Hello,

I've got a 1989 GTA with a 5.7 40k miles with only minor modifications (headers installed and apparrently 24# injectors) that I have been experiencing longer than normal cranking to start both when cold and hot. It has good fuel pressure when running. Took it to the dealer who blocked off the fuel tank lines and tested pressure going to injectors and found they lost pressure. Informed me they though it has leaky injectors. So, I ordered a set of reconditioned Bosch D3 22# injectors, installed them and the car runs terrible and won't idle now. Turns out I had Lucas 24# injectors in there which seem to run fine just had hard time starting the car, plus it would smoke a little after sitting a while when first starting. 22# injectors don't seem to smoke much at all when first starting now, but still started hard after sitting over night.

So, questions I have, the car came stock with 22# injectors and someone changed them out at some point. Would they have had to change the computer programming to tune it to the new 24# injectors? If that is the case, could that computer programming be causing the long crank during starting or could leaky injectors be causing longer crank times when starting?

I've been chatting with SouthBay Fuel Injectors where I got the Bosch D3's from. At this point I am thinking to swap the 22#'s out for a set of 24# and see if that makes a difference. If the car was tuned to run with the Lucas 24# injectors, will it need to be retuned for a set of Bosch 24# injectors?

I've tried disconnecting the battery for 20 mins to see if the ECU would relearn for the new injectors, but no luck. The way the car runs on the 22# injectors definitely seems to have the wrong air to fuel ratio. Purred like a kitten and idled great with the Lucas 24# injectors, only had a hard time starting.

Anyone have any thoughts on this and what I should try next?

 

If the computer was tuned to have 24# injectors then it will help to have 24# put back in. Another, incredibly likely, cause of problems is a vacuum leak. A large number of injector swaps turn into a vacuum leak issue. Just a heads up.