Can anyone help me with a stumbling prob?

Busted Knuckles · 12-23-2007, 06:58 PM

I got my '88 Supra N/A as a hand-me-down from my dad last year. I've been drooling over this car for 17 years before he just gave it to me. It's been meticulously maintained, and barely shows any of the 235,000 miles the odometer reads.

But, I've got a problem. The computer shows no codes, but when I accelerate a bit hard, it will stumble until it hits 2200 RPM. Then the torque hits like a hammer, and away I go. The car idles fine. But, I can get it to stumble out of gear by just revving it. This happens when the car is fully warmed up. The best way I can describe it is like an old carbuerater that needs overhauling. But I have OEM EFI.

I was chasing a problem when I first got it (wouldn't pass emissions), and have replaced the MAF sensor, CTS, Fuel pressure regulator, and O2 sensor. As I mentioned, the computer is giving me no codes. Anyone have any ideas what to look for?
Thanks.

Pretaco · 12-24-2007, 02:56 AM

Does it pass emissions now?
What did it fail on? hydrocarbons, nox, or co?
I am willing to bet the two problems are related.
The other sensor I would test it the tps.
What is your fuel pressure at?
Ray.

Busted Knuckles · 12-24-2007, 03:07 AM

Yes, it has passed emissions twice now. The original problem was a bad O2 sensor, and the replacement O2 sensor was bad as well. Finally had a mechanic who specializes in Toyota's look at it, and he found that problem.

I don't know what the fuel pressure reads. I have a gauge, but it is for GMs and Ford's with screw-in schreader valves. The guide I have says to make an adapter by drilling a bolt. Does anyone have a better adapter/solution?

Pretaco · 12-24-2007, 03:30 AM

There are adapters to fit toyota's but it might be too expensive just to test this out.

Does it feel like one cylinder is missing, or all of them? I would check the plugs, and wires, timing, and test the tps. Otherwise I really don't know.

Busted Knuckles · 12-24-2007, 05:33 AM

Yeah, all of them. I'll try that. Thanks.

12-23-2007, 06:58 PM	#1
Busted Knuckles 12psi boost Join Date: Dec 2007 Location: Atlanta Posts: 300	Can anyone help me with a stumbling prob? I got my '88 Supra N/A as a hand-me-down from my dad last year. I've been drooling over this car for 17 years before he just gave it to me. It's been meticulously maintained, and barely shows any of the 235,000 miles the odometer reads. But, I've got a problem. The computer shows no codes, but when I accelerate a bit hard, it will stumble until it hits 2200 RPM. Then the torque hits like a hammer, and away I go. The car idles fine. But, I can get it to stumble out of gear by just revving it. This happens when the car is fully warmed up. The best way I can describe it is like an old carbuerater that needs overhauling. But I have OEM EFI. I was chasing a problem when I first got it (wouldn't pass emissions), and have replaced the MAF sensor, CTS, Fuel pressure regulator, and O2 sensor. As I mentioned, the computer is giving me no codes. Anyone have any ideas what to look for? Thanks.

12-24-2007, 02:56 AM	#2
Pretaco 3" Exhaust Join Date: Dec 2007 Location: Glendale, AZ Posts: 126	Does it pass emissions now? What did it fail on? hydrocarbons, nox, or co? I am willing to bet the two problems are related. The other sensor I would test it the tps. What is your fuel pressure at? Ray. __________________ '88 Supra Targa 5 speed w/ '90 7M-GTE Currently Running Good For Sale: Light blue body parts, Blue interior parts all from '90 supra targa turbo manual. Also for sale: R154 trans, brake pedal, master cylinder, booster, abs actuator, sensors, abs ecu, driveshaft, 3.90 lsd rear end, radiator, wiring, speedo cable, 8 saw blade wheels, '88 ecu, relays, cruise control actuator (bad cable), empty fuel tank, etc....

12-24-2007, 03:30 AM	#4
Pretaco 3" Exhaust Join Date: Dec 2007 Location: Glendale, AZ Posts: 126	There are adapters to fit toyota's but it might be too expensive just to test this out. Does it feel like one cylinder is missing, or all of them? I would check the plugs, and wires, timing, and test the tps. Otherwise I really don't know. __________________ '88 Supra Targa 5 speed w/ '90 7M-GTE Currently Running Good For Sale: Light blue body parts, Blue interior parts all from '90 supra targa turbo manual. Also for sale: R154 trans, brake pedal, master cylinder, booster, abs actuator, sensors, abs ecu, driveshaft, 3.90 lsd rear end, radiator, wiring, speedo cable, 8 saw blade wheels, '88 ecu, relays, cruise control actuator (bad cable), empty fuel tank, etc....

12-24-2007, 05:33 AM	#5
Busted Knuckles 12psi boost Join Date: Dec 2007 Location: Atlanta Posts: 300	Yeah, all of them. I'll try that. Thanks. Last edited by Busted Knuckles; 12-24-2007 at 05:39 AM.

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12-24-2007, 03:07 AM	#3
Busted Knuckles 12psi boost Join Date: Dec 2007 Location: Atlanta Posts: 300	Yes, it has passed emissions twice now. The original problem was a bad O2 sensor, and the replacement O2 sensor was bad as well. Finally had a mechanic who specializes in Toyota's look at it, and he found that problem. I don't know what the fuel pressure reads. I have a gauge, but it is for GMs and Ford's with screw-in schreader valves. The guide I have says to make an adapter by drilling a bolt. Does anyone have a better adapter/solution?