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'96 GSX said:
I have. There were only discussions on a fix coming out but never an actual fix. Perhaps I missed something, but I don't think I did.

-'96 GSX
i had that problem but i was running TOO rich, the baro sensor wire mod was screwing up the signal i was wrunning 1.0 02's and hitting fuel cut from maxing out the 450s. i asked mike about it he said just to lean it out so that's what i did.
 
Baro Issue:
Some 2G computer have a different input impedence than others this causes the Baro to read low. We weere not aware of this when we made the unit initially. Our test cars did not show this. We have a fix you need to contact me and send me the unit.
Mike Licht
Full Throttle Speed & Style
 
And to elaborate further, a low baro signal results in a lean condition, so be sure you are datalogging if you are using one of these. All zeros could actually be 20-25% lean. Most people with this issue will have the knobs 4-5 clicks too rich (compared to where it "should" be for the injectors being used) as a result to compensate.
 
Ive heard of us 6b swapped 2G people that have used them, sometimes they are set too lean and people have melted pistons and havent known why.

I have the pot mod on my 2G to stop the random misfires, and have my MAFT setup at the house. It'll be interesting to set all of this up and see what happens.
 
Well here is an interesting tidbit. IF you do have a MAFt that puts out the low baro signal, about 3.2 volts, it corresponds to somewhere near 6k feet altitude IIRC. This is basically what 1gina2g poeple are trying to achieve with the baro wire mod ;) If you are in this situation (random misfire with 1gina2g swap) and have the "bad" MAFt, I would leave it "broken" and get fuel tuned back in with the AFC or whatever fuel tuning device you use. You shouldnt have any random misfire issues. Its not adjustable with the MAFt like a pitentiometer is, but hey, there is no wiring to do :) Of course you are responsible for anything that happens if you try this, be sure to datalog everything. Just thought it might be an interesting idea to the very few poeple that might find themselves in this particular situation ;) As a side note, I HIGHLY suggest anyone with a 6 bolt swap get DSMlink. Its the only "correct" way to get rid of the RM crap using a stock ECU...
 
Discussion starter · #86 ·
Today was a great day...

I installed even bigger 720 ND injectors and upped the base fuel pressure to 43 psi. Then I installed my eprom ecu and a Keydiver chip and zeroed out the s-afc and all of the MAFT dials. Took her out and immediately ran her hard. Perfect timing curve and she is not fighting herself up top because of too much timing advance.

I had a friend in the car, he told me that he'd have to go big block to be able to keep up with me. :D He noticed the difference before and after the chip install and finally realized what I was really talking about all this time. Now she pulls like she was meant too!

I love the MAFT, what it does and it's performance, but if you need big injectors and big fuel pressure you will hit a wall just like you do with the s-afc. Pulling too much air signal can be bad. The Keydiver chip and an eprom ecu is one way to conquer this.
 
van,
did you get the keydiver programmed for 720 or did you have it done for 750 or 780? i've heard of people going higher on the injector size compesation with "easier" tunability.

i'm also running a maft. and i'm about to order my keydiver chip to replace my tmo stage 3. i need a higher rev limiter, idle speed, and of course injector compensation. just trying to figure out if i should get it programmed for 780's or maybe even 850's. i'll be running 750's.
 
Discussion starter · #88 ·
720's at 43 psi base pressure.

I left it alone and matched them so that when I add race fuel and turn up the boost it should keep me in the same timing map.
 
Nice Van..

Van said:
if you need big injectors and big fuel pressure you will hit a wall just like you do with the s-afc. Pulling too much air signal can be bad. The Keydiver chip and an eprom ecu is one way to conquer this.
Good to hear. I'm planning to go the same route but stick with my 650cc's instead. Now I need an EPROM ECU..:eek:


Nice Numbers Brent btw.:)
 
Discussion starter · #91 ·
After a couple of days now and fuel trims going steadily rich, I'm still having to mess with the MAFT base dial some to lean her out a little. Dammit.

More to come as I find it. ;)
 
Van, Does the key diver chip compensate for higher fp since we have 36 psi stock and people up it to 43 psi? Or did you tune that with the safc or maft? sorry about posting in here but i figured you would notice this faster than the other thread.
 
Discussion starter · #93 ·
You'll need to tell Jeff what base fuel pressure you want to run the injectors at when you order the chip. Then he figures that into the fuel correction in the eprom.

You may still have to fine tune your set-up a little bit with the s-afc though.
 
Discussion starter · #94 ·
Been awhile... :D

Just new info relevant to the MAFT and some MAFT users.

I've fought part throttle knock for awhile now. It totally kills all power in first gear and sometimes second gear when taking off from a stoplight. The knock gauge will sometimes just peg while just quietly cruising on the freeway. I mean 43 counts right now, with no throttle impetus, the exhaust note changes, power gone. Not phantom knock, as leaded race fuel eliminates my knock.

I've used quite a few different Keydiver chips with Jeff totally kicking ass trying to help. I've tried slightly different fuel pressures, etc. I now have a chip in that seems like it is right on the money, but I still have the knock. For those just tuning in, I'm using a Keydiver chip in my ECU to eliminate the excess timing issues caused by running 650's/720's with the MAFT as outlined previously in this thread.

Today I reset my base timing. It was set at 6-7* until today. I backed it down to 2-3* this afternoon and now have a ton less knock.

Pertinent mods are, ND720's, 43 psi base fuel, 3" GM MAF in blow-thru, MAFT 2.0 chip, Keydiver chip with compensation, FP3065, 2-216 IC, afpr, Magnus Sheet metal intake, etc. The honeycomb has been removed from my MAF.

About the MAFT set-up. If you have the 2.0 MAFT and you got your fuel trims normalized, watch the O2 trim as you just get into the throttle (before it goes open loop) and adjust the Mid dial according to what you're seeing. Leaner is better, but you don't want it going to 145% or something like that. With the s-afc, you'll want to isolate the throttle position it happens to you at and then "box" it in and move the fuel accordingly. I'll let someone else post more info about this as I'm currently trying to utilize the MAFT for the most part at this time.

I just did this today and will post back in a couple of days after I see if it holds true for awhile, but initial results were promising. So I wanted to get the info out there for others to try.

For newbs: To check your 1G's base timing, you need a timing light and a jumper wire. Plug in the timing light, make sure your logger isn't plugged into the diag port by the fuse box, then uncap the timing lead by the battery and ground out the single terminal with the jumper wire. Set the timing by rotating the CAS at the valve cover, just loosen the two 12mm bolts/nuts there to rotate it a little.
 
Just to add to this, I had also been fighting ALOT of the "phantom knock" experienced with the MAFT + Keydiver chip. Basically 43 counts would just come out of nowhere. I could be driving on the highway (cruising - constant throttle - in vacuum) and Baaap!! It sets in. It was very frustrating and I honestly believed I got a bad chip since swapping the chip cured all this.

Unlike Van's scenario, mine could not be eliminated with race gas.
Replacing my fuel pump fixed this issue and the car runs much better now. :)

My major mods include: FIC 850cc's, AFPR & 37psi fuel base pressure (Jeff O. recommended,) GM-MAF (descreened)blowthrough, MAFT Ver. 1.3, SBR-GT-12 turbo, DT FMIC etc

With my idle set a few clicks lean and the WOT 3 clicks rich(er) I experience no knock. (That was impossible before) My base timing is more than 5* so when I readjust it back to stock, I should easily run around 20-22psi with minimal knock on pump 93. Now, if it can only stop raining. :mad:
 
I guess I am not the only one trying to fight "phantom" knock.
I have 660's, 190lph f/p, FMIC, 264's, GM MAF/MAFT, Keydiver chip.
I also get knock upwards of 43 counts, seems like for no reason.
I could be just crusing, and bam, my knock goes up.
Sometimes it happens all the time and sometimes it's fine for days.
I've replaced plugs, wires, o2 sensor, will be getting a new knock sensor and a fuel filter.
With the keydiver, I got the timing under control, WOT seems to be fine, but crusing isn't.
I am inclined to think it's the MAFT/GM MAF set up that's causing it.
My base setting is 3 clicks leaner, the idle is 2 clicks rich, and so is MID and WOT.
With these settings, my low trim is around %92, mid %103, and high is at %82 :confused:
I guess I have to lean it out a bit more. Strangely enough, whenever I change the base settings on the MAFT the phantom knock goes away for a few days, and than it comes back.
I'll just fix other things for now and not worry about it too much.
http://users.wpi.edu/~ktarry/dsmtech/phantomknock.html#contact

I've read that people have added this code to the Keydiver 1G chip. I believe Jeff O. (that's his name right?) will do it if you ask.

This is supposed to work really well.
Has anyone used this with any success? I am a bit reluctant, but maybe this is the cure. If replacing the knock sensor does not make it go away, I think I'll go ahead and try this solution.

For the knock meter using the stock boost gauge, anyone else sees it move up and stay there even though the logger shows no knock?
 
With my 850cc's and everything zeroed out, I actually run slightly rich with my 850cc's. Not too bad though with my GT30 turbo. At around 20 psi I actually have only the MID and WOT dials at 1 click rich"er" and I get 0 knock through my pulls. :)

You don't really need to mess with the aux. dial if you are not running nitrous imho.

I also seem to be getting some of that PK back. :eek:
 
Count me in for another case of MAFT + keydiver low throttle knock. Same symptons as everyone else, knock out of no where. Seems like Full Throttle Speed should take some responsibility and really look into this problem seeing how they can't keep them in stock.
 
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