I have a stock 86 gn. When idling warmed up i'm reading about 30 lbs on my fuel pressure gauge with the vacuum line on. My question is, when i remove the vacuum line from the regulator, should the fuel pressure IMMEDIATLY jump to 38-39 lbs or does it take a while? I have to wait about 5 to 10 minutes for the fuel pressure to rise once the vacuum line is removed and even then it only reaches about 35 lbs on the gauge.
bad fuel pressure regulator?
- Thread starter 86grdnatl
- Start date
It should immediately jump. I've checked FP more than a few times, and every time the pressure jumps as soon as the vacuum line is pulled. If you want, I have a known working Bosch 237 regulator from my car that runs right at 43 PSI line off. I just pulled it off about 2-3 weeks ago while doing my valve springs. You can have it if you want to try it to see if it works. If you want it, PM me your mailing address and I'll send it to you.
I mean, my car barely makes it up to 30 lbs when its idling and i just checked again and when i removed the vacuum line from the regulator the gauge didnt even move. It may have went up one lb but thats it. Also, fuel pressure doesnt rise 1:1 with boost, it just stays at 35 the whole time. With all of these symptoms, do you think that my regulator is bad?
I'd suspect vacuum leaks first. Then maybe the fuel pump. However, a fuel pump hotwire kit MAY help.
If you've got a vacuum leak, then the vacuum you SHOULD be developing on the FPR isn't there. Therefore, when you pull the line off, no much happens to make it go up. Along the same lines if that same vacuum leak that is there at idle is STILL there while you're driving and under boost, then it's basically a boost leak. This would cause your FP to fail to rise.
Run ALL your vacuum lines FIRST. Basically trace them from the vacuum block until you can't see them any more. Check for cracks everywhere along the lines and any connectors. There are also some "hard plastic" or nylon lines. Check those to make sure there are no breaks in those lines. I'm betting you'll find a leak. I guess it's possible that a bad regulator will cause your problem, but I don't think it's likely.
How long have you had the car? Was it kept / maintained well before that? Did it sit for a long time in a garage without being driven?
If you've got a vacuum leak, then the vacuum you SHOULD be developing on the FPR isn't there. Therefore, when you pull the line off, no much happens to make it go up. Along the same lines if that same vacuum leak that is there at idle is STILL there while you're driving and under boost, then it's basically a boost leak. This would cause your FP to fail to rise.
Run ALL your vacuum lines FIRST. Basically trace them from the vacuum block until you can't see them any more. Check for cracks everywhere along the lines and any connectors. There are also some "hard plastic" or nylon lines. Check those to make sure there are no breaks in those lines. I'm betting you'll find a leak. I guess it's possible that a bad regulator will cause your problem, but I don't think it's likely.
How long have you had the car? Was it kept / maintained well before that? Did it sit for a long time in a garage without being driven?
phil_jordan
Active Member
- Joined
- Aug 22, 2012
What kind of gauge are you using? Made a diff with my car as i was using a cheap gauge initially. Swapped out gauges, and realized that my FP was a lot lower than what it really was. As far as the FP rising 1:1 with boost, you would need to check fuel filter, and be sure that your fuel pump is hotwired. If all else fails, you can assume your pump is bad.
phil_jordan
Active Member
- Joined
- Aug 22, 2012
Do you have an aftermarket boost gauge? If you have one with vacuum readings as well as boost, it should read a steady vacuum at idle after warmed up...say about 17 or so?
Good idea, Phil! Also, ScanMaster readings can be a good indicator of a loss of vacuum. High BLM's or IAC reading of 00 is an indicator of vacuum leaks.
Also, where are you located? There may be some guys around you that would be willing to help. I see that you're not as old as most of us. It's good to see some young blood with an interest in these cars!!
Also, where are you located? There may be some guys around you that would be willing to help. I see that you're not as old as most of us. It's good to see some young blood with an interest in these cars!!
I have had the car for over a year now. It had been sitting since 1993 when i bought it in may of 2011. I pretty much replaced EVERYTHING on this car. I did put a new walbro 255 pump in it with a hotwire. Also, new fuel filter. I replaced the hoses connected to the vacuum block with new hoses two months ago and they look good. I also replaced all of the vacuum hoses in the engine going to the fuel vapor canister and everything. Replaced the pcv hose, and put new check valves in wherever they were needed. Is there a best way to try and find vacuum leaks?
I do have a boost gauge phil, but it is a vdo and only reads boost pressure not vacuum sadly
phil_jordan
Active Member
- Joined
- Aug 22, 2012
If im not mistaken, it should stumble a little.
phil_jordan
Active Member
- Joined
- Aug 22, 2012
x2
phil_jordan
Active Member
- Joined
- Aug 22, 2012
Did you inform us on what FP gauge you where using? Or am i blind. Lol. I make a lot of mistakes
Idle should increase. That's what happened when I had a leak at the connection of my vacuum block to PCV line.
Again - where are you located? There are usually great minds everywhere that can help.
Im in coatesville pennsylvania about 40 minutes outside of philadelphia.
The fuel pressure gauge i am using is a fuel pressure test kit that just screws onto the test port on the fuel rail. The schrader valve does not need to be removed to use this guage because inside the connector for the gauge there is something that compresses the schraer valve in the fuel rail.
It's just bothering me that before i put the new maf and translator on my car had a constant blm of 105. And as soon as i put the new stuff on, my blm is at 150.
The fuel pressure gauge i am using is a fuel pressure test kit that just screws onto the test port on the fuel rail. The schrader valve does not need to be removed to use this guage because inside the connector for the gauge there is something that compresses the schraer valve in the fuel rail.
It's just bothering me that before i put the new maf and translator on my car had a constant blm of 105. And as soon as i put the new stuff on, my blm is at 150.
Changing the MAF out and installing the translator is a GOOD thing. Your previous MAF was probably bad and not reading correctly, therefore changing the fueling to an incorrect number. Now that you have a good MAF and the translator, you should feel confident that the numbers are correct.
No matter what the BLM's were before, your BLM is now 150. That's a little high and indicates a possible vac leak. What's your IAC reading? This needs to be taken at idle, warmed up.
No matter what the BLM's were before, your BLM is now 150. That's a little high and indicates a possible vac leak. What's your IAC reading? This needs to be taken at idle, warmed up.
the iac was at 13 last time i let the car warm up. it says on the translator instructions that you may have to drive around a bit for the blms to change. Would this be something to try because i have not driven the car on the road yet since i put the new stuff on.
Similar threads
