87 Turbo Supra rough engine problem

bowhunter951 · 06-25-2010, 09:13 PM

The problem started as the weather started to heat up (Jackson MS). It started when I would drive my supra (running great) warming it up then park it, not letting it cool all the way. When I would go to start it, it would seem to be missing in one cylinder and the miss would stay there till i parked it and let cool all the way down (hours). After a few months (and it getting hotter outside) A few times it has been running on 3 cylinders but that has not persisted or happened in over a month. Now sometimes it runs great sometimes one cylinder goes in and out while driving and sometimes it exibits the classic symptoms ie (see italics above). I brought it to a good shop(in my opinion and experience) they put new spark plugs and wires on it first, that did not fix it. even thought they said that the missing was from time to time alternating cylinders they tried putting in a new fuel injector in the cylinder that was primarily missing.

The shop said that it had fuel fire and air and that there was no reason it should be missing.

The shop said they checked the fuel and put a new distributor cap on. I'm sure they checked many other possible issues.

When I got it back from the shop I decided to look into the ignition coil I took basically the same one off a 1987 cressenda and put it on the supra when the supra was doing it's stalling thing, but it made no difference.

The only things that I could think of that It could be would be maybe the distributor it's self, the ignitor, or the power transistor in the ignitor, but my guess is that the shop ruled all those potential problems out along time ago.

the car has 50,000 miles on the engine and has great compression in all cylinders.

Help me if you can Please.

SupraKat · 06-25-2010, 11:37 PM

My Supra's missing problem persisted for months, my mechanic finally figured it out, it was the EGC valve stuck closed, or open, one or the other (It's been awhile, I forgot which one). The reason it was so difficult to diagnose was because all symptoms points to a missing cylinder but it's not. Try replacing the EGC valve, it's a cheap item. Let me know if it works.
Suprakat

bowhunter951 · 06-26-2010, 02:23 AM

Hey thanks for the reply! I hope that that will solve the problem. I just wanted to verify that it was the Exhaust Gas Recirculation (EGR) valve not EGC valve? And do you know if he cleaned it or replaced it? Thanks!

SupraKat · 06-26-2010, 05:33 AM

Yes, I think EGR is what it was. And I believe he just clean it out. It's been several month since then, I have no more problem.

06-25-2010, 09:13 PM	#1
bowhunter951 Stock Join Date: Sep 2008 Location: Starkville, ms Posts: 5	To clarify further... The problem started as the weather started to heat up (Jackson MS). It started when I would drive my supra (running great) warming it up then park it, not letting it cool all the way. When I would go to start it, it would seem to be missing in one cylinder and the miss would stay there till i parked it and let cool all the way down (hours). After a few months (and it getting hotter outside) A few times it has been running on 3 cylinders but that has not persisted or happened in over a month. Now sometimes it runs great sometimes one cylinder goes in and out while driving and sometimes it exibits the classic symptoms ie (see italics above). I brought it to a good shop(in my opinion and experience) they put new spark plugs and wires on it first, that did not fix it. even thought they said that the missing was from time to time alternating cylinders they tried putting in a new fuel injector in the cylinder that was primarily missing. The shop said that it had fuel fire and air and that there was no reason it should be missing. The shop said they checked the fuel and put a new distributor cap on. I'm sure they checked many other possible issues. When I got it back from the shop I decided to look into the ignition coil I took basically the same one off a 1987 cressenda and put it on the supra when the supra was doing it's stalling thing, but it made no difference. The only things that I could think of that It could be would be maybe the distributor it's self, the ignitor, or the power transistor in the ignitor, but my guess is that the shop ruled all those potential problems out along time ago. the car has 50,000 miles on the engine and has great compression in all cylinders. Help me if you can Please.

06-25-2010, 11:37 PM	#2
SupraKat Stock Join Date: Aug 2009 Location: Chino, Calif. Posts: 5	Supra rough running problem My Supra's missing problem persisted for months, my mechanic finally figured it out, it was the EGC valve stuck closed, or open, one or the other (It's been awhile, I forgot which one). The reason it was so difficult to diagnose was because all symptoms points to a missing cylinder but it's not. Try replacing the EGC valve, it's a cheap item. Let me know if it works. Suprakat

06-26-2010, 02:23 AM	#3
bowhunter951 Stock Join Date: Sep 2008 Location: Starkville, ms Posts: 5	Thanks! Hey thanks for the reply! I hope that that will solve the problem. I just wanted to verify that it was the Exhaust Gas Recirculation (EGR) valve not EGC valve? And do you know if he cleaned it or replaced it? Thanks!

06-26-2010, 05:33 AM	#4
SupraKat Stock Join Date: Aug 2009 Location: Chino, Calif. Posts: 5	Egr Yes, I think EGR is what it was. And I believe he just clean it out. It's been several month since then, I have no more problem.

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