Tuning Questions

[l008com]

Not sure if this is the best place for this thread. If not, please move accordingly.

My first question here is, anyone know of any performance shops in the greater Boston area that can do a street tune? I've had one suggestion but I've had such a hard time communicating with this person, plus given the distance, I'd rather find someone else more local that can do it. I'm just north of Boston.

Moving on. Would the tuner be the guy that can also adjust my speedo for bigger tires? Or is this something I can do myself. I'm getting new tires that will be bigger, although I may not be getting the new tires before the tune.

The main reason I want this tune is to get rid of the terrible throttle delay, what people tell me is torque management. There's terrible delay when you get on the gas, and I feel like there's also delay when you get off the gas. The throttle seems to release slower than you're actually getting off the pedal. It's enough to make me want to get a cable and wire it up the old fashioned way. This is a 5.3 V8.

I was also wondering about traction control. Is it within a tuners abilities to make it so traction control is OFF by default (with the dash light off), and pushing the button turns it ON (and turns the dash light on). I don't want to mess with the stability controls, but I find traction control tends to get in the way more often than it's useful.

Heres the question that the other guy couldn't answer for me. Are there any other options I have? Besides general "improve performance and efficiency of the engine", what else can a tuner do? The only thing I like better than system preferences, are hidden system preferences

 

[Mooseman]

I believe that year can be adjusted for the speedo. @limequat could answer that one and would also be an excellent tuner to use if you can't find one locally.

A tuner can't do anything for traction control as it is a function associated to the BCM and EBCM. I don't think there are any stock trucks those years without it so loading it with another software version probably wouldn't work or would disable TC completely.

A few things a tuner can do. Eliminate torque management, improve shift firmness and response, improve torque converter clutch engagement, kill fan codes (not needed for your year truck), improve power and fuel mileage (usually minimal though).

 

[djthumper]

A tuner can adjust the speedo on 2006 and newer on the GMT360 platform

 

[Wooluf1952]

Have you cleaned the t-body? This is a bigger problem on the 4.2 I6, but it could be the cause of the feeling that the throttle is closing to slowly.

 

[fletch09]

as far as the speedo adj. for bigger tires, on my 09, the chevy mechanic was able to go in and adjust for bigger tires.

 

[l008com]

Have you cleaned the t-body? This is a bigger problem on the 4.2 I6, but it could be the cause of the feeling that the throttle is closing to slowly.

It doesn't feel like it's sticking, it feels like it just has a slow-release sort of delay. But once it warms up I can certainly clean it out anyway for the hell of it and see how it goes.

 

[AWD V8]

When I had my '99 Jimmy I sent out my PCM to a guy on the S10 forum who does mail order tunes. He removed the torque management and the throttle delay and tightened up the shifting, and many other trucks. It felt great after. Don't think I picked up much HP but it was way more responsive.

When I bought my '03 Envoy 5.3 I purchased a hand held tuner. With that I can adjust for tire size and gearing among other things. I tightened up the shifting, for that alone it was worth it!!

You could buy a hand held tuner and play within the limits of the tuner, or you could have a local guy tune it if you can find somebody you can trust. Locally it would cost me upwards of $400 to tune it! No deals around here. You could pull the PCM and mail it out. You truck is down of course. When I sent mine out, from the West coast to Pocono PA I had it back in a week. It cost me about 100 bucks.

If you are interested in the mail order option I could PM you the contact info for the guy. He did 2 PCM tunes for me as well as many others on the forum. He only does GMs.

 

[l008com]

Mail order is out of the question. As of Monday, my Trailblazer is my only vehicle.

It's off topic a bit but I'm curious about the 99 Jimmy. I thought those trucks were still using a throttle cable? So the throttle wouldn't be controlled by the computer. Meaning the response should be great and also not changeable?

 

[AWD V8]

Yes the throttle is cable controlled.

Response is not just the throttle butterfly opening and closing. The PCM can dial back the timing to "soften" the throttle response. The softening of the throttle is to preserve the transmission and improve passenger comfort. Tuning my PCM eliminated this timing foolishness and was simply straight up for performance.
The timing in general was bumped to improve throttle response. Old school, with a carb and simple HEI, bumping the timing the timing and making the advance curve more aggressive greatly improved the response of the engine.

Shifting is also softer as the timing is knocked back just before the shift it made.

 

[Mooseman]

I know that PCMofNC can send you a loaner but their tune for the 5.3 is already more expensive than Limeswap's making it even more expensive. But @limequat doesn't have loaners for the 5.3. You could try to find another PCM/TCM but they are expensive used too.

 

[l008com]

I really don't want to do a mail order tune. I'll start bugging the mechanics I know if they know anyone else local that does this sort of thing.

 

[l008com]

What about disabling DRLs, is that something they can do?

Also AWDV8, are you the same AWDV8 from the S10 forum? That put a V8 in a Blazer and an AWD transfercase from a bravada or some crazy thing?

 

[AWD V8]

Well yes and no.

Yes I'm the same AWD V8, but the engine didn't make it into the truck. I did convert it to AWD and had the 5.3, but I sold it as a project because I had too many projects going.

What about disabling DRLs, is that something they can do?

Also AWDV8, are you the same AWDV8 from the S10 forum? That put a V8 in a Blazer and an AWD transfercase from a bravada or some crazy thing?

 

[dmanns67]

What about disabling DRLs, is that something they can do?

@Midnyteryder196 can help you with that by using one of his kits.

 

[l008com]

I like this 5.3 trailblazer, but i still miss my ZR2 Blazer. I also tried to get a 5.3 installed in it, but my mechanic just didn't have the time to do it. But wow a ZR2 with a 5.3 would be sooooo much more fun to drive than either of these trucks.

 

[limequat]

Well Mooseman, you fielded the tuning questions better than I could have!
One thing I'd point out is that GM virtually tunes powertrain enrich right out of the trucks. This means that if you floor it, your AFR will be 14.7 right up until it shifts.

OP if you must have an in person tune, you may find it worth it to go ahead and purchase HPTuners for your self. Also, on Coloradofans.com there's a listing of people that have HPTuners.

 

[l008com]

One thing I'd point out is that GM virtually tunes powertrain enrich right out of the trucks. This means that if you floor it, your AFR will be 14.7 right up until it shifts.

Ummmm... what? I have no idea what this means :-/

 

[AWD V8]

Actually, at WOT the PCM is much richer than 14.7

14.7 is what the PCM maintains based on feedback from the O2 sensors, up to 3/4 throttle.

14.7 is what the PCM is maintaining in the below screenshot, oscillating, up until the throttle is WOT, then it goes richer as seen in the maxed out reading.

 

[limequat]

^ Are you tuned? Almost every GM truck I've tuned starts with the PE enable set at > 90% throtttle.

 

[AWD V8]

Not tuned except with the hand held.

The above photo is not my truck, just one of the many vehicles I've run on my scanner.

3/4 throttle, actually is a ballpark for most vehicles. I realize that some are later than that. The point I was making is that the O2s are only used at less than full throttle. At WOT the O2s are not even used. O2s are only used to maintain the 14.7 ratio for emissions and fuel economy.

 

[l008com]

I'm a little late to reply back to this thread, but I'm still not sure what you guys were talking about 14.7 what? I do know what WOT is and I don't think I've ever seen that on my truck. This thing is screaming when it's at 4000 RPM, I can't imagine literally flooring it!

And I haven't gotten my tune yet, it's on my list but the guy is an hour away and I'm semi broke etc.

 

[Blckshdw]

14.7 is the air to fuel ratio

 

[DAlastDON]

WOT=Wide Open Throttle or floored

 

[Nexus1155]

i am in Boston and will do a basic performance street tune for you just got to find out the cost of the credits i need to purchase first. I tuned a few denalis with that motor. It wakes it up a good amount. I still love my 4.2 though. Let me re read your post and what you are trying to have accomplished. Most factory GMs I have touched are pretty good in the fuel area already. They just need some ignition tweaking depending on what gas you want to run...

 

[Nexus1155]

if youd like you can e-mail me at N.Goyuk@gmail.com if i am allowed to put my email? I am in Peabody most days at work at Mini, but the tune should be a cakewalk as long as everything is working well and no misfires. The stability control, I don't know if you can exactly switch it, but I have dealt with some people asking me to bump line pressures to unsafe areas, if its a safety concern, I will not do it even if I can because that is beyond my preference of tuning. I will tune for most power and best gas mileage and over all better driving condition and pedal feel, but I won't do goofy stuff anymore. I can tweak some hidden goodies though that youll like if it is available. Also free reflashes in the future if you change tires sizes, etc. unless you add a turbo or sc where it requires more crediting...

 

[l008com]

My mechanic buddy is going to get his own copy of HPTuners and is going to try to start tuning engines himself. I may be the guinea pic and I'm ok with that as long as I finally get to ditch this horrible throttle lag.

But just to confirm back on a few things...

So theres nothing you can do about traction control? I would even consider killing it all together (as long as it didn't affect stability control). It's such a pointless feature, and the TB's traction control is so damn active. Super buzz killer. I may get a trutrac DSL, and if so, I'd definitely consider just killing it all together. But an ideal set up (and one that I htink should be stock on many/most vehicles) would be Traction control off / stability control on by default. And a button to turn Traction control on when needed only.

Also just to confirm, theres nothing HPTuners can do about DSLs? If I ever do my HID upgrade, ill need to kill DSL and i'd rather do it in software than hardware (if possible).

Is there any way to set up two different sets of shiftpoints that you can easily switch between (i assume no because how would you make that switch?) My thinking here is how much, even with teh V8, having a tow/haul mode would be nice. It drives me nuts that a truck with a nearly 7000 lb towing capacity doesn't have a tow mode.

 

[Mooseman]

HPTuners only deals with engine and transmission controls.

So theres nothing you can do about traction control? I would even consider killing it all together (as long as it didn't affect stability control).

Cannot be tuned out, even with a Tech 2, but you can turn it off when needed with the switch on the shifter. Push once to turn off Traction control, push and hold the button turn turn TC and Stabilitrak off.

Also just to confirm, theres nothing HPTuners can do about DSLs? If I ever do my HID upgrade, ill need to kill DSL and i'd rather do it in software than hardware (if possible).

Same deal. Just search for DRL killer on this site.

Is there any way to set up two different sets of shiftpoints that you can easily switch between (i assume no because how would you make that switch?) My thinking here is how much, even with teh V8, having a tow/haul mode would be nice. It drives me nuts that a truck with a nearly 7000 lb towing capacity doesn't have a tow mode.

Maybe but I doubt it without a physical switch. I'm not fully familiar with HPTuners so maybe someone with more intimate knowledge might be able to shed some light.

 

[RedRocketZ28]

If your buddy is not familiar with tuning at all then it will be a VERY steep learning curve. I've owned HPTuners for 5 years and used to tweak things on my Camaro and other GM vehicles I have had. I am still not great with it but could make AFR, spark, etc. on my Camaro when needed. I have since switched to MS3PRO standalone ECU on the Camaro for the added functions, ease of use, and safeties built in. Price you pay when need/want to make close to 1000 rwhp. On the Buick I have played with timing, shift points, shift time/pressure, and torque management. It runs a lot better than it did before the tune.

You can tap into the PCM fairly easy for a tow/haul mode button and turn the function on in HPTuners. I bought a newer shift knob that has the TC button on it and I plan to use that for my tow/haul mode switch. That is if I ever get around to doing it before I get rid of the Rainier.

 

[l008com]

How would one "tap into the PCM fairly easy" ? I do have the shifter with the TC button, but if I repurpose that (it should be tow/haul button anyway), then how would you turn off Traction/stability? Also any chance there is an unused tow/haul icon in the dash cluster that will let me know when it's turned on, if I do use enable feature?

 

[l008com]

Here's the update to this. My mechanic hasn't brought up tuning in months so I don't think that's happening, so I'm going to have lime swap do the tune-by-mail. I'd still prefer the guy in Brockton or whatever do it while driving the truck, but he doesn't like customers.

So here's what I need to know. Where the hell IS my computer exactly? And how do I remove it (and swap it with the loaner)?

 

[Blckshdw]

Where the hell IS my computer exactly? And how do I remove it (and swap it with the loaner)?

It's on the driver's side of the intake manifold. Here's an old pic, you can see the white, grey, and blue harness connectors. That's the "where", I'm confident once you pop your hood and take a look, you'll be able to answer the "how" on your own .

 

[Mooseman]

His is a V8. It's just below the battery behind the radiator.

Jeremy has a spare? Last time for my Saab, he didn't have them as they are pretty hard to find and expensive. You would also have to send in your Transmission Control Module (TCM). It's on the back side of the PCM.

 

[l008com]

Ok this is finally happening and we're working out the details right now. One of the things he can change is the idle RPM and that got me thinking. The default is 600 RPM (5.3L). This should be the idle RPM only once up to operating temperature. But, what if I lowered that? I've been saying for years that auto-stop should be a feature in all cars. Sitting in traffic or at red lights is what really kills your fuel economy the most. Well, this isn't auto-stop, but in theory lowering the idle RPM would make my truck use a bit less fuel when I'm sitting around.

I wouldn't want to go so low that the engine starts running rough though. And this is a mail order tune so it's not like we can do any real-time experimenting in the truck itself.

Thoughts?

 

[Mooseman]

Funny you should mention auto-stop because it has been dispelled as BS by this guy:

Lowering the idle speed would not make a noticeable change in MPG. It could affect the alternator's ability to supply enough power. It could also affect your A/C if it doesn't stall it.

 

[l008com]

He doesn't really dispel is as BS, he just talks about why he hates it, then he spends half the video defending it against the common arguments against it. That was a weird video in that sense.

 

[Mooseman]

Well, he is Australian after all. Still, auto stop is like DoD, expensive to implement and expensive to fix with little return. It just helps manufacturers meet CAFE. It's all 'boolsheet'

 

[Reprise]

It's all 'boolsheet'

I was expecting 'merde'...LMAO

Seriously, though - I had 3 hybrid vehicles over the past 20 yrs - and, since that's pretty much built in to a hybrid powertrain by default, it *is* helpful, especially if you're trying to make that EPA-rated 50 (or whatever) MPG.

You'll probably see this on regular gassers in the next 5yrs or so, if the CAFE standards / schedule stay where they're at now (which is a coin flip, given the rumblings by the auto lobby and the current regulatory climate in DC.) GM already has done this in the past with their 'BAS' system (not sure if any vehicles use it currently, but I don't think it would be onerous to re-deploy it in the future (on non-hybrid vehicles) - nor do I think GM will be the only one doing it.

 

[l008com]

I'm sure someone who drives in more rural areas, where their commute has maybe a handful of stop lights and many long stretches of 50mph driving... would call the system garbage. But people who have to drive around suburbs and into cities regularly would see a lot of benefit I'm sure, at light after light after light. Then you hit a drivethrough and you don't know if it's going to be a minute or 6 minutes. The only real downside the guy in the video says is that it can be rough when it restarts. Oh well, I could get used to that, doesn't seem like a big deal. This is all off topic anyway, I am not going to try to program my own auto-start system into my truck

 

[Matt]

Well, he is Australian after all. Still, auto stop is like DoD, expensive to implement and expensive to fix with little return. It just helps manufacturers meet CAFE. It's all 'boolsheet'

You JUST KNEW I'd see that.

 

[Mooseman]

I do like how he says "boolsheet"

Hybrids do use a different starting system than regular gassers. They use a flywheel mounted motor/rotor/coil/generator thing without a regular starter motor. Well, at least on some GM's.