Hey boys...

So I just checked my fuel pump resistor(?) the double spade connector cruiser's talking about on the first page.
It seems fine, I disconnected it and started the Jeep up to see if it would give me similar starting issue.
But no, she started up just fine and then she died due to no fuel I assume.
Connected it up again, and she started fine once again.

Really annoying when it comes and goes as it does...
Not sure what to do next?

 

I might turn off the ign the second it dies, than depress the deal on the schrader valve there on the fuel rail and see if it spurts fuel into the rag you are holding there. Or see of if runs with little shots of starting fluid.

Also I would check spark if it wasn't starting.

That rear wire off the resistor goes straight to the pump Btw.

 

Not necessarily the timing, more the way a 93 CPS, (hooked to your PCM), works, compared to the way an, 87-90 CPS works, (that had an ECU).

There are still gaps 120* apart, but in a different pattern.

 

She suspense is killing me....the 94 "system", is starting and running with a torque plate from an 89? Did you find that it had fuel pressure after it's died?

 

Uhm think you're talking to the wrong guy in this thread. Mine is a 1990 xj.
And it hasn't died on me for 2 weeks but starts every time.. So strange..

 

???? OK, my mistake! I got my "S's" mixed up. scooter and stew...

 

Scooter and stew... What an insult, it's seww!

 

It is easy to be confused when somebody hijacks another's thread. Scooter should have created his own thread and left your thread alone, unless he had something to aid in the troubleshooting your problem. That was just poor forum etiquette.Seww,
It sounds like you have a fuel pressure gauge. Just connect it to the fuel rail and leave it connected until you have your problem fixed. For now don't worry about how long you have to crank it to get it started, or how long it takes for the pressure to bleed off. If the rail gets to about 25 PSI, the engine should start. The pressure will bleed down sometime AFTER you turn the key off. How long, who cares? You are working on a no-start problem. We don't care now how long that takes, the question is only IF the engine starts. You said you installed an aftermarket CPS, but you also said the CPS output voltagewas 0.5 ACV, correct? Although the ACV test is by far the most reliable CPS test, no CPS test is absolute. I would never trust any new CPS, but one from the Jeep dealer. Please tell us what your fuel pressure looks like now. I would also start thinking about sources you may have for an OEM CPS.

Don't worry about your fuel pump resistor or relay, unless you see the fuel pressure drop below 25 PSI.

 

Yeah I agree Scooter kind of hijacked the thread a bit
Oh well..

To correct you, no I dont have a fuel pressure gauge. Haven`t had time to track one down either, gotta get on that hopefully this week.
The thing is, the jeep has started as normal now for over 2 weeks. Every time. I have tried to find a youtube video of the same issue but no luck.

If you think it`s the fuel pressure, I will find a gauge and we`ll go from there.

Thanks ****!

 

It would be good to do a fuel pressure test. It might give an indication of a dying pump.

 

Correct me if im wrong, but if any part was failing, should not the problem be more consistent?
Last time it died on me was over 2 weeks ago and before that over a month, almost two.

But i will try and get a fuel pressure gauge to cross that off the list.

 

With the engine running, check the voltage at each end of the resistor. Should be battery voltage at one end and about 10 volts at the other end. You might have fixed your problem already in your connector refreshing.

 

No sir, not always. It's really not uncommon for a part to begin to fail intermittently before it goes completely belly up.


This is especially true with electrical stuff.


The intermittent problems are the hardest to diagnose!

 

The crank position sensor is notorious for failing intermittently. Have you priced an OEM CPS yet?

I recommended the Fuel pressure gauge, because people have been dancing around fuel system electrical tests and fuel parts replacement, but you have no data to support any fuel system parts replacement. With a gauge connected, you could glance and the gauge and know whether you need to go down the fuel system path, or go back to the factory CPS (which is still my most likely suspect). A bonus, at least here in the states, the OEM CPS is about 30% cheaper at the Jeep dealer than an aftermarket CPS at the chain discount auto parts stores.

I realize it must sound like I am talking out of both sides of my mouth here. On one hand I emphasice the importance of logical troubleshooting, with data-based desisions, but I also am saying to just replace the CPS. I feel this way because:

Your intermittent symptoms sound like a typical intermittent failing CPS.

A failed CPS is the most common cause of a no-start. I have one under the back seat of all 3 of my XJs, a 1987, 1990, and a 2000.

If this were my XJ, I would install a new OEM CPS now, Sure the part will cost you money (how much, have you priced them?), but it could save you a few weeks of guessing and possibly some unneeded parts. You will be glad if it keeps you from getting stranded beside the road on a snowy winter night.

 

Excellent advice^^right here.