kiznar

96 t100 sr5 automatic 4wd 230k miles 3.4 v6
hello i'm kinda at a loss right now i just purchased this truck 2 weeks ago and do not know the history of the vehicle. i have been driving it around town and was running great it failed smog test high nox other stuff was okay. This vehicle does not have a egr it has the back plat on the 3.4 V6. now to the problem i drove the truck out of town for the fist time confident to how well it was running no stumbling always starts drives great. I made it 100 miles out side of town to my destination while i was up there i replaced the spark plugs they where the wrong kind for the truck but gaped correctly i replaced the plugs with ngk single post iridium spark plugs. it felt like it had more power after the plugs where installed the other ones where bad but still running fine. i also put sea foam in the gas tank and drove around town burning half a tank of fuel no problems ran fine. i drove it back home while doing this the truck shutoff i did not even know i lost power i made it about 95miles right by my house now the truck will start for 1-2seconds and shut off or die it almost as though the computer is telling the injectors to shut off. I towed it to a shop where he said it was the fuel pump had him replace it same problem wont start runs 1-2seconds dies he said it was the icm and there 500.00 new i honestly dont want to spend that much money on a maybe at this point i still have the cat that i think needs replaced and o2 sensors possibly. my code reader says p1300 ignition timing adjustment terminal his code reader says Igniter Circuit Malfunction . we both spent alot of time looking it over the plugs have spark is there anything you think i should check or where i need to go any advice is much appreciated at this point. checked all fuses they seemed okay. i forgot to mention he put a light a pulse light on the injector passenger side by the firewall and it did run then it stopped running i dont know if it was luck but i figured id mention this.

wyoming9

iTrader: (1)

That code P01300 will cause the fuel to be shut off so the injectors quit firing .

That is why it will start and then shut off.

Now remember this is the complete circuit the igniter all the wiring to the ECM and the ECM itself

What is happening is the ecm is not seeing the igniter signal it shuts off the fuel to the engine that it thinks does not have spark

Could be the igniter got hot if this was the first long trip.

Might be the ECM although unless it got wet or had a voltage spike they tend to be pretty long lasting

Might also be a poor connection that got hot

This has nothing to do with your Cats or O2 sensors or your fuel pump

kiznar

thank you for the response i just ordered another igniter im hoping that it will fix it i will post back here after i get it installed wont be here till the 9th of jan.

wyoming9

iTrader: (1)

Good luck I really hope that cures your problem!!

kiznar

got the icm installed today no change does the same thing how ever when i pull up on the ecu wires slightly it will runs so im guessing a short looking for a diagram not really good with this kind of stuff .

wyoming9

iTrader: (1)

No your not looking for a short!!

a short causes circuit protection to open or burnt and melted wires or vehicle

What you are looking for is a open circuit ( broken , burnt , chewed , corroded or loose wires)

Well since you bought a new Igniter a new ECM may as well pony up for a new Engine Harness if you can still buy one.

T100 curse strikes again !!

kiznar

im assuming the loose wire broken chewed wire is going to be right in that insulation because if i pull up it will run .
if i move the harness from the position its in to that tab it runs so im hoping its right there.

Rocky1

You have my sympathies! I'm in the middle of trying to diagnose a P1300 on my 96 4runner - I have fuel, wiring connections check out between ECM and igniter, but no spark. Replaced the igniter (with a used one) and no change - no spark. Am wondering if a bad Camshaft Position Sensor or Crankshaft Position Sensor can be signalling a problem to the ECM which keeps it from allowing the igniter to charge the coils? I know I'm in over my head, but at this point, it looks like the next step is to replace the ECM - something I don't want to do for obvious reasons (money!), so am looking for other possibilities. Any ideas?

atcfixer

iTrader: (1)

I've had similar issue, but I bought the truck with a bad ecu and tried to plug in the wrong one (auto vs manual) and burnt the 3 coils and ignitor. Repinning the ecu connectors to match the version I had for the replacement and replacing the 4 parts got my truck running.

Anyway, based on your description, I'd assume a broken wire, corroded (someone piked a hole in the insulation), or a critter did some chewing. What you need to do now is if you don't already own one, buy/borrow a multi meter, cheap tool but very useful for electrical work. And the multi meter is to test each wire from the ECU plug to the igniter. When I was testing mine I could do it without extending the leads.

I took a paper clip and hit it with a hammer to make it flatter and it would plug right into the ecu connector quite well. The paper clip adds a bit of resistance, but I'll ignore that since we are looking for very high resistance or no connection. Wire diagram and connector pin out (as you look at them from the end the pins go into it) are located at the bottom of my post for your exact truck.

The ECU is fairly easy to get to, it's located in the kick panel area on the passenger side of the cab just in front of the door. After the trim is out of the way, I'm pretty sure it was 10mm bolts holding in the ecu. Once it's free it should be fairly easy to unplug. It's best to have the battery unhooked while poking around like this, it's also safer for the ecu when you reconnect the connectors.

Test points (all should show low ohms 0-100ohms, wiggle wires around to see if any changes like you did before)

Igniter pin 3 (brown wire) to battery neg (it grounds though the body, but should have good connection to the neg terminal for battery)
Igniter pin 4 (black/yellow wire) to ecu plug E7 on pin 12 (pretty sure this is the signal the igniter sends back to tell the ecu the engine is running/sparking and is probably the wire at fault)

These bottom 3 I'm pretty sure would only cause a miss on 2 cyls, but doesn't hurt to test anyway.
Igniter pin 5 (black/white) to ecu plug E7 on pin 26
Igniter pin 6 (brown/black) to ecu plug E7 on pin 25
Igniter pin 7 (black/blue) to ecu plug E7 on pin 24

This one I'd guess runs a different route, but it ends up at the AM2 fuse as the positive/power wire. You will need the ignition switch to on to see connectivity.
Igniter pin 9 (black/red) to AM2 fuse (or battery positive terminal [still with it unhooked from battery] should work too)

Let us know if you find any bad wires. If you do you'd have a couple options to fix it, the "easy" way is to run a new wire from one side to the other bypassing the bad spot in the wire, but the more proper fix is to find the exact spot it is bad (the test before is to find which wire(s) are bad) and fix just the bad spot. Do NOT use scotch locks! Proper butt connectors with a good crimper and sealing with adhesive heat shrink (has glue inside) or soldering and sealing with adhesive heat shrink should be what you do for a long term fix. NAPA has it even though nearly every salesman there has no clue they have the stuff lol. NAPA part number is 784755. It's not the greatest stuff around, but it's much cheaper than the high end stuff I use on my wire harnesses I build. Here's the link to the stuff I use, but shipping and min order makes it expensive for a one time fix. http://www.cycleterminal.com/sleeve-tubing.html - scroll down till you see the black and red tubing. It shrinks down very well and remains smooth etc, the NAPA stuff doesn't quite as well since 18 gauge wire is the smallest it can go. Heat gun/solder rework station is ideal, but a lighter works too for sealing it.

Good luck on the repair, hopefully it's a pretty simple fix. Once you're done it's best to reseal up the harness well and secure it as well as oem (zip ties work just don't make them too tight).