Random stalling

[Blindedlegacy]

Originally Posted by cre

Haynes/Chilton suck. I've got a ton of factory service manuals from a dozen different auto manufacturers and I've yet to come across one which is as poorly written as those two companies' offerings.

I posted a better means of testing the VAFM than what is specified in the Haynes/Chilton and TSRM just the other day: http://www.toyota-supra.info/forums/101981-post10.html You still need to test the FC switch (VERY important to pay attention to as it's a complete cutout switch) and the temp sensor as prescribed in the TSRM. The FC switch or its wiring is another possibility.

The load specific behavior of the failure isn't decidedly characteristic of a faulty EFI Relay or Circuit Opening Relay but they're simple enough to test and their failure may cause intermittent cut offs.

I don't recall you mentioning having tested them yet, but test the 100A fusible link (the old wire type used in earlier models will eventually corrode to the point of becoming a crippling restriction in the electrical system) and test the relay and resistor pack for the fuel pump.

We talked about this in my other tread. They bolted the white and black wires together. I order a new harness and fuse box and saw that 100a wire hard as ever. I was told to test the relay and resistor pack after warm up but I couldnt find the diagram and specs in time for work today. And ordering the factory manual totally slipped my mind. And I agree those manuals are bad for the main reason that they combine every year together

[cre]

Originally Posted by Blindedlegacy

I order a new harness and fuse box and saw that 100a wire hard as ever.

Just throwing shit at the barn and hoping something sticks? You'll be out of cash and REALLY hating the MKIII in no time.

[Blindedlegacy]

Every thing ive replaced was tested and failed except the alt. The fuse box thing was because of the alt wire which ive came to find out that it is normal for those wires to be bolt together for this car. Only thing I want to know is this ecu shorted internally but this is no real test for that and the only thing I can do is just replace it and I am already sick of this car because this issue is not even close to a common problem

[cre]

Sure you can test it. Just find a shop which has the RARE Toyota TCCS test computer.... A suitcase with a dozen adapters and simulates a running vehicle. The TCCS ECUs are VERY robust. Aside from leaking capacitors or moisture damage they rarely fail.

And... WOW, that car is a nightmare (see: perfectly normal MKIII ).


The TCCS tester looks much like this (but this isn't it):


As common as the N/A MKIII is, I'd look for someone who's got one in your area and give 'em $20 to let you try theirs in your car for an hour. They're very commong.... I think I've got a couple buried in storage somewhere (probably being use to keep one of my chests of deisel tools off the ground :P ).

[Blindedlegacy]

Originally Posted by cre

Sure you can test it. Just find a shop which has the RARE Toyota TCCS test computer.... A suitcase with a dozen adapters and simulates a running vehicle. The TCCS ECUs are VERY robust. Aside from leaking capacitors or moisture damage they rarely fail.

And... WOW, that car is a nightmare (see: perfectly normal MKIII ).

As common as the N/A MKIII is, I'd look for someone who's got one in your area and give 'em $20 to let you try theirs in your car for an hour. They're very commong.... I think I've got a couple buried in storage somewhere (probably being use to keep one of my chests of deisel tools off the ground :P ).

wow man... above and beyond. i am asking a friend for an ecu from one of his part cars and my question now is the year range and is auto and manual a different ecu?

also i found this!!!!!! http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=31

and i can use the diag box. but first im going to pull out the connectors and inpect for the usual ( bent terms, that good green stuff, etc)

and for those ppl who are looking at this thread i know one of yall had to have encountered a problem simular to this so.... HELP!!!

[cre]

The ECUs are a little different, but for your purposes it should work without modification... I can't recall but I'm pretty sure that at the worst you'll get an error code stored in the ECU for the ECT.

The diagnostic information in the TSRM is decent but it's nothing compared to a running diagnostic.

[Blindedlegacy]

found time to let the car run. and do some test and here are some notes

alt is only putting out 12.66v at idle and head lights are on after 20 plus mins of running. bat is at 12.55

at about 2k rpm its around 13.5v (couldnt check battery)

car dies as if fuel pump has been cut off (unplugged the relay and it died like ive been describing)

fuel pump resistor pack has 1 ohm of resistance and spec says .7

main relay has 70 ohm of resistance.(guess thats normal because i tested another one)

car is only missing at idle (held the engine at about 2k no missing. unplugged the tps and no missing)

did the wiggle test on harness that is exposed and no change.( the airflow meter area, fuse box area, and hole in firewall)

i believe its not throwing that code because like i was saying the ecu might be messing up and i didnt get around to that because its dark. and questions?

[cre]

Bypass the fuel pump resistor pack and relay, look at the TEWD for wiring info.

You've inspected and tested both TPS and ISCV, correct?

Did you test the VAFM in the manner I described? Is the FC switch showing a ground signal when the vane is open?

Turn the ignition on (not the engine) and unplug the VAFM. This will set codes 24 and 32 in the ECU. Turn the ignition off and then back on and wait a minute to be sure. Now turn the ignition off and set the diagnostic jumper... check for codes, if there are any then the ECU isn't losing power when the ignition is off and the diagnostic functions are operational. Don't reset them yet.... Go for a drive or run the car until it dies, now check for additional codes making sure that the 24 and 32 are still present. If they're still there but there's nothing new this negates the possibility of a problem with the EFI relay, the circuit opening relay and makes for a huge argument against the ECU being damaged and not storing codes.

I don't know if you're being selective about what you're testing, you're just not giving results of all the tests prescribed or I'm missing them but read back through and if there are any tests you've neglected then do them.

What was the cause of the error code 41 you originally reported and what did you do to remedy it? That's indicative of a TPS failure and may cause significant issues when transitioning to idle.

Sorry if some of this is repetitive but this thread's getting a bit long for me to keep reading and I don't recall some things being tried or answered.

Voltage drop with the headlights and heater on isn't uncommon.... old wiring, weathered grounds and a VERY small alternator are to blame. The ECU won't even hiccup until the voltage is a couple tenths below 11v.



EDIT: I have been through this with a N/A MKIII before. It was the AFM in my case but only when hot.... I found it by testing components with a hair dryer one by one. I had no diagnostic codes being stored either.

[Blindedlegacy]

Originally Posted by cre

Bypass the fuel pump resistor pack and relay, look at the TEWD for wiring info.

You've inspected and tested both TPS and ISCV, correct?

Did you test the VAFM in the manner I described? Is the FC switch showing a ground signal when the vane is open?

Turn the ignition on (not the engine) and unplug the VAFM. This will set codes 24 and 32 in the ECU. Turn the ignition off and then back on and wait a minute to be sure. Now turn the ignition off and set the diagnostic jumper... check for codes, if there are any then the ECU isn't losing power when the ignition is off and the diagnostic functions are operational. Don't reset them yet.... Go for a drive or run the car until it dies, now check for additional codes making sure that the 24 and 32 are still present. If they're still there but there's nothing new this negates the possibility of a problem with the EFI relay, the circuit opening relay and makes for a huge argument against the ECU being damaged and not storing codes.

I don't know if you're being selective about what you're testing, you're just not giving results of all the tests prescribed or I'm missing them but read back through and if there are any tests you've neglected then do them.

What was the cause of the error code 41 you originally reported and what did you do to remedy it? That's indicative of a TPS failure and may cause significant issues when transitioning to idle.

Sorry if some of this is repetitive but this thread's getting a bit long for me to keep reading and I don't recall some things being tried or answered.

Voltage drop with the headlights and heater on isn't uncommon.... old wiring, weathered grounds and a VERY small alternator are to blame. The ECU won't even hiccup until the voltage is a couple tenths below 11v.



EDIT: I have been through this with a N/A MKIII before. It was the AFM in my case but only when hot.... I found it by testing components with a hair dryer one by one. I had no diagnostic codes being stored either.

tps has been adjusted and rechecked. I unplugged the coolant temp sensor for the computer and it turned the light on. Plugged it back in and light went away. Didnt test afm because I was more concerned with the fuel pump area because thats how my car seems to be dying. The tps thing I just replaced and it never came back. Ill test the isc and afm tomorrow with a hair drier and post my results along with checking the ecu wiring. But I still believe something is wrong with it because a kid done a lot of stupid things to it

[cre]

Hacked harnesses are always a blast.

The AFM does affect the fuel pump. That's the FC switch that I said must also be tested. (FC = Fuel Cutoff)