Retrop

I was driving home from work and my 96 T100 with 3.4L V6 and an automatic tranny died. It just fell flat on its face; I had to have a tow truck come get me off of the bridge I was crossing I have done some trouble shooting and found that I don't have any spark. The lower crank position sensor was out of tolerance (1980 Ohms) according to my manual it should be (~2035 - ~3100 Ohms). I replaced it with a new one but it didn't make a difference. I have also replaced the ignitor and tried swapping out the ecm with no luck. I have verified that the coil packs and ignitor are getting 12 volts. I haven't replaced the camshaft sensor but it appears to be within tolerance and harder to get at. Truck turns over fine and is getting gas; I have well over 3/4 of a tank. I am new to YotaTech and really hope somebody can help me get my truck running.
Thx!!!

Slednutjetskier

Did you check your timing? Are you coil packs operating properly? Cap and rotor condition?

My friends used to pull out the coil wire just enough to have a bad connection but leave the rubber connected.. Or they would rip the tip out of the wire but then put the tip back in the rubber cap of it.. Check those wires and connections all the way to your plugs and the timing to start off.

Retrop

I have not checked the timing yet. I'll have to borrow or buy a timing light. How do I check if the coil packs are operating properly? It doesnt have a cap and rotor but I have checked all the connections.

RandyÄ

My first checks would be fuses and relay. There are at least 3 fuses that would be suspect. EFI, IGN, and OBD. Also the EFI relay plays a part. The fuses are easy enough. The relay you'd need to pull and power the 1 - 2 pins and check that 3 -5 close (i think the #s are right, there's a diagram on it).

Just because there is power at the coil packs does not rule out one these fuses.

Beyond that, the only routes are systematic tracing or pay the alligator.

Retrop

All my fuses are good. I will try and check the EFI relay; is it in the fuse panel under the hood? I am really trying to stay away from the stealership if possible.

Retrop

EFI relay is good. Please keep the ideas/suggestions coming...

MTL_4runner

How did you check for spark?

Make sure all your grounds on the engine are good, a bad ground can stop the ECU dead in its tracks. Fuses and relays are another common issue that can kill spark to the motor. I'm attaching the igniter circuit and flow chart from the FSM for you to troubleshoot your own vehicle.

Slednutjetskier

I cant believe I didnt think to mention that! (good thinking MTL_4runner)

Grounds are the most important and easiest way to lose spark if you wheel. (sticks, corrosion, heat wear..blah blah) Its always a good idea to check those about 1/4 as often as you check your nutting function, so basically once a week.

Retrop

I am checking for spark by pulling a plug and wedging it against the intake while turning the engine over (Works on my 4Runner). I have checked all the obvious grounds I could find. Should I check any ground in particular? Can I install an additional ground just to make sure?

MTL_4runner

Main grounds are on the driver's side of the intake plenum.
There is also one on the back of the head on the passenger side.

Failing in that, start going through the FSM flow chart.

doctorturbo

re-place the coil

Retrop

My T100 lives!!!! I should have spotted the problem sooner... I replaced the timing belt around 500 miles ago and torqued the crank shaft pulley bolt to spec however the bolt came loose and the pulley walked out. This time I used a 1/2" breaker bar with a cheater; definitely should not be coming loose again!

mjwalfredo

LOL!!!

Be careful that the woodruff key for the pulley went into it's slot on the crankshaft. When I had my timing belt done the, the dealership's tech didn't do this and I had to drive from Atlanta, Ga to Columbia, SC with the pulley walking off every 60 mi. I had tools to tighen it back up as much as I could but I didn't know a damn thing about timing belts and the cranshaft pulley when it happened. That was a long drive!

Now, I've got a scared crankshaft that the dealership just screwed me on. They said it's not a racing engine so the scar on the crankshaft won't do any harm.

MTL_4runner

Double check that woodruff key and the crank to be sure they aren't damaged. Also check those torque specs (217 ft-lbs MINIMUM) again and use some loctite red on that bolt to keep it from backing out or you may be in for more problems later.