I read that some guys are setting there TPS voltage to .60 V to get the computer to go into power enrichment mode sooner. Is this a good plan? Is there downsides to it?

------------------
1987 T/A GTA 5.7L, Bored .020 and ported for .202 valves, edelbrock headers, flowmaster exhaust, JET STAGE II chip, Comp CAM, Adjustable fuel pressure, Airfoil, K&N filter, B&M stage 2 shift kit, and a home depot ram air(Hey it looks good and it works)

 

Nope. These parameters are all controlled in the eprom. The ecm actually puts you in PE (the real name for WOT) much sooner than 100% TPS. Depends from ecm to ecm and RPM you are in. From 0-3199, you only need 50% TPS on an SD 7730 ecm, 3200 - 4800, just over 60% and over 4800 rpm, 70%.

If you want PE to engage sooner or later, then you just modify the table.

These "mechanical tricks" cause more problems than they are worth. They were developed in the 1980s when peopel didn't know how to get inside the eprom. We are in the 21st Century now. If you REALLY want to adjust when PE is engaged, get into PROM Burning and do it right.

Then you will see there is a lot more things you can control about PE, than just when it engages @ %TPS. You can control how much additional spark you give it and how much additional fuel you give it. These are far more important for tuning than just when it is engaged.

That is why you cannot even adjust the TPS on an SD car...GM smartened up and realized that inside the eprom is the right place.

 

Hey! i just set mine to .78 so when i floor it it goes to 4.21 volts. MAkes it easier to WOT, still, anyone think this might screw with stuff?

------------------
1986 IROC Camaro
305 TPI "LB9"
3.23 gears
Doesn't know enough about cars.
AIM: jesusathome

 

If you are pushing down on the throttle @ WOT where does it engage any sooner. It is still @ 100% and you only need 70% for PE to occur.

This would only matter if you only pushed down on the throttle less than 70%, and then the difference is only a few % points. But if you are "pushing the pedal to the floor", there is no difference as in either case the ECM is seeing > 70%.

 

.78 should set off a code... thats too high..
i think .63 is the highest you are able to go without throwing a code.

 

Glenn,

What about us poor folks that want cheap mods? We can't afford custom PROM burning or the burner to do it ourselves.

I realize you have a lot of experience with PROMs, but what about us guys that have basically stock engines, where a custom PROM will not be cost effective?

Also, I have a TPIS Level 3 PROM. Should my TPS setting be @ stock .54?



------------------
Mike L.
It ain't pretty.......

1987 IROC Z TPI 350 A4 3.27 Borg-Warner.

Mods: 2300-2500 Stall Converter, Shift Kit(GM parts), TPI Specialties Stage 3 PROM, Modified Airbox w/ K&N's, homemade cold air, Relocated MAT sensor, Gutted MAF, 160* thermostat, Accel 8mm Wires, bypassed TB coolant, Flowmaster 3 chamber single 3" in/out muffler, 3" MAC mandrel intermediate, custom dual !cat Y-pipe. airfoil, ported plenum. !smog

http://www.MichaelLasiuta.home.att.net

**BOYCOTT LAPEER DRAGWAY**

 

How much did you spend on the TPIS Level 3 PROM? Probably more than you would have spent to get all the prom burning equipment...prom burning is NOT expensive.

I too have a basically stock L98, and I can say there are benefits for "stockers". In fact, it is best to get into prom burning while your engine is still basically stock. The change that I mention above (changing the %TPS to invoke PE) you could do in 5 minutes...5 minutes. That is a VERY SIMPLE change.

My real point is that adjusting the TPS to go into PE (I prefer to use the correct name) does not accomplish anything. You are already in PE by the fact that even at the highest rpm (4,800) it only takes 70% to make the ecm go into PE. It goes into PE sooner at lower rpms.

If your engine cannot go into PE with the TPS at the stock position, then you have a more serious problem than a simple adjustment can fix. This is a useless modification IMO. What is probably more important (and no one adjusts) is the actual blades to ensure they allow the maximum amount of air into the plenum.

But simply adjusting the TPS to get a higher voltage @ WOT will not make PE engage any sooner (it is already @ 70+% which is like only 3.5 volts). This is the only thing the ecm is concerned about with the TPS. The actual fuel/spark (other than PE) is controlled by other tables (MAF & SD) and it has nothing to do with TPS (than invoking PE).

Are you starting to see where I am coming from?

 

Got it for $100 thru their garage sale. It was originally on my 88 Vette with similar mods.


Yup. Thanx.

So can you point me in the right direction to get the PROM burning equipment?

Can I reprogram the TPIS POS?


------------------
Mike L.
It ain't pretty.......

1987 IROC Z TPI 350 A4 3.27 Borg-Warner.

Mods: 2300-2500 Stall Converter, Shift Kit(GM parts), TPI Specialties Stage 3 PROM, Modified Airbox w/ K&N's, homemade cold air, Relocated MAT sensor, Gutted MAF, 160* thermostat, Accel 8mm Wires, bypassed TB coolant, Flowmaster 3 chamber single 3" in/out muffler, 3" MAC mandrel intermediate, custom dual !cat Y-pipe. airfoil, ported plenum. !smog

http://www.MichaelLasiuta.home.att.net

**BOYCOTT LAPEER DRAGWAY**

 

I cannot say about re-programming the TPIS eprom, as they often use "special" setups to stop copying.

With your setup, the best thing to do is start with the ARAP BIN, designed for 89 350 F-bodies. Just "search" on ARAP on the DIY PROM Board.

As for wanting to learn about eprom burning, just scope out the DIY PROM Board and click on the link on the top titled "PROM BURNING Introduction". It has virtually all the information you would want to know (what's involved, what equipment you need, how to program the prom...etc). And, then you have all of us guys to help you too.

You can use Craig Moate's software as a scan tool (its free) and then you just need to get a burner (Pocket Programmer for $149.00). We have also recently figured out how to use a "Flash Prom" with the 165 MAF system so you don't even need a UV Eraser. It erases electronically by the Pocket Programmer.

If you invoke "Highway Mode", the gas you save will pay for equipment in only a few months. And you still can make it "pollute good like a car should" when you stomp on it.

 

Is Highway mode already invoked on the ARAP bin without touching the code???

 

Last I looked, yes it is...but it is "mild". I run a much leaner mixture with absolutely no problems.

The two major things to change in the ARAP BIN is the "part throttle" spark advance (its quite high...like 47*) and set the Fan Operation Flag to "Normal Operation". You can also play with the locking of the convertor, which I find annoying to have it "lock and unlock" on rolling hills. I just set the "Lock Prevention Speed" to 45 MPH to avoid this...a personal prefernce. Not much more...other that maybe a bit of "tweaking" to your "personal preferences".

I wish they had something similar for SD cars...I had to develop my own version for SD (after many hours of testing...fun testing.. but testing none the less).