MightyMonte88

Hey guys just joined the forum, i've got a friend with a 1993 4runner, 2 wheel drive automatic. I'm trying to help him sort this thing out but it's turning into a nightmare.

It stalled out on him on the way back to his house and he had it towed, at first it was throwing codes 12 and 14, and the code for the knock sensor but that was intermittent. The first thing i did was check to make sure the engine didn't jump time, then started diagnosing to see what was going on with the ignition.

I ended up replacing the distributor because somehow it was leaking oil internally, the cap was almost filling up with oil? thought that was kind've strange. I replaced the ignition coil as well because it wasn't giving me a strong read out. Reset the codes and the car ran great for 3 days, then died out again and is now throwing code 14.

I tried replacing the ignition control module (igniter) and no prevail. Can you yall help us get to the bottom of this? guys got an 800 miles trip coming up in a few days, i'd hate to see him have to abandon and sell this car..

Could the wiring harness / connections at the ECU be the culprit ?

Gevo

give details about the car.

Why would you suspect wiring harness at the ECU?

What are the symptoms?

MightyMonte88

It's a 1993 toyota 4runner, 2 wheel drive automatic 3.0L. 279k millage haha, it's had a long life.

I suspect the wiring harness / ECU because it appears to be all that's left in the system. Code 14 means the ECU is not receiving a signal from the ignition coil/ module correct?

We've replaced the distributor, coil, and ignition module (igniter) and the problem still remains that it will crank, but will not try to start, as if it where not getting spark.

Gevo

Code 14 seems like an easy one to fix. Assuming it is not your ECU, check the IGF and IGT signal wires between the Igniter and ECU. Check them for resistance (should be 1 ohm or less) and then check them for continuity (and resistance) against a known ground. Unplug both ends from igniter and ECU while making these checks. The wiring diagram here should help you with what the wire colors are.
http://snjschmidt.com/wiring/Engine_Control_3vze_3.jpg

If you have a resistance between the ends of the wires less than 1 ohm, and they have no continuity (or show no resistance reading against ground) then your wiring is ok. Check the connectors and make sure the contacts are clean.

Then check to see if the igniter is getting the 12 volts.

If all of these tests are positive, I think what's left in the mix is your igniter and much less likely but possibly your ECU.

MightyMonte88

Ok thanks for the info Gevo, i'll post results when i get off work later tonight/ tomorrow morning.

MightyMonte88

Alright finally got back around to this, tested the IGF and IGT wires and got no continuity or ohms reading. I ran two dummy wires for testing and the car fired right up. I'll be repairing the wiring harness today, thanks for the tips.

scope103

Thanks for the post-diagnosis! As you navigate this site you will see lots of reports of problems, but you don't always hear the eventual tested solution.

Prunejuice

I have no mechanical skill, I can turn a wrench, but have zero knowledge about engine wrenching.
That, said I just bought a 93 4x4 pickup with a 3vze motor in it. I WAS just going to replace valve cover gaskets and thermostat, but now I'm falling down a rabbit hole. My truck is throwing a code 14, it starts okay, it idles kind of rough but runs fine. It is gutless, takes a long time to get through gears, and backfires/pops when going downhill with resistance in the gears. I think the pops might be normal... Similar to when you pop start a vehicle....? I read this thread and still have no idea what to do.
I don't know where to begin with the code 14. I just joined this forum and found that thread about 'what every owner should know', and now my head is spinning.
I'll tuck this in here to save a new thread or add-on: any suggestions/tips for a newbie taking the intake manifold off to get to the valve covers to stop the leaking oil? I've literally never worked on an engine before. Done brakes and electric work, that's it. I'm overwhelmed by the number of hoses and wires and tubes connected to the manifold.
Thank you for your time.

Robert

2ToyGuy

Hi, Robert, and welcome

First, find the problem with the code 14 you have.. According to the book, you know, THE book (the FSM ), that's one of the IGn signals not reaching the ECM. You need to find out why. Is it the igniter, or coil, which are doubtful, as the truck runs ok, so obviously you've got spark. This tells you you have a broken wire someplace between the ignition (coil and igniter), and the ECM. It could be the plug at either end, a broken wire in between someplace, whatever. Remember, a wire can be broken, or partially broken, inside the insulation, with no external indication. It could also be the ground on the ECM, so make sure it's good too.

Start at the igniter, terminals IGT and IGF, and ohm to the ECM (under the passenger kick panel). If those wires ohm good, then ohm each terminal on the ECM (IGf and IGT) to ground. A clean, shiny metal area of the body.

You'll need an FSM to be able to identify the various terminals, and so forth.. Do a search on this site for one, electronic (PDF file) or paper version. They are still available, just not easily If you can't find one, Google it. They are still out there, honest. I don't have one for that year, or I'd provide you with pictures.

The FSM will also help you identify where all the various wires, plugs, vacuum lines and so forth, belong on the intake manifold. Remember, everything you pull off, like the throttle body, the intake manifold, and so on, have gaskets, that MUST be replaced before you re-install them. Never reuse a gasket. You tighten one bolt down onto a gasketed part, that gasket will need to be replaced the next time you remove it. Even if you realize you forgot something, and remove that one bolt in 2 minutes, the gasket must be replaced then. That includes the injectors, and crush washers on the pressurized fuel lines. Never reuse them.

When you start removing things, BTW, you can mark both ends with a piece of medical fabric tape, with some code you understand. Like vacuum line with one mark, then next vacuum line with two marks. It doesn't have to be complex. One mark, two marks, something. A piece of tape on the vacuum line, one on the place it goes, both with one, two, whatever , marks. You can do the same for water lines, electrical connections, everything. You will know that vacuum line with one mark doesn't go to water line receptacle with one mark, you see?

I hope something in all my rambling will help a little...
Pat☺

Prunejuice

Thank you! I'll get on it and see what I find. I'll let you know how it goes.

Robert

studawg66

Any resolution to this?