High idle

[Q_SHIP]

My car seems to have a high idle. I really have to be on the brakes to get it to staop. When I let off of the brake, the car takes off pretty good with no throttle. I would have to say the car speeds up to about 15 m.p.h. just by lifting off of the brake and no throttle. In neutral, I see R.P.M.'s between 1,000 and 1,500. Is this normal? I have a fuel pump on it's way here because mine is cranked wide open. Could this be doing it?

[pito11213]

I dont think that a fuel pump would cause your idle situation. Maybe check out your throttle body cables. Could be to tight and binding. If you pull up on the accelarator pedal does the idle go down a little? Check that first then maybe your idle needs to be physically reduced. Do a search as I have an idea but dont want to give out misinformation.

[Q451990]

I agree with pito11213 - check your throttle cables. There should be a few mm slack in the cables at warm idle. I tightened mine once and had a similar problem. Definately DO NOT ADJUST the screws on the throttle body.

Heath

[Jesda]

What's the name of the device that measures coolant temp when you start up the car?

[elwesso]

What's the name of the device that measures coolant temp when you start up the car?

Coolant temp sensor???

Theres another thing called the fast idle cam, and if you adjust that it will cause funky idling.... NEVER touch...

one time my idle was messed up because i didnt adjust the IAC right.....

Id clean the TB first and see what that does.....

[jtesensky]

Check out your TPS, it sounds like an exact symptom of a sticking TPS.

[Q451990]

TPS issues are very rare on the Q45... Joe have you sold many? I know this is what happened on your truck, but I've only heard of one or two confirmed TPS failures on a Q45.

Heath

[jtesensky]

I've actually sold 5 this year on the G50, I still stock 2.

[elwesso]

Hmm,

I have a high idle.. idles about 800 RPM... When i cleaned the MAF it because a little higher.....

Maybe my MAF is going goofy?

[jtesensky]

It could actually be that damn connector, maybe try some contact cleaner??

[3rd Q]

Qship,Does your idle stay high all the time or just til it's warmed up? I ask because my '90 does something similar, but only til warm- then it behaves perfectly.

[Q_SHIP]

It does it even after the warm up.

[Q451990]

Qship,Does your idle stay high all the time or just til it's warmed up? I ask because my '90 does something similar, but only til warm- then it behaves perfectly.

That's what it's supposed to do...

Heath

[Q45tech]

Measure hot warmed up TPS voltage should be adjusted to 0.44 volts but [0.4>0.5 volts] as read by ecu as displayed by Consult is acceptable..........VOM won't be accurate enough.......... for exacting work!

IAC duty cycle 10-15% warmed up at desired idle rpm -----no load no ac no lights on in Park.IAC purose is to be centered at bottom [thus 10%] so it can mostly raise rpm under increasing load not decrease rpm more than 35-50 rpms to compensate for something else.

Intermitent coolant ecu temp sensor can raise to 1200-1500........remember the ecu has its own more accurate sensor not connected to inside temp reading........fools many.

MAF doesn't raise idle speed! Usually the converse.

You must have access to a Consult to optimize.

[Q451990]

QShip - have you checked the throttle cables yet???

Heath