Help a guy out... Bad tunes from 2 different "tuners", trying to get back to stock

[RacnJsn95]

First let me start with the back story... My friend has an 03 Silverado, 4.8, Auto. This process was started probably a year ago. He installed a CAI, long tubes, and an ebay regrind cam (.550/.550" 112deg LSA, dont remember the duration, cant find the seller on ebay). He took the truck to one "tuner", guess the guy did a poor job, went around and around, friend wasn't happy, so the first guy gave him a cd with some tunes and a stock tune back up..

Fast forward to the next "tuner", friend leaves him the truck for an extended period of time, friend picks up truck and it runs worse than before. Tuner says he can make it run, lies... Friend gets discouraged, truck sits in back yard for months. Friend decides its the cam, I say its the tune, we don't have tuning software, so the cam gets pulled. Swapped back in the stock cam.

Yesterday, the "tuner" came to the house and put a different tune in the truck. Turns out the kid lost the CD with the stock backup, and claims his stock tune on his computer was lost in a computer crash. Now we're screwed, we have no stock tune, and this thing keeps running worse and worse everytime this kid touches it. It was kinda driveable with the previous tune and the stock cam, after yesterday, its hardly driveable, backfiring out the exhaust under load, no power ect...

So back in the current time, truck runs like crap, we have no stock tune... Can I download it from somewhere? I've read on here that you can take the truck to GM and ask them to flash the stock tune into it if the ECM isnt locked. The nearest GM dealer is 3 hours away, so that's not an option at this time.

Questions I have:

1. Can I download a stock tune somewhere?
2. If I buy HP tuners, can I modify his current ECM since it can't be restored to its original tune , or is it locked to this kids computer? If not what are my options?

Truck symptoms:

Backfiring A LOT under load, idle surging, trying to stall after start and randomly at idle. NO POWER AT ALL.

I'm new to HP Tuners, but my father and I are familiar with Subaru tuning, and carbs. I believe my friend and I can get it to run if we can access the ECM with HP Tuners if we buy it.

Sorry for the long post, but figured might as well give you all the info now. Thanks in advance.

[murphinator]

there is a tune repository on here for members , I checked for you and there are 2 stock 03 silverado 4.8 auto tunes in there for you to reference to return your friends tune to stock and go from there.

as far as tuning for his combo you will want to post where the members with similar vehicles hang out which would be gen 3 v8 engine tuning area

you would have to access his pcm via tuner to find out if it is tuner locked or not

[flame]

No codes? Sounds more like a plugged cat, low fuel pressure or bad MAF. I can't see 2 different people screwing up the tune that bad with those minor mods.

[RacnJsn95]

I think it did throw some codes, but I cant recall what they are. I'll have to find out. I think the MAF is new, there are no cats, we live in a non-smog area.

Thing is it ran perfectly normal before any of these "tuners" messed with it. Now when I say "tuners", I mean kids that are calling themselves that probably because they have the software, and attempt to tune. These are not legit shops, or mail order tunes. One of them showed my buddy another truck that he was "tuning", and it ran exactly the same as my buds, bad. Pretty lame.

Anyway, I think if we can get it back to sqaure one it will be easier to really try to tune it, and now with the stock cam back in it, I don't imagine it will be as difficult. I figured there would be a stock tune in the repository, but not really sure how that works, and couldnt see it.

[viper1_2001]

First let me start with the back story... My friend has an 03 Silverado, 4.8, Auto. This process was started probably a year ago. He installed a CAI, long tubes, and an ebay regrind cam (.550/.550" 112deg LSA, dont remember the duration, cant find the seller on ebay). He took the truck to one "tuner", guess the guy did a poor job, went around and around, friend wasn't happy, so the first guy gave him a cd with some tunes and a stock tune back up..

Fast forward to the next "tuner", friend leaves him the truck for an extended period of time, friend picks up truck and it runs worse than before. Tuner says he can make it run, lies... Friend gets discouraged, truck sits in back yard for months. Friend decides its the cam, I say its the tune, we don't have tuning software, so the cam gets pulled. Swapped back in the stock cam.

Yesterday, the "tuner" came to the house and put a different tune in the truck. Turns out the kid lost the CD with the stock backup, and claims his stock tune on his computer was lost in a computer crash. Now we're screwed, we have no stock tune, and this thing keeps running worse and worse everytime this kid touches it. It was kinda driveable with the previous tune and the stock cam, after yesterday, its hardly driveable, backfiring out the exhaust under load, no power ect...

So back in the current time, truck runs like crap, we have no stock tune... Can I download it from somewhere? I've read on here that you can take the truck to GM and ask them to flash the stock tune into it if the ECM isnt locked. The nearest GM dealer is 3 hours away, so that's not an option at this time.

Questions I have:

1. Can I download a stock tune somewhere?
2. If I buy HP tuners, can I modify his current ECM since it can't be restored to its original tune , or is it locked to this kids computer? If not what are my options?

Truck symptoms:

Backfiring A LOT under load, idle surging, trying to stall after start and randomly at idle. NO POWER AT ALL.

I'm new to HP Tuners, but my father and I are familiar with Subaru tuning, and carbs. I believe my friend and I can get it to run if we can access the ECM with HP Tuners if we buy it.

Sorry for the long post, but figured might as well give you all the info now. Thanks in advance.

It seems that you are voicing your opinion and not facts, Joe wanted his truck flashed with a stock tune and that's what I did. No tunes got lost, I back up everything on 3 computers. I have been using Hp Tuners for 5 years and tuned many different vehicles and setups but I don't call my self a tuner I just tune my stuff and friends that ask me. A few friends of mine have referred people to me without asking me first. I offered to help Joe because I felt bad he was having such problems with his truck and from the beginning I said there was something wrong with the truck. I offered to try and find out what was wrong with it then go from there, but Joe was convinced it was the tuning the other guy did and if there was something wrong with the truck he would take care of it. Now since the truck is almost completely stock with the exception of a rigged together CAI and Ebay headers and is flashed with a stock tune with the rear O2's deleted it is obvious there is something wrong with the truck like I said in the beginning, because it maxes out the ST fuel trims almost instantly. And what truck of mine was running bad? I would like to know because that's news to me. This is why I don't like tuning other peoples trucks because I get people who think with a mouse click they can have 100 more horsepower and they don't really know how a motor works and certainly don't know how modern fuel injection works. Tuning is my hobby not my job. Before you criticize someones work why don't you ask some questions so you really know whats going on?

[RacnJsn95]

Ok, big guy... I am voicing my opinion, going off of other opinions, but FACT IS the truck ran before anyone started "tuning it"... It was still drivable. If you put a stock tune in it, then in theory it should run again, and at least be drivable...

I will buy HP Tuners and attempt to make it run. If I do, good for me... If it's something wrong with the truck, then I guess you were right, and I will apologize... No offense intended, man. No names were mentioned. I'm going off of what I've heard. I was just trying to get information.

[viper1_2001]

The truck didn't run fine, Joes exact words were "it ran crummy before and worse after the headers" thats why he had the first guy tune it. So if it ran bad stock then something is wrong. Tuning wont fix a mechanical problem.

[RacnJsn95]

I agree, tuning won't fix a mechanical problem. But if it ran perfectly fine before the tuning, wouldn't you think it wouldn't be a mechanical problem? It ran great completely stock, fine after the original cai, crummy after the cam, and worse after the headers. Only makes sense...

[Montecarlodrag]

The only help we can provide is take a look at the tune/datalog. If no files, there is little anybody here can do (other than suggest you to buy HPTuners and tune it yourself).

I'm not taking sides here and I don't know who's right, but as far as my experience, I have had several customers and friends who had problems with their vehicles and had the idea I could fix them with tuning.
The first few I tried to fix the vehicles because I wanted to help, but I ended doing a lot of unpaid work.

Now, I first ask the owner to take me for a ride to see how the car performs. Then I scan it and download tune from PCM to check if it's stock. When I find something wrong I tell the owner to fix his car first then come back for tuning. Some of them do that, some ask me to fix it.

If something is wrong with the car and you accept the job, now the problem is yours and the owner will blame you for everything.
So I always make myself very clear and explain to the owner His car has a problem which needs to be fixed before I touch the calibration. If they don't agree with my terms, they can take their vehicle somewhere else.

This has saved me a lot of headaches and problems.

[vortec]

I know what you mean,they think mechanical problems can be fixed by tuning.Those are the ones That have alot to learn

The only help we can provide is take a look at the tune/datalog. If no files, there is little anybody here can do (other than suggest you to buy HPTuners and tune it yourself).

I'm not taking sides here and I don't know who's right, but as far as my experience, I have had several customers and friends who had problems with their vehicles and had the idea I could fix them with tuning.
The first few I tried to fix the vehicles because I wanted to help, but I ended doing a lot of unpaid work.

Now, I first ask the owner to take me for a ride to see how the car performs. Then I scan it and download tune from PCM to check if it's stock. When I find something wrong I tell the owner to fix his car first then come back for tuning. Some of them do that, some ask me to fix it.

If something is wrong with the car and you accept the job, now the problem is yours and the owner will blame you for everything.
So I always make myself very clear and explain to the owner His car has a problem which needs to be fixed before I touch the calibration. If they don't agree with my terms, they can take their vehicle somewhere else.

This has saved me a lot of headaches and problems.

[DSteck]

Sounds like a vacuum leak. Just saying...

[viper1_2001]

Sounds like a vacuum leak. Just saying...

Thats what Ive been thinking, with the cam the most it would make is 74kpa but I guess that could be about right, it was 112 lsa on a 4.8l
Now it sits about 48-52 kpa with a stock cam, and that also seems about right since its running badly.
So I need to take a close look at the truck and try I few things, I'm going to shut off ST and LT trims to keep it from maxing them out. That should narrow things down alittle.

[viper1_2001]

I agree, tuning won't fix a mechanical problem. But if it ran perfectly fine before the tuning, wouldn't you think it wouldn't be a mechanical problem? It ran great completely stock, fine after the original cai, crummy after the cam, and worse after the headers. Only makes sense...

You clearly don't want to listen to what I'm saying. The truck DID NOT run correctly before anyone tuned it(the only person to mess with it at that time was the owner with a predator tuner). Some things were changed, bolt-ons were added and it ran worse. Then with a tune it ran better but still poorly, then flashed to stock it runs even worse.
You don't have to trust my ability's tuning trucks, but try to trust my ability's as a mechanic that's how I put my self through college. At the GM dealership I worked at I saw alot of crazy things that shouldn't happen but they do, so trust me when I say there is something wrong with the truck and its not the tune. Most likely there is something wreaking havoc on the O2 readings.

I uploaded the tune, as you can see it is a stock tune for a 03 4.8l auto 3.73 with the rear O2's deleted

[RacnJsn95]

You clearly don't want to listen to what I'm saying.

Apparently you aren't reading what I'm writing! When the truck was BONE STOCK, NO TUNING, it ran completely normal... The more that was added the worse it began to run, which makes perfect sense because its still a stock tune. Now aside all the add-ons on top of a stock tune, could something else have happened? Sure.

That being said, today we replaced the spark plugs, plug wires, and o2 sensors. We had planned on doing this anyway prior to me getting on here to gather information. The truck runs again. We found one bad spark plug wire, probably the source of the misfiring. The spark plugs looked old as hell with huge gaps. And 2 different style o2 sensors. We also searched around for vacuum leaks but found none.

While I certainly was not ruling out the fact that it could have been a mechanical problem, it sure seemed strange how it seemed to get worse and worse each time someone with a computer hooked up to it.

So, I apologize for any offense you may have taken to this. As I said before, I was trying to gather information, no names were mentioned. Should have waited another day to get on here and post. Makes me wonder how it would have ran with the truck running correctly with your tune.

Thanks for everyone's help. Looks like I can hold on to my $650 bucks for a while.

[detroit]

Reading this I would measure your push rods. with a regrind if you lose any material in the lobes the push rods will make up that differance.

A truck can run with a crappy tune and seem to run good, then when you flash a new tune it will run worse. Leave the blame out and find the issue and get this truck on the road!

Find someone local with tuners and get some logs and pull the tune off to see.

[diablotruck]

I had a similar problem it turned out to be a broken valve spring. Hope this helps.