PCM tune... with pics

 

Platinum Member
Username: Nd4spd18

Philadelphia, PA

Post Number: 10896
Registered: Jul-06
My latest mod... not audio related, to increase power.

For those who don't know the powertrain control module is the computer that controls the vehicles electronic engine and transmission components. It comes with a default program from the factory but this can be modified. In this vehicle the PCM itself can not be flashed, rather it uses a ROM chip containing the program, which can be swapped.


Vehicle is the 94 S10 Blazer 4.3L 4-spd auto. I had Alvin at pcmforless.com burn me a chip with the following options:

Disable EGR. This is an emission control but it also gunks up the inside of the engine with excess carbon... sorry environment but my engine sure as hell don't need that.

Raise shift points. There are set rpm points where it shifts to the next gear, these are now higher so there is more power at the top of each gear... at the expense of a bit of fuel mileage.

Firm up shifts. The transmission is set to shift smoothly from one gear to the next from the factory for a smooth ride. Now it will shift firmly and quickly with less loss of power in the shifts, like a camaro/firebird. And here it is:

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The PCM is under the passenger side dash with a bunch of other electronic controls. Pull off dash underside cover, kick panel cover, pull back carpet and there it is.

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PCM unit out of the vehicle

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That thing with the blue cover is the stock chip

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Pulled that out and plug in the new one into the slot

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Put the unit back in the vehicle and that's it. It makes a noticeable difference, the truck feels like it has more power now from the higher shift points, and a bit more top end power from the lack of EGR. The 1-2 shift especially is now firm and quick where before it would hesitate. I'm happy with the result... worth the $200 for the new chip? Not quite sure. Definitely an improvement just wish it cost a bit less.
 

Gold Member
Username: Van_man

Boston South, MA

Post Number: 5139
Registered: Mar-06
Interesting. Now can that one be flashed?
 

Silver Member
Username: Armykyle1

Ms Us

Post Number: 857
Registered: Dec-08
MS that truck is OB1 correct? OBD2 or OBDII can be flashed usually. There's less tunning options with OBD1 than there is with 2. If I'm not mistasken that truck is TBI which only has two injectors. If its MPI it has six. Much more fun lol. Nice dude
 

Platinum Member
Username: Nd4spd18

Philadelphia, PA

Post Number: 10897
Registered: Jul-06
No chip in this unit can be flashed without removing it.


It is OBD1 yes. Not tbi though, CPI. One injector with six valves, makes about as much power as a MPI without the need for as many injectors.

Only downside is I live in a g.a.y. state with emissions testing on inspection and it will not pass, I will have to put the stock chip in for inspection.
 

Gold Member
Username: 04redmach1

Giggidy, GA USA

Post Number: 2657
Registered: Mar-06
I have never seen a stock chip. The computer itself is the stock tune.

OBD1 can be tuned by chip or piggy back. OBD2 can be flashed. I use to be a certified tuner and do A LOT with Fords. Dyno tuned boosted cars and such on my dyno.

Use to firm up shift points to mess with people. Kind of crazy to see a 2001 Lincoln towncar spin tires going into 3rd. Not great on the transmission though.
 

Platinum Member
Username: Nd4spd18

Philadelphia, PA

Post Number: 10899
Registered: Jul-06
Then you must have never worked on an early 90s GM as they all have that removable chip containing the stock tune.

Shifts are firm but not enough to squeal tires that would be bad for the trans.
 

Gold Member
Username: 04redmach1

Giggidy, GA USA

Post Number: 2658
Registered: Mar-06
Thats very weird. I have only delt with OBD2 GM vehicles though. Form 1987-1995 OBD1 Fords they do not have a chip, but a place to insert one. Same with 1996-2004 OBD2, no chip but place to install aftermarket.

My buddy still has his 2004 GT I tuned and bumped shift pressure up and no problems out of his tranny as of yet. Only time though, cause car is still all stock but that is what he wanted.

PS: should have seen what we did to a 7.3 f250 :-)
 

Silver Member
Username: Armykyle1

Ms Us

Post Number: 862
Registered: Dec-08
I wanna tune my daewoo lol
 

Gold Member
Username: Hdubb

Team Revolution

Post Number: 4264
Registered: Nov-04
^^^ LMAO
 

Silver Member
Username: Armykyle1

Ms Us

Post Number: 867
Registered: Dec-08
I'm half joking lol. But I'm sick of hondas and crap talkin shite lol. I wanna go out and beat down SIs and celicas and watever else. I've read about ppl putting down 200hp+ at the wheels on motor. Cams shaved head high flow exhuast. Port matching. I have an extra engine I blew cause it had 209k miles on it lol. Extra trans too. I dunno I wanna try my hand at tuners. I know how too build a 383 to put down 400+ hp and tq. That's easy
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