MATEOZ28

I've isolated the ticking to the fuel rail. Its loud as hell and when I grab my fuel sylinoyd line coming from the schrader valve it fells like a small kick everytime the tick occurs. I have 30lb SVO injectors I bought used so there is no telling what kind of abuse they went through in the past. I put a screwdriver to my ear and touched it on the fuel rail and this is definatly my ticking problem.

Is this what happens when an injector is bad? How do I test them?

I am also having BAD power problems. When I say bad I mean BAD........try 15.3 with a 450HP crate engine

John Millican

iTrader: (1)

I have SVO injectors and they ticked right out of the box. I wouldn't worry about it, they are just louder then the AC Delco ones and about 1/5th the price.

chubb rock

Not too long ago I had to change all 8 of my injectors. What happened was my car would stall at lights and hesitate when I pressed the gas. I went in to my local Chevy dealership, thinking they knew how to troubleshoot and diagnose problems on high performance cars (which they don’t, but that’s another story!). Needless to say, I had to go to a local shop (Halton Auto Electric) to have the problem properly and professionally diagnosed.
The problem it seems is that 4 of the injectors where electronically damaged. The injectors themselves had a cleaning and where to spec in that regard but electronically they were out of spec.
The test the technician did was to use his ohmmeter and check the resistance out on the injector’s contacts (pins, connectors).
For a 305, the injectors should have a resistance of 14-16 ohms. 4 of the injectors were at about 8 ohms, and the rest were in tolerance.
The computer was over compensating for the 4 bad injectors and the car was running rich because of it. Its like the old carburetor cars, if it isn’t tuned just right your either running rich or lean and the car won’t run properly.
I never experienced any knocking.

Vader

Mateo,

You can test the injector coils as Chubb suggests, but that is only part of the story. The electrical tests say nothing about flow rate and spray pattern. Unfortunately, the injectors need to be removed for that kind of testing.

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Chubb,

You were lucky in that the four bad injectors must have been distributed across both banks. Resistance that low all in one bank would have likely damaged the switching transistor in the ECM. And for arguments' sake, the tolerance for new injectors is 14-16 ohms DC resistance. The service limit is down to 12 ohms on a used injector, but no lower.

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John,

You've done an excellent job on the LT1 intake site. All that work, and you're just offering up the information for free. My hat is off to you, man. I hope your mill is staying busy.

MATEOZ28

The car always lets out white smoke on launch, and its always running rich. What do I set my ohm meter at and do I test while the key is to the start position or off? Is there a link for instructions on how to do this test? What should be the resistance for 30# SVO injectors?

MATEOZ28

"What happened was my car would stall at lights and hesitate when I pressed the gas. "


Same thing with mine. A new set is fairly priced. Think its worth just buying a set?

Vader

Set the ohmmeter on the lowest resistance scale (highest current resistance test) and read the resitance directly.

John Millican

iTrader: (1)

Thanks,

I do offer the tech article as a free as well as many e-mail questions. I would be happy if I help just a few people run their best.
I am keeping my mill busy as not everyone can do the machine work.