tilac999

I wish Ken's chip fit my '85 ROW

Jon B.

I think they are. Seems like this is gonna be the last update though.

PorKen

Last major update. I may have a small update later if any problems appear that I haven't seen.


There is one last thing I want to experiment with, a variable WOT input. The WOT input to the LH goes through an A/D converter. In theory you could use a 951 TPS (which is a real throttle position sensor) and program a variable WOT threshold and/or addition. Or, perhaps more useful, I'm going to try putting a variable resistor on the WOT wire (along with some programming) to be able to adjust the MAF scale slightly, or add or subtract from the WOT addition to be able to fine tune the WOT AFR for different engines.

One reason for the adjustment: MAFs don't all read the same. Generally, new/rebuilt ones read rich (more airflow), old ones lean (less). My tuning MAF is a few years old rebuilt.

PorKen

With your dual fuel engine, you should use the Plus chip. You must use the recommended NGK plugs with the Super chip, and the gap is too wide for LPG, AFAIK.

I don't know anything about the LPG plugs, sorry.

IIRC, GTS wiper arms have two springs. I might try to get some of those. Very unpleasant when the wipers float above the water at that speed.

The ohm-less plugs combined with the larger gap only add a few tq/hp (no easy way to up the HP anymore). The plus is in part throttle. The larger gap burns more of the mixture, so you need less throttle to go the same speed, it gets better mileage, and emission tests are cleaner. So far, no one has reported any radio noise. There are resistors in the rotor and spark plug connectors.

The resistor plugs are only good for a little over 0.035" before the engine 'fades' at high rpm, so I recommend a 0.032" gap (high end of the factory spec) for those.

billtool

I can hardly stand it...but guess I'll wait for Ken to work out the final final product. If they're better than the set I put in 8 or so months ago - I'll probably get into a bit-o-trouble...

PorKen

Bill - this is pretty much the final. Anything from now on will be minor (or experimental). I'm tired of chips...


The variable WOT input didn't work. Or I couldn't make it work properly. After driving home in disgust after a test run, I realized that the CO adjustment might work if I can find room for the math to use it to add or subtract from the WOT fueling. (If the MAF CO is adjusted plus or minus from 380 ohms to get a 14.7 AFR at idle, then it should apply to WOT. The CO adjustment normally only modifies the fueling slightly, not appreciably at WOT.)

BC

Ken where should I put the MAF pot in expectation of your chips?

What else can I do to prepare the engine. High miles, but running quite well. Maybe some vacuum maintenance. Your spark plugs.

PorKen

380 ohms is 'zero'. MAF should probably be rebuilt if it has lots of miles. Fuel lines. Intake refresh. Injector cleaning.


It may amount to nothing, but I wrote my longest piece of hex code to date today (47 bytes - woo hoo!) which adds or subtracts from WOT fueling based on if the CO pot is adjusted above or below 380 ohms. (Or simply adds a fixed amount if the octane loop is connected.) An initial test seemed to work. Have to do more comparison tests with my other MAF.

BC

380 Ohms between which pins?

PorKen

6 and 3 or 4 at the MAF, or 14 and 25 at the LH plug.



I'm expecting another MAF from Inj. Labs here in about a week. Depending on how that one logs, I think I'll send my tuning MAF in for a checkup. Of the rebuilt MAFs I have, they register the same at 2700, but they differ by a small amount at 6000. A tiny change in voltage has a large effect on WOT fueling at high rpms.

Mrmerlin

more MAF info

https://rennlist.com/forums/928-foru...ht=maf+setting

Darklands

Ok ! Than send me the plus chips.
The special lpg plugs are named laserline and are iridium ones.

PorKen

OMG, that was an ordeal! I could not for the life of me get rid of this infrequent stutter in the V3 chip. After trying basically every combination, the only thing I can think of that caused the error is a worn out binary. I made many thousands of changes to the same file - somewhere there must have been a tiny error. I started with a new x721 binary, applied all of my changes, and the stutter disappeared. In trying to squash that bug, however, I learned a lot more about what the code does, and made the overall chip better.

I've added code (>50 bytes!) that changes WOT fueling based on the CO adjustment to compensate for the range of MAFs out there. (MAFs vary a lot.) If you adjust for 14.7:1 AFR (λ=1) at idle (Blink'r), IE the stock CO setting, the difference from 382 ohms will be added (or subtracted up to a limit) from the WOT fueling to keep a target WOT AFR of ~12.5:1 from 2500-6000. The LH 'octane loop' will make the WOT mixture a little more richer if needed, eg. if you need to run Plus with the Super chip. (FYI, after more testing, there's no restriction on spark plugs for either chip.)

The 'final' chipset has no caveats, runs great straight from a cold start...pretty much acts like a factory chip until you mash the throttle. When cruising, it takes just a tiny bit of throttle to glide along (you can putter along at very low rpms, too). Full throttle is deceptive in that it's so smooth, you hardly realize the speed you're accelerating at. I luv my '86.5 auto with it (not just because I'm so tired of testing in the 5-speed), because it glides like a ZiL, but goes like katyusha when I puts pedal to floor.

svp928

Ken, fyi- I just passed smog with your chips, no problem at all. Just a tailpipe test, no rolling dyno.

I'll be happy to test the new ones if you want!...

Great work!
Steve

Don Carter

"blah, blah, blah, The 'final' chipset has no caveats, runs great "!

Thanks Ken, first part was over my head, but glad you understand it. As I've mentioned to you, I get the stutter occassionally, no big deal really, but will be glad to have it gone, and the chips improved once again.