Just returned from a very good trip to a local J-Yard. I pulled a nice pair of TBI with the following GM numbers 5235905 which does not match to any known TBI injector numbers.

Color code is black-orange and they came off the late 80's 1500 truck. No engine ID, VIN number is 'K" Any ideas what these injectors really are for sure? Based on color alone it looks like 350. Thanks for checking...

//RF

 

If you cant find the number anywhere you probably misread it. Those numbers on top of those TBI injector can really play tricks with your eyes. Try to clean them up some more (if they aren't already clean) and get a good look at them. A magnifying glass helps a lot, even if you have good eyes.

Did you pop that number into google and breeze through a couple pages to see if you see any result that looks like it might have anything to do with GM, or cars, or fuel injectors?

 

Darkshot

Thank you for reply. Per your suggestion and my curiosity this is what I found.
Indeed, part number 523-5305 is a suspect. The second '3' could be a nine '9'. Google returned nothing for 523-5905. A closer look at injectors indicates that these units were re-manufactured by GM - see photo. Question is why there is no part number information available anywhere?

Before I take these injectors for flow testing (i.e. spend money) I would like to find out if these are 55 lb injectors as color coding suggests...


//RF

 

If they are from a K-vin 350 truck, they are 61 lbs/hr units.

 

I'm with Fast with these injectors. Everything points to a 61#/hr injector. The vehicle they came from along with the paint color codes.

RBob.

 

be kind of usefull if we had a table of fuel injector color codes and original applications they came in, make it easier for tuners to know what they are looking for

 

This is a follow up on original posting:

I sent two injectors (5235905 originally marked Black - Orange) to be cleaned, tested and reworked if necessary. Injectors were cleaned and tested (results are after cleaning). Test Pressure 43.5 psi:

Injector: 1 2
Static Flow 220 212 cc/min
Pulsed Flow 128 120 cc/min @ 2500 rpm
Fuel 880 848 cc/min @43.5 psi

CC/Min = Lbs/Hr x 10.5 (need Lbs/Hr)
83.8 80.7 lbs/Hr @43.5 psi
Reduce fuel pressure from 43.5 to 15psi
F2 = (√P2/√P1) x F1
49.2 47.4 lbs/Hr

So much for Orange-Black 55lbs/Hr injector rating or perhaps GM pulled a different part number for application specific requirement (CA emissions on 5.7 truck application???).

//RF

 

Thank you for the followup.

I am submiting the following as possible explanations of the flow rates you observed.

GM Injectors for the TBI engines are anything but linear at higher pressures. The higher the pressure gets, the greater the error from the calculated flows. At 45 PSI, I have found injectors to flow up to 10-15% less than calculations claim.

BTW, that is a rather large variation in flow.

I also find it weird, because I have actually done flow-bench testing on injectors and seen the regular 350 injectors flow right at 61 lbs/hr @ 12 psi.