turn of the key it does not start, so you release the key and then turn the key again.

KLXJ,

Sounds like the check valve in the fuel pump is not holding pressure. There is a test in the book to verify check valve operation. You hook up a fuel pressure gauge to the fittling on the fuel injector rail monitor it. The pressure is to only drop something like 1 psi or 7 KPa in 1 hours time but don't quote me on those numbers.

I have heard guys say after 1 minute they had no pressure so they change the pump since the check valve is internal to the pump and post that it solved their problem.

There has been a post on here complete with a BMW part number, it is an external check valve, it solves the problem and you don't have to pull the fuel pump out of the tank.

Martin

Is there any other ways of finding out if it is the fuel pump? I don't have a fuel pressure gauge.

Thanks

KLXJ said:

Is there any other ways of finding out if it is the fuel pump? I don't have a fuel pressure gauge.

Thanks

Click to expand...

The quick and dirty way, as I mentioned above, would be to let the pump pressurize the fuel rail before you crank. Turn the key to ignition, and wait about 5 seconds. To be doubly sure, turn the ignition off and do it again. This will run the fuel pump twice through its pre-start cycle before you crank, and if your problem was that there was no fuel in the system, there will be now, and it will start better. If it still doesn't start well, you might be looking at some other problem.

Yup got it, did like you said and it had the same ol symptoms so will have to check the ignition now and plugs I suppose.

Thanks

Dont forget cap and rotor.

You dont know WHEN those were changed last.

I would get all new plug and coil wires too. Especially if you see any signs of corrosion, or other wear.