Not starting, spark yes, fuel yes? (help)

This is a bit long but I want to give the full picture.

Over the last 3 days he old (89) XJ has been a bit slower starting. The other day it would not start so wiggles wires, unplugged and plugged the CPS and it finally started. It started several more time that ay without a problem.

As the starter is the original and is sounding a bit weak I pressure washed that area just in case I need to replace it. That was last night. After the was the jeep started up better than it had for a couple of days. (was expecting worse).

This morning it would not start. It will crank.
Check for spark, yes.
Checked for fuel, yes. Good flow from the pump before and after the filter. But in checking I noticed a couple of things and would like to know if they are normal.
1) when I press the pressure relief valve on the fuel rail a small bit of feul leaked out. After checking the pump (see next question) and with the key in the on position some fuel, more that before, will come out but the pump does not re-pressurize the rail. Also the fuel does squirt out but some times not very much and is is more of an ooze. I would expect more from 30+ psi.
2) I pulled the return fuel line by the tank and the fuel will squirt out just like the line from the pump.

Could this be a bad pressure regulator?

One other recent issue, may or may not be relevant. About a week ago I noticed some wires were touching the side of the engine and the split loom was melted. Looked more and found the wires were run in a bad place. These wires go to the O2, knock and 1 other sensor. The leave the wire bundle by the fuel pressure regulator. They were routed straight down past the exhaust manifold. I look up pictures on the net and saw they were usually routed over and down past the power steering pump. So I unplugged the sensors pulled the wires up. Yuck, the one wire that I saw touching the motor has exposed wires. Touched it up with liquid e-tape wrapped a new layer of regular e-tape around the bundle put on new split loom and routed it over and down past the p-steering pump. I can only think that on 1990 when the exhaust manifold cracked and was replaced under warranty by the stealer that the wires were routed incorrectly. It is a wonder they lasted this long. I noticed no difference before or after this fix on starting.

This is my DD, so I'm off work today, can't get there, trying to get this fixed.

I found a post (http://www.naxja.org/forum/showthread.php?t=51646&highlight=pressure+regulator) by old_man on a way to test if the pressure regulator is bad. I clamped the return hose to the tank. It made no difference. I used a large spring clamp.

If I turn the ignition swith to on, the pump wil run for a few seconds. It was the sdame with hte return hose clamped.

I then clamped he feed hose before the filter. The pump ran the same, a few seconds. If I turn the key off and back on the pump did not run again. If turn the switch off and wait 5 seconds the pump will run for a couple od seconds.

In the past when I have checked the pump it woudl run for a couple of seconds the first time I tunred the switch on and may a second after that.

It sounds to me like the pump may have a bad releif valve. DOes that sound correct to anyone out there.

Check your CPS

skierbri10 said:

Check your CPS

Click to expand...

That was the first thing I checked.
If it was the CPS would that not prevent a spark?
I do have a spark.

I was thinking it is a fuel pressure problem. The pump does work. Is there a way to test without a pressure tester?

I recently had a simular problem on my '89. Turned out to be the hose between the pump and the tank bracket in the tank. I replaced the short piece of hose and it started right up. The old hose was shot and all the fuel was pumping back into the tank instead of up to the fuel rail. HTH
Read this one other time, worked on buddy's 89 badge714
[email protected] good luck

Do yourself a favor and do a compression test. I spent three days going through every wire, every hose, every sensor, every oddball thing I could think of as to why this 87 XJ with strong spark and perfect fuel pressure and clicking injectors an proper cam/spark timing wasn't started, even with a shot of ether.

60psi in the #1 cylinder was enough to convince me what the problem was. Dropped some ATF in all the bores and the thing started right up like there wasn't any problems. Time will tell whether it stays running or not.

badge714 said:

I recently had a simular problem on my '89. Turned out to be the hose between the pump and the tank bracket in the tank. I replaced the short piece of hose and it started right up. The old hose was shot and all the fuel was pumping back into the tank instead of up to the fuel rail. HTH
Read this one other time, worked on buddy's 89 badge714
[email protected] good luck

Click to expand...

Did you have fule at the rail? My pump is working and fuel is making the round trip through the rail and back to the tank. I just used the pump to empty half the tank so I can check the pump but it appears to be working. I have heard of a relief vale in th epump that can go bad. Might be that.

ChicksDigWagons said:

Do yourself a favor and do a compression test. I spent three days going through every wire, every hose, every sensor, every oddball thing I could think of as to why this 87 XJ with strong spark and perfect fuel pressure and clicking injectors an proper cam/spark timing wasn't started, even with a shot of ether.

60psi in the #1 cylinder was enough to convince me what the problem was. Dropped some ATF in all the bores and the thing started right up like there wasn't any problems. Time will tell whether it stays running or not.

Click to expand...

My spark is there but it may not be the strongest. It is rather white or yellowish in color. Been to long so I cannot remember if that has changed.
With a plug out I can smell the gas so it is getting into at least one cylinder.
What is the ATF trick?
Is that ATF dropped into the spark plug holes?

OK, I spung for the fuel pressure tester. Turned out that it the pressure was leaking out the feed line. So the new fuel prump is in and the pressure is good.
The coil tested good and I do have spark.
But... it will not start. Some times it will just start to fire but not catch and then just keep cranking.

Any ideas?

Pull the plugs, and disco the power to the fuel pump. Crank it over for about 20 seconds. Put in a fresh set of plugs and reconnect the fuel pump.

After trying to start an engine for quite a while, you can get the plugs wet fouled. Pulling the plugs and cranking it gets fresh air though the system and will air it out.

Might want to put a little oil or ATF in the cylinders after doing the above. If you're dumping alot of fuel down the pots you may have washed all the oil film off the bore walls and have a drop in compression.

-Brad

Re: Not starting, spark yes, fuel yes? (help) (Started)

Pulled the plugs and they were all dry. Did the run without fuel or plugs anyway. Stuck the plugs back in. Still not starting.

Turned out that the wires in the harness to the 3 sensors was worse off that I thought. My last effort was to pull it apart and seperate each wire to give it a good look. Had to give a couple a good coat of liquid e-tape and let cure. Then some individual wraps before wrapping up the bundle again. Started right up.

I still cannot believe that those wire were run there in 1990 and lasted this long.

Thanks a bunch.

DaveW said:

That was the first thing I checked.
If it was the CPS would that not prevent a spark?
I do have a spark.

I was thinking it is a fuel pressure problem. The pump does work. Is there a way to test without a pressure tester?

Click to expand...

When my CPS went out the engine would run but mysteriously turn itself off.

skierbri10 said:

When my CPS went out the engine would run but mysteriously turn itself off.

Click to expand...

CPS is fine. Been there done that.

It was a combo of a bad check valve in the fuel pump and shorting wires. I think it would still have run with the fule pump, but now I do not have to worry about that on the trail.