Hi,
Currently i have a '87 IROC, that has a 1227165 ECM.
I just got myself a chip that has "ARAP" code for F-body (VATS removed).
Guy told me that i need to plug the cold start injector, because it's not going to be used in that code.
Could somebody tell me why i just can't leave it there... if ECM doesn't use it anymore what harm can it do since all 1227165 ECM 's are interchangeable, or am i wrong?

Will my car run with 9th injector in place?

If i need to unplug it, is it enough if i pull wiring only and leave the injector there?

Thanks.

 

Some folks just leave the cold start injector hooked up. The reason is that with ARAP the engine will crank quite a while before the injectors fire. However, once fired the engine will then run a bit richer then normal until the cold start inj shuts off.

To prevent the cold start inj from firing just unplug the connector from it. The injector can be left in place.

The cold start injector isn't controlled by the ECM. There is a thermo switch in the thermostat housing for it.

RBob.

 

Great, thanks for the info....

 

Any ideas what might be wrong.....i installed that chip with ARAP, and car fired up immediately,but runs very rough....when i threw original chip back, it ran smoothly again.
Has anyone experienced this with ARAP?
I haven't taken any ALDL data from ECM yet, will do that during weekend....

 

Unplug the cold start injector and try it again. Need to remember that ARAP is a y-body calibration: aluminum headed L98 w/auto.

RBob.

 

Tried with and without 9th injector...it has no effect,runs rough still.
My engine is not stock, it has 10.5:1 (true) CR, Crane 113931 cam, Edelbrock headers,1.6 alum. rockers,ported iron heads that flowed 456hp (lost datasheet,so i don't remember cfm anymore)...just dynoed it, and it had 238ps on wheels, and 482 ft-lbs....this was with stock chip.

Could MAF have something to do with this?

 

ARAP has way too much timing in it for that much compression and Iron heads, unless they have excellent quench and you have a very wild cam (you didn't post the cam specs and I don't have time to look it up). Not to mention that the Corvette weighs a lot less so therefore less load.....

You might want to burn your own chips...... See the DIY board, it's a lot of fun!!!!

Every change you make to the engine changes what the engine wants. The first thing you need to do is datalog. Do you have a laptop? If so, there is plenty of "Freeware" out there to enable you to do so. After looking at the results, you can make choices as to what changes you want to make to your "tune".... Read up as much as you can on the DIY board!!!!