MR2 Acceleration Troubles

ac604605 · 05-08-08, 08:16 PM

I own an 85 MR2 that recently had a rebuilt engine installed. The engine runs great except for one thing; when you reach 6000RPM the car quits accelerating, almost as if you took your foot off the gas. It holds steady and won't accelerate even downhill. If you rev the engine, or ease into it at about quarter throttle, you can make it to the 7,500RPM red line. I've checked everything I can think of, and everything the BGB can think of, including fuel systems, exhaust, ECU, MAF, injectors and diagnostics. I have yet to check to see if the converter is plugged, or injectors, however I doubt it would be them. If it makes a difference, when the rebuild engine was installed, the old TVIS, MAF and electrical systems were used. Thanks for any help.

ac604605 · 05-08-08, 08:25 PM

My apologies, I meant I have checked the resistance for the injectors, but have not actually pulled them apart to check their output.

ken_79-fj40 · 05-21-08, 09:00 AM

I would double check that the vacuum lines on the TVIS are connected properly. I rebuilt the engine in the 85 MR2 I used to have and screwed this up when I reinstalled the engine. It seemed to run fine, but it would fall on it's face before redline. After I fixed the vacuum lines it was fine. I think the secondary butterflies weren't opening all the way how I had it hooked up.

WristPin · 05-23-08, 06:25 PM

is it possible the ECU has been modified to prevent over revving?

ac604605 · 06-29-08, 09:52 PM

Sorry I haven't responded in a while. As far as the ECU goes, it isn't possible, as far as I know. The ECU was used on the previous engine, before we installed this one. The old engine never had any issue like this.

WristPin · 06-30-08, 01:08 AM

timing not advancing??

05-08-08, 08:16 PM	#1
ac604605 IH8MUD Rookie Join Date: May 2008 Posts: 3	MR2 Acceleration Troubles I own an 85 MR2 that recently had a rebuilt engine installed. The engine runs great except for one thing; when you reach 6000RPM the car quits accelerating, almost as if you took your foot off the gas. It holds steady and won't accelerate even downhill. If you rev the engine, or ease into it at about quarter throttle, you can make it to the 7,500RPM red line. I've checked everything I can think of, and everything the BGB can think of, including fuel systems, exhaust, ECU, MAF, injectors and diagnostics. I have yet to check to see if the converter is plugged, or injectors, however I doubt it would be them. If it makes a difference, when the rebuild engine was installed, the old TVIS, MAF and electrical systems were used. Thanks for any help.

05-21-08, 09:00 AM	#3
ken_79-fj40 IH8MUD Addict Join Date: Jul 2002 Location: New Hampshire TLCA# 15247 Posts: 644	I would double check that the vacuum lines on the TVIS are connected properly. I rebuilt the engine in the 85 MR2 I used to have and screwed this up when I reinstalled the engine. It seemed to run fine, but it would fall on it's face before redline. After I fixed the vacuum lines it was fine. I think the secondary butterflies weren't opening all the way how I had it hooked up. __________________ 79 FJ40,85 Mustang GT,05 Tacoma,00 4Runner,89 pickup

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05-08-08, 08:25 PM	#2
ac604605 IH8MUD Rookie Join Date: May 2008 Posts: 3	My apologies, I meant I have checked the resistance for the injectors, but have not actually pulled them apart to check their output.

06-29-08, 09:52 PM	#5
ac604605 IH8MUD Rookie Join Date: May 2008 Posts: 3	Sorry I haven't responded in a while. As far as the ECU goes, it isn't possible, as far as I know. The ECU was used on the previous engine, before we installed this one. The old engine never had any issue like this.