Here is my problem. My fuel pressure doesn't stay where I set it. It seems to drop off after only a few minutes of run time. For example: I started my car this afternoon and checked the FP, it was 40 psi LINE ON. Drove the car probably three or four miles and checked it again. 31 psi LINE ON. This happens all the time except it usually drops around 5 psi. The car has been checked and there are no vacume leaks present. The fuel pump is a hotwired 307 that is 3 years old (i don't know if the sock was changed). Regulator is an accufab that is 2 yeas old (I have also tried a Mark Martone unit with the same results). The car has done this for the longest time now and it needs to be fixed. Has anyone experienced similar symptoms and are there any suggestions?
Where'd my fuel pressure go???
- Thread starter Bens87tr
- Start date
tim87tr
Obsession or Digression?
- Joined
- Sep 19, 2001
I had a problem similar to that once and it was the adjustable stock appearing regulator gone bad. I have an Accufab now with no problems though. This may help you narrow the problem down: http://www.gnttype.org/techarea/fuelsystem/fpsys_check.html
I had a similiar problem, turned out to be fuel filters ( two in succession). The cone shaped diffuser in the inlet cocked sideways. Could not for the life of me figure out why pressure would DROP as soon as I built any boost. Every thing seemed to check out as well as the filter as I had just replaced it. But when I looked in the filter It was pretty obvious. Went back and looked at the old filter and same thing. FRAMS by the way. Couldn't handle the double pumper I guess. A possibility to check anyways. Good luck.
Before you go to the trouble, be sure it isn't the guage itself. Been down that road. If there was a vacuum leak, fuel pressure would rise and probably would fluctuate. Try crimping the rubber part of the line momentarily when the problem is not there, then do it when the problem reoccurs and note pressure readings. If no difference, look to the reg. If there is a difference, look to pump.
salvageV6
Daily Driver
- Joined
- May 25, 2001
There should be published data on the 307 for gallons per hour. Pump a large pail for 2 minutes or so with steady power that you measure first with a multimeter. Say battery power at 12 volts car off using the prime wire. Then look at the flow chart and calculate how much fuel should be in the bucket. I will do a search later and help if I can.
PS: Use a second gauge to verify it ain't the gauge. I assume you notice drivability problems when it happens on the street?
PS: Use a second gauge to verify it ain't the gauge. I assume you notice drivability problems when it happens on the street?
You should really check and adjust it with the "LINE OFF" When vacuum is applied it will vary because engine vacuum changes in different stages of warm up,rpm's and load. Also get a good tester not those 1" Mickey mouse gauges that mount on the fuel rail.
I have not really had driveability problems with it yet. The car runs pretty hard. The BLMs can be all over the place though. I'm afraid that one time when I hit it on the street the FP will have dropped and not support the boost.
UL,
I usually check it with the line off, I was just stating an example with line on because I know that 31 psi line on isn't going to be the 45 psi line off that the extender chip is supposed to have. I do use a small guage, so I guess I can check the accuracy of that too.
UL,
I usually check it with the line off, I was just stating an example with line on because I know that 31 psi line on isn't going to be the 45 psi line off that the extender chip is supposed to have. I do use a small guage, so I guess I can check the accuracy of that too.
An interesting thing happened today
While the car was idleing I heard the fuel pump "stutter" for a second. What I mean is that the usual high pitch whine of the pump seemed to slow down for a split second, as in lost a little power, then went back to normal. This happened twice today. I don't know if this is normal, as I may be playing head games with myself trying to find a problem. Is this a usual occurance?
I wish my car was ready for LVD. Between this and my cracked PASSENGER side header, it'll be a little while before I hit the track.
While the car was idleing I heard the fuel pump "stutter" for a second. What I mean is that the usual high pitch whine of the pump seemed to slow down for a split second, as in lost a little power, then went back to normal. This happened twice today. I don't know if this is normal, as I may be playing head games with myself trying to find a problem. Is this a usual occurance?
I wish my car was ready for LVD. Between this and my cracked PASSENGER side header, it'll be a little while before I hit the track.
salvageV6
Daily Driver
- Joined
- May 25, 2001
Hey Ben did a quick test and my car leaks down a lot quicker than I thought. From 39-40 when shutting the key off down to 10 psi. in an hour and a half.
No problems with delivery or anything on my car, it's an old Kenne-Bell in tank pump that I was told was actually a 307.
Anyway I have the gauge with a 1 foot hose if you want to check it against yours.
I'd start with the easy tests first.
No problems with delivery or anything on my car, it's an old Kenne-Bell in tank pump that I was told was actually a 307.
Anyway I have the gauge with a 1 foot hose if you want to check it against yours.
I'd start with the easy tests first.
salvageV6
Daily Driver
- Joined
- May 25, 2001
Down in Hamden.
Work in Cheshire.
Might go to the Hooters show up in Newington on Friday 6pm or so. Might not too.
LVD is out they have some event Wed. night. "Cold front" hasn't done much here yet anyway.
Mine doesn't reach the windshield it's just like a tire gauge think with a 1 foot line but made for fuel. You can let pressure out with a button and hose too. I have an incar gauge on the WE4 so I only use it for the GN for checking and setting that car.
If you want to do it at my work I'm there M-TH 8am-4:30pm prefer to do it during working hours.
Friday we get out early around 1-2pm.
Big parking lot that mostly empty too.
Not sure when I'll be up your way again in Manchester.
Work in Cheshire.
Might go to the Hooters show up in Newington on Friday 6pm or so. Might not too.
LVD is out they have some event Wed. night. "Cold front" hasn't done much here yet anyway.
Mine doesn't reach the windshield it's just like a tire gauge think with a 1 foot line but made for fuel. You can let pressure out with a button and hose too. I have an incar gauge on the WE4 so I only use it for the GN for checking and setting that car.
If you want to do it at my work I'm there M-TH 8am-4:30pm prefer to do it during working hours.
Friday we get out early around 1-2pm.
Big parking lot that mostly empty too.
Not sure when I'll be up your way again in Manchester.
MIXDup2TRs
New Member
- Joined
- May 24, 2001
hello.. I remeber this problema nd I think we talked ont he phone.. did this problem ever get resolved and what was it??
I don't know if that post was directed to me, but I didn't talk to you on the phone. Anyway, here is an update on my situation with the FP.
Dropped the tank to check the pump and sock. Everything looked ok. Did some mods to increase flow will it was out. Changed gauges too. So far everything seems to be Good so far. Probably the guage.
No if only I could get rid of the boost creep. Took the turbo off and I'll port the wastegate hole some more. There is a little room left to take out. I have a Ramchargers boost controller waiting to go on too. Anyone have experience with that?? I'll be running 2 solenoids when I get it hooked up. Maybe it will help with the boost creep?? I hope so anyway.
Dropped the tank to check the pump and sock. Everything looked ok. Did some mods to increase flow will it was out. Changed gauges too. So far everything seems to be Good so far. Probably the guage.
No if only I could get rid of the boost creep. Took the turbo off and I'll port the wastegate hole some more. There is a little room left to take out. I have a Ramchargers boost controller waiting to go on too. Anyone have experience with that?? I'll be running 2 solenoids when I get it hooked up. Maybe it will help with the boost creep?? I hope so anyway.
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