how to test for leaky injector besides ohm
11-13-2011, 09:30 AM
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how to test for leaky injector besides ohm Let me start off saying car is a 98z28 152k mile tr230 cam only most supporting mods m6. it is on the factory fuel system as of now. Recently when I come to a stop after driving a distance my RPM will only come down to 1500 rpm for around 20 seconds before dropping to 800 or so. My oil has a slight gas smell. Car performs good other than that. Gas in the oiil scares me as i know it can wash the cyl's if diluted too much. I did search on here and found to ohm the injectors my results were 12.3-12.6 on all cyl- that should be good right? I also read about a noid test but don't have the tool(where and how much for one)- this only test voltage right? I thought about removing fuel rail with injectors and priming up pump to see if they leak..any other easier less messy way? I also need a fp guage. How do i test the fpr since its in the tank. PLEASE HELP WHERE SHOULD I GO NEXT thanks-Brandon
11-13-2011, 04:13 PM
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Let me start off saying car is a 98z28 152k mile tr230 cam only most supporting mods m6. it is on the factory fuel system as of now. Recently when I come to a stop after driving a distance my RPM will only come down to 1500 rpm for around 20 seconds before dropping to 800 or so. My oil has a slight gas smell. Car performs good other than that. Gas in the oiil scares me as i know it can wash the cyl's if diluted too much. I did search on here and found to ohm the injectors my results were 12.3-12.6 on all cyl- that should be good right? I also read about a noid test but don't have the tool(where and how much for one)- this only test voltage right? I thought about removing fuel rail with injectors and priming up pump to see if they leak..any other easier less messy way? I also need a fp guage. How do i test the fpr since its in the tank. PLEASE HELP WHERE SHOULD I GO NEXT thanks-Brandon
its $15 per inj.service includes internal ultra sonic cleaning,flow bench test,measuring of all 8 injectors flowing together and all new filters,o rings, pintle caps etc.
11-13-2011, 06:39 PM
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i agree and that sounds like a great deal until i upgrade injectors with some heads...but this is my dd right now until i get my yukon engine swap done how fast is the turn around. Also come on other peeps what else do i need to do to troubleshoot and find what my problem actually is. BTW I only drive it 6 miles each way to work.
11-19-2011, 06:39 AM
#6
1.Start with a data log, and see what shows up.
2.A noid checks for inj pulse, can be purchased at most ap stores, not much $.
3.An ohm test will show inj coil issues, if any.
4.A fuel psi check is done at the rail, not the tank. The test results can then be looked at to see what's up w/ the system.[55-58psi is OK.]
5.Hanging idle can be caused by several problems.[Refer back to item 1].
2.A noid checks for inj pulse, can be purchased at most ap stores, not much $.
3.An ohm test will show inj coil issues, if any.
4.A fuel psi check is done at the rail, not the tank. The test results can then be looked at to see what's up w/ the system.[55-58psi is OK.]
5.Hanging idle can be caused by several problems.[Refer back to item 1].
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11-22-2011, 11:01 AM
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why not just pull off the injector rail w/ the injectors and prime the pump? this is how we found a leaky injector on a friends car.
as long as you have the stock rails that clip the injector to the rail you can just pull it up and prime the pump a couple to times to see which one is leaking.
as long as you have the stock rails that clip the injector to the rail you can just pull it up and prime the pump a couple to times to see which one is leaking.
03-01-2016, 11:21 AM
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04-10-2016, 05:43 PM
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If the connectors are still hooked up, priming the system will result in each injector squirting a small amount of fuel. With them unplugged, the pump will pressurize the system without the injectors firing. If you have a leaky injector, it will spray/dribble out even with the connector unplugged. Dont be afraid of a small drip or two from good injectors, if you have a leaky injector, it will be obvious
If the connectors are still hooked up, priming the system will result in each injector squirting a small amount of fuel. With them unplugged, the pump will pressurize the system without the injectors firing. If you have a leaky injector, it will spray/dribble out even with the connector unplugged. Dont be afraid of a small drip or two from good injectors, if you have a leaky injector, it will be obvious
06-29-2016, 02:21 PM
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hey guys I have a 1999 trans am and I am having major fuel problems. car and mods after upgrading my ls1 block with ls6 heads cam springs etc) ended up with the fuel leaking down into my crank case and oil and out the exhaust..which lead to throwing a rod through my ls1 block. well that's history at least for now. it was my first attempt at an engine build EVER !!! even though I went 100% by the book I figured I might've did something wrong right?... 7k dollars later I bought an ls3 crate engine with all proper adapters, extensions and conversions (Lingerfelter crank and cam conversion box, I am using my ls1 MAP sensor, ls1 knock sensors (relocated to the side of the block), ls1 oil and temperature sensors) I start the car only to find out that my ca is leaking fuel out the exhaust ... only thing I didn't do is get it TUNED (but would that cause excessive fuel leakage ? and I'm not convinced a fuel relator could be the cause of this since I get 60psi at idle and it stays constant without changing
06-29-2016, 04:14 PM
#14
With all the old sensors reused, it sounds like you're running the old PCM on the new engine which absolutely will run super rich untuned. Stock 24/26lb injectors LS1 vs 42lb injectors LS3
Its doubtful your new injectors are leaking, you are simply getting too much fuel into the cyls and there isnt enough air to burn it all. Get it tuned
Its doubtful your new injectors are leaking, you are simply getting too much fuel into the cyls and there isnt enough air to burn it all. Get it tuned
07-07-2016, 05:17 PM
#15
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Let me start off saying car is a 98z28 152k mile tr230 cam only most supporting mods m6. it is on the factory fuel system as of now. Recently when I come to a stop after driving a distance my RPM will only come down to 1500 rpm for around 20 seconds before dropping to 800 or so. My oil has a slight gas smell. Car performs good other than that. Gas in the oiil scares me as i know it can wash the cyl's if diluted too much. I did search on here and found to ohm the injectors my results were 12.3-12.6 on all cyl- that should be good right? I also read about a noid test but don't have the tool(where and how much for one)- this only test voltage right? I thought about removing fuel rail with injectors and priming up pump to see if they leak..any other easier less messy way? I also need a fp guage. How do i test the fpr since its in the tank. PLEASE HELP WHERE SHOULD I GO NEXT thanks-Brandon
Why do you "need" a fuel pressure gauge ? What problem is there that you need to check this ? And you check pressure at the rails, near the injectors.
If it's your daily, stock injectors and you really do think there is an injector problem, then just buy some replacements, they'll be cheap anyway
That means no downtime.
High idle could be any number of ecu related issues, someone competent at tuning etc should be able to take a look and ensure everything is normal when this is happening.
07-09-2016, 08:52 AM
#16
Just a computer tune, any dyno shop should be able to handle it. Id avoid driving it very much because running that rich will wash the cyls down and cause pre-mature ring wear. Would seriously suck to have low compression in your new crate engine over something simple
