speedshifter Posted March 30, 2003 Share Posted March 30, 2003 Hey guys. Platform is a '97 Yukon. I'm doing a "Stage 1 upgrade" to it including a new cam. I've been told that I need to get my ECM tuned for the cam. Im looking at www.fastchip.com Why do I need to tune the ecm? What gains will i get from it? What will happen if I dont? Can I drive it for a while before I tune the ECM? Will it still pass emissions after the ecm is tuned? Heres a link to a thread about my mods: LINK Link to comment Share on other sites More sharing options...
americanmuscleman Posted March 30, 2003 Share Posted March 30, 2003 Hey guys. Platform is a '97 Yukon. I'm doing a "Stage 1 upgrade" to it including a new cam. I've been told that I need to get my ECM tuned for the cam. Im looking at www.fastchip.com Why do I need to tune the ecm? What gains will i get from it? What will happen if I dont? Can I drive it for a while before I tune the ECM? Will it still pass emissions after the ecm is tuned? Heres a link to a thread about my mods: LINK Your probably getting tired of my posts, but I'll give you my 2 cents anyhow The reason you need to get the cam tuned is, the cam is going to require more air and fuel to make more power. Your stock programming is designed for a lot less aggressive camshaft and stock heads. The computer's response to adding a larger cam is going to be its going to run the truck real rich. Its likely going to chug gas. Its not going to idle well (since the idle is likely going to be too low, and the air/fuel ratio is going to be different as well as the timing advance being wrong). Your truck may not idle at all actually. When you put the truck in gear, it puts a load on the engine, and when the engine isn't tuned, it often will surge and possibly stall out. Also, you'll probably want to change your rev-limiter to allow the engine to rev higher if your cam makes power above 5500rpm or wherever the stock Vortec 350 shifts. Your truck will run so much smoother, idle well (in and out of gear), get better mileage, produce a LOT more power, and shift at better suited shift points with tuning. I would highly recommend getting tuning. Just my 2 cents! Link to comment Share on other sites More sharing options...
TarheelZ Posted March 30, 2003 Share Posted March 30, 2003 VERY well stated, Steve! Link to comment Share on other sites More sharing options...
speedshifter Posted March 31, 2003 Author Share Posted March 31, 2003 Steve, thank you for explaining it to me. I was listening to your previous posts, I just didnt understand exactly why I needed the ECM tuned. I just assumed that the sensors would just compensate for the more air/fuel required by the cam. Link to comment Share on other sites More sharing options...
CMNTMXR81 Posted March 31, 2003 Share Posted March 31, 2003 Fastchip is Ed Wright, errr, Ed Wrong! After three attempts to tune mine despite numerous A-tap logs, dyno sheets, A/F readouts, etc, etc, he still couldn't get it right and was turning stuff off (my EGR) even though I told him not too! Others have had less than satisfactory experience with Ed. Although you have the old school SBC which he doesn't to seem to have as much a problem with. He seems to be real good with LT1's also. LS1's though, he's out in space on! I eventually went with Steve Cole at TTS. He for a mail order tune hit a pretty dead on shot with his power loader programming. Unfortunately he locked the PCM so I can't go in with LS1 Edit and "tweak" things. I instead had to go out and get another PCM which I will be using to tune on the dyno with LS1 Edit. Personally, I'd ask for more info from Ed before attempting to have him tune it. Link to comment Share on other sites More sharing options...
americanmuscleman Posted March 31, 2003 Share Posted March 31, 2003 Fastchip is Ed Wright, errr, Ed Wrong! After three attempts to tune mine despite numerous A-tap logs, dyno sheets, A/F readouts, etc, etc, he still couldn't get it right and was turning stuff off (my EGR) even though I told him not too! Others have had less than satisfactory experience with Ed. Although you have the old school SBC which he doesn't to seem to have as much a problem with. He seems to be real good with LT1's also. LS1's though, he's out in space on! I eventually went with Steve Cole at TTS. He for a mail order tune hit a pretty dead on shot with his power loader programming. Unfortunately he locked the PCM so I can't go in with LS1 Edit and "tweak" things. I instead had to go out and get another PCM which I will be using to tune on the dyno with LS1 Edit. Personally, I'd ask for more info from Ed before attempting to have him tune it. CMNTMXR81, your right about Ed. People seem to have awesome experiences with him, and some seem to have a terrible experience. One bad thing is he does lock his computer. My experience is he's been a nice guy and I've had him burn a chip for my truck in the past, and it worked great. I ended up adding more mods, so I needed a new chip... and ended up using another company that doesn't make chips anymore... but I was happy with Ed's tune while I had it. Since I live in Tulsa where Ed Wright is located, if I was getting tuning I would get a dyno tune. He seems to do good dyno tuning. I don't know a ton about his mail order tune since no one around here gets a mail order tune by him. Link to comment Share on other sites More sharing options...
speedshifter Posted March 31, 2003 Author Share Posted March 31, 2003 Where can I find more info on TTS? If there is that much of a chance that Ed is going to screw up my ECM, then I won't even consider using him. Why do comanies lock ECMs? If its my ECM and I'm paying $350 to have it tuned, then I should be the one to decide whether they lock it or not. Also, since the engine is pulled already, this would be a good time to send off the ECM. I might buy a 2nd ECM for the truck and have that one tuned. My dad got me this truck for college and if it doesn't run when we put it back together, he will be furious. So I better keep the stock ecm just in case. I havent had this truck for a while, and don't have a Service Manual yet, so would you mind telling me is the ECM in the glovebox area or in the engine compartment? Any ideas where I can get a factory service manual for cheap? Thanks! Link to comment Share on other sites More sharing options...
speedshifter Posted April 1, 2003 Author Share Posted April 1, 2003 Pardon my ignorance, but what is the TTS Power Loader II? I see that it costs $395 for my truck. Is it like the Hypertech Power programmer? Also, how much did your custom tune cost from TTS? I just thought I wouldn't NEED to do anything with the ecm because of the cam. The Comp Cams website says nothing about any ECM mods. They also say that the cam should retain the stock gas mileage if not improve it. Link to comment Share on other sites More sharing options...
speedshifter Posted April 26, 2003 Author Share Posted April 26, 2003 well steve, you are the man!!! Every single thing you said would happen w/o the ecm tuned did except for stalling in gear. It smells super rich. Surges bad at idle. And I got 8.7MPG on the last tank. Im skeptical about Ed because of throwing $350 into a $100 ECM and he has no garauntees. He is my last resort. If don't find anything else within the next week, I'm going with Ed. Can sombody clarify what the TTS Power Loader II is? Also, WHY does my truck surge at idle? What can I do to fix it? How will the ecm tuning fix the idle surging? Thanks. Link to comment Share on other sites More sharing options...
speedshifter Posted April 26, 2003 Author Share Posted April 26, 2003 Oh yeah, I filled up today. After being easier on this tank and actually having some decent gas in it, I got 11.3 MPG. I'm gonna be real easy on this next tank and hope I get 13 MPG. How much improvement in mileage can I expect from the ECM tuning? Will there be a noticeable torque increase in the low/mid range? After these questions are answered, I will probably wind up going to Ed at fastchip and get it done. Link to comment Share on other sites More sharing options...
americanmuscleman Posted April 27, 2003 Share Posted April 27, 2003 There are a number of reasons your truck is idling ruffer than stock. The main reason being the Comp cam you installed has a lot more duration than the factory cam. Its also ground with a lower LSA (lobe separation angle). Numberically lower LSA's (like 110) will idle more aggressively than a cam ground with a higher LSA (like a 114). Your running stock tuning, which is designed for a smaller cam, so you getting an improper amount of air at idle, and too much fuel (the computers attempt to adapt for the larger cam). I'm not sure if you know this... but when you install a more "aggressive" camshaft (more duration), your trading lower rpm power and efficiency... for midrange and top-end power and efficiency. The ruff idle your hearing is your engine no longer being as efficient at lower rpm. Which is why your gas mileage is dropping. At lower rpm, your engine is less efficient than it was with the stock cam. Tuning will help the problem. Once the tuning is right, the engine won't be dumping too much fuel into the engine. With aftermarket tuning, the ECM is still going to be putting more fuel into the engine than it did with the stock cam (to account for the added duration), but it won't be "over correcting" like it is now. You will definitely get better gas mileage with tuning, but your never going to get as good of mileage as you did with a stock cam. You should also see a huge power difference with good tuning. Your mid-range and top end power especially should be much stronger. For comparision, my cam is in the 210/215 ballpark, and with the stock chip, my truck chugs at idle and barely runs. With my aftermarket chip, it will idle in gear at 700rpm all day with no objectionable cam surge. I'd ask Ed if he's done tuning in the past on a cammed Vortec 350. I would recommend you request close-to-stock part throttle shift points, but with raised full throttle shift points. (That way your not shifting at 2500+rpm everywhere you go. Its really annoying.) I would also request near stock shift firmness, or slightly firmer. Aggressive part-throttle shifts are also really annoying. (On a 4L60E, the factory full throttle shift pressure is as high as it can go already... so by requesting firmer shift points, its only going to firm up part-throttle shifts which is just going to give you an unnecessary, jerky ride around town. You'll have to install a mechanical shift kit if you want firmer full throttle shifts.) Anyway, good tuning will make a world of difference! Link to comment Share on other sites More sharing options...
speedshifter Posted April 28, 2003 Author Share Posted April 28, 2003 Cool! I'm working on getting a 2nd ECM now. Should hopefully have it sometime this week. I wish I would have gone with the stage one cam instead, oh well. Hopefully the ECM tuning will improve as much as you say it will. I'm looking for like 13~14mpg city when I keep my foot out of it. Its just so hard to do! The cam is just asking me to give it more throttle! Sometimes I cant control myself! I also found out that I might be getting slightly better gas mileage than I have reported. Turns out the 17" Escalade tires and rims are slightly taller than my stockers. I made a hwy trip yesterday that is usually about 145 miles give or take and the odometer only read 136 mi. No real big difference, but I want to calibrate it so I don't get speeding tickets. Thanks for all your time and help Steve! Link to comment Share on other sites More sharing options...
americanmuscleman Posted April 29, 2003 Share Posted April 29, 2003 No problem Matt, and I hope the tuning works well for you! Keep us informed on how she's running Link to comment Share on other sites More sharing options...
Black02Silverado Posted April 30, 2003 Share Posted April 30, 2003 Question, is it a good idea to get technical info on what to do from the cam manufacture? Say you by a cam by Crower, they should have what info for what cam you by and what to do to the computer right? Link to comment Share on other sites More sharing options...
speedshifter Posted April 30, 2003 Author Share Posted April 30, 2003 I don't think they will. Comp told me that it should run fine with the stock ECM. They also told me after I bought it that its not made for computer controlled trucks. Hmm, last time I checked, GM didn't use any carb'd engines in trucks in the late '90s ??? Link to comment Share on other sites More sharing options...
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