1996 3000GT SL DOHC
Engine running rough and need help diagnosing
Well heres the story, bought my purple 96 SL about a month ago knowing it had a couple issues, when i bought it it ran and drove ok, but i got it for cheap cuz the owner couldnt figure out one issue, The motor wont rev past 3000 RPM, very weird, almost feels like it has a rev limiter, it just wont go past (this limit varys slightly, sometimes as low as 2800 RPM but ive gotten it up to 4K a few times)
anyway, one day im driving, and the engine dies on me out of nowhere, so i pull over, engine starts but only for a second at a time before dying again, by time its towed home its a crank no start. Spray starter fluid in throttle body, starts for a second, dies again, so i give it a fuel pump and filter. after a lot of BS putting the thing in and redoing all the fittings, I finally get the pump going and seems to be getting its 14 Volts all the time now, (New MFI and fuel pump relay too) so now the motor will finally start.
Now heres the issue, im suddenly having tons of issues,
Idle is very rough, if i dont keep tapping the throttle every once in a while it will stall, (Very weird tho, if i take the intake off the throttle body it seems to be better, idle right at 800-900 and never stalls. so idk what thats about)
Also if i try to drive it, it makes very little power and stalls very easy, could barely make it down the street before I pushed it back.
So i finally brought it to my mechanic to have the check engine codes scanned and he says there are a bunch of codes, he listed the MAF airflow sensor, crank sensor, and something about an idle control motor? idk i know i replaced my idle airflow valve just a few weeks ago cuz it was throwing a code for that.
So, we have rough idle, stalling, no power, and wont rev past 3000 RPM
How can i diagnose this? is my ECU going bad? or is it realistic that all those sensor just suddenly stopped working? maybe over the course of the couple weeks it wasn't running? maybe the fuel pump wasn't to blame after all? it was due for replacement tho so whatever. My mechanic doesn't even wanna touch it with all this stuff, Please help!!!!!!!
Also I wanna mention, when I try to start the car it often just clicks and doesnt crank, I have to try over and over until it decides to crank, clicking sounds like its coming from way down in my started motor kinda area, I know this is a somewhat common problem but now that all this stuff is happening its kinda on and off so idk what that's about
Also I should probably mention, previous owner claims the motor was rebuilt, and has new heads, not sure if this is even true (didnt see any paperwork) but the engine itself looks pretty good and heads and intake manifold are painted, also the cam gears and pulleys all look pretty new, maybe a few thousand miles old.
Any help is greatly appreciated, this car is my daily driver (Stupid me)
and i need it back on the road ASAP ASAP ASAP
**** UPDATE
Put a new ecu in because the shop I brought the car to said the ecu was fried.
New ecu changed nothing but I have a couple new symptoms
Car will not shut off when I take the key out, the lights and stuff will but the engine keeps running...
The guage showing batters voltage stays around 14-15ish instead of 12 now.
No idea what this means but I hope you guys will have some ideas.
Thank you
Engine running rough and need help diagnosing
Well heres the story, bought my purple 96 SL about a month ago knowing it had a couple issues, when i bought it it ran and drove ok, but i got it for cheap cuz the owner couldnt figure out one issue, The motor wont rev past 3000 RPM, very weird, almost feels like it has a rev limiter, it just wont go past (this limit varys slightly, sometimes as low as 2800 RPM but ive gotten it up to 4K a few times)
anyway, one day im driving, and the engine dies on me out of nowhere, so i pull over, engine starts but only for a second at a time before dying again, by time its towed home its a crank no start. Spray starter fluid in throttle body, starts for a second, dies again, so i give it a fuel pump and filter. after a lot of BS putting the thing in and redoing all the fittings, I finally get the pump going and seems to be getting its 14 Volts all the time now, (New MFI and fuel pump relay too) so now the motor will finally start.
Now heres the issue, im suddenly having tons of issues,
Idle is very rough, if i dont keep tapping the throttle every once in a while it will stall, (Very weird tho, if i take the intake off the throttle body it seems to be better, idle right at 800-900 and never stalls. so idk what thats about)
Also if i try to drive it, it makes very little power and stalls very easy, could barely make it down the street before I pushed it back.
So i finally brought it to my mechanic to have the check engine codes scanned and he says there are a bunch of codes, he listed the MAF airflow sensor, crank sensor, and something about an idle control motor? idk i know i replaced my idle airflow valve just a few weeks ago cuz it was throwing a code for that.
So, we have rough idle, stalling, no power, and wont rev past 3000 RPM
How can i diagnose this? is my ECU going bad? or is it realistic that all those sensor just suddenly stopped working? maybe over the course of the couple weeks it wasn't running? maybe the fuel pump wasn't to blame after all? it was due for replacement tho so whatever. My mechanic doesn't even wanna touch it with all this stuff, Please help!!!!!!!
Also I wanna mention, when I try to start the car it often just clicks and doesnt crank, I have to try over and over until it decides to crank, clicking sounds like its coming from way down in my started motor kinda area, I know this is a somewhat common problem but now that all this stuff is happening its kinda on and off so idk what that's about
Also I should probably mention, previous owner claims the motor was rebuilt, and has new heads, not sure if this is even true (didnt see any paperwork) but the engine itself looks pretty good and heads and intake manifold are painted, also the cam gears and pulleys all look pretty new, maybe a few thousand miles old.
Any help is greatly appreciated, this car is my daily driver (Stupid me)
and i need it back on the road ASAP ASAP ASAP
**** UPDATE
Put a new ecu in because the shop I brought the car to said the ecu was fried.
New ecu changed nothing but I have a couple new symptoms
Car will not shut off when I take the key out, the lights and stuff will but the engine keeps running...
The guage showing batters voltage stays around 14-15ish instead of 12 now.
No idea what this means but I hope you guys will have some ideas.
Thank you