fuel puressure question

[talon187]

ok i thought my regualtor was set at 38psi well it kept stalling when id go to give it gas somtimes when taking off and looked again and it was only at about 25psi im running about 10lbs of boost if i watch the gauge ive got some creep and had a few spikes to 15 would this cause alot of damage to the motor ive turned it back up to 38 now that i noticed the problem

 

[Burnett03]

ok i thought my regualtor was set at 38psi well it kept stalling when id go to give it gas somtimes when taking off and looked again and it was only at about 25psi im running about 10lbs of boost if i watch the gauge ive got some creep and had a few spikes to 15 would this cause alot of damage to the motor ive turned it back up to 38 now that i noticed the problem

Please re-type this so it makes sense.. What a cluster.

 

[talon187]

Sorry about that. i added an aeromotive fuel pressure regulator to my car about a month ago. when installed it i had it set at 38 psi. About 2-3 weeks ago i noticed that when id go from reverse to first and take off somtimes the car would stall. i checked the fuel pressure today and it was at about 25psi so i adjusted it back to 38psi. the car runs soother. my real question is while it was so low with 10-15 psi of boost can i have damaged the motor ?

 

[DSMunknown]

Here ya go:

Base fuel pressure is always set with the vacuum line off. Base pressure for 1G is 37 and 2G is 43.5. When vacuum line is connected, it should drop 1:1 with the manifold pressure, 1psi = 2inHG.

 

[talon187]

ok thanks but that doesnt answer my question i would like to know for the 2 weeks or so i was drving around with it on 25 psi if it would of hurt my motor or not with 10-15 lbs of boost...

 

[zippyshoe]

ok thanks but that doesnt answer my question i would like to know for the 2 weeks or so i was drving around with it on 25 psi if it would of hurt my motor or not with 10-15 lbs of boost...

When you measured your fuel pressure at 25psi, was this with the vacuum line connected or disconnected from the AFPR? For a 1G, you should set the AFPR for 37psi with the vacuum line disconnected from the AFPR. Once you set the AFPR in this manner, then you should see your fuel pressure drop when you re-connect the vacuum line with your car idling. The amount that it drops depends on your manifold vacuum while idling. For example, if your manifold vacuum at idle is 18 inHg, then your fuel pressure should drop by 9 psi, which would put it at around 37psi - 9psi = 28psi.

If your base fuel pressure (vacuum line disconnected) was actually at 25psi instead of 37psi, then you would indeed be running lean.

 

[talon187]

yeah it was alittle on the lean side. i now know why. the nut that should hold the adjustment screw came loose for some reason... i hope i didnt do any damage.. i checked the fuel pressure with the vac line off and it was alittle higher and i turned it down and hooked it up and the ide was a tad rougher i guess you could say so i turned it up about 2-3psi and it ides nice and smooth it should be ok right? ever car is diffrent when it comes to that doesnt?

 

[zippyshoe]

yeah it was alittle on the lean side. i now know why. the nut that should hold the adjustment screw came loose for some reason... i hope i didnt do any damage.. i checked the fuel pressure with the vac line off and it was alittle higher and i turned it down and hooked it up and the ide was a tad rougher i guess you could say so i turned it up about 2-3psi and it ides nice and smooth it should be ok right? ever car is diffrent when it comes to that doesnt?

All 1G's are designed to operate at a base fuel pressure (vacuum line disconnected) of 37psi. If your car has a rough idle with the base fuel pressure set to 37psi, than I would suspect that there is some other problem causing your rough idle. Another possibility is that your fuel pressure gauge is inaccurate/defective. You may want to check your base fuel pressure with another gauge for comparison.