as long as the VMAF is reading correctly (this is the first line of kicking the pump on) the fuel pump will kick on, if you dont get initial response from the fuel pump, the MAF (mass air flow) sensor could be reading wrong. A good way to test is by a great thread by 4 crawler, jump the diagnostic box with a paper clip in ports fp and b and see what happens. It worked on my rig 3 days ago, finally got fuel coming up properly to the main feed line. Circuit relay is possibly bad on my rig.

See if the fuel comes freely if not may have a clogged filter or line, if you get good fuel flow, then you have something from the fuel pressure reg to rail to injectors, and so on. It only takes about a minute to figure it out.

 

my old truck did the same thing and it turned out to be a clogged fuel filter and injectors. I cut the filter in half and it was full of gunk.

 

ok further into the problem...here we go...now it wont start...

I found the Air Flow Meter has a broken spring, and ordered one from a junkyard in Oklahoma. it should arrive in 2 days

Tonight i decided to try and "repair" the spring. really, i did it, i reattached the clockspring to the shaft. The spring is about 1% shorter so the spring rate might have gone up just SLIGHTLY. the variable resistor varys voltage from 2.5v-7.5v as the air flow door goes from closed to open. the IAT sensor meets specification. The fuel pump kicks off when the plate fully closes as it should, and it kicks back on when the plate is opened a little. Everything inside of this origional Air Flow Meter appears to be doing its job now; i played with a voltmeter with it with the key on for about 2 hours just learning how it works. obviously i had the black sealed cover removed from the top of the Air Flow Meter so i could play with a voltmeter with the key in the on position.

i tested both sides of the coil, 12.6volts. the ignitor box is getting 12.6volts to it from the center top wire of that harness.

i could not get power to either of the 2 pins in the harness going to the distributor. (cam sensor?) maybe there's not supposta be power going to it.

still just crank, no start. garage smells like fuel now. it ran (very crappy)before i pulled it into the garage TODAY and played with the Air Flow Meter and the water pump. now it won't even start.

other things i did to the truck tonight:

yes, everything is connected. TPS, Cam sensor, air flow meter, coil, plugs, injectors, 5th injector, all solenoids. both of the temp sensors under the throttle body. EFI fuse is good. fuel pump runs. coil has power on both sides when key is on. i only removed 2 belts, fan, shroud, water pump, and the intake tube, and airbox. there are no cracks in the intake tube and everything is tight.

i know i've got that new AFM coming in 2 days, but i think REALLY did successfully did repair my origional AFM. What if the new AFM doesn't fix it?

if i really did fix this Air Flow Meter, i think the ignitor or coil miraculously went bad on me, today. is the voltage of the negative side of the coil supposta "pulse" when the engine is cranking? i would think so.

i'm going to bed, thanks for reading. i'll be looking forward to your ideas and comments.

 

the pulsing voltage should be the distributor triggering the coil,on off on off. I would think that's normal.

 

how do i test coil? ignitor? pcm?

 

Test the Throttle Position Sensor. Resistance at closed throttle is important as well as changes in same as the throttle is moved. I forget now what the different resistance values are supposed to be but if there is no continuity at closed throttle, no signal to ECU.

 

You can get the info to test for this and readjust it off of 4crawler.com.

 

i have no idea if this could be it or not, but what about your egr valve? i dont think this would make it not run at all but if it was stuck open it could make it run like cap and mabey even foul the plugs. this could be a stretch and just plain stupid but its an idea.are you still getting spark? if not check this out and best of luck

 

good thinkin. i vacuum tested the EGR valve the other day during my initial diagnosis. the engine struggled, proving that the EGR was working correctly.

 

i still say block it off anyway. i did it recently and it seamed to improve drivability

 

No need to block it off, just disconnect everything from it. Mines still connected:

 

acctually a just plugged the vacuum lin going into min and it did the job. no CEL or ill effects so far. but mines a 3.0. but same diff. for emissions i can just un plug the vac line and hook it all back rite and im golden

 

Refresh my memory, you were checking the fuel line that leads out of the fuel regulator after it pass through the injector rail?

This sounds a lot like another vehicle of mine where the regulator bunged up and wouldn't release fuel from the rail....

 

no, the vacuum hose going to the FPR did not hav fuel leaking out, meaning the diaphram was not ruptured.

yeah, i've ignored the regulator for now until i get this air flow meter thing figured out. it comes in the mail this afternoon, i'll try the new part today.

 

I had the exact same problem. i replaced the tps and set it correctly, the symptoms changed slightly, but problem re-arose after about a week. Then i replaced all of my vacuum lines, same deal, ran good for a week, then back to the issues. then I blocked off my egr, adjusted idle air screw, same thing, ran good for a week, then back to problems. then I did plugs, wires, rotor, and cap, same thing, fine for a week, then bad. then i swapped the ecu with a good tested used one, cleaned the TB, and tightened the clamps around the air intake tube at the afm and the TB, and for the past week, it has been running fine, so, with my fingers crossed, I am seeing how long this lasts, or if this actually fixed the problem. hope maybe a little of this helps ya or at least gives ya something to think about. oh, and through the whole thing, no codes have ever been present

 

UPDATE

i installed the new (junkyard) air flow sensor today. IT RUNS!!! but... it runs smooth and at 1100rpm's when cold. but, its still VERY VERY RICH!!! keep in mind, it may just be running smooth because of the high cold idle. its possible when it warms up, the lower idle could be pretty rough.

here's some tests i did tonight:
when i disconnect each plug wire one at a time, the rpm's drop for each cylinder. each cylinder has spark.
when i crimp the fuel line return hose, the engine bogs down, because of the increase in fuel pressure.
i blew the water out of my Coolant Temp Sensor from the other night. it ohm's out fine by the way.

i may go unplug each injector one at a time. maybe one is just dumping a crazy amount of fuel in for some reason.
i think tonight i'll check the TPS also. i've printed off the info from 4Crawler.

 

another update real quick.

maybe it doesn't run rich, haven't concluded that yet.

pulled codes:
13
14
22
24
43

HAHAHAHA!

 

you can test the coil by holding the distributor end of the coil wire with some plastic pliers.if you hold it bare handed you ride the lightning,it tickles.hold it about one inch from where it goes into distributor cap while someone cranks the engine for you. you should see a blueish color spark if you still have charge in your battery.less than 12 volts effects your ignition strength.if it's sparking at all igniter is fine.dealer tech said they rarely fail.

 

if you are getting trouble codes in test mode I would think it's fine.fords send a code for each test that signals the pcm is fine.I don't know about toyotas.

 

FIXED!!!!!!!!!!!!!!

it runs perfect now. although its a little slower (partially because of the airbox silencer is installed now), the throttle sure is much smoother than it has ever been. its actually easier to drive now.

ok first i want to thank everyone for reading this post and helping out. it has been a great help to me and i learned alot.

the problem WAS that clockspring in the origional air flow meter. when i installed the new (junkyard) air flow meter tonight, i though it was still running rich because of all the fuel that was STILL in the exaust. the codes were in my computer from the other night when i was cranking on it with alot of stuff disconnected, etc.

let this be a lesson to everyone, if this happens to you, check the clockspring in the air flow meter.

by the way, with all of my searching, i found an online shop manual for a 93 Toyota Pickup....

http://personal.utulsa.edu/~nathan-buchanan/93fsm/

enjoy. thanks again.