4AGZE SC Runs Rough at WOT
Posted: Mon May 20, 2019 12:58 am
A recent problem has crept up on my new to me 88 SC. Under normal part throttle acceleration the car runs fine. When I go WOT and the SC kicks on the engine feels and sounds like it has a misfire--it is slow to accelerate but makes 7psi. I initially thought maybe there was a lean fueling issue but I triggered the cold start injector to run on a switch I activated at WOT. No change. I thought maybe it was a bad coil or ignitor--swapped those with some spares--no change. New spark plugs--no change.
The running got so bad that I lost all power and could barely make it up my driveway. However, this happened after I was changing the ignitor and coil and for some reason the noise filter arced while reinstalling it. Swapped noise filters--no improvement.
I finally got smart and pulled the codes--I got a 43 and a 51. 43 is a starter signal but the car starts fine. 51 is the AC switch signal which corresponds to the AC circuit (currently not being used) and a TPS error.
Before this all went south my idle was very high--2000rpm plus. I couldn't get it to consistently stay at a normal speed.
Car never overheated and as I stated--drove just fine at part throttle.
So, I'm guessing I should start with the TPS? I have a spare--I've had MR2s for 20 years but this is my first SC and I'm a bit rusty as most of my time has been spent on my 82 Starlet which has a dual Webers and a very simple electronic ignition. I'm a bit rusty. I do have the 88 BGB.
Also, do I need that noise filter? I think it's sometimes called a condenser...? Little black plastic square with two metal prongs and two wires leading to a blue plug.
Thanks
JP
The running got so bad that I lost all power and could barely make it up my driveway. However, this happened after I was changing the ignitor and coil and for some reason the noise filter arced while reinstalling it. Swapped noise filters--no improvement.
I finally got smart and pulled the codes--I got a 43 and a 51. 43 is a starter signal but the car starts fine. 51 is the AC switch signal which corresponds to the AC circuit (currently not being used) and a TPS error.
Before this all went south my idle was very high--2000rpm plus. I couldn't get it to consistently stay at a normal speed.
Car never overheated and as I stated--drove just fine at part throttle.
So, I'm guessing I should start with the TPS? I have a spare--I've had MR2s for 20 years but this is my first SC and I'm a bit rusty as most of my time has been spent on my 82 Starlet which has a dual Webers and a very simple electronic ignition. I'm a bit rusty. I do have the 88 BGB.
Also, do I need that noise filter? I think it's sometimes called a condenser...? Little black plastic square with two metal prongs and two wires leading to a blue plug.
Thanks
JP