Need help with Rich Idle

[brusk001]

7.4 Vortec engine
0411 PCM
Important Mods - I/H/E, towing cam XR264HR-13, 42lb@3bar injectors

I'm trying to get my truck running properly and finding that it seems to be running very rich. I watched several videos and clearly aren't doing something right. What tables control the AFR at idle? My LC1 is showing anywhere from 10.5-12:1 most of the time. It seems to start a little rich and just keep getting richer the as the engine tries to warm up. Basically stock 7.4 tune file with some minor changes for injector size and to get it to start and idle better. I maybe have to adjust the injector size as the place I bought them said they would be about 52lb@4bar the truck runs but looking at some online calcs it maybe be closer to 48.5.

[danmw2003]

Wrong injector data most likely. You need to have all the injector data for flow vs kpa, ign volt and a couple others for the injectors you're using. If that data is wrong, or never been changed from stock, you will never get the truck running right. Put the stock injectors back in if you the supplier did not give you good injector data.

[brusk001]

Wrong injector data most likely. You need to have all the injector data for flow vs kpa, ign volt and a couple others for the injectors you're using. If that data is wrong, or never been changed from stock, you will never get the truck running right. Put the stock injectors back in if you the supplier did not give you good injector data.

The stock injectors are tiny, if I recall like 19lb. From what I could find LS1 injectors are a good upgrade. Problem is some of these GM's ran 4bar and all the injector ratings are at 3. I can try the 48.5 flow data instead of 52 but I can't imagine that little bit would would cause it to be that far off, besides if it has smaller injectors than what the PCM think I would assume it would come up lean initially not rich. Or am I missing something.

[blindsquirrel]

You are missing something. The flow rate table is probably the least important of all the injector data. The other tables tell the PCM how much delay there is between the commanded pulsewidth and the amount of time that fuel actually comes out, so at small pulsewidths the amount of that delay is a bigger proportion of the on-time. You need real actual accurate injector data for the actual injectors you have, or you need different injectors that have data available.

[brusk001]

You are missing something. The flow rate table is probably the least important of all the injector data. The other tables tell the PCM how much delay there is between the commanded pulsewidth and the amount of time that fuel actually comes out, so at small pulsewidths the amount of that delay is a bigger proportion of the on-time. You need real actual accurate injector data for the actual injectors you have, or you need different injectors that have data available.

Help me understand. I've put aftermarket injectors in several vehicles with either minor table adjustment to just using piggy back fuel controllers with no issues. I'm told by so many people over the years how easy GM's are supposed to be and I'm so close to the end of this never ending rabbit hole. So far this has been the worst experience I've ever had and my 2nd GM vehicle, which includes taking a 12k loss on a diesel Mercedes that kept breaking. This is my 3rd set of injectors, first set of stock replacements 3 of 8 leaked. I got a set of upgraded injectors from fiveomotorsports to find out they didn't fit right and were causing intermittent vacuum leaks that took me forever to find. Finally everybody said to just get some LS1 injectors so I got a set of flow matched 42lb LS1 injectors online. What information do I need from the injector company and what tables would that have to be entered into? I would assume most each group would be pretty similar for EV1, EV6 and EV12's.

Forgive my frustration but I'm going on 3 years and $16k of never ending BS on a truck that just needed and engine and trans that I could tow with. And a wife who's tired of it sitting there forever and wants me to just sell it as is for whatever I could get, everybody knows unfinished projects don't go for much.

[eXo3901]

If they are not ID or FIC injectors, I doubt you'll get any data from the seller. But are they otherwise OEM LS1 injectors? If so, they should have a part number on them. Find out what GM platform used that part number. Pull a stock tune for that platform from the repository and copy over the injector data to your file.

You need data for the following tables: 12311, 12315, 12316, 12310, 3055, 12314. (ctrl+N to search for these if you cannot find them, but they are all under fuel->general)

[blindsquirrel]

No LS1 ever came with 42lb injectors. What they mean when they said that was that they are physically the same - same body type, same spacing between o-rings, same connector.

I mean, I imagine you could get just about any flow rate you wanted in a LS1 format. But they would not use LS1 data from a stock file.

[magius231]

i have some stock 1999 LS1 injectors laying around your welcome to try if you want. They haven't been cleaned or anything but its maybe worth a shot, and you can get good injector data for them.

[brusk001]

help me understand what a tuner would do when they do not have all this information. There's endless company's out there selling injectors as upgrade replacements without all this information. One possible fault I see with my tune is it came with just the flow rate in the flowrate vs kpa table. I was told be a few other guys on their 7.4 setup all they did was just adjust that table and didn't have any other issues. GRG has a video where he knew what size injector without the other data and just increased the factory settings by X percent several times until the flow at a specific PSI and said he'd have to do some adjustments to VE and others to make up for the lack of knowing the data.

I even asked about this on some EFI and HPTuners groups and was told I should just try to find some EV14 injectors. Nobody ever mentioned a requirement of getting all the other information and I assumed since the minimum pulse widths were lower on newer injectors and that I wasn't going with a huge injector the minimum tables could "get by". Again I would assume I could get this data from other similar style injectors. I've contacted the company I got them from in the hopes he has some of it. Looking at the pics they are most likely a USCAR EV6 type injector.

[gtstorey]

http://injectordynamics.com/articles...racterization/

https://eficalibrator.files.wordpres...oring-math.pdf

http://injectordynamics.com/articles/low-pulse-tech/

[blindsquirrel]

help me understand what a tuner would do when they do not have all this information. There's endless company's out there selling injectors as upgrade replacements without all this information. One possible fault I see with my tune is it came with just the flow rate in the flowrate vs kpa table. I was told be a few other guys on their 7.4 setup all they did was just adjust that table and didn't have any other issues. GRG has a video where he knew what size injector without the other data and just increased the factory settings by X percent several times until the flow at a specific PSI and said he'd have to do some adjustments to VE and others to make up for the lack of knowing the data.

I even asked about this on some EFI and HPTuners groups and was told I should just try to find some EV14 injectors. Nobody ever mentioned a requirement of getting all the other information and I assumed since the minimum pulse widths were lower on newer injectors and that I wasn't going with a huge injector the minimum tables could "get by". Again I would assume I could get this data from other similar style injectors. I've contacted the company I got them from in the hopes he has some of it. Looking at the pics they are most likely a USCAR EV6 type injector.

Sure, sure. Go do it that way then. I bet anybody who tells you it won't work is only saying that because they make money from generating characterization data that isn't really needed.

[Alvin]

7.4 Vortec engine
0411 PCM
Important Mods - I/H/E, towing cam XR264HR-13, 42lb@3bar injectors

I'm trying to get my truck running properly and finding that it seems to be running very rich. I watched several videos and clearly aren't doing something right. What tables control the AFR at idle? My LC1 is showing anywhere from 10.5-12:1 most of the time. It seems to start a little rich and just keep getting richer the as the engine tries to warm up. Basically stock 7.4 tune file with some minor changes for injector size and to get it to start and idle better. I maybe have to adjust the injector size as the place I bought them said they would be about 52lb@4bar the truck runs but looking at some online calcs it maybe be closer to 48.5.

Where did you get the injectors from?

Having proper data makes a huge difference honestly.. but having injector data has been a relatively new thing. When ID came to the market they were really the first ones to come out with comprehensive injector data.. Before that we were stuck guessing.

You should be able to get the tune pretty close even without data.. Without data you might have a odd surge here or there, rich decels, odd shaped VE tables down low etc.

The big problem now days with injectors is customers buying knock off injectors.

But to answer your question.. As long as there are no MAF codes the MAF table is where fueling is coming from (mostly)

[brusk001]

http://injectordynamics.com/articles...racterization/

https://eficalibrator.files.wordpres...oring-math.pdf

http://injectordynamics.com/articles/low-pulse-tech/

Well stated. Assuming the place I got injectors from can't supply those which will be unlikely. Point me to some new injectors that will come with all the data I need. I picked 42lb as that gave a pretty decent size window in case I actually like the truck and it was a common enough size on most injector sites.

[brusk001]

Where did you get the injectors from?

Having proper data makes a huge difference honestly.. but having injector data has been a relatively new thing. When ID came to the market they were really the first ones to come out with comprehensive injector data.. Before that we were stuck guessing.

You should be able to get the tune pretty close even without data.. Without data you might have a odd surge here or there, rich decels, odd shaped VE tables down low etc.

The big problem now days with injectors is customers buying knock off injectors.

But to answer your question.. As long as there are no MAF codes the MAF table is where fueling is coming from (mostly)

I found Smart Fire Injectors, they have a website but I came across their ad on Ebay. They supposedly test each injector and match the sets and the customer service was quick and friendly. I was just happy this set allowed me to even drive to the gas station to fill up so I could try to tune it. 1st set was OEM EV1 style replacements, 2nd set was upgraded set which was really like 28lb EV6 Mustang injectors that were about 1/8 shorter than OEM and would occasionally move and leak air, this set went in perfect and fired right up. I wasn't trying to spend much but at the same time didn't trust the EV1's. This truck has a custom build trans, rebuilt engine, basically every drive component or sensor replaced. I wanted a truck that would run like new and last the next 200k towing my toys the way I want to tow.

[2xLS1]

It wasn't until Injector Dynamics started supplying injector data that everyone started saying the sky is falling if you don't have all the data. And that is probably in the last 10 years or so. It's what forced other injector companies (some) to come up with data for their injectors. It is said some companies just take other's data and say it is right for the injectors they sell. Whose to say that the data you get with someone's injectors is even correct. Oh they provide some data so it must be correct. When HP Tuners was released in 2004, and LS1Edit a few years before that, no one provided injector data like some do today. And before that there was OBD1 tuning with only IFR data. How did we make anything run at all? I'm not saying it isn't a good thing to have all the data, but for years we did it with just IFR.

[Alvin]

It wasn't until Injector Dynamics started supplying injector data that everyone started saying the sky is falling if you don't have all the data. And that is probably in the last 10 years or so. It's what forced other injector companies (some) to come up with data for their injectors. It is said some companies just take other's data and say it is right for the injectors they sell. Whose to say that the data you get with someone's injectors is even correct. Oh they provide some data so it must be correct. When HP Tuners was released in 2004, and LS1Edit a few years before that, no one provided injector data like some do today. And before that there was OBD1 tuning with only IFR data. How did we make anything run at all? I'm not saying it isn't a good thing to have all the data, but for years we did it with just IFR.

To be fair.. A random (like brand) set of on the large side injectors (42+ back then) could really kick your ass too. It would have been hell getting something like a 1000 to behave nicely without data. But we managed.

[2xLS1]

To be fair.. A random (like brand) set of on the large side injectors (42+ back then) could really kick your ass too. It would have been hell getting something like a 1000 to behave nicely without data. But we managed.

But how?

[2xLS1]

And if you think any injector that is mass produced by sometimes the hundreds of thousands each perform exactly the same then you don't know anything about mass produced parts manufacturing. They are all built with a certain acceptable tolerance. These are not MIL Spec parts. And that's why fuel trims are built in. Remember it is still just an ICE, not the space shuttle.

[blindsquirrel]

19421333 - 29lb
12587269 - 33lb
12580426 - 35lb
12594512 - 36lb
12613411 - 38lb
12576341 - 42lb
12609749 - 50lb
12613412 - 51lb

All used in OE applications with stock tune files available to pull data from for free.

[gtstorey]

Well stated. Assuming the place I got injectors from can't supply those which will be unlikely. Point me to some new injectors that will come with all the data I need. I picked 42lb as that gave a pretty decent size window in case I actually like the truck and it was a common enough size on most injector sites.

Maybe you can start here. https://www.psiconversion.com/tech/l...re%20rows%20At this point I'm not sure what injectors you have now to try and match them up.

And stay away from EBAY/Amazon.