ZARTT

I helped my son-in-law swap in another 3VZE motor in his 95 4RNR 4x4, with an A/T.
All went well mechanically.
First start try-no spark-no start. Cranks OK-good battery.
Last thing we did before the swap, is drive it into the garage with the old motor, and then took out the battery.
There is no chk engine light now, when the ignition is turned on. All other dashboard functions operate.
I have triple checked every electrical connection that was removed and replaced during the swap.
All fuses have been checked as good.
I am from a less complicated generation of backyard mechanics, and I am unfamiliar with ECM controlled cars.
Any guesses???

thanks
Art.

wrnchplr

I just went thru that same issue not long ago.....if there is no spark start there. is there power to the coil? is the coil it's self hooked up?? sounds simple but after a few hours under the hood it's easy to miss something.

Innervision

Check all the grounds on the driver side. Make sure there is good contact sand and replace if they are rusty or grease covered. There are a few small gage ground wires on the driver side that are easy to overlook.

ZARTT

Did an ignitor/coil tap test, and got a nice fat spark from the coil wire to ground.
The distributor has been swapped out with a servicable unit.
I still don't get a spark when I crank the engine.
I have checked all of the wires from the ECU to the ignitor/coil/distributor for continuity, and all are OK.
The CEL will illuminate with the key, if I put a test lamp between the CEL pin on the ECU and ground, but will not come on without the test light in the circuit. At least I know the bulb in the dashboard is good now.

The distributor is rotating when I crank the engine, but if the timing belt was off a tooth or two, would that keep the ignition from working???
This is starting to look like the ECU took a hike, but most techs that I talk to say that an ECU dying is very rare.

ZARTT

Hasn't anybody ever seen or had this problem???
The bulb is good, but doesn't illuminate when the ignition is turned on.
This prevents me from pulling codes with a jumper.
Is it common for the ECU to die??

aussiejetpilot

ZARTT we have the same problem. I have 1994 pickup with the 3VZE engine that I just replaced. The old engine blew the head gasket and I went with a rebuilt long block. The old engine was still running when it was removed so its a fair assumption that the parts should still work.

There has been no spark on the new engine since day one.

I've tried all the tests mentioned on yotatech. and replaced the ignitor and coil with a working used set.

I also have NO Check Engine Light when I power on the ignition, I removed the instrument cluster to check the CEL bulb, and it works just fine.

Tonight I tried another (used) ECM, no change in the CEL behavior.

Last night I had a couple of Toyota techs take a look at it, the engine is too old so they had not been trained on it but after conferring with some older techs today, their advice is to change the distributor. With no working CEL, I think I'll wait to spend $250 on a rebuilt distributor.

Sorry I don't have the solution for you, I am starting to think damaged wiring may be to blame.

I hope someone else has seem this problem and will help solve the problem for both of us.

ZARTT

I have made no progress on my dead ignition problem.
I have swapped out the distributor with a working unit to no avail.
I have ohm'd out every circuit for continuity and grounds.
I have swapped in another ECM also.
I can light the CEL by grounding pin A5 on the ECM harness with the ign. sw. on, which proves out the bulb.
The ignitor, coil, circuit opening relay,EFI main relay, integration relay, and all fuses, are good
Nothing seems bad.
Is there some kind of anti-theft circuit that would immobilize the vehicle that I don't know about??
I don't see one in the wiring diagram, but there is some kind of horn thing mounted under the hood on the fender house up in the corner by the hood hinge. There appear to be some disconnected wires under the left kick panel that are associated with the horn thingy.
Could that be some kind of immobilizing burglar alarm??
None of that stuff was touched while doing the engine swap.
Would a bad AFM cause the ignition system to quit??
Anybody want to tak a stab at it???


Art

aussiejetpilot

Check the "cant get spark" thread. I removed the VAF (air mass flow sensor on the air cleaner) connector and my spark came right back, the engine even fired up for the first time. I have the plastic top off my my VAF now but I can't see any obvious problem.

ZARTT

Are you sure that you are not looking over my shoulder?
This is really strange.
I went out this A.M. for another shot at diagnosing, and went down the same path you did with the same results.
I now have a CEL when I turn on the ignition switch.
I haven't tried to start it yet, but keep your fingers crossed.

ZARTT

Problem solved...........MAF was bad.
Discovered it with a VOM. Two of the pins in the assembly should read between 200 and 600 ohms according to the procedure, mine read zero ohms.
I pulled off the MAF plug, and when I switched on the ignition switch, the CEL light came on.
I think that it shows some poor engineering, that the MAF can totally disable the vehicle like that.
Oh well....the replacement 3.0 runs pretty good, good oil pressure, and normal range for temp.
It has a ragged idle, and doesn't smooth out till about 2500 RPM.
I still have some work ahead of me.
Thanks to all on this forum for the wealth of knowledge you all share.
It's good to know that you are out there.

Art.

aussiejetpilot

Nice, did you buy a new MAF?

I flipped the lid off of mine and found some some tin contacts that the the rheostat arm hits at the air mass flow increases, these had shorted out. What does this do does anyone know?

Mine idles great with the MAF (VAF) sensor disconnected but won't accelerate. I can't keep it running with the MAF connected, again, anone have any ideas?

ZARTT

Pilotguy:

I went to the dismantle yard. They had 2 of them to choose from. I ohm'd out both, and purchased the one that was closest to the values on the check sheet in the FSM. It was $55.00US

http://www.ncttora.com/fsm/1990-1995...5/contents.htm

This is the URL for the site that has the complete FSM. There are procedures for checking just about everything that could be causing your problem.
Give it a shot.

Art

ZARTT

Ragged idle turned out to be incorrectly hooked up EGR vacuum feed.
EGR was on all the time.
Swapped the feeds, set the idle, and checked the timing, and all is smooth as silk.
Thanks again one and all.

Art.