Glenn (Glenn91L98GTA)and I adapted the ARAP code for my car (89 305 TPI 5-speed) and after I drove the car for a bit I noticed some unusual characteristics: The car ran fine at speed on the freeway, but when putting along in stop and go traffic it was not happy at all. It would hesitate, and surge, but ONLY under very light load at under 2500 RPM.
I have traced this problem to the way which this bin operates the E.G.R. valve. When the T.P.S. reaches the point of turn on, the computer instantly sets a E.G.R. Solenoid Duty Cycle of 100%, which fully opens the valve. It does this even if the car is stopped and I am revving it lightly in neutral. When I switched back to my old PROM (G.M. Motorsport) The EGR solenoid operation was TOTALLY different. The EGR would not even come on when free revving in neutral, except at much higher revs, (above 3500) and even then the duty cycle was only 25 to sometimes 50%.

I fing this fascinating, but I cannot see where I can adjust the control of the EGR except in the constants where the TPS turn on and off points are set, (using TunerCat that is), and obviously there is much more to it than this.
Anyone have any indepth insight into what controls the EGR and how to modify?
For now I am going to use a different BIN as a baseline and move some of the more critical paramaters from the ARAP bin (Spark, Fuel, Etc.) and see if that makes a difference. I will update.


------------------
Karl Hunter
Hunter Motorsports
Vancouver, B.C. CANADA

 

Using WinBin you'll find the table labelled: EGR Duty Cycle vs LV8 and RPM

That table can be found in the 89v3.ecu file avaliable on the Yahoo! third gen website. It's also in the recently-posted 6Ev005.ecu file.

You could download winbin and use it to modify your EGR settings.

Just as a note, however, my '89 stock APYU code has 100% duty cycle set.

[This message has been edited by afgun (edited June 24, 2001).]

 

This might explain the problem I'm having. I've been running the $6E in my '87 and feel a slight "miss" while cruising at 55-60 mph. It gets far worse when coasting or going down a slight grade (just off idle TPS). I don't really feel it above 70 mph.

I've suspected EGR and/or CCP, but can't prove it. I've been going nuts watching block learns, pulse widths, etc. I've pulled plugs, wires, cap & rotor, and checked everything I could think of (including vacuum leaks) to diagnose this problem. I even swapped out my ported plenum for an unported plenum to see if grinding off those "ramps" in front of the EGR ports had any effect. It basically goes away when I go back to my stock '87 chip. Until I figure this out, I'm gonna run a modified '87 ($32B). I sure hate to miss out on the potential benefits of running the $6E code, but this behavior is unacceptable.

------------------
'87 IROC 5.7l TPI - original owner!

 

hmm, interesting indeed, I stuffed the reasonabbly stock ARAP Bin in my car (programmed for a 305) and it worked wonders, i can actually break loose, just a tinge (PERFECT). My Idle is GREAT, and I don't have any problems with highway speeds. Granted I only drove her about 40 miles to check it out, but it is nice...

John

------------------
87 Formula Yellow/Black
Engine & Transmission
.040 over 5.0 converted to TPI, 9.5:1 Compression, SLP Cam Dur 206/212, Lift 480/487, Cent Line 112, SLP headers, SLP cat-back exhaust, K&N Airfilter, Modified Stock cold air intake, Ported & polished Stock TPI intake, Holley Adjustable Fuel Press regulator, AC Rapidfire Spark Plugs.
Gil Younger (no yo-yo) Shift Kit, Aluminum Driveshaft, 3.73 Posi gear
Suspension & Brakes:
Baer 12" brakes 4 wheels, KYB AGX Adjustable Shocks & struts, Hotchkis strut tower brace, South side machine frame connectors, Custom reinforced control arms and pan hard bar.
Interior:
Custom Leather interior, CUSTOM Yellow Gauge Faces, Kenwood Receiver, Pioneer Speakers, Kicker Substations, Kenwood 10 Disk Changer, Pioneer Amp.

87 Formula TPI (5 Speed) Yellow/Gray STOCK

1967 Buick Riviera 430hp Turns high 14's (Not bad for 4300 lbs)

83 Camaro (Parts)
83 T/A (parts)

http://www.3rdgenformula.com

 

Karl, a question for you.

GM Motorsports Prom? Is this the ones that GM equiped their players motor sport cars with?

I have been looking to find one of these to see what GM programmed into them. I had heard rumours that each team had to leave a heafty deposit to get these chips and they had to have them in order to compete on an even playing field.

I figured GM would have upped the spark, tossed the EGR, and tweaked the fuel curve.

What was the PROM # on your cal pack?

Mark.

 

I was looking thru my Illistration & parts catalog for 82-92 Firebirds, and was interested to find that there was no ARAP codes listed.

WHERE exactly did this BIN come from?? does anyone know or is it a mystery.

John

 

The Snap-on book shows it.
I released the info about it, after a tip from a gm guru.

 

BTW, 89 MY, and vin 8

 

Still seems trivial, I know it is for an 89, and a 350 VIN code 8, It has to be from a F-body or Y body, But something does NOT jive.

Was it a Camaro ONLY item, or what, Not to be rude, as far as I am concerned some aftermarket books seem to be misinformed. Take the Nextgen page from Year One for example. They claim there is no distinction to why some Formulas have the 5.7 callout on the hood, when others do not. The GM book has it clear, 87-90 Formulas, no callout, 91-92 Formula's had 5.7 callout.

I would trust Snap-on, but if GM does not show the ARAP then where did it really come from. GRANTED, I am only looking at the Pontiac Book, the Camaro book may have it, that is all I want to know.

 

Well in my reference (snap on I believe), I can find a ARAP code. Prom code 4194 ARAP, scan code 4131, part# 16134193. It only lists it as a "running change".

Interesting, the 4194 ARAP is listed as replacement for the 3533 APYZ which was a replacement for the 1304 APKC.

Another interesting note. The part numbers is near the end of the list numerically, so it was a late revision. There are a few others after this. One thing my listing does not say is what gear ratio, or application it was for.

Oh well, interesting read.

I am still interested in the GM Motorsports Prom. I recall those series quite well. I still believe GM had some good tuning in those proms. Hunter ... are you there?

Mark.

 

There really wasn't much to the G.M. Motorsport BIN, no disabled EGR, and the spark and fuel paramaters appear to be very close to most other BINs from an 89 305-5speed car. The most segnificant change is the addition of a rev-limiter at 5750 RPM. If you were running without a rev-limiter in the series it would have been harder on the motor (G.M. was still warrenting the race cars) and it could have been a competitive advantage to have more RPM capability.

Yes the cars in the G.M. Motorsport (Players) series ran very well, but that had more to do with the hand assembled, balanced, and blueprinted engines than the PROM tuning.

The ARAP BIN has WAY more spark than the Motorsport BIN. Many other differences also. But, The ARAP was designed for a 350, and none of the series cars (R7U) had 350s.

One of these days when I have some extra time (oh please can I have some extra time!) I will dig deeper into the code of the Motorsport BIN and see if there are any real secrets of note. As of now, it really does not seem to be all that trick.

------------------
Karl Hunter
Hunter Motorsports
Vancouver, B.C. CANADA

 

That would make sence that the ARAP is a superceded part rather than originally installed in a F-body.

I was just wondering, thanks fout clearing that up.

 

Karl,

If you wouldn't mind, could you send a copy of your motorsport Bin to me. I'd love to browse through it (when I can find some free time.). (mstrembi@home.com)

Can you tell me what the part#, scan code, or what the sticker on it says?

Call me a history buff, I like this stuff.

Mark.

 

Karl, I'd like to look at that bin too, just for the fun of it. Thanks!

------------------
Greg Westphal
'87 IROC 355TPI/A4

 

Yeah - me too!
(lee@hsh.com)

 

bttt

 

Well I was just at

http://holman.cs.uml.edu/~sdurphey/bccfind/

and I found

http://holman.cs.uml.edu/~sdurphey/b...b.cgi?BCC=ARAP

they think the ARAP BIN came from an 89 Vette, POSSIBLY a ZR1, Considering the ZR1 used a Lotus Engine, this might be unlikely.

 

Karl, you out there?

bttt

Mark.