Custom Tuning

SWDoodle · September 3, 2009

I think I'm going to go ahead and get a custom tune rather than a handheld programmer. After doing a lot of research I'll spend the same on a custom tune and keep my old pcm for what it costs for a good programmer. However, I have a few more questions. First off, if I keep my old pcm and tune a new one can you switch back and forth between the two without doing a crank relearn? I've been told you don't have to by the tuner but wanted to make sure. At first I wasn't going to keep my stock pcm but for $100 as might as well have it as a backup. Second, concern is with check engine lights. Say down the road I have a check engine light come on. I take it to the dealer and he scans it to look for codes. Does this reset anything? I've heard that people swap out pcm's to stock when they take it to the dealer for service because it may "reflash" the pcm and they will lose the programing. Another question is if you have a diagnositic code throw on the tuned pcm and then swap out for the stock pcm will it still throw the same code? And vice versa if you have the stock one in and swap the tuned will the trouble codes be the same? Lastly, I think I'll just do the 87 tune. I don't always have acess to 91 out where I live. I'm not looking to have a drag racer just something with more pep starting out any maybe pick up a 1-2 mpg if possible. Is this tune even worth doing?

96chevy7.4L · September 3, 2009

well you can clear the Check engine light codes either way. If it it triggers a code tuned it will most always trigger the same code with the stock PCM as well. Most only put the stock PCM when they go back to the dealer for WARRANTY work only. The 87 tune you will notice a slight difference but not near as much as you would with the 93 tune. Once you put the tuned PCM in you will most likely not ever want to go back to the stock one. The truck is entirely a different animal when tuned. Yes you will pick up fuel economy as well IF you keep your foot out of it. Hope that helps.

brims · September 3, 2009

You do the crank relearn 1 time and then the computers will know your engine's crank position and won't have to do it ever again.

SWDoodle · September 5, 2009

How many of you guys that do tuning keep a stock pcm? Just curious?

txab · September 5, 2009

How many of you guys that do tuning keep a stock pcm? Just curious?

Unless you're doing a tune with your own handheld, it's nice to have the spare modules. You can mail off your ECM if you want it re-tuned in the future and you can still drive your truck with the stock tune

Kodiak450 · September 6, 2009

So what exactly are you guys noticing after you get a custom tune? Acceleration improvement? Read about little better mileage gains. What about torque gains? Able to light the tires up?

brims · September 6, 2009

I kept my stockers.

I notice the lack of most of the torque management and delay in opening the throttle plate, the trans shifts firmer and faster, the trans shifts earlier than stock under 50% throttle, shifts later more than 50%, I know there are some other things but can't think of them now. I saw no gain in milage. I have access to more of the power this truck was supposed to have from the factory. I can't light up the tires, I think you might have to do internal work to the engine to do that. My 0-60 time is still 10 seconds, I don't think there's anything that can be done about that without opening up the engine and replacing parts.

Well worth the time and money.

SWDoodle · September 7, 2009

I kept my stockers.

I notice the lack of most of the torque management and delay in opening the throttle plate, the trans shifts firmer and faster, the trans shifts earlier than stock under 50% throttle, shifts later more than 50%, I know there are some other things but can't think of them now. I saw no gain in milage. I have access to more of the power this truck was supposed to have from the factory. I can't light up the tires, I think you might have to do internal work to the engine to do that. My 0-60 time is still 10 seconds, I don't think there's anything that can be done about that without opening up the engine and replacing parts.

Well worth the time and money.

You still can't light up the tires even after the tune? I thought removing the TM was really supposed to helpful getting the thing going. I'm planning on getting a tune, but I'm starting to have second thoughts. I'd like to gain some mileage and drivibility, but I'm starting to find more posts with people saying they aren't seeing significant gains with a tune alone. Most say they are happy with the tune so that's what confuses me!

txab · September 7, 2009

I can light up my tires with no problem.

brims · September 8, 2009

The tune does a considerable amount, the engine doesn't have 600 ft-lbs of torque. There's a point where you need to dig into the engine. If you want to drag race your truck, you need to do some major internal work to the engine AND a tune. The tune frees up what the stock programming is holding back, but it's not going to give you more than the engine is capable of in it's stock form if it did, Comp Cams, Magnacharger, etc wouldn't be in business. Drivablility has increased significantly, the truck might actually have 315 HP but that's all it has. If you feel that everyone that is happy with a tune but doesn't see an extra 150 HP gained is full of it, then just drive your truck as is. Lighting up tires isn't the only reason people get a tune.

superjim · September 8, 2009

You still can't light up the tires even after the tune? I thought removing the TM was really supposed to helpful getting the thing going.

I have ridden in Darkanions truck.

It has 20 inch wheels and (I think) 285 tires on it.

It "WILL" light up the tires with no problem at all.

Leaves a real nice smoke screen behind it.

SWDoodle · September 10, 2009

The tune does a considerable amount, the engine doesn't have 600 ft-lbs of torque. There's a point where you need to dig into the engine. If you want to drag race your truck, you need to do some major internal work to the engine AND a tune. The tune frees up what the stock programming is holding back, but it's not going to give you more than the engine is capable of in it's stock form if it did, Comp Cams, Magnacharger, etc wouldn't be in business. Drivablility has increased significantly, the truck might actually have 315 HP but that's all it has. If you feel that everyone that is happy with a tune but doesn't see an extra 150 HP gained is full of it, then just drive your truck as is. Lighting up tires isn't the only reason people get a tune.

Yeah that makes sense. I guess I wasn't meaning that I wanted to roast the tires off, but at least be able to break them loose so I feel like the tune was worth it! I don't mash on my stuff. From the info I've been gathering I'll probably wind up doing a tune. It's probably the best upgrade for the money.