john22rebuilder

First off Aloha guys my first post here! I hope im in the right thread for this.
Ok, so here goes it.
My neighbor has a 99 taco 2.7 4x a few weeks ago it would no start at the store, so he had a "mechanic" (lol) look at it. He said it was the fuel pump, so he changed it that took 2 weeks!!! Shoulda been the warning there but whatever. Then he says still dont start and he tried swapping all sorts of stuff, including the ecm and that the problem was in fact, get ready :gasp: the ECM. He couldnt locate another from the juckyard supposedly he was using one from a friends truck so after another unfruitful week we had it towed here then we ordered one (ECM) from an online juckyard installed it and same problem tested that ecm on another taco and it does work. So he lied instead of saying he couldnt figure it out. Heres the rest that has been done: replaced crank and cam sensors, tested the circuit opening relay (both for open and closed with 12v power) tested the "hot wire" type air flow meter, snap on scan tool showed no signal for ignitor bank 1 (code: p1300), replaced Both ignitor coil packs. Taco still will not stay running i.e.: turn key on fuel pump primes up start engine, runs smooth for 2 seconds and dies. Very nice spark truck will run if ether is sprayed into brake booster vaccuum. Very good fuel pressure as well(new pump,strainer, and filter). Seems to boil down to injector pulse any ideas? Thanks so much any advice is awsome!
Aloha!
John

wyoming9

iTrader: (1)

welcome!

If you think both the ECM and igniter are good I would look to the injector ground.

Possible in all the swapping of things they got moved or bumped does not take much for them to lose contact.

Have you got to the point of checking to see if the injectors are getting the signal.

In the little you have had the engine running has the P1300 comeback if this is still in the ECM it might keep it from running.

I know with my 3.4 that was the case start and shut off yours sounds about the same.

Be nice to know where you are if your close I would be glad to help.

john22rebuilder

Thanks Wyoming! Injector ground huh? Where is that just from the rail to the body ? I have a nice multi meter and a small 3w test light how would i go about testing for a signal to injectors? Or do i NEED and led type test light? I will get one if thats the case. Oh and im in Hawaii thanks for the offer tho!
John
Oh and battery was removed to clear codes just to be sure.

wyoming9

iTrader: (1)

Standing on the left side (drivers side) it should be on the first intake manifold as the Injectors ground through the ECM it has been a long day

I am sure you need the noid lights to check the injector pulse.

Like all else you get what you pay for!!

john22rebuilder

Will pick up noid light today and check grounds n pulse tonight if u or anyone else can think of something im game. Am i right in assuming if the o2 tps and or maf were bad it would still start right?

j2the-e

I found a feather once on the wire in the maf sensor causing a no-start. You can unplug the maf and try to start it to rule that out. If you unplug it then try to start, it will go into open-loop fail safe mode. If it still won't start, look elsewhere

john22rebuilder

Thanks j2! Yes i ran the ohm meter test too. Unplugged maf as well starts and dies as before. Same condition as when it died originally.Got the noid lights just now!!!! Wooohoo only 20 bucks, 6 lights and a sweet red storage case!!!!

john22rebuilder

Ok status update:
Pulled grounds off sanded till shiny & reinstalled, plugged in new noid test light(hint its the gm pfi one) pulse till start gone after that still will run on ether but no pulse to injector

j2the-e

Have you checked all of the fuses? Any chance the cam is broken? The part the sensor picks up? Or the crank sensor is loose or the wheel behind the timing cover got damaged? Any codes come back after clearing from testing?

vital22re

iTrader: (2)

I think its either the pump or wiring to the pump (COR). Try hot wiring the pump so it constant on or make sure you've got 12v at the pump when its trying to run.

john22rebuilder

Checked all fuses. You can hot wire the fp on this one at the cor just jump b+ to fp like all the earlier models its missing the jumpers at the diagnostic port. And yes still no run. What i need to know i which component sends the pulsle to the injectors. All sensors were installed correctly as well. No codes
I guess i could pull off valve cover and inspect cam. Thanks for all the advice! I have a feeling. the fix is real close

wyoming9

iTrader: (1)

Your injectors are fired by the ECM perhaps corroded connections is this the original one or is it the yard one.

It could just be dirty.

The ECM sees it like all is good.

john22rebuilder

So today i will remove all plugs and connectors i can access including the fp on at the tank as the pm may have done something awry also at ecm &etc clean with qd cleaner and lube up with some dielectric grease....
@Wyoming this is the jyard ecm the original is on oahu with my neighbors son he wanted it to try and match up at a yard there to no avail. Will be recieving that back shortly.
I also belive that the injectors are clean because it does start and run (only for a moment tho) but looses the signal somehow. I know someone has had this happen and its gonna be such an easy fix.

rokblok

iTrader: (1)

This may be a long post, but I will throw it out there...

I swapped a 2.7 into my '84. It has died on me twice and both times it was a relay that I added. The reason for the relay was to lighten the current load on the 84 ignition switch. The 84 doesn't have near the electronics of a Tacoma, so I was worried about frying the wiring. Well both times my truck died it was that added relay killing power to the ECM and such. Gave an igniter code both times, but I don't recall which one. I finally eliminated the relay and it hasn't acted up once since.

So if you can get ahold of a FSM electrical wiring diagram, I only have 1998 version which may be the same, you can check voltages at ignition switch and at ECM connectors. Certain positions of switch provide voltages at different places on ECM. I'm not saying this is your issue, but it probably wouldn't hurt to eliminate it. It's an easy check with diagram.

On my 98 motor, it was originated at a 30amp fuse(AM2), be sure to check both sides of this fuse, then white/red continued to ignition switch terminal AM2, exited ignition switch as a Blk/red(IG2), which powers coils and injectors. Not the signal, just the power. Black/red to anything in engine compartment is 12V positive. So check that 30amp AM2 fuse and 7.5 amp IGN fuse(which controls EFI relay) and go from there.

Kiroshu

Suspect Engine RPM signal Via Crank shaft position malfunction. Check wiring harness for CKP sensor for damage... possible faulty part...? Possible short circuit and or short to ground Via damaged CKP harness...?

Re-flash computer...?

john22rebuilder

Rokblok awsome info will definetly give that a look late day at real job so will give all this a look over on Saturday
Kiroshu well i changed the crank and cam pos. With new and still acts same so i got extras now... no can re flash this one either like i said ecm tests fine.
Thanks guys/gals !!! Its getting close
Aloha!

john22rebuilder

If none of these tests come out good i will pull valve cover just to get a lookie loo but i thing its gonna look great in there.

Kiroshu

On these set-ups Ignition(spark) and fuel supply(gas) are not provided until the computer sees engine revolutions(RPMs) during cranking time.

rokblok

iTrader: (1)

Kiroshu, in my opinion, that's only partially true, if you're referring to a EFI set up. The fuel pump is turned on via ignition switch, relays, etc, and not the cam/crank sensors and ECM. Granted, the injectors aren't receiving a signal if the ECM isn't getting cam/crank sensor signals, but fuel is still supplied to the rail. If you had a faulty grounded injector wire, it would remain open and allow fuel to enter combustion chamber. Yes, the injector would likely get fried eventually, but it would allow fuel to pass through.

So, to the OP, there are essentially only a few things that could be wrong, excluding COR and fuses and wiring and ignition switch--- the ECM, cam sensor and/or crank sensor. But I'm thinking this problem is fairly simple to repair, since you've already replaced the ECM, and checked the COR. Because since you did the noid light test, and received no signal, you also have to remember that the injector needs the positive(12V positive via fuses and ignition switch) to accurately perform the test. You may have been getting the negative signal from the ECM, but without a positive, the circuit can't complete and the noid light won't illuminate. Just my thoughts...

Kiroshu

I believe on the Tacoma's the fuel pump is only energized for 2-3 seconds when the Ignition switch is turned to the "ON" position and then re-energized during "cranking time" VIA signal from starter relay.

I believe anyway. Been a while since I've been around one ^_^. But lots of vehicles do operate this way with variations obviously.