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- #21
Regulator is also new. 2 months old. Bought it from Rockauto.
Hard Start: Fuel Pressure Loss at Engine Shutdown (1 Viewer)
- Thread starter DesertCruiser80
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- 1992 3fe hard start
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Regulator is also new. 2 months old. Bought it from Rockauto.
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- #23
Copy that. I did not know @jonheld had his own website. I'll follow that write up. I will also do a valve adjustment, throttle cable, and kickdown cable adjustment soon, per his recommendation. I have asked for an estimate from a shop who LOVES land cruisers. (Has a fzj80 with a smallblock + whipple supercharger running nitro and a fj40 also running smallblock nitro that used to be raced in Baja and other places.)
And question for @jonheld: Does the FSM you sell work for 1992 FJ80's? I see it says specifically 1991.
And question for @jonheld: Does the FSM you sell work for 1992 FJ80's? I see it says specifically 1991.
Fuel pump check valve is part of the pump. It's one of those long term failure parts when a failed FPR is over-pressurizing the system. Very common with consistent hot hard starts. The check valve becomes stuck in the closed position. Not likely the issue the OP is having, assuming he replaced the pump with an OE pump. His fuel pressure also appears to be slightly below spec of 37-46 psi.
The system should hold at least 21 psi for at least 5 minutes after shutdown according to the FSM. If it's bleeding off within seconds, then there is a significant leak.
The OEM FPR is discontinued, so it's hard to say if the aftermarket one is doing its job correctly.
There are some slight differences with engine wiring harness connectors, and late 1992 3FEs came with a 90 amp alternator. 1991-early 1992 was an 80 amp unit. Other than that, it's the same tractor.
I don't think I've updated that website in 10 years. I no longer send out CDs (that's so Y2K), but I can send you a DropBox link to download the files to the device of your choice.
I'm half sleeping, but the FPR is run from its VSV. If that VSV is not working the way it should, or if there is a significant vacuum leak, the FPR won't work properly.
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- #27
So following your logic, an internal leak could be caused by failed (leaky) injectors or a malfunctioning regulator. A malfunctioning regulator could be intrinsic to it, or due to a failed vsv or vacuum leak.
I would like to rule out a vacuum leak because I've gone over those lines various times. I don't see any glaring issues. And if you say a significant leak, then that would show other symptoms, no?
So possible culprits are: injectors (pressure washed by shop), FPR (new, aftermarket), or VSV
Is there a way to test regulators and vsv's? Maybe to test the FPR I could run the engine, then remove the vacuum line to the FPR. See if there is a difference? If not, then that means it was not working anyway?
I would like to rule out a vacuum leak because I've gone over those lines various times. I don't see any glaring issues. And if you say a significant leak, then that would show other symptoms, no?
So possible culprits are: injectors (pressure washed by shop), FPR (new, aftermarket), or VSV
Is there a way to test regulators and vsv's? Maybe to test the FPR I could run the engine, then remove the vacuum line to the FPR. See if there is a difference? If not, then that means it was not working anyway?
I extracted the pages from the FSM regarding fuel pressure tests. Read through them and follow the recommendations.
I'm also unclear about the timeline.
Was the hard starting when cold always a problem with this engine, or did it develop over time, or was it fine one day and bad the next?
Was the hard starting when cold always a problem with this engine, or did it develop over time, or was it fine one day and bad the next?
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- #30
Thanks for those, will read through them as well as your 3FE diagnostic doc.
It has gradually gotten worse over time I feel. I let it sit for about 4 months last year because I cross threaded the fuel damper into the fuel rail and needed to source new-to-me rail. So I'm resuming the baselining as of recent. I do think it was always there, possibly getting worse. What I have been doing on rough starts is barely tapping the accelerator to stop it from bogging down. Once its at normal idle, its fine. I feel I have needed to do that more frequently.
Edit:
I'll attempt to give a better timeline:
It has gradually gotten worse over time I feel. I let it sit for about 4 months last year because I cross threaded the fuel damper into the fuel rail and needed to source new-to-me rail. So I'm resuming the baselining as of recent. I do think it was always there, possibly getting worse. What I have been doing on rough starts is barely tapping the accelerator to stop it from bogging down. Once its at normal idle, its fine. I feel I have needed to do that more frequently.
Edit:
I'll attempt to give a better timeline:
- On Aug 9, 2019, I posted a thread about the same issue. Low rpm's until I give throttle. At that time I had done new battery, fusible links, new plugs, cap and rotor, new fuel filter, new EGR modulator, and new air filter. I then tried to replace the FPR and damper and jacked up my fuel rail.
- Truck sat until Feb 2020 when I had the truck towed to a shop to install the new rail along with the new damper and FPR. At the same time, I asked the injectors be cleaned.
- I replaced the fuel pump in early April 2020. Cleaned the cold start injector a week alter. Tested it last week.
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reference the fuel pressure test, pinch the supply line instead of return line to see if makes any difference?
do it as mentioned:
start - pinch supply line - ask helper to shut off asap and observe.
If the FPR is run by a VSV which I kinda doubt, toyota provides manifold vacuum to the FPR via a smoothing filter - anyhow - check its vacuum line to see if has any fuel or traces of fuel - that would suggest a leaky FPR. If the injectors are leaking that bad, you car should be running visibly rich.
EDIT: also someone was asking about the non-return valve, it is inside the fuel pump on these things - I have seen them bad on new pumps as well. ALso make sure you got the correct pump, sometimes pumps are similar, look the same but come without the internal no return valve. I'd make sure the part# is correct.
another way to test your injectors is to kinda make a jig that would let you apply pressure to the fuel rails while you see the injector tip to see any fuel seepage. Of course, you need to remove the rails and injectors for this test.
do it as mentioned:
start - pinch supply line - ask helper to shut off asap and observe.
If the FPR is run by a VSV which I kinda doubt, toyota provides manifold vacuum to the FPR via a smoothing filter - anyhow - check its vacuum line to see if has any fuel or traces of fuel - that would suggest a leaky FPR. If the injectors are leaking that bad, you car should be running visibly rich.
EDIT: also someone was asking about the non-return valve, it is inside the fuel pump on these things - I have seen them bad on new pumps as well. ALso make sure you got the correct pump, sometimes pumps are similar, look the same but come without the internal no return valve. I'd make sure the part# is correct.
another way to test your injectors is to kinda make a jig that would let you apply pressure to the fuel rails while you see the injector tip to see any fuel seepage. Of course, you need to remove the rails and injectors for this test.
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- #32
I was starting the diagnostic written in the FSM pages provided by @jonheld and when I inserted the jumper wire to +B and FP I heard a squeak. Similar to the groan of a door hinge when it is dirty and squeaks. The sound got louder and higher in pitch. I only had the jumper wires in for about 5 seconds. I decided to stop the test and ask here if that is normal.
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Tag Jon when you are asking him a question. or reply to one of his comments. That will notify him
When you jump those terminals with the key in the ON position, you're bypassing the fuel pump logic and it will run. I don't think I've ever heard it squeak. Where is the sound coming from?
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- #35
Somewhere under the hood. Couldn't pinpoint it before I yanked the wires to prevent damage.
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- #37
Yes sir. (8) and (1). I referenced IG- as that faces the firewall.
I decided to not do the test with the jumper wires becuase I know my pump works. I started the engine (started horribly) with fuel gauge attached and checked pressure. 35 psi. Perfectly in spec when idling.
I then pulled the vacuum hose of the regulator and pressure went to 42 psi and held. Within spec per the pages you gave.
The only issue seems to be the pressure is not maintained after engine shut down. The FSM says "If pressure is not as specified, check the Fuel pump, pressure regulator and/or injector." New pump, new FPR. I think it must be injectors.
when you short FP it runs the fuel pump
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- #39
I understand that. My concern was with the noise that happened.
fuel pump has a whining sound too, where does the noise come from?
