Longtime engine miss after hot soak

I have had this problem now for 2 years. after engine has been run up to temp and shut off for a short period, (eg.) fueling, and restarted it runs like absolute crap for a few minutes. Items that have been replaced include complete engine and new head, injectors, o2 sensor, coolant temp sensor, air intake temp sensor, knock sensor, repaired broken ground from main harness to dipstick tube (corrected intermittent high idle), supplied ground to intake,new tps and iac, installed extra batt to engine ground, installed new motor to firewall and batt to fenderwell grounds., replaced fuel injectors- ford 5.0 liter injectors,fuel pump,fuel filter, installed bmw check valve, replaced fuel pressure regulator, cool taped complete intake manifold.replaced plugs wires,cap and rotor Could it be the fuel injector wiring harness? Has anyone had troubles with this? at my wits end.

89 xj, 4.0 complete rebuild, auto.

mine does the EXACT same thing.
Im starting to think that its either a crap lifter or a bad injector.
BTW mines an 89 too

big black xj said:

mine does the EXACT same thing.
Im starting to think that its either a crap lifter or a bad injector.
BTW mines an 89 too

Click to expand...

I have new lifters and have replaced injectors, When I had a lifter go it missed as well but you could hear the lifter really clicking away. I will probably replace the injectors again the ones I have are reman ford injectors, and may try and make a new injector harness (any pointers or recommendations for wire gauge, type, how to join?) Drive ya carzy doesn't it!! especially on a wheeling trip with a dozen people looking at you and your stupid jeep is sputtering away

yea it does, especially when it shakes the whole truck as i sputter off.
I think im gonna try to back probe the injector harnes to make sure the injector drivers in the computer arent trying to take a crap.
Its really weird that if it sits over night, it will start up no problem. If i stop to put gas, .... i get to sputter off.

Chrysler had a TSB for this problem on the later models. My 01 will do that when wheeling unless I turn on the e-fan for a few minutes. The fuel in the rail at the #3 & #4 injector gets hot enough to vaporize, and then won't spray properly if not allowed to cool and condense.

The TSB called for an insulation barrier to be added around the manifold/fuel rail, but mine still does it after a long hot soak at low speeds. Normal driving; no problem, wheeling with no airflow = stumble.

When I read IllianaXJ's post, I had to look back in my 200 FSM. Now I have to badmouth Chrysler engineering. (Sorry, I love my XJ, but I realize the weaknesses. Every vehicle has 'em.) To my way of thinking it is BS to design a system that doesn't flow the deadheaded fuel back to the tank and recirculate. My '93 F150 does that. The pressure regulator is on the fuel rail and bypasses the excess pressure back to the tank to keep the fuel flowing instead of sitting in the fuel rail percolating. XJ has the pressure regulator in the tank (with the only fuel filter) and has no recirculation fuel line. Time to respell Jeep as Cheep (sorry).

Does anyone make a replacement pump/pressure regulator/filter unit to fix this? You could run a recirc line out of the Schrader valve fitting and put the pressure relief valve there. Connecting back into the tank would need to be secure, but I supppose you could go back in through the filler tube.

Another patch up fix is reminded to me by an old Datsun B210 (?1975?) I briefly had that had a small fan blowing on the carburetor. This was a stock factory feature to minimize carburetor gasoline percolation.

I think that using premium fuel also helps this issue, but that's pretty expensive.

Im having this problem now.

If I shut it off, and restart, it runs horrible, the CEL flashes, and I have to restart it, and rev it to clear it out.

anyone solved this issue?
Mine is getting worse. Now its to the point that it doesnt like to start at all.
I have to crank it for a minute or so to get it to fire. And then i get to sputter off

Don't have this problem on my XJ, but similar problem with Big Bronco after changing to an aluminium intake and Edlebrock 1460. On hot days the fuel in the filter before the carb would almost boil.

Fix was changing to a Flex dual elecric fan with a manual overide toggle on the dash. Stop for gas/burger/whatever, hit the switch and let the electric fan cool the engine compartment.

You should be able to rig something similar up using the OEM e-fan. Just don't forget to turn it off if you are going to be gone a long time--no need draining the battery.
D

big black xj said:

anyone solved this issue?
Mine is getting worse. Now its to the point that it doesnt like to start at all.
I have to crank it for a minute or so to get it to fire. And then i get to sputter off

Click to expand...

My 2001 XJ has this problem anytime it's warm or after long climbs.
The two mini-cats (Cal smog) on the exhaust manifold dump a lot of heat into the engine compartment.
I have tried insulators and shields with little success.
Whatworksit for me is to leave the e-fan on 2 minutes or so after shutting the engine off to cool the radiator and remove some of the heat from the exhaust.
To make this easier, I installed a 12-volt delay timer that, when activated by a button, turns the fan on for 2-3 minutes.
No need to stick around for 3 minutes, the timer shuts itself automatically.

ELK-960 delay relay/timer
http://www.at-fairfax.com/ConstructionElectronics/RelayBoardDelayTimers.htm

It's not the best fix but it beats the rough restart and the clearing the CEL.

srmitchell said:

Im having this problem now.

If I shut it off, and restart, it runs horrible, the CEL flashes, and I have to restart it, and rev it to clear it out.

Click to expand...

big black xj said:

anyone solved this issue?
Mine is getting worse. Now its to the point that it doesnt like to start at all.
I have to crank it for a minute or so to get it to fire. And then i get to sputter off

Click to expand...

lazyxj said:

My 2001 XJ has this problem anytime it's warm or after long climbs.
The two mini-cats (Cal smog) on the exhaust manifold dump a lot of heat into the engine compartment.
I have tried insulators and shields with little success.
Whatworksit for me is to leave the e-fan on 2 minutes or so after shutting the engine off to cool the radiator and remove some of the heat from the exhaust.
To make this easier, I installed a 12-volt delay timer that, when activated by a button, turns the fan on for 2-3 minutes.
No need to stick around for 3 minutes, the timer shuts itself automatically.

ELK-960 delay relay/timer
http://www.at-fairfax.com/ConstructionElectronics/RelayBoardDelayTimers.htm

It's not the best fix but it beats the rough restart and the clearing the CEL.

Click to expand...

IllianaXJ said:

Chrysler had a TSB for this problem on the later models. My 01 will do that when wheeling unless I turn on the e-fan for a few minutes. The fuel in the rail at the #3 & #4 injector gets hot enough to vaporize, and then won't spray properly if not allowed to cool and condense.

The TSB called for an insulation barrier to be added around the manifold/fuel rail, but mine still does it after a long hot soak at low speeds. Normal driving; no problem, wheeling with no airflow = stumble.

Click to expand...

lazyxj said:

My 2001 XJ has this problem anytime it's warm or after long climbs.
The two mini-cats (Cal smog) on the exhaust manifold dump a lot of heat into the engine compartment.
I have tried insulators and shields with little success.
Whatworksit for me is to leave the e-fan on 2 minutes or so after shutting the engine off to cool the radiator and remove some of the heat from the exhaust.
To make this easier, I installed a 12-volt delay timer that, when activated by a button, turns the fan on for 2-3 minutes.
No need to stick around for 3 minutes, the timer shuts itself automatically.

ELK-960 delay relay/timer
http://www.at-fairfax.com/ConstructionElectronics/RelayBoardDelayTimers.htm

It's not the best fix but it beats the rough restart and the clearing the CEL.

Click to expand...

As long as you keep your downstream cat, you can ditch the pre-cats without any worries. Several people that I know that had newer dakotas with pre cats just run longtube headers, or get a custom Y-pipe in place of them.

When I put the Ford injectors in, I had problems with fuel leaking on a hot soak, so I found some stock injectors and the hard starting went away. If you could release the pressure on the fuel rail after you shut it off, and then see if it starts any easier, than an injector could be the problem.

metmknice said:

As long as you keep your downstream cat, you can ditch the pre-cats without any worries. Several people that I know that had newer dakotas with pre cats just run longtube headers, or get a custom Y-pipe in place of them.

Click to expand...

[FONT=&quot]

That's wishful thinking and illegal. It would never get by a good smog tech.
During my last smog test, I watched the tech check all three cats, along with the rest of the smog equipment, all of which had to be checked off on the testing machine's computer.
I'm not interested in finding a shady tech or in anyway upsetting the AQMD.
California is a difficult enough state to live in without looking for trouble.
Getting caught removing emissions equipment is trouble. With our state’s budget problems, fines are sure to soar.

Removing the mini-cats would require somehow fooling the ECM, since each of the mini-cats have their own oxygen sensors, more fun and game to deal with.
I'm looking for a solution to the heat soak problem that is both effective and legal. Until a superior solution is found, the $20 fan timer does the job. [/FONT]

I've been dealing with this for about a year too. Mine only happens when wheeling. short or long drives the temp stays normal...my temp has to hit 210 and then be shut off.
This problem caused me to buy a OBD-II reader before I knew what the problem was.

I have been planning to insulate the rail & injectors with this fire resistant tape that I used on my OBA hose to stop it melting where it passes near the pre-cats. It has worked great on that, so I am hopeful.

I got the tape from a local hardware store.

I'll post if it works or not


_______________
2001 XJ Sport AW4 NP231 D30/35

good luck with the heat tape,hope it does the trick for you,let us know. hey u on crawlinbc?

Secshunate said:

I've been dealing with this for about a year too. Mine only happens when wheeling. short or long drives the temp stays normal...my temp has to hit 210 and then be shut off.
This problem caused me to buy a OBD-II reader before I knew what the problem was.

I have been planning to insulate the rail & injectors with this fire resistant tape that I used on my OBA hose to stop it melting where it passes near the pre-cats. It has worked great on that, so I am hopeful.

I got the tape from a local hardware store.

I'll post if it works or not


_______________
2001 XJ Sport AW4 NP231 D30/35

Click to expand...

OK,
i fixed mine.It ended up being a fuel injector.
I put all 6 new injectors when i built the stroker about 3 years ago.

Lucky for me, that when i was lookin for 6 new injectors, all i could find was sets of 8.
I put a fuel pressure gauge on and then started it up.
Then, one by one, i pulled each injector and noted the fuel pressure difference for each injector. i also noted that with every injector i pulled, the engine ran worse.
I got to one injector that would not make any difference in how the engine ran, AND made no change in fuel pressure.
I popped in one of my extra injectors, and now all is well.
Keep in mind, that i had to get the engine to operating temperature before i could start doing any of these tests.

Before i started the whole fuel pressure thing, i used a stethescope with a metal tip on the end and listened to each injector "tick". as i unplugged each one, the tick would go away. KEEP IN MIND.... that the bad injector was still "ticking" as it should have been, but there must have not been any fuel being passed to the cylinder. Upon further inspection, the bad injector did NOT have any clogged holes on the tip of the injector, AND it passed the injector ohms test at a perfect 16 ohms. (go figure)

Good troubleshooting.

Very logical deduction. Is that you, Mr. Spock?

Install the heat wraps around the #3 and #4 injectors from the TSB and replace your spark plugs with NGK v-power

they're model # ZFR5N at AdvanceAuto

this is what cleared my heat soak misfire up