Quick injector question
Thread Starter
Le Mans Master
Joined: Sep 2002
Posts: 6,569
Likes: 2,401
From: Redacted
Quick injector question
Im installing Stg 3 243 heads to go with the cam Ive had in the car for a while and plan on upgrading to the FAST 36lb/hr injectors (actually flow 43 lb/hr at our fuel pressure). My question is am I ok installing these things and then driving it down to Virginia Speed for a tune, or should I have them install the new injectors when they do the tune?
Ive seen posts about the possibility of a bigger injector thats not tuned causing the car to run pig rich, wash down the cylinders, no lubrication, bad things, etc, etc.....
I may be an idiot, but just wanted to make sure Im not going to damage anything driving it down to the tuner with the new injectors installed.
Ive seen posts about the possibility of a bigger injector thats not tuned causing the car to run pig rich, wash down the cylinders, no lubrication, bad things, etc, etc.....
I may be an idiot, but just wanted to make sure Im not going to damage anything driving it down to the tuner with the new injectors installed.
Le Mans Master
Joined: Jan 2002
Posts: 5,320
Likes: 4
From: Kyle TX (Because Mojo Made me fill it in)
My vote is to drive there with your current injectors and swap to the new ones there for them to tune. Id be hesitant to run the car with 43lb injectors firing at the rate of 28lb injectors.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
What I've done a few time is.............send the PCM to the tuner with a list of mods, he will get it real close...close enough to drive. Then the cost of the mail order tune is deducted from the total tune cost. So your out 0 dollars and just a week-ish of time.
Good luck with the car....
Thanks...........
Good luck with the car....
Thanks...........
Thread Starter
Le Mans Master
Joined: Sep 2002
Posts: 6,569
Likes: 2,401
From: Redacted
ok cool, glad I asked. VA Speed is only a few miles down the road so Ill just baby down to them on the factory injectors and let them install the new ones and do the tune. Thanks for the input 
Thread Starter
Le Mans Master
Joined: Sep 2002
Posts: 6,569
Likes: 2,401
From: Redacted
What I've done a few time is.............send the PCM to the tuner with a list of mods, he will get it real close...close enough to drive. Then the cost of the mail order tune is deducted from the total tune cost. So your out 0 dollars and just a week-ish of time.
Good luck with the car....
Thanks...........
Good luck with the car....
Thanks...........
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I'll throw this out only as a reference. I recently rebuilt a SBC marine motor (Merc) that was an EFI/MP motor. New motor consisted of a stroker assembly, standard bore, way bigger cam, Dart heads etc. I kept the original Merc EFI with 24 lb injectors for initial start up and system check. Using a real time wide band O2 sensor/gauge the idle AFR was low 12.x to high 11.x with a stock tune and 24 lb injectors.
I then installed the new 42 lb injectors and with the same bone stock tune the idle AFR went to 10.7! Pig rich was an understatement. Now keep in mind this was done on a test stand for short duration and I soon afterwards trimmed out the fuel tables to accommodate the new cam and injectors.
The results I expected indeed happened so I would imagine you would have experienced the same issues.
I then installed the new 42 lb injectors and with the same bone stock tune the idle AFR went to 10.7! Pig rich was an understatement. Now keep in mind this was done on a test stand for short duration and I soon afterwards trimmed out the fuel tables to accommodate the new cam and injectors.
The results I expected indeed happened so I would imagine you would have experienced the same issues.
