Greg Klima

I have a 93 toyota pick up with a 22re.The problem I am having is the truck will not start.It is an electrical/fuel problem i think.If I jump the (Fp) to (+B) pins in the diagnostic port the truck starts right up but runs a little rough.I have replaced a lot of parts to try and fix.The parts I replaced are fuel pump, sending unit, fuel filter, air flow meter, cold start injector, and computer. Are there any other suggestions you guys might have.Any help you guys could give me to steer me in the right direction would be greatly appreciated.
Thanks Newbie

thook

Have you checked the timing at any point?

Greg Klima

yes.Its right on

rdharper

I'd get the electrical diagram... trace the line that provides B+ (including the fuse). It does sound like the fuel pump is not being driven. Probably a relay involved in that circuit as well. Likely suspects are fuse, relay, connections and lastly broken wires.. roughly in that order.

captain_howdy

this is gonna sound really stupid, but check your starter ground cable. comes off the battery, goes to the starter. tighten it on there real good. mine was loose, I'd have to get out and move it so it would ground right, and it would start every time... sort of...

84sr5yoty

What do you mean by not starting? Does the engine crank, but not run or does the engine not even crank over at all?


I'm not sure what component cycles on by jumping FP to B+, but I have a good idea that it's the fuel pump. You're going to pissed, but I think your problem is just a bad circuit opening relay (fuel pump relay). Jumping the fuel pump connection bypasses both the circuit opening relay and the air flow meter, cycling the fuel pump on. That's why the truck runs when it's jumped.

TomThumb

Got the same problem I had. If it was the Fuel pump relay it would not start even jumping the terminals, In the VAMF sensor on top of your air box there is a sensor or switch that starts the fuel pump when the baffle plate inside moves when you crank the engine. Replace your VAMF and truck should start fine, learned this the hard way on my 91.

dcg9381

The relay is activated by the switch at the VAFM. If the switch on the VAFM is broken, then your pump won't run. If you look at the wiring diagram, you can actually figure out what gets closed when air flow is detected.

There is no relay on the AFM that runs the fuel pump.

Greg Klima

If you are talking about the air flow meter on the air box. I already tried that.I took one off another truck just to try and I had the same results.The truck will crank but no start.If I jump those pins in the diagnostic port, it starts right up, just runs a little rough.I am baffled, i dont know what to try next.Keep em comin guys I appreciate all the help.

dcg9381

Have you physically moved the AFM flapper with the key in the ON position and the AFM hooked up? When you do so, you should hear the pump come on.

You need the wiring diagram from a 1993. When air flows, you're closing the connection between two wires on the AFM. This is a ground circuit and it turns on the fuel pump relay.

If the AFM "switch" is working, you've either got a bad ground or broken connection on one of those two wires. You'd need a diagram to trace it.

Greg Klima

Thanks I will try that right now

Greg Klima

ok, when I push the flapper the pump does not run.Like i said i tried a new afm.So it must be wiring.Where do i go from here.

dcg9381

Wiring diagram. Check continuity from AFM connector to the relay that powers the fuel pump.

I have a 1st gen. Without a wiring diagram, I can't point you in the right direction.

Greg Klima

thanks for all the help. I have a haynes manual in front of me trying to figure it out. Its not the best diagram but hopefully it will do.I will keep you informed

dcg9381

Might check 4x4 wire for the 93 manual, also...

Greg Klima

found the problem. it was the circuit opening relay. it was full of water.

bigt

i think that deserves a cold one!

Greg Klima

yeah it does. I didnt think I would ever figure the problem out

rdharper

hmmmm.... duplicate

rdharper

You are welcome!