Random stalling
 

This problem is getting annoying. 1986.5 na 5speed. When I am driving and I decide to reign on the heat I lose speed and can't acclerate for about 3 seconds. Also if I am at a complete stop out of no where she cuts off and I don't even notice it. and I notice it only happens on warm days, both issues. If anyone had dealt with this before please help

Have you checked for diagnostic error codes? Look in the FAQ section for a how-to if you need. Start with that.

I don't understand what you mean by "reign on the heat"... you just referring to running the engine hard or is your climate control or engine temp part of the issue?

I meant to say turn on the heat. And there are no trouble codes

No stored codes or just no check engine light? Sorry have to ask, a lot of people think that the CEL comes on if ANY codes are stored and that's not true, MOST don't cause it to light up.

The bogging when the heat comes on is something I'm going to have to think about.... The first thing that comes to mind is that the heater is drawing more current than the alternator can provide... could also account for stalling. Check the voltage from the alternator and then while watching the meter have someone turn on the heat.

As for the stalling I'd start with checking that the ISCV (Idle Speed Control Valve) isn't clogged and test it; Then test the AFM; Test and calibrate the TPS; Check for vacuum leaks or openings in the intake piping.

ok im sorry this took so long but i just got the codes.
22 Engine Coolant Temperature Sensor signal.
24 Intake Air Temperature Sensor signal.
41 Throttle Position Sensor signal.

if i am right 22 is that makes the car hard to start if not plugged in and its not doing that and it is plugged in

24 i have no clue where that is

41 is also plugged in and working

are these stored codes or what? also im going to try the tps calibrating

Code 41 isn't a calibration error. Either the TPS has been unplugged at some point, is damaged or the wiring harness or ECU is damaged.

Code 22 doesn't always result in difficulty starting... It may result in difficulty starting difficulty starting in significantly cold or hot weather. Essentially though it causes the ECU to run as if it were cold: see Lots of extra fuel, base timing map, open loop operation.

Code 24, like code 41, is set if the AFM is disconnected while the ECU is powered up or if it is damaged or the wiring or ECU are damaged. I believe that if the error is persistent the ECU assumes an ambient air temp of around 70?F; If the actual air temp is significantly different this will also severely affect performance.

While these codes will all remain stored in the ECU they should not affect performance if the problem has been corrected. You may clear them and see if they return after a drive or two.

Do note that the ECU temp sensor is not the same one used for the dash gauge; So don't go thinking that because the gauge works the sensor is fine.

i clear the codes by disconnecting the battery right and my gauge is messed up anyways going to get a new one. do you know what the air temp sensor is?

You only need to pull the EFI fuse for about 10 seconds. I think a minute is the recommendation. The intake air temp sensor is integrated into the AFM. Look in the EFI section of the TSRM for diagnostic info.

ok i just reset the codes and calibrated the tps. i put my distributor back as close to the last known right spot. (going to buy a timing light soon) im going to test it when i go to work today and hopefully the random stalling goes away. if not i am going to take it to autozone for a starting and charging test

Went back to this old thread because i have a question. opened up the distributor and did a brief look around and notice that i can turn the rotor a bit. i am pretty sure im not suppose to do that also i was reading somewhere that i might have gotten moisture in there and i can use wd 40 to get it out. true or false?

No, do not spray anything in there. There are weeps in the cap and in the distributor body to allow for some circulation and to allow any seeping oil and condensation to evacuate.

Dry it lightly with a hair dryer, mop up any oil and replace the distributor's O-rings.

Do not try to drive it until you get the ignition timing set!

There isn't any oil in there. Where can I get the o ring from. And what about that freeplay

There shouldn't really be more than a couple degrees of movement. If there is pull it back out and make sure the retainer pin for the drive gear is firmly in place and that the gear has no play on the spindle. The O-rings I'd just buy from Toyota... There are only two and the should be inexpensive.

Im going to get the timing right tomorrow and check the electrical side to see if it is in spec, raining right now, and I will get back to you with the results

i was just on the tsrm site and came across this
http://www.cygnusx1.net/Supra/Librar...px?S=Main&P=45

and at the bottom in fail safe said or "or else stops the engine" should i look into above mention systems? also when it says "input signal 1,4,9,10,11" and "sensor 1,2,10,11" what are they talking about

Wow, props for actually reading the additional notes! No one ever seems to actually READ these days. The information about numbered input relates to the engine's count from the sensors.... not anything you typically need to worry about. If the coils read proper resistance with a meter and the pickups are properly gapped you don't really need to focus too much more on the CPS.

Failsafe mode or any failure significant enough to cause it should set an ignition/CPS related code(s) if that were the case. I've yet to see a MKIII actually drop into a fail safe mode from the CPS being off... they just run like ass.

Yea when I got a problem this bad I am reading alot of things. But I am going to start with that timing thing and check the gap and resistance. I hope its just the distributor because I am just clueless

ok timed it right it was off by 5 and i need to double check with someone if i am right

with the multimeter set to 2k ohm g1 and g2 of the distributor read .329 and the book says 140-180 is the good zone. i have not used an ohm meter in a long time so i am not 100 sure on this. with the meter on 2k position and i get .329 thats 329 ohm right?

new distributor installed and timed and didnt fix the problem. i going to do what i should have done from the beginning. replace battery and alternator because ive talked to techs and google thing and everything is pointing to that so im going to get those parts and update with my results. also a fuel filter because i dont know when it was changed

Before replacing the parts, do the test suggested earlier in this thread and check the voltage at the alternator and at the battery (with the car running). If the voltage at the alternator is higher than the battery, you likely have a bad connection somewhere in the charging system wiring. The voltage should be the same at both the battery and alternator, and you should have about 13.5 volts. If it's significantly lower, your alternator is likely bad and should be able to be tested at a parts store for free. Be sure to test it both with nothing extra turned on (lights, heater, etc) and with everything turned on and make sure it still produces that 13.5 volts.

Ive done that with car not running then running. Loads on and off. The readings get lower and lower from cold to operating temp. I havent tested around when it starts to shut down which is about 15 to 20 mins. But when I go to work and park my car I turn on a load such as my efans or blower motor and everything shuts down

Update.,new bat alt and belts and it still dies with an electrical load after hitting operation temp

I was talking to one of the techs at my job. Told him the story about my car from the begininh. Jumped my bros car the around the time I got my supra. That same day my coolant temp gauge stopped working. 2 techs heard that and gasped and said I might have fried my computer

Unlikely... EFI relay or fusible link are more likely and should be inspected.

"Techs" from where?

Cavalier ford. And you know which pin outs are for the ground circuits so I can at least I can do the voltage drop test

Those dealership auto techs are always such drama queens... Unless... I hope you're not just talking about the lot techs. ;)

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/

It was 2 of em. But it would make sense. I found a guy with the exact same issues as me on a different forum and I msged him and now waiting for a response. That is the 1990 so I didn't think it would apply to me but u notice that the ground wires are white and black so is it the same for the ecu

There are very few differences between pre89 and 89+ GE electrical systems... unlike the GTE. You may go by that online manual and if you get hung up due to a discrepancy just ask.

I suspect either a bad EFI relay or a bad AFM. Try testing them both after heating them up with a hairdryer. ;) Another possibility would be a problem with the fuel pump relay and resistor pack. You can bypass both at the harness to test if this is the case.

I tested the air flow meter based on the haynes manual a while back and it passed. And would a relay cause the whole electrical system to do this?

And this guy had the same problem as me. http://www.supraforums.com/forum/sho...0-Voltage-drop

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

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

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

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):
http://i168.photobucket.com/albums/u.../EFItester.jpg

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!!!

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.

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?

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

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)