Car broke down - ODB error codes 14 and 24
 

Car about 2 weeks ago flicked up an engine light and wouldn't let me go past 2000rpms. Tried to get car to go past 2000rpm few times, then sat behind traffic for 5 minutes, car then ran as normal.

Drove car for further 2 weeks, no problems. Ran sweet as.

Then did a short run 3 miles. Stopped car, did shopping. Then drove back 1/2 mile engine light came on, all other lights came on also. Car stopped dead, power steering stopped working. Tried to re-start, but then cut revs to 0rpm and stalled, all lights on. Tried again after 5 mins, got it about 30 yards then stopped. Called the AA and let car sit for 1h 20mins. AA started car, drove fine for 1 mile. Then we drove back home, 3 miles. No problems.

Did the paperclip method diagnostic - pulled codes 14 and 24.

Code Description Causes
14 Ignition Signal Circuit
Open or short in IGF circuit from ignitor at ECU
Ignitor
ECU

Code Description Causes
24 Intake Air Temp Sensor Circuit
Open or short in intake air temp sensor circuit
intake air temp sensor
ECU

The car has a TOMS ECU and a MPH converter attached, stock twins, boost controller Blitz.

Should be worth noting I had a rad failure about 3 months ago, fluid all over the engine bay. I am not sure if this has had some effect, e.g.corroding some connector or something.

As far as I can see it's either intake Air temp sensor, Ignitor or ECU.

Ignitor symptoms seem to be car won't start - my car starts fine but randomly dies. Not sure if this is the issues.

My plan of action is to look is to trace the wires back to the ignitor (where is this btw?).

Otherwise, please help with some suggestions to fix.

The ignitor is in the engine bay, near the fuse box. It looks about the size of a pack of cigarettes, except it's all black.

Can you bypass or replace the Toms ecu and go back to a bone-stock configuration? Regardless, I'd suggest checking the ecu<->harness connection as one of your troubleshooting steps. Also check all of the ground wires that have been tapped into near the ecu - one of the locations where problems occur in modified Mkiv's is the ground connection near the ecu over towards the front of the door.

Where can I read more about the Toms ecu? Can you share a link?

Thanks, I'll try to check all the grounds. My mechanic says harnesses and such like just don't fail in Toyotas though. I have to work through

- coil packs test
- spark plugs
- ignitor test

As the car warmed up, then failed. Cooled down for 1h20mins then ran. I am considering something is getting hot and failing e.g.ignitor.

The TOMS ecu does a few things, delimits boost, delimits speed. Ignition timing advance (more responsive lower rpms). Boost seems to be set to 1.6bar on this one if you let it control the solenoid - my solenoid is controlled by Blitz boost.

If you run it, you'll need 99RON at worst, 100RON ideally.

No links but you could check the TOMS website.

Agreed - harnesses and such like just don't fail in BONE-STOCK Toyotas. However, yours isn't. :) As you might guess, the quality of work associated with aftermarket modifications varies widely, which is why that is the most significant variable in why your Supra is behaving so erratically...and thus our first candidate for troubleshooting.

Note: The coil pack test specified in the TSRM is pretty useless. Oem coilpacks get weak long before they fail, and the only way to test a weak coilpack is to swap it out*. However, there is one thing related to the coilpacks you can check for: The heat from the 2jz-gte often causes the plastic coilpack harness connectors to fail (the plastic breaks inside the connector), which can result in erratic ignition. New coilpack connectors are inexpensive and can be ordered from Toyota; they're pretty simple to install too.

In addition, the easiest way to test the ignitor is to swap it out with a used one from another Mkiv Supra Turbo.

If your Supra hasn't had the coolant changed regularly, I've seen oem temp sensors fail from corrosion...that could be related.

Re: The TOMs ECU - is it completely 'plug-and-play'? ...or does it need to be wired in (solder/crimping/etc.)?

Do you have a link to the Toms web site?

*Since oem coilpacks are consumeable - they really only last about 75,000 miles - purchasing a spare one for testing isn't a bad investment at all. If the problem ends up being the coilpacks and your mileage is >75K, just get five more coilpacks and swap them all.

Thanks - what is the symptom of an erratic coil pack? I thought the car would misfire and stutter first....in my case the car just DIES and the engine runs sweet otherwise.

My temp sensor seems fine, had a rad failure few months ago so the fluid has been changed.

The TOMS ECU is an entire ECU. It is a Toyota ECU reprogrammed by TOMS. It plugs straight into the connectors, so I doubt there is a duff connection here, but obviously cannot rule that out either.

I'm going to fault trace the ignition system and sparks/coils this week. See what I can find.

I was only telling you about coilpacks since you mentioned them in your post. I agree bad coilpack(s) doesn't seem to be the primary cause of your Supra's issue(s).

Good luck with troubleshooting. If you have the TSRM, I'd recommend following the step-by-step procedures within. Please keep us informed.

Thanks, will post up my findings here. I'm leaning towards the ignitor or a bad ECU, outside chance coil packs/MAF.

Any updates?

I haven't had my friend over with the oscilliscope to do the testing.

However, I did this

- started car, let idle. Car cut out between 20-30minutes. Felt the ignitor, it was hot/warm.

- let car cool down, prob 30 mins. Started car, cut out immediately. Felt ignitor, it was cold.

This is making me consider it isn't the ignitor.

2nd thing I did was pull the TOMS ECU. I found brown liquid stuff on one connector of the 5 connectors of the TOMS ECU. I thought this would be the problem. So I clean up the connector, and put in a STOCK ECU inside this time. Car still cut out. Damn.

I took apart the TOMS ecu, didn't see any components leaking. Odd.

Spoke to my mechanic, said check sparks, HT leads, ignitor, coils. He then said I'd have to check the fuel pump after this...

I will hopefully check by next week, although if we presume something is heating up and failing, then it tend would rule out the ignitor as this was stone cold and the car still failed to start. The car then started fine the following morning. It could still be the ignitor of course but it's an outside chance. And I think I can rule out the ECU also.

Have you ruled out the Air temp sensor?