Diablosport Forums

I just installed the diablo tune on my 2001 camaro ss a4. It's already running alot better!!!!!

I had an issue prior to installing the tune of my car not downshifting to the previous gear when going above 50mph when I floored it. It's still not downshifting even with the tune, but it does seem to be accelerating faster above 50mph.

Question 1 : Is there a way I can tune the car to downshift to the previous gear(ie 3rd, when in 4th or 2nd when in 3rd) when going anywhere from 50-70mph or something like that(basically, I want to be able to floor the car when on the freeway doing 60-70 and I want the car to downshift and haul balls) and if so please tell me exactly how to do it?

Question 2 : I'm wanting to do a datalog on the most critical areas to make sure everything is running correctly. I don't have the serial to usb cable YET, so is there a way I can datalog those key areas and read the findings on the tuner? Then I can maybe ask you guys if eveything looks good after I get the readings? If so, please tell me exactly how to start and stop the datalog process as well as which areas I need to datalog?

Will it downshift when below 50 mph when you get on it? Can you manually pull it into 3rd when crusing above 50 and get it to downshift?

yeah it downshifts perfectly under 50mph but not above, and yes I can manually downshift from overdrive into drive and it will downshift into 3rd. But even in 3rd when going over 50mph, it won't downshift any further(i'm not sure if it should or not)

I think my throttle cable could need adjustment although it doesn't make sense that it would downshift normally under 50mph. I've recently(in the last 6 months) replaced the following parts, so these can most likely be eliminated as the culprits for this problem :

All parts STOCK ac delco : Mass Air Flow Meter, both pre-cat o2 sensors AFS98 & AFS97 and the Throttle Position Sensor. My engine is also 6 months old, less than 4K on it. It's a stock LS1 crate motor from the GM dealer.

Yes it should downshift to 2nd when your running over 50 mph. The top speed of 2nd is roughly 70 to 75 mph, on stock gear ratio. Mine will shift down to 2nd when crusing at 65 mph if you punch it. If you just part throttle it, it'll hit 3rd every time. I don't know if the data list on the tuner will show you commanded gear or not. I haven't looked though the data list on the tuner yet to see what's all in there. If it does, see if it show's that it command's 3rd or not when you try to get it to kick down.

Is there any trouble codes stored?

Use your tuner and go into the diagnostic's part and look for throttle position sensor reading. "With engine off" Make sure that when you put it to full throttle that it shows 100%. That will show if the cable is right. Also check the tps voltage. The voltage should be under 1 volt at closed throttle and over 4 volts at full throttle.

This will rule out the tps and the throttle cable.

ok i did what you said ......I did a log on the throttle position with the car off but the key on......the most percentage I got when holding the pedal to the floor was 79.22%.....It should be 100% right?

does this mean I need to adjust the throttle cable?

also I did a short log of the LTFT's on my way to work......I'll do a proper log later......at idle the throttle position was jumping from 0.00% to 0.39%.....the LTFT bank 1 was 7.81 and bank 2 was 5.47.......when going 55mph in overdrive for 2 mins.....the bank 1 was no higher than 9.50 and bank 2 was no higher than around 6.20......

Yes you will have to adjust the cable to get proper throttle movement. All you have to do is lift the adjustment lock button (1) up and then pull the cable adjustment slider (2) rearward until all slack is removed from cable, but without opening the throttle. Then just push the lock button back down till you hear it snap back into place.



Then recheck and make sure that you can get 100% throttle now.

Might want to ask 06MonteSS or mikel how to do the adjustment without the computer hookup ability. If I remember right there is a guide somewhere on here that tells a person how to do it. Don't remember where I saw it at though.

Awesome, Thanks Rage for your help....this picture above along with your instructions help me alot! I will be trying this tonight(weather permitting) and I'll let you know what happens.....thanks!

yep....it was the cable.....I got it reading 100.1% now, and the car feels insane......i've been driving it for 6 months like this and I thought it was pretty fast...I even beat a few mustangs...lol......but now especially with the diablo tune and now that the cable is right.....it feels sooooo fast.....it shifts sooo hard into 2nd gear, and also when going 40 it will now downshift it 1st gear and burn the tires all the way to 2nd gear!!!!

Thanks rage for helping me and thanks diablo for making a baddass tuner!!!!!!

Nice!!

good info Rage!!!

Looks like we have us a resident GM Tech now!

Good info Rage!!!