87-4runner

Are you looking for a fuel issue or a fire issue?
Seems like it would be helpful to isolate one or the other first...

Co_94_PU

iTrader: (-1)

If your fuel pressure did not climb to max this indicates a problem with the fuel system

bensyota

87-4runner

NEW FPR from where? I got a brand new one that didn't work... of the check valve inside the FPR isn't working right
it let's the pressure bleed off...

wallytoo

iTrader: (1)

it might run at 15 to 25 psi, but it won't run well within that range (probably will idle ok, but above idle it will sputter). 30 to 35 minimum "running" pressure. pressure should jump to 45 to 55 psi with the return line gently squeezed.

bensyota

Co_94_PU

iTrader: (-1)

There is a spec in the boom for what pressure it holds over a given timeframe, have you checked this? It will help identify a pressure problem.

Did "we" (You) check the flow rate out of the FPR, did it pass?

With a new pump and functional regulator there are two other issues that could.cause low flow, one we see alot of after all these years is damaged or plugged up lines, the second is low power to the pump due to wiring issues.


...

You can test the distributor pickup, check it HOT vs cold.

scope103

The spec for fuel pressure at idle is 33-37psi http://web.archive.org/web/201003261...87fuelpump.pdf . The pressure ACROSS the injector is (supposed to be) constant, so the amount injected is determined solely by injector on-time. So if your pressure is, say, 25psi, you'll only get one-third the fuel the ECM is commanding. I can imagine it would run rough leaned that far out.

Start at the beginning. When the truck is idling, does your gauge read in the spec range? If not, the gauge is probably not working, and you rely on it at your peril. When it won't start, what pressure do you see? If that pressure is low, check the flow out of the FPR (6mm vinyl hose to gas can). There's no spec, but I get 1/2 liter/min. If there is much less than that, I would suspect something to do with the pump (as others point out, your truck is not a LEGO. Don't just replace the part you suspect; a problem with the pump could be wiring, not the pump itself.)

If flow-out is okay, but the pressure is low, squeezing the fuel return line (to back up pressure to the FPR) SHOULD raise the pressure, and indicate a bad FPR. DON'T assume the FPR is bad just because it wasn't built by someone's favorite supplier. Yeah, they can go bad, but if you don't test it first you're wasting money and time.

bensyota

scope103

No. The computer counts on the FPR to hold the pressure across the injectors constant. Under circumstances where you could get vapor lock, the ECM can command the Fuel Pressure Up system to raise the fuel pressure slightly while starting.

If your truck is idling at 20psi, either your gauge is wrong, or you have a weak fuel pump system, bad FPR, or both. Testing the flow out of the FPR will tell you a lot.

"Start and run for 5 seconds" is the classic sign of a problem in the VAF-COR circuit. A switch in the VAF holds the COR closed (to power the pump) when there is air flow through the VAF. If that connector is loose, it will run for a few seconds and quit.

bensyota

bensyota

Okay so the truck doesn’t stall on me anymore. That prob was when I stupidly pulled the plug on the afm trying to clean ˟˟˟˟ I didn’t know. Had to solder and bend ˟˟˟˟ back. That is all golden now. Just have the warm start issue. Now!!!....clarification...it will start when warm if I start it within say 15 min of shutting it off. But that 20 min and on is the questionable part. I haven’t checked the return line by squeezing it yet. Can somebody clarify where this line is and where I can reach it at to squeeze it? Stupidest ˟˟˟˟ stumps me sometimes. If this means the return off the FPR I have done this before and it does increase rpm

i mean every time this happens I start it with starting fluid. The truck doesn’t have just a normal sounding start. Like a lot of tinging or something right off the bat for the first split second.

TonyG!

Funny, my 88 4runner with a 22re does this same thing. Restarting after about ten minutes of it being parked hot and it stumbles. It acts good again on its own if I don't touch the throttle for about a minute, maybe less. And the "correction" comes on immediately. It's my own built in anti theft. Touching the throttle makes it worse till it dies. I'll be going down this rabbit hole soon. Yay.

bensyota

Okay . I have checked return line out of FPR before and it does raise the idle. The issue occurred yesterday and Fuel was still reading 30psi when it wouldn’t start. I can smell gas. I checked dizzy readings and they check fine every time. I checked my secondary coil resistance and it was reading around 25.k ohms when this occurred and slowly dropped to 10.? But still wouldn't start. I’m guessing maybe has to fully cool if this is the issue. Spec reading is 11.-18. when hot. Has anybody done this reading before or can they please check after running their vehicle what its reading. Very simple check. Just don’t want to over assume this if it’s just a normal ghost reading. Thank you so much in advance if capable.

bensyota

Update!!!! I MAY HAVE SOLVED IT......(MAY)

so my battery has been horrible for a while with terminal corrosion. I’ve cleaned it before but it just keeps coming back. So I went to clean it again and it was so bad that it ate away the clamp screws. Needless to say I jacked the negative terminal up trying to get it off. The battery is prob over 5 years so I said hell with it. I went and got another battery that was pretty strong. Brand new clamps. Cut the ground wires back about and inch. The corrosion worked its way through the loom back into where I cut fresh wire. I wasn’t going to replace the wire at this time. But I spread the loom and cleaned it up. Put grease on everything and it’s all super clean. I just ran around town and stopped at quite a few different places and it started right up every time. Not even hesitating. One defect I had was when I originally got the battery they gave me the wrong one. I put it in the cradle and hooked it up. Well the wrong battery had opposite terminals that I wasn’t paying attention to. So yeah. After it not wanting to start I realized I blew out my alternator 80amp fuse. Pain in the ass by the way. Returned the battery and they gave me the fuse for free. My radio won’t work now. Kick panel Fuse is fine. And I don’t have that buzz that you hear while the key is turned on and the pump is priming. I don’t know what controls that but if anybody knows please release the info. So yeah. I am crossing all fingers and toes and praying that that resolved it. Grounds are nothing to mess with I suppose. Or to take lightly

scope103

Your fuel pump doesn't "prime." It doesn't turn on until you turn the key to STArt (so you won't hear it over the starter).

Some cars (Hondas?) will start the fuel pump for a few seconds with key-on. Not Toyotas.

bensyota

Im sorry I’ve mistaken that. But that initial buzz for about 5 seconds when you turn the key to the on position.

Many ideas? Haha

Co_94_PU

iTrader: (-1)

Buzzer is the key warning (under/next to steering column) or possibly a power antenna that's fell thru into the fender well.