How to test fuel pressure regulator?
#1
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Location: WA
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How to test fuel pressure regulator?
Im looking for the best or easiest way to test the FPR on my 85 Pickup. I know there is a way to do it with a pressure gauge but not really sure how to do it or if there is a certain type I need. The truck is also not running right now. When it was running it was really rich so i want to check this before i try and mess with the TPS. Any help on this would be appreciated.
Thank you, Reid.
Thank you, Reid.
#2
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Make sure the vacuum line is connected to the FPR:
http://www.4crawler.com/4x4/CheapTri...ine_Pix/8.html
If not, you'll be running too rich at low engine loads.
You can use that vacuum line, connected to a hand vacuum pump to vary the fuel pressure and listen for a change in pitch in the sound of the FPR with the fuel pump is running:
- http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump
I have heard you can rig up a temp. test point by modifying the banjo bolt fitting for the cold start injector with parts from NAPA. Or I installed a permanent pressure sender on my fuel rail:
- http://www.4crawler.com/4x4/CheapTri...rPressureGauge
http://www.4crawler.com/4x4/CheapTri...ine_Pix/8.html
If not, you'll be running too rich at low engine loads.
You can use that vacuum line, connected to a hand vacuum pump to vary the fuel pressure and listen for a change in pitch in the sound of the FPR with the fuel pump is running:
- http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump
I have heard you can rig up a temp. test point by modifying the banjo bolt fitting for the cold start injector with parts from NAPA. Or I installed a permanent pressure sender on my fuel rail:
- http://www.4crawler.com/4x4/CheapTri...rPressureGauge
#3
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All my vacuum lines should be in the right places. The dealership gave me a print up of the vacuum hoses, although my 85 has a few more lines then what is showing. I went through the whole intake, had my injectors cleaned, new filter and fuel pump. Ive checked my AFM and TPS with an ohm meter. Not sure if the TPS is set correctly though. I was just told if the vacuum line port off the FPR holds at 10psi it should be good. Have you heard of this? Not sure what to get to test that out though.
#4
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I am also trying to find out how to test the FPR. Or at least the fuel pressure making it to the FPR. If I got the M12 x 1.25 banjo bolt adapter, would I just screw it where the FPR goes and unplug the VSV?
#7
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Ok, so I couldn't find a M8x1.0 banjo bolt for the CSI, but I did find an adapter to fit where the FPR is on the fuel rail. I tested the pressure and it was at a steady 20psi. Shouldn't the pressure be somewhere around 33psi or so with the FPR removed?
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#11
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Would I just put a multimeter on the + & - terminals at the top of the pump? Or would I actually have to take the pump out the tank and test it? And would you happen to know the specs for that?
#12
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You of course want to test the pump under load, so that is it pulling the full current through the circuit. So test the terminals on the top of the pump or if that is hard to get to, someplace along the wiring close to the pump. General rule of thumb in the Toyota test procedures for such things is that the voltage at the load should be within 1/2 volt of the battery at the same time. So if the engine is off and you have the pump jumpered on, and you have 12.5 volts at the battery, you should have something like 12 volts at the pump. If you see something like 6 or 9 volts, then that is probably telling you that there is a voltage drop someplace in the circuit, trace back and find it. Why do that test? Well, if you do have a drop someplace in the wiring, and you pop $100 or whatever on a new pump and put it in, guess what? You'll still have low fuel pressure and you'll be out $100 to boot!
#13
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Now I believe my PS pump/pulley is bad! The belt on the PS pulley is screaming! I've heard you can get a shorter belt and bypass it or get a free spinning PS pulley. Does anyone know how to do this?
#19
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So, I took my p/s belt off and replaced my idler pulley... When I started it, it had a bad lag/hesitation when turning over, finally caught and started (cold), ran pretty rough for about 30 secs and then died and wouldn't start again like it has been doing... Example: Previous time I had it running and took a test drive, I drove about .5 mile, stopped at the stop sign and wouldn't start! Do you have any idea what is goin on or where I could start? I know I need to test the voltage on my fuel pump since I only have 20psi coming from the pump... I have to borrow my buddies multimeter tomorrow and will get that done. But what is the lag when starting? Could it be my timing? Which I adjusted earlier before I started it! Please help! This truck is turning into my worst nightmare!