Back story, I've had my 1988 FJ62 for about 3 years now. When I got it went on jack stands while I went through everything and cleaned it up. About a year or so ago it started having starting issues. It'll crank and crank just until you start questioning if it's actually going to start and then finally catch. I check the cold start injector a while ago and made sure it was clean and operating correctly. When I pulled it, it was spotless, no junk or build up on it. Have just been living with the issue and throwing parts at the rig every once in a while to see if anything would change.
Fuel Pump screen was replaced by the PO just before I bought it.
I replaced the fuel filter about 12k miles ago when I first got it.
Replaced the Fuel Pressure Regulator with an Standard Motors Products P/N: PR88 about 2k miles ago.
Replaced the Cold Start Injector Temperature switch about 1k miles ago.
Finally today I went and bought a fuel pressure gauge kit from Hobo Freight ($49.99). Btw the banjo fitting is M8x1.0 if anyone needs to know.
"Bench" tested the cold start injector, by shorting terminals +B and FP of the diag terminals and giving the connector some power.
Spray pattern looked great. Checked the Cold Start Injector Temperature switch as well as per the FSM and it Ohm'd out fine.
Finally, hooked up the fuel pressure gauge and preformed the fuel pump operation inspection as per the FSM on page FI-47.
Here were the findings:
39 psi with terminals +B and FP shorted
31 psi at idle with FPR vacuum connected (directly to intake manifold, I gave away the FPR VSV when I desmog'd the engine cause I didn't know any better. If anyone has the FPR VSV P/N 25860-61010 let me know)
43.5 psi at idle with the FPR vacuum disconnected
All of those readings were within spec per the FSM. Intake Vacuum was about 21.5 inHg if that's worth noting.
The real issue is that when I shut the engine off the fuel pressure dropped to 0 psi within seconds.
It's suppose to maintain at least 21 psi for 5 mins after the engine is off.
Obviously the FSM lays out the suggested issues right there, but I'm wondering if anyone has run into this and point me in one direction or another.
The FPR is new, but who knows with parts no days, especially aftermarket/non-oem.
I've dropped the tank before to fix some wiring and pulled the pump just to look at it.
Luckily I still have a pick of that.
Not the greatest looking thing but I pulled everything apart and cleaned it and it seemed fine.
Not sure if the pumps have check valves internally, but if so maybe that failed.
As for injectors, I've never pulled those. Could have sworn I had a receipt from a PO showing that they were sent off to get cleaned and tested, but I can't find that receipt anymore.
However, I'm guessing if one of the injectors was stuck open I'd have other noticeable issues as well.
Plus I have bad habit of buying Techron or Sea Foam whenever they're on sale and dumping them into all my cars, probably to often if that's even possible.
So I'm leaning towards them being fairly clean.
Also tried listening to them with the old mechanic "stethoscope" while I have the diag terminals shorted to see if I could hear fuel following through/pass them, but didn't hear anything.
Has anyone had this issue before and what was the cause?
Is there any way to check if the FPR is bleeding the pressure off after the engine is turned off?
Thoughts on just throwing an inline check valve on the fuel feed line somewhere to see if its the pump?
Fuel Pump screen was replaced by the PO just before I bought it.
I replaced the fuel filter about 12k miles ago when I first got it.
Replaced the Fuel Pressure Regulator with an Standard Motors Products P/N: PR88 about 2k miles ago.
Replaced the Cold Start Injector Temperature switch about 1k miles ago.
Finally today I went and bought a fuel pressure gauge kit from Hobo Freight ($49.99). Btw the banjo fitting is M8x1.0 if anyone needs to know.
"Bench" tested the cold start injector, by shorting terminals +B and FP of the diag terminals and giving the connector some power.
Spray pattern looked great. Checked the Cold Start Injector Temperature switch as well as per the FSM and it Ohm'd out fine.
Finally, hooked up the fuel pressure gauge and preformed the fuel pump operation inspection as per the FSM on page FI-47.
Here were the findings:
39 psi with terminals +B and FP shorted
31 psi at idle with FPR vacuum connected (directly to intake manifold, I gave away the FPR VSV when I desmog'd the engine cause I didn't know any better. If anyone has the FPR VSV P/N 25860-61010 let me know)
43.5 psi at idle with the FPR vacuum disconnected
All of those readings were within spec per the FSM. Intake Vacuum was about 21.5 inHg if that's worth noting.
The real issue is that when I shut the engine off the fuel pressure dropped to 0 psi within seconds.
It's suppose to maintain at least 21 psi for 5 mins after the engine is off.
Obviously the FSM lays out the suggested issues right there, but I'm wondering if anyone has run into this and point me in one direction or another.
The FPR is new, but who knows with parts no days, especially aftermarket/non-oem.
I've dropped the tank before to fix some wiring and pulled the pump just to look at it.
Luckily I still have a pick of that.
Not the greatest looking thing but I pulled everything apart and cleaned it and it seemed fine.
Not sure if the pumps have check valves internally, but if so maybe that failed.
As for injectors, I've never pulled those. Could have sworn I had a receipt from a PO showing that they were sent off to get cleaned and tested, but I can't find that receipt anymore.
However, I'm guessing if one of the injectors was stuck open I'd have other noticeable issues as well.
Plus I have bad habit of buying Techron or Sea Foam whenever they're on sale and dumping them into all my cars, probably to often if that's even possible.
So I'm leaning towards them being fairly clean.
Also tried listening to them with the old mechanic "stethoscope" while I have the diag terminals shorted to see if I could hear fuel following through/pass them, but didn't hear anything.
Has anyone had this issue before and what was the cause?
Is there any way to check if the FPR is bleeding the pressure off after the engine is turned off?
Thoughts on just throwing an inline check valve on the fuel feed line somewhere to see if its the pump?
