Cuts out, no hot restart

I did search but I didn't find anything similar to what mine's doing.
91 XJ 4.0 AW4 231 189k

If you give it more than a quarter throttle lately it will lurch, seemingly die for a split second then go then die and either straighten out and take off or completely stall. If it stalls it WILL NOT restart without starting fluid sprayed into the intake. When it's not running I can spray some in it and it will start up and run as if nothing happened..until I go to get on the gas again. Seems to only do this hot. Occasionally just shutting it off while it's running normally and at temp will result in the no start condition as well.

Since it runs with starting fluid in all cases I think sparks okay, and since its able to run on with some help from the starting fluid I'm guessing it's a fuel issue? Injectors were supposed to be replaced by PO and they do look new. Same with fuel pump (although it's noisy.) It has a flexplate knock at the moment but I don't think that's related to this

I've tugged every wire I can see while it's running trying to get it to die and it runs fine. Any starting points?

Update: Won't do it for the first minute or two of running. Seems like as it gets warmer I can give it less throttle before it cuts out. Just died on me and could restart it by disconnecting the CTS but it would still cut out with throttle application. Will start looking for pinched wires.

Does this sound like it could be the CPS? I kinda doubt it since its dependent on throttle but..

Do a fuel pressure test. Sounds like your fuel pump is dying.

Headed out to get a tester for it now.

Also noticed when it's cutting out the tachometer drops to zero, then as it comes back (if it hasn't stalled) it swings up to whatever rpm it was at. Will idle high for a few seconds after too.

91Red4.0 said:

Headed out to get a tester for it now.

Also noticed when it's cutting out the tachometer drops to zero, then as it comes back (if it hasn't stalled) it swings up to whatever rpm it was at. Will idle high for a few seconds after too.

Click to expand...

Your CPS is probably dying, also.

I agree that a fuel pressure test with a gauge is job #1.

Fuel pressure readings are okay. They are as follows:
40 psi during cranking (This is when the engine won't run, and when it starts normally)
31 psi hot idle
39psi hot idle with FPR vacuum line disconnected.

I might check out the CPS and while it could be failing it appears as though I have spark at all times since it will always start and continue to run with starting fluid. It's pretty odd since it idles perfectly and does okay as long as you're under a quarter throttle. When it's hot. If it's cold it doesn't act up at all.

Beyond ohm checking the CPS I'm not sure where to go from here?

Seems to be a bit better. I can go 3/4 throttle now without it lurching forward then cutting out. I added $10 of gas since I was a bit low and checked out the CPS connector. Still won't restart if it's hot without starting fluid. I'm going to clean the grounds today and I may test the pickup sensor in the dist if I can find the procedure for it. Still no check engine light yet

Test the synch sensor in the distributor--on the Renix years it won't prevent the engine from running, but your 91+ it will.

Do the "Renix 101 ground fix" anyway, even though it's not a Renix.