OP
How long did it take to lose pressure? It was getting below 30 pretty quickly after I shut it off and after priming, and from there it continued to drop down slower.
Long crank
- Thread starter Joseph
- Start date
OP
Within 5-6 seconds it would drop down to 30 and then continue to slowly trickle down in pressure. I didn’t have it hit zero but it was getting close to 10.
Try to see what the pressure does when you try to start cold, if it doesnt come up to 49, it maybe the issue.
OP
It was nearly cold when I did the test. I’ll rent the tester again tomorrow I guess cause I already returned it for the night.
If it pumps up on the first try of the key, that may not be your problem, if it takes a couple of tries, it maybe the regulator.
OP
That’s what I was thinking. Seems like to me it’s getting good pressure from the pump but isn’t retaining the pressure. First turn of the key I get perfect 49psi pressure, but it loses it quick. Running, 49psi. Shut the Jeep off and it loses that pressure again.
It only needs to retail the pressure long enough to start, the pump runs for like 3-5 seconds, if pressure is up, then it will start, no pressure, no start. I may not be saying it right, try to google how the regulator works, but it needs the 49 psi to get adequate volume throuh the injectors to start the engine, once there is crank signal, the pump turns back on and continues to run until the engine is shut off.
OP
Shouldn’t the fuel rail keep constant pressure though, even when the Jeep is off? I’ll look into it more.
OP
Haven’t found much besides mixed answers on whether or not the rail should maintain pressure after shutdown. I’m seeing that it should totally depressurize after a few hours.
I will add that this long crank problem will happen when it’s cold, but also when the Jeep is slightly warm it’ll still take a bit long. As in if I go to start it an hour or two later I still get a long crank. I can shut the Jeep off and start it again a few minutes later with no issue. Apple picking today I parked, walked around for about an hour - hour and a half, got back in the Jeep. It started but pretty immediately died. Fired right up after that. That’s pretty consistent with what’s been happening.
I depressurized the rail, attached the pressure tester to the valve. I put the key in the “on” position, it immediately jumps to 49 psi and drops right back down. Turn the Jeep on, it runs at a consistent 49 psi. Shut it off, and it drops just as quick as when I prime it. The Jeep was sitting for two hours at this point. I will try again tomorrow I guess with the Jeep totally cold, but I’m kind of expecting the same results. Any input would be greatly appreciated. Don’t want to drop the whole gas tank again but at least 6/7 bolts won’t be rusted to hell.
I will add that this long crank problem will happen when it’s cold, but also when the Jeep is slightly warm it’ll still take a bit long. As in if I go to start it an hour or two later I still get a long crank. I can shut the Jeep off and start it again a few minutes later with no issue. Apple picking today I parked, walked around for about an hour - hour and a half, got back in the Jeep. It started but pretty immediately died. Fired right up after that. That’s pretty consistent with what’s been happening.
I depressurized the rail, attached the pressure tester to the valve. I put the key in the “on” position, it immediately jumps to 49 psi and drops right back down. Turn the Jeep on, it runs at a consistent 49 psi. Shut it off, and it drops just as quick as when I prime it. The Jeep was sitting for two hours at this point. I will try again tomorrow I guess with the Jeep totally cold, but I’m kind of expecting the same results. Any input would be greatly appreciated. Don’t want to drop the whole gas tank again but at least 6/7 bolts won’t be rusted to hell.
I am thinking it is the check valve, but you want to check all possible causes. It could be a crank sensor, cam sensor, or a coil. I have had all of these cause intermittent cold starting problems along with a fuel pump. When you have problems, sometimes they just suck to troubleshoot.
OP
I’m gonna start with fuel first. I can only imagine the quick loss of pressure before I even start the jeep must have something to do with it.. Won’t hurt to replace any of those things anyway if fuel isn’t the issue. Jeep could use a tune up lol
You wouldn't happen to know the part no. for the Bosch unit would you? Or if there is a different number for different year ranges? I would like to try to source one if i can before they're all gone
disregard. panicked too soon. i figured it out, carry on
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You wouldn't happen to know the part no. for the Bosch unit would you? Or if there is a different number for different year ranges? I would like to try to source one if i can before they're all gone
disregard. panicked too soon. i figured it out, carry on
I do not know it off the top of my head. @Jerry Bransford may or may not know it.
EDIT: never mind, just saw the latter half of your message.
liquidfluidity
TJ Enthusiast
Talking injectors, if it's never been done, change the o-rings. Made a huge difference pertaining to how well mine runs.
I'm in the midst of a slow start too although all I have to do is turn the key on for 3 seconds or until the gauges come to life. Pops right off. I'm going to try and hold out for a Bosche pump assembly. Hoping to find one soon.
Good luck!
I'm in the midst of a slow start too although all I have to do is turn the key on for 3 seconds or until the gauges come to life. Pops right off. I'm going to try and hold out for a Bosche pump assembly. Hoping to find one soon.
Good luck!
I grabbed 1 up as soon as I heard they are going extinct. Got it on Amazon. There were a few vendors that had them. This was 1 or 2 weeks ago. Hope that helps you find 1.
Is the fuel pump the same for all years? I noticed the OP has a 2002 and I have a 2005, wondering if it is going extinct too.