I have a 1998 GMC Sierra Z71 and was wondering what I could do to get
slightly more power from the engine. The engine has about 70,000 miles on
it and it has been maintained very well. I am experiencing a rough idle a
slight lack of power and quite a noisey fuel pump. I purchased a set of
Delco Platinum plugs but haven't put them in yet. What else should I change
on this truck for a performance oriented tune-up?
Thanks in advance,
All the standard tune-up stuff should be a good place to start, including a
new fuel filter. If you think you are having problems with your fuel pump,
put a pressure guage put on it to see if it is delivering the required
pressure. If it is not, then maybe a replacement would be in order. I
would also consider new plug wires, air filter, pcv valve, etc. as well as
cleaning out the EGR valve and passages.
Cheers - Jonathan
On Sun, 14 Aug 2005 21:25:24 -0400, "Blair Chesterton"
there are a number of ways to get more power. Most of the time it
boils down to how much money you want to spend and how wild do you
want to go.
Changing the ECM pron or having it re-programmed, installing headers,
installing true dual exhaust with free flowing mufflers, installing a
higer flow air fillter and air fitler housing are some of the easy
another issue is what state you live in and what you are allowed to
do to your truck.and of course how mechanically inclined you are.
think through what you want to do and ask around to see if anyone you
know has done something similar. Installing headers and getting them
to seal can be a pain in the ass, but I think most people would agree
they offer some degree of "Free Power", you have to pay attention on
your power sterring set up, as far as the brackets are concerned and
how they attach to the exhaust manifold.
I think there are a couple of companies that make "cold-air" intakes
for your year model truck, and I know there are various places that
sell different style exhaust systems. Plus I'm sure there are one or
two who make either a ECM programmer or new chip... for the ECM.
There are a number of other things you might do, but they'll cost some
more $$ and a good bit more effort.
I would go thru this for you, but it would get rather long. - An increase in
compression will make more power - and an increase in intake efficiency
(bigger valves or more valve lift) also will contribute quite a few horses.
You might want to change the camshaft, but dont get carried away - a good
street and strip type of cam is more than sufficient here. Too far on the
cam, and the thing is a dog at any kind of legal speeds. Remember, changing
cam profiles simply moves the power around in the rpm range - and you would
not want a vehicle that you have to rev up to 6 grand every time you want to
push some snow or pull a trailer ! More lift, rather than duration, is a
good plan to follow on street trucks and cars, since it won't have these
problems anywhere near as much.
But the "more lift" on the valves has its limits as well. you dont want the
piston "kissing a valve"..... and valve springs for really high lifts get
pretty esoteric, as you need a lot more spring to control these high lift
jobbies. I wont go into great detail here on this, since it is a science of
long ago that is rather involved...
Aftermarket intake and exhaust manifolds can give quite a few ponies as
well - but this game gets expensive in a hurry. Anyway, these are the basic
"paths to power" on an un-supercharged motor. You might want to consider a
supercharger, since it is actually the right way of souping up a 4-stroke
piston motor, with very little modification to the innards of the motor...
And the cost is comparable to going thru all this normally-aspirated machine
work and aggravation. It all depends on how much you love to tinker, get
grease under your fingernails, etc, just to step on that pedal. listen to
her "talk" to you, and get a good neck snap when you DO step on her.... Only
one question - do you want it bad enough to work for it ?
New plugs, wires, cap,rotor, new air filter, fuel filter, run some top
engine cleaner through it, check the injectors for flow and pattern
after cleaning them, change the O2 sensor(s), synthetic oil change (for
trans,engine,rear end,transfer case)
"Blair Chesterton" < firstname.lastname@example.org> wrote in message
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