Just wondering if anybody knows a good way to check for bad injectors. I'm building a new 350 but I'm using 305 injectors. I could buy a SVO set, but for the time being would like to use the existing set if they're OK. Anybody done this off-car?(fuel rails and such are not on the car right now)

 

The simplest thing you can do is check the resistance on each of them. They should all be close together and no less than 12 ohms. Most people's fall within the 14-17 ohm range.

 

yeah, checking the resistance is all good except you could still have a bad injector and have it check out alright. i personally think resistance tests for the most part are a waste of time.
the thing i noticed is that bad injectors hide themselves well. first, check all of your plugs and see if they are alright. if one plug is different from the rest i would start looking at that cylinder. verfiy spark their and take that out as a variable.
i have in the past started unplugging the injector while the engine is running and see if it changes momentarily. usually you will intially hear the difference then the computer will compensate for it. if it doesn't change then (and it is the same cylinder as the spark plug showed irregularity) you can be pretty sure you have a bad injector.

that is how i solved my injector problems when i put my 350 in. resistance test said the injector was alright. does anyone else have a different method cause i wouldn't mind hearing how others might have solved their problems. i am sure mine isn't a full proof way but it worked for me.

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87 iroc-z 355 TPI 5 spd. 51006 SLP cam adv. 4* (106.5* centerline)
hypertech stage II chip/ 160* stat./ Airfoil, accel AFPR
19# injectors, ported plenum and runners. 9.8:1 compression
stock heads, pocket ported, 1.94 int., unshrouded.
stock exhaust manifolds and y pipe! hopefully soon to change
3.45 rear (stock)
Flowmaster, K&N w/ hacked airbox/removed MAF screens
14.38@100mph 2.2 60'

 

The best thing to do is have them checked and flow matched since they're off. It will cost you about $100, on an exchange basis. This will make a world of difference. I used 305 injectors on a mild 355, and I get great power and an honest 25mpg on the highway. Just increase the pressure. The side benefit is that they stay cleaner longer because of the higher pressure.

 

355 IROC-Z: I found my bad injector the same way... but since they're are off, might as well send them off to get cleaned and flow matched

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90 IROC 5.7l (L98)
ram air, K&N's, air foil,Flows

LIKE A ROC

 

Yeah, I usually check them by pulling the connector with the engine running too and I think that's the best way, but I figured he wouldn't want to put it back on the engine, run the test, and then pull it again to replace any injectors. You can still find many injector problems with a resistance test, although it is not as fool-proof as the method 355 mentioned. If you have money to spend on it, send them to cruzinperformance to be cleaned and flow matched.

 

not as fool proof or full proof, lol. glad to hear other people take this approach too. but yes, definately while the injectors are out, send them to rich at cruzin performance. i was very pleased with my injectors when i got them back and the price was excellent on top of that.

 

Can't wait to get my hands on some of those new Accel injectors he's carrying too!

 

Thanks for the ideas, but who is cruzinperformance and how much does blueprinting injectors cost? You're right, I'd hate to tear the motor half apart to replace a bad injector right after installing it.

 

My bad. He just said $100. Still, I don't know ho cruzinperformance is!

 

http://www.cruzinperformance.com/

was $10 per injector when i had mine done