Deceleration Problems 89 6 spd
Thread Starter
Instructor
Joined: Aug 2001
Posts: 173
Likes: 0
From: Worcester MA
Deceleration Problems 89 6 spd
Just got a new 89 6 speed and following high rpm use, engine decelerates too slowly. Kinda hangs for a few seconds before letting go and returning to idle. Anyone know what could cause this?
New Guy
THX
Brett
New Guy
THX
Brett
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Deceleration Problems 89 6 spd (C4RAG)
Probably a problem with the Throttle Body / IAC. At least a good place to start.
Go to the tech tips section and you will find a write-up by Lars on removing and cleaning the TB and minimum idle set proceedure. Very simple and a good place to start on your problem. I would replace the IAC with new GM.
Couple of tips while your in there: Check the "slop" on the shaft that holds the butterfly valves where it goes through the TB, I had to replace my TB as there was a lot of wear there and air was getting in.
Soak the bolts on the cover of the TB where the coolant passes through - these tend to get gunked up - I had to buy a new set for the coolant side.
Also a couple of hundred miles after install - re-torque the TB to plenum bolts; they will work loose and need to be re-torqued after several heat cycles.
You can buy a new gasket set and IAC from Jeff Koop or TLD at a discount.
Good Luck,
Pete
Go to the tech tips section and you will find a write-up by Lars on removing and cleaning the TB and minimum idle set proceedure. Very simple and a good place to start on your problem. I would replace the IAC with new GM.
Couple of tips while your in there: Check the "slop" on the shaft that holds the butterfly valves where it goes through the TB, I had to replace my TB as there was a lot of wear there and air was getting in.
Soak the bolts on the cover of the TB where the coolant passes through - these tend to get gunked up - I had to buy a new set for the coolant side.
Also a couple of hundred miles after install - re-torque the TB to plenum bolts; they will work loose and need to be re-torqued after several heat cycles.
You can buy a new gasket set and IAC from Jeff Koop or TLD at a discount.
Good Luck,
Pete
Thread Starter
Instructor
Joined: Aug 2001
Posts: 173
Likes: 0
From: Worcester MA
Re: Deceleration Problems 89 6 spd (C4RAG)
Sounds good but I might add that it only does it once in a while and only when it is hot... Originally didn't think it was the TB so figured I would ask...
