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I just downloaded a tune from a guys truck... and not sure I can believe everything that I am seeing... the owner tells me he has E-bay 80 lb/hr. injectors that came with one of those crappy sheet metal intakes (CHINA TRASH) that another shop installed and "tuned" for him... Look at the injector data.. Also... this guy DROVE this truck to me... Is it a SPEED DENSITY tune, or is it a MAF tune...? You decide.
I cannot believe the sheer volume of BS that I am seeing in this tune. The timing is sketchy. The BRAF is sketchy. The idle spark, and idle over speed and underspeed do not look like they have been touched. The main spark tables seem way far off for a "performance tune" that he paid for. They also leaned out PE to 13:1-I guess they had too because it is running so rich with the wrong injector data... I don't know where to begin to help this guy. My thoughts were; Step 1. We have to get either different injectors, or good data for the existing injectors.. He's running non-vacuum-regulated fuel system with an in-tank pump, and Corvette fuel filter. I can get rail pressure if that is needed. Since the injectors are CHINA TRASH I'm kind of wondering how to tune around not having the data. I know you old guys from back in the day were able to tune for bigger injectors without having the data... Ima need some of that type of guidance. I'm trying to get him back to a point where it will idle, and he can actually drive it. I have a wide band and can work the VE table, and MAF table, and I have the BRAF charts/channels/graphs all sorted so I can do that... but I can't really do anything until I figure out the injector situation. I will spend quite a bit of time working on it with him.. but I'm also teaching him how to tune along the way. Any help you guys can offer would be appreciated.
Here's the details on the truck-BIG cam (unknown specs) sounds like a sloppy stage 2 to me.. but you can't really tell just by sound
Circle D 3000 stall on a SMALL 9" housing
4L60E Trans
4:10 gearing
29" tall tires
LT headers
CAI
GM Gen IV intake (he had vacuum leaks with the china sheet metal set up so I told him to take it off and put the Gen IV intake on it which he has done-but he wants to keep the China injectors)
The engine was built by a 3rd party and sold to his "tuner". The "tuner" then sold him the engine-but no one has cam specs, head gasket thickness, flat top pistons or dished... all of that unknown. It IS a 5.3L With 862 heads.
Again, any help, tips, insights, on where to go from here would be greatly appreciated. The injector situation is what is holding me up.. If I had a KNOWN set of GM injectors with appropriate data-I'd be all over this...
I agree with you 100%. At this point I think the best way forward is to buy a set of GM injectors that have readily available data, and then plug them in and go from there.
On a side note, did you look at the tune? It has the MAF turned off, and Speed Density turned off. How is it that he was able to drive it at all? I'm going to have to make some serious changes right off the bat to get this thing back on track.
I just downloaded a tune from a guys truck... and not sure I can believe everything that I am seeing... the owner tells me he has E-bay 80 lb/hr. injectors that came with one of those crappy sheet metal intakes (CHINA TRASH) that another shop installed and "tuned" for him... Look at the injector data.. Also... this guy DROVE this truck to me... Is it a SPEED DENSITY tune, or is it a MAF tune...? You decide.
Again, any help, tips, insights, on where to go from here would be greatly appreciated. The injector situation is what is holding me up.. If I had a KNOWN set of GM injectors with appropriate data-I'd be all over this...
I wouldn't tune a vehicle with ebay injectors to begin with... my suggestion is to send him away as you will be the last one to have touched it and when something goes wrong you will surely be to blame... seen it hundreds of times.
Originally Posted by Kawabuggy
On a side note, did you look at the tune? It has the MAF turned off, and Speed Density turned off. How is it that he was able to drive it at all?
What makes you say speed density is disabled? It just has the MAF failed...
When I worked at the shop, we never continued on with someone else’s tune mess. Who knows what all they changed? So we would figure out how to get it back to stock and start over.
Cheap injectors with no data end up costing way more time and $$$ to get to work right. By then they either end up in the trash, or really expensive from all the tune effort.
LS3 (42 lb) or some of the flex fuel injectors have gm data available and are plenty big unless it’s a forced induction deal.
China injectors, china intake.....we turned them away 100% of the time. Its even listed on our website we wont tune them. Also you should always flash something back to 100% stock before re-tuning it, trust me it will save you hours of headaches.
A lot of good replies in here from people that have tuned professionally in a shop. I can tell by their replies because they have "been there".
We learned the hard way, early on, about ebay/knock off injectors. Wasted too much time and lost too much money. Now there are only certain injectors we will even mess with.
"Typically", the cheapest customers are the biggest PITA.
However it's always good to take a few minutes to help educate the customer and explain why. Some don't know any better and are going off what they read on the internet.
Some "know" everything and are going off what they read on the internet.
I 100% agree with some injectors with good data and start over from a stock tune.
I have lost count on how many times someone has come into the shop that "just needs a tune" then thousands of dollars later after fixing some half *** work some internet expert did, it was ready for a tune.
I'll have to take a look at that tune, you guys have peaked my curiosity.
So, the owner of the truck just got in touch with me and said... that the injectors were marked as 12613412 on the receipt that he has for the intake.
I have already looked at the injectors on the rail and there is NO # MARKED ON THE INJECTORS.... These are NOT GM Injectors.. Should I tell him he has been had, and to just buy a complete set of KNOWN GM Injectors and let's move on? I'm thinking that is the ONLY way to get this thing back in action without wasting a bunch of time as indicated by the much more experienced tuners above. I don't want to attempt to mess with China injectors.. Especially if there is no real way to make the truck run properly.
I have expressed to the owner of the truck that this post exists, sent him a link, and i'm sure he is reading every reply. Anything you post-he is seeing just as I am.. I'm not charging him anything for my time-just trying to help him out and get his truck up and running.
I was scanning a little bit earlier today and the IAC counts were "0" at operating temps because the last "tuner" simply cranked the throttle blade open with the set screw until it would idle.. the PCM is pulling timing trying to get the idle down to the commanded idle because the set screw is JANKED... OMG... It is a NON-BRANDED 92MM throttle body... He may need MUCH more than new injectors at this point. Should I post the name of the "tuner" here in the forums so that other people will know? I don't really care either way.. but if it helps ONE person going forward, I think it's a good idea.. Otherwise, I'm ready to just get on with fixing the issues, and getting him back on the road. The throttle body is.... unknown? I have personally tried one of the Ebay 92MM throttle bodies in the past and it was HORRENDOUS..Those posts are here on this website for all to see. To the point I wound up buying a NICK WILLIAMS unit and ONLY THEN was I able to get my truck to idle.... Holy crap.. I'm beginning to see the WISDOM listed above... Walk away.. Tell the customer, you are beyond help, and get on with my life... This is a young kid (19 years old) and he has just trusted in the WRONG people. I'm not charging him a PENNY to get him back up and running... But he is paying for the lessons through replacement parts.... Right Daniel? It's a tough spot to be in, but the money you have wasted is just that. wasted.. Only because you believed in what people were telling you... Read the responses above... KNOW that these people are MUCH SMARTER than your "tuner"... and let's get this thing resolved. Whatever you guys post next-is the path that we will take. I am personally fond of the 12613411 injectors as there is information readily available for the Gen 3 PCM's. and that they absolutely work as I have them in my built 6 liter, and it's running PERFECTLY with the data available.
Again, thank you to everyone that has responded. I will keep updating this post with what we are doing moving forward to resolve this situation and get his truck running right.
Not surprised that he had vacuum leaks with the china intake. I have one sitting on a shelf right now that has over .100" clearance on one edge against the heads when the other edge is flat, and it is identical on both sides. I saw a funny video of a guy in Russia trying to fix the exact same problem by cranking down the bolts holding it to the heads while heating it with a torch in an attempt to bend it to the correct angle.
Just looked thru the horror story on the bastard inj and tune... Scary stuff.
These were in a Turbo Buick app.
Customer bought them off the bag as "new", and obviously couldn't get it "tuned".
Were listed as "Smartfire" injs.
Would be interesting to see the injs in question on a bench.
Last edited by Old Buzzard; 07-19-2023 at 10:06 AM.
Yeah, there was zero injector data available or settings to even change but size. Off slope inj settings made the giant injectors possible on the street for 4cyl.You can tune around no injector data with the VE table. You got to turn off every background fuel related adj. we usually can’t see all of them in modernish ecu. Also, u can tune it with known injectors once it is correct u out the unknown injectors in and u can figure the settings out, takes a min.
You know the VE and inj data is correct when u can make a change to target AFR and get the correct change.
I use injector dynamics for the data, it really speeds things up to not be chasing injector data.
07-17-2023, 06:20 PM
WOW! Have You Seen A Tune This Bad Before? 
Tune these... 
