Irratic High Idle

[GRW]

Can't control Idle, when put in Drive, using no Peddle Acceleration, increases fastly up to 40 MPH on it's own.

 

New IAC, MAP, TBI Rebuilt with New Injectors, Fuel Sending and Pump, etc...

[CamGTP]

Does it do the same with the throttle linkage disconnected?

 

If it does, then something is holding the throttle blades open or there is a leak between the TB and intake.

[richard wysong]

what are we working on?. TB base gasket was a common vacuum leak,PCV system leak, brake booster leak? Intake manifold gaskets? pull the PCV and breather  from the valve covers and see if there is vacuum internal

[GRW]

10 hours ago, richard wysong said:

what are we working on?. TB base gasket was a common vacuum leak,PCV system leak, brake booster leak? Intake manifold gaskets? pull the PCV and breather  from the valve covers and see if there is vacuum internal

 

[GRW]

1995 Chevy C3500 Gen5  7.4-454

 

Engine completely Built by Chevy Builer, all Gaskets upgraded and New, Rebuilt TBI, all sensors New, including Pig Tails, New Vaccum Cannister and Lines?

 

Roller Rockers with Beehive Springs, Cam, 4.25 Stroker Kit, etc...

 

Rebuilt ECM, Engine Builder said 12 to 1.

 

Thank's 

[GRW]

13 hours ago, CamGTP said:

Does it do the same with the throttle linkage disconnected?

 

If it does, then something is holding the throttle blades open or there is a leak between the TB and intake.

 

[GRW]

Just now, GRW said:

 

I will try and let you know.

 

Thank's 

[richard wysong]

Wow! That's a ton of new work, If the throttle linkage checks out the next thing I would check is for vacuum leaks, If they milled the block or the heads the intake manifold may not seal properly without being milled as well. Check the throttle body and make sure the throttle plates are completely shut. What are the IAC counts doing? any codes? How do the 02 sensor readings look? 

[GRW]

Hi Richard,

 

Didn't get to check the rest yet, have the 02 Sensor extended behind, running Duals no Cat.

 

Block was Decked by Builder. Will Post response after Checking. No OBD1 Sensor, was taken. Going to get it Checked again since too...

 

Thank's 

[CamGTP]

I had no idea it was a stroker kit, there is no way the stock TB unit will support that and no way a stroker tune can just be made out of thin air and put on the stock computer.

 

You'll have to go with a stand alone engine controller and something better than a TB unit if you really want this thing to operate right and make lots of power.

[GRW]

On 10/28/2022 at 5:18 PM, CamGTP said:

I had no idea it was a stroker kit, there is no way the stock TB unit will support that and no way a stroker tune can just be made out of thin air and put on the stock computer.

 

You'll have to go with a stand alone engine controller and something better than a TB unit if you really want this thing to operate right and make lots of power.

Hi Richard, I appreciate your time and help. I had a Chip made for it from Motorvation, haven't put it on yet. It runs the same after TBI linkage was removed, and Plates do ******?

 

Was told by someone to try to get it running close to normal, disconnect

Battery, and turn on Light's to erase all. Then put Chip in/on? Any idea's in regard?

 

Thank's...

[richard wysong]

I'm not the guy for ECM  changes, Maybe Cam has some pointers