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Cranks, but takes a second to fire

D

dagr8tim

NAXJA Forum User
Location
Columbus, Oh
I've searched, and can't find anything that describes my situation.

When I turn the key, the engine turns over about 3 to 7 times before firing. After it starts, it runs like a top.

I've had the battery checked & cleaned the battery terminals with no change.

I'm thinking it's fuel related, but am looking for suggestions before I start swapping fuel related parts. I don't hear the fuel pump prime like I can in my cars.
 
Year? Size of engine? If it is an 87-90, that is normal Renix stuff. Search long cranking times, renix, etc. It really helps to have a good battery and larger mains (battery cables, firewall cable, etc.) If it is newer 91+, start checking into tune-up stuff (plugs, cap, rotor) and check the fuel pressure.
 
Normal for Renix--fuel pump runs 3 seconds with key in "RUN" position, then when cranking is has to wait for the CKP (aka CPS) to pick up the right number of RPMs before powering the fuel pump.

If you don't have a Renix could be needing a check valve in the fuel line.
 
Thanks guys, sorry for not giving all the info.

It's a 97 4.0. If you drive it for a bit, turn it off, and then turn it back on. It fires nearly instantly. That's why I'm thinking it's fuel related.

I just replaced the spark plug wires (because one of the boots was arcing to the head), and pulled the plugs while I was at it. They are Bosch Plat 4's that are in really good shape. The coil has been replaced with an accel "performance" coil, so I'm assuming everything tune up related is fine. I will pull the cap and check it for scoring and the rotor.

I'm sorta leaning towards a fuel pressure regulator that may be slowly releasing the pressure in the lines as it sits.
 
Had similar problem with my 2000 Grand Cherokee. The gasket at the top of the fuel tank had a leak, and was loosing pressure overnight. In the morning it would take a couple of cranks to get it started. After that it was fine for the day.
 
BrokenXJ said:
Had similar problem with my 2000 Grand Cherokee. The gasket at the top of the fuel tank had a leak, and was loosing pressure overnight. In the morning it would take a couple of cranks to get it started. After that it was fine for the day.
Click to expand...

Could you smell gas?

With mine, if it sits for afew hours, it's still takes afew cranks to start.
 
It's pretty common to lose fuel pressure after sitting. Depending on how bad it is, you can usually get some improvement by a couple of steps. First, just try waiting about 3 seconds between turning the key to ignition on position and starting. That gives the fuel pump time to get the pressure up. If the leakdown is severe, you can cycle the ignition on sequence two or three times, then start. If nothing else, you can do this as a test. If starting time improves, then it's pressure leakdown. I would not bother to worry about this as long as it always starts.
 
My Grand was in rear-end accident, the body shop that replaced the tank, I guess messed up the gasket. Once that was replaced with new rubber, every thing was fine. No gas smell.
 
Ok, I've tried the key trick and that doesn't seem to affect it. I'm not in a super hurry to fix it, but it's on the todo list. Any suggestions?
 
like stated above, check the fuel pressure. It sounds like it might be fine since after you start it it will run fine, but it never hurts to check it out. My 98 and 99 both started to do that and I just turned the key to the "on" position and would listen to the pump cycle and once it quit I would crank it and it would start fine. It was just loosing line pressure after it had set overnight. I ran the 99 for a few years that way and had no problems FWIW.
 
I did see something posted on the internet about a "BMW Mod" that had something to do with a BMW check valve modification to the fuel pump to keep the pressure from draining off.

Can't find the link, try a Google search.
 
joe_peters said:
I did see something posted on the internet about a "BMW Mod" that had something to do with a BMW check valve modification to the fuel pump to keep the pressure from draining off.

Can't find the link, try a Google search.
Click to expand...
There should be some kind of thread here about it if you can find it. My understanding is that BMW uses an in-line check valve, which can be inserted into the line near the fuel tank end, without having to pull the pump.

It sounds as if the problem here may be something else, though, and I'd try to borrow or scrounge up a proper fuel pressure gauge first, to check it before buying any parts. If you put a fuel pressure gauge on the rail, and leave it, it should tell you soon enough whether your check valve is dying.
 
I actually have a spare BMW check valve if someone is interested.

Also, until you fix the problem.. What some people do is turn the key to ON, let the pump run, turn off then on again and that usually has pressue in the system to fire up.
 
Johnnie Walker said:
I actually have a spare BMW check valve if someone is interested.

Also, until you fix the problem.. What some people do is turn the key to ON, let the pump run, turn off then on again and that usually has pressue in the system to fire up.
Click to expand...

Hmmm...In my situation, I can turn the key to run and let it sit for 30 seconds to a minute without there being any change in the crank time. Are you saying, let it crank for a second, turn it off and then try to start?
 
dagr8tim said:
Hmmm...In my situation, I can turn the key to run and let it sit for 30 seconds to a minute without there being any change in the crank time. Are you saying, let it crank for a second, turn it off and then try to start?
Click to expand...
Turn key to on, let the pump run/shut off.. turn key off and on again one or 2 more times. And then see if that helps.

When was the last time you changed your fuel filter?
 
Johnnie Walker said:
Turn key to on, let the pump run/shut off.. turn key off and on again one or 2 more times. And then see if that helps.

When was the last time you changed your fuel filter?
Click to expand...

I'll have to try that.

As for the fuel filter, I've checked the parts stores and none of them list it. Also, where is it located?
 
Go to gas tank, follow fuel lines from tank to filter. Really it is about a foot from the tank.
 
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