I just purchased a TPI unit and I was wondering how to tell what size injectors they are and how to test then if they are still good. The Unit is from an 87-88 i beleive because it still has the cold start injector. Thanks in advance Mike

 

Pull an injector, spin it around, and read the tiny little umber that is stamped on the side.

Generally, 305 TPIs got 19.2 pound/hour injectors, and 350 TPIs got 22.1 pound/hour injectors. You really never know what you might have purchased, however.

Incidentally, GM rated injector flow at 43.5 PSIG (3 BAR) rail pressure, while many of the aftermarkets rate flows at a higher pressure to be able to "look better" to unsuspecting customers. Accel has come around to the 3 BAR standard, but IIRC, Ford SVO (Denso) used a lower pressure or around 39.1 PSIG, while Dodge used a higher rating pressure of 55.1 PSIG. LS1/6 injectors are also rated at 50 PSIG.

Caveat emptor.

 

Thanks vader, I looked up the #5235436 at http://www.geocities.com/ttskipp/injector.html and it list them as 20.7 lb Injectors So Still not too sure what its from.