i just rebuilt my 7MGTE and on start up, the engine barely starts and when it does, it revs crazily by itself (not touching the gas pedal). I thought maybe the throttle linkage got sagged on something, but everything appears fine. I'm thinking the TPS is stuck or the idle control valve is doing something weird? One of the hoses is not connected on idle control valve (the smaller port). I have the larger port connected by a hose to the plug in after the MAF sensor, but the other one im not sure where it goes to. anyone have suggestions or direct answers? thank you.
7MGTE revs out of control on start up
- Thread starter fast427
- Start date
The big hose goes to the intake. The smaller hose, there should be 2, will have coolant going through it. So if you have one connected and the other one not then coolant should be going everywhere. You can bypass them but its not recommended in colder areas. And really no point to unless its getting relocated and running a standalone or something.
Check your codes first off.
And second sounds like tps is bad or needs to be adjusted.
Check your codes first off.
And second sounds like tps is bad or needs to be adjusted.
well I rerouted the coolant line from the cylinder head by passing the throttle body and it continues into the coolant piping around the engine block. I remember i took off the idle control valve to have intake cleaned, maybe i put something in backwards?
---------- Post added at 11:09 PM ---------- Previous post was at 11:04 PM ----------
also, on my dashpot, the little filter is missing at the bottom. is that possbile for surge revving? i can take pics if needed
---------- Post added at 11:09 PM ---------- Previous post was at 11:04 PM ----------
also, on my dashpot, the little filter is missing at the bottom. is that possbile for surge revving? i can take pics if needed
If its revving out of control, it sounds like its more than just a messed up tps. It has to be getting air from somewhere. If the throttle body is closed, it shouldnt rev out of control no matter what the TPS is telling the ECU
Have you checked the IAC valve? If it gets dirty it can hang up in a bad position.
Try plugging all vacuum ports on the intake manifold and try a test start. If it still revs high, plug off the throttle body. It might seem crazy, but its worth a shot.
Try plugging all vacuum ports on the intake manifold and try a test start. If it still revs high, plug off the throttle body. It might seem crazy, but its worth a shot.
i will check for any open ports that weren't plugged off, but im pretty sure everything is sealed off, except for the dashpot. im going to look closer at the TB, and IAC, and i will update soon.
The isc need to have the little filter thing with the orange thing on the inside of the manifold. Unplug the tps and see what it does.
well i ran the diagnostic codes,21, 24, 51 ( i think 51 is a repeat). so it doesnt tell me anything useful
24afm(air temp sensor in the tps), 51 tps , 21 o2 sensor or circuit.
http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx
If you removed a/c and push the a/c button you will get 51. If you have a/c and i think the tps is your main problem.
http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx
If you removed a/c and push the a/c button you will get 51. If you have a/c and i think the tps is your main problem.
My supra had this problem once where i would start it up and it would rev all over the place anywhere from 1500rpm to 3500rpm. I to thought it was a bad tps sensor but it turned out my maf needed to be replaced. ANDD i had that same code 24
but my car continues to rev, if i dont shut it off, it would throw a rod..haha it kinda gives me the chills knowing a completely new engine is being revved to hell without a proper break in.
Ya i wouldnt run it long without breaking it in.
Get a new afm and set the tps. Both can be done with the engine off. IF you started it with the o2 unplugged i think that throws 21. Or the o2 is bad.
Get a new afm and set the tps. Both can be done with the engine off. IF you started it with the o2 unplugged i think that throws 21. Or the o2 is bad.
well im going to remove the AFM completely and im going to put in a wideband, hopefully this problem will resolved soon, i really appreciate all your help.
is any of the accelerator linkage moving when this is happening...? Cruise control or auto tranny linkage?
with engine off check that the throttle body butterfly is completely closed
if that is fine i would suspect you ISCV is bad
have a friend start the engine
tap on ISCV with a wrench or something but nothing like a hammer lol
dont need to tap hard just lightly
if your idle changes then the ISCV is bad or needs cleaned
do you have a vaccum/boost gauge that is not the stock 1?
if so what is the vaccum when it starts up?
if that is fine i would suspect you ISCV is bad
have a friend start the engine
tap on ISCV with a wrench or something but nothing like a hammer lol
dont need to tap hard just lightly
if your idle changes then the ISCV is bad or needs cleaned
do you have a vaccum/boost gauge that is not the stock 1?
if so what is the vaccum when it starts up?
Unless the throttle plate is being held open by something... (Cruise control actuator, bent linkage, mis-adjusted cable, something stuck inside)
Wow y dont u just change ur spark plugs while ur at it. Pull off the big hose that goes to ur iac and stick ur finger in there. Have a friend start the car. U might need to let a small amont of air in with ur finger to keep it runing. The only hole large enough to make it rev like crazy is the tb and iac. If that works trouble shoot the iac.
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