Cranking issue: maf? fuel pump?
 

Well,

Thanks to you guys I got my coolant leaking taken care of. It was the pipe between the heads for anyone that saw those posts. Now here is my next issue.

Cranking, It started off only happen once a month. Would turn the key and the engine would turn over, crank, run for a second or less, then die. Would do it on a warm engine or cold. Let it sit a bit (around an hour), and it would crank up.

Now the problem has moved to everytime I try and start the truck. I can crank it and press the gas to the floor, it will run like utter you know what for 20-30 seconds and then you get one good rev and she runs fine.

With the pedal on the floor while trying to crank the engine sounds like it is missing horribley, loud clunk sound, and then that one good rev and presto she runs like a dream.

No hesitation while driving, after she gets cranked everything is peachy. As my regular transportation I am a little worried (got to our downtown offices this afternoon to drop off some stuff and thought I might be stuck, and you know, stuck at work = homicidal thoughts.) Plugs and wires are fairly new (within 6-7 months), didn't do the distributor or rotor though.

New fuel filter (3 months old).

I tried doing the FP pin to B+ in the diag box, it worked twice but hasn't the last couple of times. A PO sprayed some kind of grease/protectant stuff all in there and it seems to be hard to get it out and get a good connection.

Edit: I think it has something to do with fuel delivery. When it would not crank this afternoon just happened to have a can of starter fluid (luck i guess, from a previous car all together). Sprayed it into the intake and cranked it and got it reved high, it idled down and ran fine. If the Fuel pump was going out, wouldn't it just quit running period though?

sounds like an oil pump and fuel filter

Im going through a very similar issue.
Oil pump doesnt sound llike the problem.
Sounds like fuel delivery to me also, cause i know that has something to do with my issue
With my ignision on i can hear the pump going, then i crank it runs good for maybe 5 seconds, then bogs down and dies.
With the fp+b jumped its fine, runs exactly how it did before my problems started.
And my fuel pump is under 1000 miles old
Trying to figure this out....ill check in soon

As for that grease protectant stuff in the Diag box, mine has the same stuff, you just have to get the paperclip or wire in there well enough, i've had it not work once, check it, tighten it in there a bit..good to go.

EDIT: replaced my EFI fuse, still same issue, going to check the fsm for the Circuit opening relay trouble shooting, thats the next thing i can think of

If it was the oil pump wouldn't I be getting low oil pressure or none at all?

I physically can not hear the pump running, I haven't stuck my head under the truck yet but it isn't noticeable standing at the engine bay.

Not positive but could be the TPS or IAC maybe even the fuel pressure regulator too!

Run a power wire directly to the fuel pump power. Under your seat is a plug and the light blue wire is the power. You should hear the pump run for a second or two when the ignition ACC is turned on.

have someone turn the ACC on while you sit outside and listen close to the tank. If the pump does not turn on its probably the FP or wiring to it!

Hey guys, I just went through this same problem on my 86 4Runner, it started out being hard to start, warm or cold it didn`t matter, then one day it just wouldn`t start at all. I did all of the usual checks, fuel pump, fuses, relays, thermal temperature sensor, and nothing worked, so i had an extra solenoid resistor laying around so i tryed that and to my suprise it started. ive never heard of that part going out before, but i guess theres a first time for everything.

I would put a fuel pressure gauge on it first and make sure the fuel pressure is within spec and if it is then check the volume. Even if the pump is running, it could be wore out with age. I didn't see if anyone mentioned it already but if they did sorry. Just a free/cheap thing to check before you dump any money into it.

The fuel pump is not on in the ACC position, in fact it only turns on in START mode or once the engine is running and pulling air past the AFM and forcing the flapper vane inside to open. You can use the fuel pump test jumper to turn the pump on with the engine off:
http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump

http://www.4crawler.com/4x4/CheapTri...s/FuelPump.gif