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He picked up a used TBI unit at a swap meet this weekend. Along with other accumulated parts, he's wanted to score a bored and modded TBI unit. This one has the shaved air horns around the bores (professionally done on a mill too, I'd say...they are nice a flat, not wavy as if done by hand), larger bores (46mm or 1.81+" as verified by dial caliper), and thin throttle shafts, tiny button head screws. The unit was less than a 8 gallons of gas ($20), so it seemed a no-brainer. The Scotsman in him fell in love with the hundreds of dollars saved!
The injectors included were supposed to be native to a 5.7L, but as he would never start a build and work on a tune from scratch with unknown used injectors, these were little more than cores, if even needed for that.
But going through the motions, I checked our pinned thread here on TBI injector paint colors. It says:
GM TBI injectors, color codes, and flow rates
These injectors are rated at the pressure used by the factory, about 13 PSI
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Color code Application Flow rate Part #
Black/White 1-3/8" bore 2bbl, from 2.8l truck ??? GM 5235430 *RPD
Yellow/Blue 4.3L ??? GM 5235203 *RPD
Green/White 5.0L 40 lb/hr GM 5235279 *RPD
Orange/Black 5.7L pickup 55 lb/hr GM 5235206 *RPD
Yellow/Brown 5.7L Cop Car 65 lb/hr ???
Blue/Black Late big block pickup 80 lb/hr GM 1708430 *RPD
Dark Red/Dark Blue big block pickup 90 lb/hr GM 5235231 *RPD
Here's what came with this unit.
To my eye, that's black and grey. So I guess that means black/white...2.8L?
The pod is only on finger tight, and has clearly been swapped recently. So it's possible they are not 5.7L units. Again, no biggie either way, but just want to be clear about what I, err, he has.
The multiple sets of 5.7L units I have ALL have Orange/Black color markings, I'd agree my friend those sure don't look like them. To be sure take some cleaner to that surface crud and search the Part Number.
Last edited by 92RS-HeritageEd; 06-09-2019 at 06:04 PM.
That's sort of what I was thinking. With the screws for the pod only being half installed, it very much seemed like the "good" 350 injectors and pod had been stripped off this unit, in favor of these throw away 2.8L pieces. This would have been built with an up-rated regulator spring at the very least, and an adjustable regulator would not have been likely. He was trying to run this on a 406, and never quite got it working right. He thought they were 350 injectors, but admitted a buddy had helped him with much of this work.
Took it apart and cleaned that surface...looks like GM 5292130, which comes up as nothing on an internet search.
It's not terribly important, as these would have just been cores anyway. If I'm changing a ton of things in the engine all at once, it's going to be more than enough of a tuning challenge without relying on used injectors of unknown quality. The plan is to replace them regardless. But from a selling them point of view, it would be nice to know what they are. Paint is clearly black and a light grey, which would be white per this table, which says 2.8L to me I guess.
06-09-2019, 04:32 PM
