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Monitoring fuel pressure while driving?
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Firebrick43
Well-known member
What car? Many newer cars you can see fuel pressure live via a scan tool that can see live data while hooked up to the OBD2 port
OBD 1 - 1980's vintageWhat car? Many newer cars you can see fuel pressure live via a scan tool that can see live data while hooked up to the OBD2 port
Firebrick43
Well-known member
Ok, again, which car? There were a lot of different types of systems in the 80's and its going to affect the solution.
Fedwrench
ALLIANCE MEMBER
Most master fuel pressure tester sets come with a gauge assembly that has a long enough hose to run it between hood & cowl and masking tape it to the windshield where you can see it.
1987 BMW 325is, there is only an option for a T.Ok, again, which car? There were a lot of different types of systems in the 80's and its going to affect the solution.
Firebrick43
Well-known member
Fedwrench nailed it. Tee it in and tape it to the windshield.
I however doubt the need for a driving fuel pressure test on an e30.
Very basic and standard type system with a pump, a FPR and a return.
A test while off and one running in park will tell you if it’s a bad pump/clogged filter, a bad FPR, or a plugged return line.
I however doubt the need for a driving fuel pressure test on an e30.
Very basic and standard type system with a pump, a FPR and a return.
A test while off and one running in park will tell you if it’s a bad pump/clogged filter, a bad FPR, or a plugged return line.
Last edited:
2ndGearRubber
Well-known member
Most master fuel pressure tester sets come with a gauge assembly that has a long enough hose to run it between hood & cowl and masking tape it to the windshield where you can see it.
This is the easiest option especially on older vehicles were the hose can easily get through the gap between the cowl and hood. Newer stuff can be so slim a gap even test leads don't fit. My rule has always been if one checks fuel pressure, we get a fuel sample. Dirty, water. E85, gotta know.
The other option is to T in a pressure transducer and use a labscope.
One option on older vehicles is to use the oxygen sensor output IF you trust the sensor. Probe into the signal wire with your meter and the voltage should stay high, 0.7-1.0, on a wide open throttle pull. Again, only use this if the sensor is trustworthy.
Since the hood is reverse just leave it unlatched and tape the gauge to the windshield. (I've done this with my E30 and E24)1987 BMW 325is, there is only an option for a T.
richfinn
Well-known member
I've taped a fuel gauge to the windscreen or hooked up a fuse loop to the fuel pump fuse and monitored current in the past on older cars.
I think current is the way to go (preferably with a scope/amp clamp) expect approx 4-5 amps constant with a good pattern
You can do it with a decent min/max multimeter too but not as good as the scope
I think current is the way to go (preferably with a scope/amp clamp) expect approx 4-5 amps constant with a good pattern
You can do it with a decent min/max multimeter too but not as good as the scope