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Any way to test injectors?

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Old Sep 5, 2017 | 09:54 PM
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Default Any way to test injectors?

So I see HPT no longer has a cylinder balance test so I went ahead and set an idle and killed injectors at both 750 and 1,000 rpm and while I notice a change it's insignificant enough for me not to be able to tell if I have a semi clogged injector. I'm not seeing any real issues in my fuel trims on either side but I am getting some KR and more bouncing of my AFR than I used to have. I checked FP at ~60PSI and recently replaced the fuel filter. THe hose isn't long enough for the FP tester I have to be seen while driving unfortunately so I can't know for sure if it isn't providing enough volume up top but the way it performs I doubt it's a fuel delivery issue but I'm trying to cover this base.


Any input would be appreciated.

Dave
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Old Sep 5, 2017 | 10:19 PM
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do you have the pro or the standard interface?

i ask because it's pretty easy to log FP with a $20 ebay sensor on the pro interface
sorry i dont know of a way to test injectors but I have used a fella named eric derr that does a good job for pretty cheap
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Old Sep 5, 2017 | 10:25 PM
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I have pro. I have a C5 and probably have open channels on my ECM. I pipe my O2 into the EGR and log its voltage that way. I assume Eric derr just flows/cleans them for you? I actually use stock injectors on a very mild build so flowing may cost more than the injectors but for piece of mind it may be worth it.

Dave
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Old Sep 5, 2017 | 10:41 PM
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so here's the sensor i use:

http://www.ebay.com/itm/0-100psi-Lin...oAAOSwDKtY1NpH

i'll pm you the fellas number. he's very reasonable. $60 to test, clean, replace o rings and baskets and re-test.
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Old Sep 5, 2017 | 10:43 PM
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Wow cheap on both fronts. Definitely going to do this. What adapter did you use from the end of the rail to this sender? Or did you not put it on the end of the rail at the schraeder?

Dave
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Old Sep 6, 2017 | 06:10 AM
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no I put it on an AN fitting as my set up is a swapped squarebody truck.

but i have friends who have used this lil guy here:

http://www.ebay.com/itm/Fuel-Rail-Pr...-/301828029424
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Old Sep 6, 2017 | 09:49 PM
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truckdoug, Thanks for the links. I have been considering logging my FP also, but had not looked into the sensor yet. I knew there were those cheap sensors out there, just needed a little reason to look.
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Old Sep 7, 2017 | 01:42 PM
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What are you using to pick up the 5v input? Are you splitting the oil pump 5v or using a resistor?
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Old Sep 7, 2017 | 03:18 PM
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Originally Posted by rpturbo
What are you using to pick up the 5v input? Are you splitting the oil pump 5v or using a resistor?
I think I'm using the oil pressure sensor supply voltage, but there are a bunch of spare 5v pins. I just looked up the pin out on lt1swaps.com and snagged an unused one.
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Old Sep 9, 2017 | 06:06 PM
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Thanks! I didn't realize there were extra outputs unused. I'll check that out!
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Old Sep 10, 2017 | 11:08 AM
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Jesus just extend the FP gauge you have and verify its not dropping. You are way over-thinking this. You could even setup a go pro pointed at the gauge, go drive, then review the footage.
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Old Sep 11, 2017 | 09:46 AM
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Well, I get your point, but for someone who is currently building a turbo setup, wait and find out how important your fuel pressure is, and let me know if you only check it once.

Besides, isn't this all about sharing info? Any guy with 2 crescent wrenches can put a 10' -4 line on, and have your fuel gauge zip tied on the cowl. Just another gauge to not watch when your making a pass, so why even have it. Its all about HAVING the data to tune with.

Maybe we should all just put a carb back on and throw out all this technology non-sense?
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Old Sep 12, 2017 | 06:16 PM
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Originally Posted by 01ssreda4
Jesus just extend the FP gauge you have and verify its not dropping. You are way over-thinking this. You could even setup a go pro pointed at the gauge, go drive, then review the footage.
The hose is fixed to one end of the gauge and is only 2' long. I have a vette so I can't exactly fit a go pro under there w/ sufficient lighting and the gauge. So I go buy a 2' 4AN line and a male to male 4AN adapter? Seems to be about the same cost.

Also you guys may have unused 5V INPUTS so you don't ever have to mess w/ HPT pro or EIO ever again. Like I said I pipe my WBO2 into the EGR (No EGR on C5) and I log and set up math to output proper AFR.

Dave

Last edited by TT_Vert; Sep 12, 2017 at 06:42 PM.
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Old Sep 12, 2017 | 07:01 PM
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logging fuel pressure becomes critical as you approach power levels that can break stuff instantly with a lean condition. i'd consider it a top ten parameter. also logging injector duty cycle (if you have spot on injector data) is great too.
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Old Sep 13, 2017 | 08:24 AM
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Originally Posted by rpturbo
Well, I get your point, but for someone who is currently building a turbo setup, wait and find out how important your fuel pressure is, and let me know if you only check it once.
I guess it would be good to constantly monitor it? Ive honestly never considered it and its not a common thing from what ive seen. At the end of the day, having a wideband in your face is the same thing/better. It gives you an indicator of an issue that you need to dig deeper into. If i saw lean the first thing id do is then verify pressure. Obviously you hope you catch it before something bad happens
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Old Sep 13, 2017 | 01:07 PM
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It's always good to know you've got good FP logging in forced induction IMO. Beyond this you can have certain safety features in place where if AFR or FP gets below a certain threshold that it'll cut boost, spark, etc. to keep an engine together. I don't think people are wanting to constantly look at a FP gauge but to have it tied into HPT is invaluable. Just like a wbo2 piped in w/ all other logging parameters. With that said I don't know if I have any more 5V inputs or outputs available on my C5 PCM and I don't want to use my EIO as it adds cluttered wiring I don't want to deal with.
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Old Sep 18, 2017 | 05:24 PM
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Originally Posted by 01ssreda4
I guess it would be good to constantly monitor it? Ive honestly never considered it and its not a common thing from what ive seen. At the end of the day, having a wideband in your face is the same thing/better. It gives you an indicator of an issue that you need to dig deeper into. If i saw lean the first thing id do is then verify pressure. Obviously you hope you catch it before something bad happens
The only issue with that, is on a fresh build. If you have say, a delay on a boost referenced regulator, without logging FP, you just basically "tune around" a issue, and not even know its there. I mean, it shows lean, so you throw fuel at it, but in reality, its a pump issue, or a regulator issue, or whatever. IMO, you can never have too much data.
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