Low End Power Issues

Brody · January 8, 2010

Hopefully I can get some insight on the matter because I'm having a hard time finding any information via a forum search or a general google search. My truck is a 1996 3/4 ton 5.0 vortec stock with a 4L60-E and G80 with 3.73s. I've just done a full tune up on it and it runs like a brand new truck except that I can't get it to brake the tires loose if it's life depended on it. Not even a brake stand will get them to burn out.

I don't want you to get the impression that I'm trying to impress anyone but the truck is just a dog down low period. Even with a 305, a 4l60-e and 3.73s should have enough torque multiplication in first gear to make it at least chirp the tires taking off. Instead, I get a lazy acceleration till about 3k when it decides it wants to pull hard.

My question is:

Is it possible my truck has some sort of traction control? I've checked my RPOs and came up with nothing. It seems similar to a 98 sunfire I had where the engine would cut power to assist in traction control. If so, is there a way to disable this? On my friends HPP Crown Vic all we had to do was to pull the abs fuse and it could actually keep up pretty well with my old mustang. Will I need a tune to disable this? Could there be some other underlying problem? Any information is appreciated.

rodram · January 8, 2010

... I have basically the same truck except for a 5.7L in mine, same transmission, same G80 3.73 rear gears

... basically the 5.0L is a lower power engine and will never be able to really give you a lot of power to the wheels

... there is no 'traction control' on these trucks ... the only traction assist you have is the G80 locking differential and it will mechanically kick-in AFTER one rear wheel starts to spin more than the other one... up to about 20-25 mph and then it will totally disengage... if you were to leave some rubber on the road from a take-off, it would be two black lines from both tires spinning

... you may have Rear Wheel ABS (I do..) but I have not heard of this affecting acceleration .. some people complain about it affecting their brakes ... there is a way to disable it, but I am not sure what you have to do ... I like mine in the snow covered streets and want to keep it!... it may not help you too much in Phoenix... I don't think you get too much snow!

... if you have done a complete tune-up, I assume your plugs, wires, distributor, etc. are all in good condition... one caution on these Vortecs is that the distributor base is plastic and can easily crack... causing performance issues

... maybe the timing is off a little ... these Vortec engines can only be timed with some kind of a scanner that reads the cam retard, without this you are only guessing at the correct timing position

... if all of that is ok, then I would start to suspect that the transmission is beginning to act like an aging 4L60E (welcome to that club too!) and that there is some slippage or power loss in the hydraulics in the transmission or torque convertor.....

Brody · January 9, 2010

Thanks for the reply, Rod. I understand the 5.0L isn't known for it's high output but it does put out more torque at a lower rpm than my previous car that had an even taller set of gears and that thing could roast the tires through first gear. Like I said, I'm not expecting a funny car, but I don't think it should fall flat on it's face from a light.

To answer your question, my truck is equipped with ABS, but I don't think that's hampering my performance, I was just wondering if it had traction control, if it was part of the braking system, which could be disabled by disabling abs, but if they don't have traction control than I've abandoned that idea. And yeah, we don't get much snow

A 5.7L swap is on my short list of things to do and I know my main seal is leaking and it's getting a little goofy on it's 3-4 upshift so the transmission is definitely going to get some tlc when I get in there. I'll have to check my distributor though, because I only replaced the cap and rotor when I gave it a tune up and they were pretty bad as it is. Thanks for the tips.

[email protected] · January 9, 2010

Don't feel bad cause the guys w/ 4.8 or 5.3's ain't burnin' no rubber either unless they got 3.73's or 4.10's.; or come slidin off a clay road onto the blacktop with the motor tached-out .... careful W/ 2 many rpm's though they'll just want to shift to 2nd 2 soon and kill the fun..(and rear-end).

Brody · January 12, 2010

Well, I have the answer to my problem and hopefully providing it to the forum will make the next person's search that much easier. If your C/K truck is having a problem laying down all of it's low end and you've repaired everything possible, this is likely your answer:

"The use of Torque management began in 1996 with the introduction of the Vortec V8's. Torque management retards timing from: a deap stop, when accelerating with heavy throttle, and just before ALL trans shifts. GM introduced TM in an effort to reduce drivetrain related warranties."

Thanks again Rod for your assistance and I hope this information is helpful to anyone else.