I rebuilt my engine last year and it went very well and it runs fantactic. That being said, ever since i did that rebuild my engine takes a while to start. It cranks for 10-15 seconds before catching and then starts right up. It's not bad but i know i shouldn't ignore it. I know better than to start throwing parts at a jeep issue so i thought i'd see if anyone knew about this. Its a 4.0 I6 engine, fuel injected. Fuel injectors are clean but older. Fuel pump has not been replaced since i've owned it (4 years). fuel filter is new. I checked the fuel rail while it was out and it seemed clear. I've run injector cleaner through it a few times and there are no improvements. 91 xj laredo
-
Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.
starting issues
- Thread starter Superflie
- Start date
winterbeater
NAXJA Forum User
- Location
- Royal Oak, Michigan
You would need a fuel pressure gage to see if the check valve is keeping pressure on the rail for a while after shutdown or just letting the fuel flow back to the tank. Or just push in the Schraeder valve 5 minutes after shutdown to see if the fuel still squirts out.
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
Winterbeater is right on this.
If the pressure is draining off you can add an inline check valve back by the filter. eBay seller jbass 195 has 3/8" inline check valves, $14 + $2 s/h.
Note: If you have a late model XJ where the pressure regulator is in the fuel tank and the fuel return line has been eliminated from the fuel rail you DO NOT want to add an inline check valve--reports of failed pressure modulators.
birchlakeXJ
NAXJA Forum User
- Location
- Melrose, MN
Pressure drop can occur and the culprit can be anywhere from the tank to the injectors.
As recommended, put a fuel pressure gauge on the schrader valve after it sits overnight. That will tell a lot.
Another "quick and dirty" way to see if you have pressure loss is to try the "poor mans prime".
1. Turn key to ON position (do NOT crank engine)
2. Fuel pump will energize and run for approx. 2 seconds
3. Turn key to OFF position
4. Repeat 1-3 one or two more times
The additional cycling of the fuel pump can help build up lost pressure. NOW crank the engine. Does it start quickly and cleanly? If it does, then pressure loss is almost assuredly your problem.
Good luck and let us know what you find!
As recommended, put a fuel pressure gauge on the schrader valve after it sits overnight. That will tell a lot.
Another "quick and dirty" way to see if you have pressure loss is to try the "poor mans prime".
1. Turn key to ON position (do NOT crank engine)
2. Fuel pump will energize and run for approx. 2 seconds
3. Turn key to OFF position
4. Repeat 1-3 one or two more times
The additional cycling of the fuel pump can help build up lost pressure. NOW crank the engine. Does it start quickly and cleanly? If it does, then pressure loss is almost assuredly your problem.
Good luck and let us know what you find!
ok, so i put the pressure regulator right on the rail while it was off, and there was no pressure in the line. the rail has a screw in point i can just twist it onto like a bike valve stem only bigger. Anyway, i turned the key and it had about 3-4 on the gauge, i started it up and it was between 34 and 35 while its running, i shut it off and the pressure just drops right back down. is the pressure supposed to stay up while its off? its a 1991 laredo xj
