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85 cold start injector problem

T

tom_85_vet

Guest
My problem is with the idle at operating temp. I have been trying to solve this problem for some time. I start getting a cycling of 3 different rpms once the car reaches operating temp (160) and the 9th injector (cold start injector) shuts off, which cause the car to run lean. My understanding is that the 9th injector is only on the 85 vet. I have tried cleaning and replacing must parts, including all the manifold gaskets.

I was told of a procedure that might help. Get the car to operating temp, disconnect the battery for 30min (clearing the computer). Start the car and put the car in drive (idle) for 5min, then in neutral for 2min, and then in reverse for 5min. What this is doing is helping the computer learn the idle. I have not tried this, but will this weekend.

Has anyone had this problem?

BTW, thanks wigman with timing problem. I did not know that the oil pump gear moves when the distributor is removed.
tom
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Oil drive

On the bottom of the distrib there is a MALE slot
(like a regular screwdriver head).

This connects to the oil pump drive.
(Female groove like a regular screw head).

There are helical cut gears in the cam & distrib, as you lift the distrib, it turns. It continues to turn AS you clear the oil pump drive.. SO

The position of the oil pump drive is not aligned correctly from where you need to be, you have to manually reposition the oil pump FEMALE drive, to put the distributor BACK to it's proper position
( Facing towards the #1 cylinder).


Mike
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
About the idle

Have you tried cleaning the IAC motor?

The 9th injector is on my 88.

Yes if you get the car up to temp... stop the car
pull the ECM fuse ( 5 min )

Try to start.. shut down the second it starts and re start, this will re learn the computer & the IAC motor.

Drive it for 10 min after about 1 minute of idle.



Mike
 

FrankM

Well-known member
Joined
Nov 4, 2001
Messages
154
Location
Derry, NH
Firstly, the cold start injector only sprays while cranking and it needs to see a cold coolant temperature.

Secondly if you are having an idle problem when hot, how do you know it is because of lean?

What is the tps and iac count?

If you want something to try that will cost nothing, dissasemble and clean the iac.

keep us posted
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
So how's things going?

Did ya fix it...any progress?

Mike
 
T

tom_85_vet

Guest
Vigman
I have not tried it yet, the vet got changed from a daily driver into a pleasure vehicle. Whenever I worked on the vet it took twice as long and had to use the wife's car. So, now I have all the time in world to work on the vet, but no money since I had to buy a third car. Once I get to the fix, I will keep you posted. Just a thought, when I installed a new IAC I did not adjust the length. I believe the spec is 1 1/8 inch. I will try that first, then the computer learning procedure.
Thanks for the info
Tom
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Ohhhhh

After market IAC..yikes..I havent had good luck with those...1& 1/8 is the correct measurement, but it has never worked as well as stock.

Mike
 

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