Engine Misfire Problem.

[David P]

"Fiddled with the Plugs...it worked fine again. Sometime mid-2007, the tachometer went crazy (bouncing between 3k-6k RPM, and ran like crap"

 

Have you made a visual inspection of those distributor parts and connections for possible damage from your shunt?

 

(In the event you trace this prob to include the ECU, note that you will pick one up for half the price here compared to US, but confirm the part no. because the J spec N/A here has MAP, and the U.S. spec have MAF, not sure if ECU is the same?)

Edited December 20, 2010 by David P (see edit history)

[Ian C]

This sounds to me like your ignition timing is out. I once reinstalled my cam position sensor in my MkIII Supra one tooth retarded, and it wouldn't rev much past 2000rpm, the manifold glowed red hot, and it barely had power to move up and down the driveway. This fits all your major symptoms - the rough idle, the backfiring (lots of unburnt and still-burning fuel in a hot exhaust), poor peformance etc.

 

If your distributor has been reinstalled with the drive gear one tooth out then you'd probably get this - or, as mentioned already, the exhaust cam might be one belt tooth out.

 

A simple timing light check will tell you what you need to know about how the ignition is working. You can do it yourself with a relatively cheap tool.

 

You can also visually inspect the cam positions quite simply. The crank pulley has a notch in it and there are some degree marks visible on the housing. Use a socket on the crank pulley bolt to rotate the engine so the notch is at 0deg, then remove the cam pulley cover and see if the dots on the pulleys line up with the marks on the pulley plate. It sounds more complex than it is, and some pictures would help but I don't have any readily to hand (maybe others can provide?)

 

-Ian

Edited December 20, 2010 by Ian C (see edit history)

[Guest TXSupra]

Disconnect the battery, and reconnect again , this clears previous faults .

Then start engine , run the gear box selector up and down a couple of times then go through the fault codes again .

Looks like someone was looking at the oxy sensor - good call

you can check the sensor voltage at the diagnostic plug -

After such a long time the sensor is probably fubar , a replacement , non genuine one can be spliced in using the original Toyota connector .

If the o2 sensor is shot you get large overfuelling and plugs will be black and can misfire

 

I've already replaced the battery and it did the same problems now as it did before i changed the battery. How can i check if the O2 sensor is "fubar"? As i said the car didn't through any codes, the CEL and MIL just stayed on.

 

"Fiddled with the Plugs...it worked fine again. Sometime mid-2007, the tachometer went crazy (bouncing between 3k-6k RPM, and ran like crap"

 

Have you made a visual inspection of those distributor parts and connections for possible damage from your shunt?

 

(In the event you trace this prob to include the ECU, note that you will pick one up for half the price here compared to US, but confirm the part no. because the J spec N/A here has MAP, and the U.S. spec have MAF, not sure if ECU is the same?)

 

I pulled off the distributor cap and looked at it.. the distributor rotor didn't appear that have anything odd on it. it had a mark in the center of it, but i don't know if that's a sign that it's messed up or if that's just normal.

 

This sounds to me like your ignition timing is out. I once reinstalled my cam position sensor in my MkIII Supra one tooth retarded, and it wouldn't rev much past 2000rpm, the manifold glowed red hot, and it barely had power to move up and down the driveway. This fits all your major symptoms - the rough idle, the backfiring (lots of unburnt and still-burning fuel in a hot exhaust), poor peformance etc.

 

If your distributor has been reinstalled with the drive gear one tooth out then you'd probably get this - or, as mentioned already, the exhaust cam might be one belt tooth out.

 

A simple timing light check will tell you what you need to know about how the ignition is working. You can do it yourself with a relatively cheap tool.

 

You can also visually inspect the cam positions quite simply. The crank pulley has a notch in it and there are some degree marks visible on the housing. Use a socket on the crank pulley bolt to rotate the engine so the notch is at 0deg, then remove the cam pulley cover and see if the dots on the pulleys line up with the marks on the pulley plate. It sounds more complex than it is, and some pictures would help but I don't have any readily to hand (maybe others can provide?)

 

-Ian

 

Those symptoms do sound a lot like mine. I know a friend that has a timing light. I will check it out tomorrow.. from what i understand..you check to see if the marks on the cam pulleys match up with the marks on the pulley plate. Hope this works.. i don't want to have to get a new ECU...i dunno where to find a fairly priced one (i priced one at Toyota and it was $1,000)

[SupraDan24]

If its an NA Auto ECU your after, they sell for alot less than $1K over here second hand. Keep an eye on the "For Sale" section.

[Guest TXSupra]

Well it's not a timing issue. it's 10 degrees BTDC (factory setting) So that's not the issue.. i guess i'll just save for the ECU. Anyone know how to install one of those?

[David P]

ECU is plug and play under the passengers feet.

However, I still remain suspicious of the distributor and nearby loom.

Do you have a pal with an N/A to trial a distributor swop with, to confirm that it isn't?

Edited December 21, 2010 by David P (see edit history)

[jagman]

Why are you starting the car in the diagnostic mode ? you short the pins and turn on the ignition it then shows the history of fault codes by flashing ,there is another pair of pins that are used for road testing diagnostics

when starting the voltage drops during start ,the diagnostic will now get real confused

[David P]

Excuse me, but we are in different time zones here, and I must get up early tomorrow.

 

If all else fails and you become convinced you need an ECU, or any other used part for that matter, contact Keron, link below, he will get any part to you for far less than you will pick it up in the U.S.

 

http://www.mkivsupra.net/vbb/member.php?676-keron

[jagman]

check that post accident they reconnected all the earth leads ,properly (ground leads)

[Guest TXSupra]

ECU is plug and play under the passengers feet.

However, I still remain suspicious of the distributor and nearby loom.

Do you have a pal with an N/A to trial a distributor swop with, to confirm that it isn't?

 

There is another N/A Supra in my town. However, i don't know whom it belongs too.. and i don't even know if it's OBD1 or OBD2.

 

Why are you starting the car in the diagnostic mode ? you short the pins and turn on the ignition it then shows the history of fault codes by flashing ,there is another pair of pins that are used for road testing diagnostics

when starting the voltage drops during start ,the diagnostic will now get real confused

 

I didn't start the car in diagnostic mode. I turned the ignition to the required position.. and the CEL and MIL stayed on. Then, whenever i start the car the CEL and MIL stay on a few moments and then they go off. I guess it was a little confusing the way that i worded it. But i pushed a bobby pin into it, one into the E1 and the other in the TE1...turned the ignition to the on position (without starting the motor) and the CEL and MIL just stayed on constantly. So i don't know if it's me not doing it correctly, but i'm about 100% positive that it's correct.. i tried pushing it as far as it would go ..as well as a little bit in there.

 

check that post accident they reconnected all the earth leads ,properly (ground leads)

 

I really don't think that there was any wiring issues on the car ... most wiring i could see being messed up in the collision was the headlight wiring. It was driver side front impact. Basically:

- Hood was barely bent. (repaired)

- Replace the battery box.

- Replace the left spindle.

- Replace the front bumper.

- Replace the wind shield.

- Replace both air-bags.

- Replace front-left corner panel.

- Pop the dints out on the door and the left-rear corner panel.

 

I'm not saying the distributor/ECU/Wiring Harness couldn't have been messed with..that's just what was replaced or repaired. Since the car was driving slow after the incident, ran fine after a messed with the spark plug wires, and then messed up not too long after that.. It could be the distributor/distributor cap or rotor.. i dunno whenever i acquire more money i will be able to replace things to rule certain things out. Currently i'm trying to check things without replacing.

[Chris Wilson]

When you say the exhaust glowed red hot once, which part of the exhaust? If just the first cat glowed red it's over fuelling. If the manifolds glowed red it's retarded timing. Put a timing light on it and a mark on the damper, see if it advances up when you rev it. Shouldn't be a difficult problem to at least diagnose, hell you Yanks are still using distributors and plug leads, should be a doddle for you

[Guest TXSupra]

The timing is correct.. it's 10 degrees BTDC. What's the possibilities of a shorting out Wiring Harness on the left side of the engine. (driver side) I think Jagman is right.. about the grounding issues.

[Guest marcelus]

hi there i've recently had a simular problem with my 1993 n/a turned out to be the ecu at fault but if you cant get hold of one the ecu off an auto aristo will get you out of trouble it will cause your manu light to flash as aristo don't have that function but will still work as that's what i had to do with mine whilst mine is away getting repaired

 

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