94 5.2L losing fuel pressure prime??
02-17-2010, 09:06 AM
#1
Seasoned Member
Thread Starter
Join Date: Dec 2009
Location: Comstock Park, MI
Posts: 253
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1994
Model: Grand Cherokee
Engine: 5.2L
94 5.2L losing fuel pressure prime??
OK so my 94 ZJ automatic with 5.2L and about 220K on the clock. I have been having this issue the last couple days with it cranking roughly 7-9 seconds before ti starts (much longer then it should be).
If I just turn the key forward, wait for the pump to start, then off and back on it will fire RIGHT UP...
My question is sounds like my fuel system is losing its prime.. either an injector leaking down or a pump.
Is this a common problem? and if so what would be issue normally?
If I just turn the key forward, wait for the pump to start, then off and back on it will fire RIGHT UP...
My question is sounds like my fuel system is losing its prime.. either an injector leaking down or a pump.
Is this a common problem? and if so what would be issue normally?
02-17-2010, 09:24 AM
#2
CF Veteran
Join Date: Mar 2009
Location: Tenn. and Mich.
Posts: 28,068
Likes: 0
Received 6 Likes
on
6 Posts
Year: 2004
Model: Grand Cherokee
Engine: 4.7L V8
I'm not sure on your vehicle, but the symptoms you describe usually indicate a bad/leaking fuel pressure regulator letting the pressure bleed down. On your '94 5.2L the F.P. regulator can be replaced and is attached to the fuel rail. JMO
Dan
Dan
The following users liked this post:
sw.slaton (07-03-2019)
02-17-2010, 01:31 PM
#5
Seasoned Member
Thread Starter
Join Date: Dec 2009
Location: Comstock Park, MI
Posts: 253
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1994
Model: Grand Cherokee
Engine: 5.2L
gottcha.. yeah it does it even after sitting for an hour.
looks like about 60.00 I should change that, I wonder if that is hurting my gas mileage
looks like about 60.00 I should change that, I wonder if that is hurting my gas mileage
02-17-2010, 01:43 PM
#6
CF Veteran
Join Date: Mar 2009
Location: Tenn. and Mich.
Posts: 28,068
Likes: 0
Received 6 Likes
on
6 Posts
Year: 2004
Model: Grand Cherokee
Engine: 4.7L V8
It's possible the diaphragm is leaking and allowing fuel into the vacuum line. Some people pull the vacuum line at the regulator with the engine idling, and see if fuel comes out of the fitting. If so, there's your source of poor mileage as it's sucking in gas through the vacuum line.
Dan
Dan
02-17-2010, 07:19 PM
#7
Seasoned Member
Thread Starter
Join Date: Dec 2009
Location: Comstock Park, MI
Posts: 253
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1994
Model: Grand Cherokee
Engine: 5.2L
pulled the line with it started and nothing...
seems like the key toggle is not helping it start fast anymore
seems like the key toggle is not helping it start fast anymore
Trending Topics
02-17-2010, 07:40 PM
#8
CF Veteran
Join Date: Mar 2009
Location: Tenn. and Mich.
Posts: 28,068
Likes: 0
Received 6 Likes
on
6 Posts
Year: 2004
Model: Grand Cherokee
Engine: 4.7L V8
I don't know if you can install an adjustable regulator in case yours is bad, but it might be a cheaper alternative to the stock one. *
The one on my '97 is mounted on top of the tank.
*This thought is just an idea from my Turbo days. Don't mind me.
Dan
02-18-2010, 05:26 AM
#12
Seasoned Member
Thread Starter
Join Date: Dec 2009
Location: Comstock Park, MI
Posts: 253
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1994
Model: Grand Cherokee
Engine: 5.2L
02-21-2010, 07:24 AM
#14
Seasoned Member
Thread Starter
Join Date: Dec 2009
Location: Comstock Park, MI
Posts: 253
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1994
Model: Grand Cherokee
Engine: 5.2L
Dealer came up snake eyes on a check valve in or by the tank/pump
I'm really starting to consider a new FPR
I'm really starting to consider a new FPR