shafner30

Hello have a question

so I have a 1990 Toyota 22re 2wd The pick up runs perfect but sometimes not all the time maybe to three times a week when the engine is warm sitting for an hour to two hours I go to start it up itt has a long crank time but It will start It have never done iit when the engine is cold I have changed out the coolant temperature sensor no change I don’t even know where to look now does anyone have any answers

thanks

Toyotabc

4Crawler has a write up on shorting the fuel pump to run when the key is in the "on" position to bypass the Circuit opening relay and the AFM relay.

http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump

Could leave it in for a week and see if it fixes anything. Then you know its either bad relay or rotten wiring. Could also be a fuel leak thats small enough to not notice and it loses fuel pressure after an hour or so.

shafner30

I am thinking it might be the fuel pressure regulator VSV Supposedly it only turns on when the engine is warm what are you guys think about that theory?

scope103

I wouldn't drive around with the FP-B+ jumper in. The whole point of the VAF-COR circuit is to assure the fuel pump switches off as soon as the engine stops sucking air. If you get in an accident that breaks a fuel line, do you want the fuel pump to keep spraying gasoline on you?

Unlikely. The spec is for the fuel rail to hold pressure for 5 minutes. Your truck is designed to start easily from zero rail pressure, every time.

Unlikely. But easy enough to tell; just unplug the electrical connector.

Toyotabc

Doing the fuel pump check connector short would atleast tell you the fuel pump and wiring to the pump is working fine and the problem lies somewhere in the wiring to the relay or afm or the units themselves. Wouldn't be surpised if a wire is broken intermittently on a 30 year old truck either. I have replaced almost my whole harness with new wiring to fix the brittle wires causing intermit check engine lights.

Unless you can borrow a afm and circuit opening relay from a friend and test one at a time I would be checking out the wiring before buying any more parts.

scope103

True. But you do it once, if it then starts, you know the problem is in the direction of the VAF-COR circuit. There's no need to drive around with the jumper in.

But shafner30's problem is not likely to be an intermittent fuel pump failure, that only occurs when warm. Much more likely something like ignition timing or O2 sensor.

shafner30

It only does it when the engine is warm and it sits for an hour or two but if it sits longer it starts up fine I think it only does it in the closed loop it has never done it in the morning When the Engine is cold

shafner30

The engine fires right up when it’s warm when it sits for less than an hour

shafner30

.......

snippits

Check the ground wire from the battery terminal to the inner fender. It's a main ground. Mine was just barely hanging on.

If you need to redo it, just snip the wire as close as you can to the battery terminal. The ground wire is 8 gauge, so buy an 8 gauge ring connector with a 3/8 inch hole, skin the wire back, and then crimp it on there good and tight. The 8 gauge wire on mine with the new ring connector was long enough to reach, and slip over the battery terminal stud. Can't remember if a 5/16 hole size ring connector will fit over the battery terminal stud or not. Pretty sure I bought an 8 gauge 3/8 hole ring connector. I bought the ring connector from a local hardware store for about .35 cents.

You can also pick up a couple serrated washers for the bolt on the inner fender. Install the serrated washers, so that they are towards the paint...one on both sides. They will get a good bite that way.

RAD4Runner

Eliminate doubt on temp senders. Clean them THEIR MOUNTING THREADS AND THREADS ON BLOCK, connectors, etc, to bare, shiny metal.
This needs to be done once every 29 years

5/16, equiv to 8mm is more like it. Very common hole for ring terminal on our trucks.

Jesse W

I know this is an older thread, but any resolution to this? I’m occasionally have a similar issue.

RAD4Runner

No problem. Still a very relevant thread that bugs the heck out of many of us. LOL! It's like the Bermuda Triangle.
I thought I dad figured it out. After I cleaned my Cold Start Injector Time Switch in 2016, it immediately went away and stayed away for about 4 years. Then sometime around 2020 it came back. I had since:
1) Checked fuel pressure - readily went to spec as soon as I cranked.
2) Bypassed CSI timer switch so CSI always came on when I crank. i crank only a few seconds at a time, then retry.
3) I would turn off my fuel pump so it dies from lack of fuel- meaning no more fuel pressure in the lines- to eliminate doubt on leaky CSI
None of the above yielded consistent results. One freezing morning in Mammoth, CA it would go TADA-VROOM! Then next cold morning and most other mornings in various temps it would not. Very rarely after parking for a few minutes it would occur. However, it often happens only at first start in the morning. It eventually starts after a few starts. While, previously I would get rough idle upon starting combustion, now it does not.
Next thing to check would be my ECU temp sensing system.

Blueman

My truck never did this originally, but I think (can't say for sure), that it started when it got changed over to ethanol-enriched fuels. My theory is it's a flooding issue. Some day I'll find some non-ethanol (straight gasoline) fuel and test this theory. I've just learned to live with it, but it's the same symptoms: after an extended time with the engine off after being heat-soaked, it'll crank for a long time before it'll catch. Perfect starts when cold, perfect starts when hot as long it's within a hour or so of shutdown. I've had the same issue with a motorcycle.

shafner30

Are u getting gas in California ? I have the same exact issue

Blueman

I'm pretty sure you cannot buy gasoline in California without ethanol. The closest option would be to buy gasoline at a aircraft pump, but it would be both illegal and damaging to your catalytic converter as it has lead in it.

shafner30

Yeah I’ve been running supreme 92 octane there is a definite difference in the way the truck runs more power and smoother running and no pinging And it seems like the truck doesn’t do the long cranking as much as before

wallytoo

iTrader: (1)

next time attempting a heat-soak start, turn the key to start without pushing the clutch pedal down. hold the key in the start position for appx 2 seconds; then either push the pedal down or push the clutch start cancel button - while continuing to hold the key at start.

Blueman

Yep. I've tried that. No difference.

wallytoo

iTrader: (1)

and you've checked the vacuum line leading from the upper plenum to the FPR, right?