Lower honeycomb removal

Took the lower honeycomb out the other day and added the 10K resistor to the mass air sensor(saw this mod on the main site) and found that my idle went up to about 1200rpm when the car is warm. The throttle cable is as far back as it can go and the Biss screw is in all the way. Any sugesstions as to why this is happening? Anyone else do this mod?(It's supposed to trick the computer into thinking that it is cold all the time thus supplying more fuel under high boost therfore no more fuel cut)

Sounds like 10K overdid it. If you can find a variable one- use it (you need more resistance then that). Now your car probably thinks its at Baffin Island. Good luck.

Gavin: Adding more fuel will NOT prevent fuel cut. Fuel cut happens when the Mas "counts" a certain amount of air going through it. It's all based on air flow, not fuel..

I think that fooling the car into thinking it's colder outside would bring fuel cut on faster. Colder air is denser, so the ECU will THINK there's more airflow than there actually is. Unless, of course you totally gut the bottom have of the mass (ie: Al Blaha's Mas mod.) This lets more "uncounted" air through, so you need to richen things up.

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

I assume the page you are reffering to is the Dimestore Fuel Cut Dispensor page. That page tells you to hook up a 10K pot (pot is short for potentiometer which is a variable resistor not a fixed value 10K). This allows you to varry the resistance from 0 up to 10K. I don't think the 10K was ever intended to be a value used... you should start at 0 and work your way up until you get some impovement.
Steve: this mod actually fools the ECU to think that it's at a different altitude, it does not make the ECU think the air is cooler. Since air is less desne at higher elevations the ECU will allow more air in if it thinks it's higher then it is. The pot is tied into the signal coming from the barometric pressure sensor and fools the ECU into thinking is higher depending on the resistance value. I think this prevents the true fuel cut only and will not prevent against min-fuel cut!
To combat minifuel cut you need to reduce the amount of air going through the metered section of the MAS... allowing more air through the unmetered section. This will lean your A/F ratio out so you'll have to richen it up somehow. You are on track about the cooler air requiring more fuel. You can trick the ECU to think that the air is cooler (through electronic manipulation) to richen the A/F ratio and then open up the unmetered section of the MAS to allow more air in that way to avoid fuel cut a little longer. I believe this is what Al Blaha does. I wish I had a schematic of the ECU so I could figure out a way to do this safely without destroying my MAS... I guess that's why we pay Al $150 US... he spent time and money mucking around getting his mod accurate. Doing this mod will also prevent true fuel cut!

Gavin.... replace the 10K resistor with a 10K pot then try again. You may prevent true fuel cut (a really rough cut out... like hitting a brick wall caused by the ECU cutting spark because it calcutlates that there is too much air to supply the correct amount of fuel) for a while but I suspect you'll hit mini-fuel cut (stumbling and hesitation caused by to much air in the metered section - MAS losing counts) around 15-16 psi or so. Most people hit the minifuel cut hurdle before reaching the true fuel cut hurdle.
Anyway I'm no bloody expert in this so if anyone finds any flaws in my logic feel free to cut me to pieces.

Later....

[This message has been edited by Mike Jackson (edited 09-08-1999).]

Thank's alot for the help and advise guys! I will try the 10K pot tonite and post the results.

Actually, I'm using the dime store fuel cut right now.. I think Gavin may have mixed the two mods up (Al Blaha's, and DSFCD) because of a resistor involved.

If you place a resistor (I used a 30k) in line on the ground wire to the pot the mod becomes a little "safer" to use.

This won't allow you to lean things out too much. Without a resistor the DSFCD can be REALLY sensitive.

One thing I've wondered though.. wouldn't it just be easier to use a smaller resistance pot instead of adding the resistor inline??

I've found with mine about 1/4 turn to the lean to give me 02 voltages around .88 and I don't hit fuel cut. (Up to 19 lbs anyway, havn't tried it further than that..)

I tried the DSFCD because I didn't like the idle I got, or the vacuum reading at idle (15 inHG) with my lower honeycomb out. Now, with the DSFCD and my lower honeycomb back in, I get a rock steady 750 idle, and 19inHG at idle..


Gavin: Did you add the resistor to the mas? If so which wire.. you may want to check with Chris Holmes and see if it's the same one Al Blaha puts the resistor on. There is a good chance your ECU now thinks it's colder out than it actually is, which WILL make you run richer.. but WON'T stop fuel cut.
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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird



[This message has been edited by Steve Kinnaird (edited 09-08-1999).]

I added it to the green with white stripe wire. Is this right?

I'm not sure which wire Al Blaha uses, but I don't think this is the route you want to take. In order to avoid fuel cut the way you're trying it, you'll have to let more unmetered air in.

I think what you are really looking for here is the dime store fuel cut defencer, as Mike suggested. I would remove the resistor from the MAS, and install a 10k pot with a 30k ohm resistor inline on the ground wire. I can't remember which pin number on the ECU the pot goes on, there is a page on it somewhere.. try a search in the digest archives for "dime store fuel cut". That's how I found it.

As I said, even with my lower honeycomb IN I get no fuel cut, or stumble (mini fuel cut) up to 19 lbs of boost.. Just make sure to keep an eye on your 02 voltages (if you've got an EGT gauge, even better..) because you CAN lean things out too much with this.

The DSFCD plays with the barometric pressure sensor in the MAS. The ECU thinks the car is getting less dense air than it actually is, so it "counts" less air. This does 2 things.. 1) pushes fuel cut up 2) leans things out.

I believe it also advances your timing, so you DO want to be careful with this mod.

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

Go here to find the DSFCD:
http://www.dsm.org/menu.epl?item=289&parent=1

Wait a sec... yuou specifically said you added the resistor to the MAS... where the heck did you find this mod? It isn't the DSFCD mod because it tells you to hook up the pot to the ECU. I guess my assumption that you were talking about the DSFCD was wrong. Late me know where the heck you found that mod, I'd love to have a read of it.

Later....


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Mike Jackson
92 Laser RS-T
-Set For Stun-




[This message has been edited by Mike Jackson (edited 10-08-1999).]

I was reading through the dsm trader a few weeks back and there was a guy charging $80us to "recalibrate" the mas air sensor to avoid fuel cut. Then this other guy came on and left a message to everyone letting them know that this was a rip off and then went on to say how he did his mod. He said to remove the lower honeycomb,and add a 10k resistor to the green and white wire coming from the mass air sensor plug. I did this and the car runs fine and I think pulls even harder than before at 15psi. The only problem I have had is the 1300-1200rpm in idle. I think it's in the performance section in the trader.

I think I might be a little leary of this. I'd try and find out exactly what part of the mass (ie: barometric pressure, intake air temp, etc..) this is affecting.

I'm, no expert on the mass, but it sounds to me like this may be a more "direct" route to the DSFCD. As far as I can tell the barometric pressure sensor is the only one you can add resistance to in order to get rid of fuel cut with no other mods.

Al Blaha's mod works by letting large amounts of uncounted air through the mass. The resistor he adds compensates for this extra air by making the ECU add fuel. It adds fuel not to avoid fuel cut (it's avoided because the mass "sees" less air going through) but to stop your engine from blowing up! (It will run WAY too lean otherwise.)

If what you've done is added 10k ohms of resistance to the barometric pressure sensor I think you'll probably be running to lean. What are your 02 voltages/EGT temps like??

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

Steve, I removed the resistor for now, but the lower honeycomb is still out. I went to Radio Shack this afternoon and bought a 10Kpot($2.79). But it does not say what terminal is what. Can you please tell me what is what so I can try this mod.(DSFCD)
I don't have an EGT gauge. How would I check my O2 voltage readings. Thank's again.

Ok, I assuming you've found the correct wire on the ECU plug here..

If you look at the pot, you'll see three pins sticking out the bottom.

The middle one (lets call this the "in") gets connected to the end of the wire going to the mass.

Either one of the end pins (your choice, this controls the "direction" of the pot. ie: turning the post on the pot towards this end will lower fuel cut, and richen your A/F ratio (up to stock)) gets connected to the end of the wire going to the ECU.

The remaining outside pin gets connected to a ground (this is the one you want the 33k ohm resistor in.. to help control the sensitivity of it.)

To watch your 02 voltages either get an A/F meter, or hook up a digital voltmeter to the 02 plug in the passenger side kickpanel..



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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

Gavin,

Go here to find out how to find your o2 wire to tap into:
http://www.myzero.com/electrical/find-o2.html

Connect the red wire from your voltmeter to this wire and connect your black wire from the voltmeter to ground. I just ran another wire to a mounting nut attached to the metal firewall inside the car around where the pedal are... then I ran that wire up to the voltmeter and attached the black wire from the voltmeter to it. The set your voltmeter to DC voltage. Under WOT you should see a value of about .09 to .094V... anything less then .09 is leaner then stock and involves some risk, anything less then 8.5V is very dangerously lean. As far as that mod goes you are on your own... I have no idea (yet) what that wire is hooked up to and what adding a resistnce will do to it. Good luck.
A volmeter gives you a much more specific number value then a A/F gauge so I always use one for trouble shooting. The A/F gauge is a nice safety feature for regular driving though... it can quickly alert you to a problem before you blow your engine ;-)
As far as the lower honeycomb being removed it should not really lean you out much, and I don't believe it will cause any other ill effects by keeping it out so if you can't get it back in don't fret too much. That is if you decide to give up on this mod and go back to stock.
I'm going to be trying a few things to get rid of my fuel cut over the next little while so if I do find a sollution I will post it here somewhere for all to see. I ain't gonna charge people a lot of money and keep the idea to myself. So keep an eye out over the next month for any news ;-)

Later....

Later.....

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Mike Jackson
92 Laser RS-T
-Set For Stun-




[This message has been edited by Mike Jackson (edited 11-08-1999).]

Okay so I have to add a 33k ohm resistor as well? And it's added to the ground? Pleae be patient with me guys. I know the wire I am splicing into is #16 on the plug. Do any of you guys know off hand what colour it is? I'm going to try this again tommorow evening and I will let you guys know what happens. So if you canm please get back to this message before 5pm tommorow it would be greatly appreciated. Thank's for the patience guys!!!!

Yes.. adding a resistor to the GROUND wire will make the range of adjustment smaller.

The higher the resistor value, the less "range" you will have.

I used a 33k ohm and find that I don't have to turn the pot much at all to avoid fuel cut up to 19 lbs..

Sorry, can't remember the colour of the wire off hand.. I'll try and find it when the wife brings my car back

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

Thank's again Steve! Are you running 19psi on the street? Are u using 94octane? I'll be trying the mod after work and I'll let you know what happens.

I run 17 psi on the street..

I was curious as to how much boost I could run before fuel cut hit with the DSFCD and got up to 19.. worried that my poor wee 14b was spinning at 8000000000000 rpm, I stopped there..


I think I've only put something other than Sunoco 94 in my tank a total of 3 times.. and then, it was only what I needed to get me home..
Lemme know how you make out..

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird



[This message has been edited by Steve Kinnaird (edited 12-08-1999).]

Gavin,

I saw the same post as you did and was kinda leery to try it but if it works for you...

Your idle is probably high b/c you don't have that nifty flapper door to lessen the airflow at lower RPMs. If I can find a good substitute for the door, AND I can find enough money to go buy a Dremel I'll do it too.

And yes, the mod is simple as splicing a resistor into the temperature sensor line and cutting away at the plastic. I don't know what the big deal is with keeping the mod such a hush hush secret. 'Free' mods should be kept free. How is this any different from drilling the BCS, removing the lower honey comb, etc? If I decided to experiment with this myself, trial and error'd and then eventually got it right and told everyone how to do it, would there be objection?

I dunno about you guys, but keeping mods secret seems to be against the whole DSM bang for the buck philosophy.

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Danny Yoo - Waaay over in Burnaby B.C.
1992 Eagle Talon TSi AWD
Running some where between 10.6 and 14.0

Here here!

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Mike Jackson
92 Laser RS-T
-Set For Stun-

I agree with the free mods thing.. but when trying them, remember to research them WELL.

I think what Gavin did was add the resistor, without "Hacking" the lower part of the mass. Just removing the lower honeycomb won't do it..

Gavin: if fuel cut is all your concerned about, then the DSFCD is a much easier way to go. But, mods ala Al Blaha (say that five times fast! ) will give you a few more horses as well...

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

Okay I tried the mod earlier today. This is what happened: I set the boost at 17psi and the car seemed to pull really good BUT I could not get a voltage reading off my voltmeter. Where should I have my voltmeter set at? Because of this I stopped playing around. Also what watt resistor did you guys use? I used a 33k 1/2 watt resistor. Is this right? And one more thing, does the o2 sensor plug have to be disconnected or connected? And the last thing, the barometric pressure wire is black right.(#16wire). Thank's again guys!!!

The volt meter should be set for 2V DC.

I also used a 33k ohm resistor.. no probs there. The + on the volt meter goes into the plug in the passenger side kick panel, the - to a ground.. If you're talking about the plug for the 02 sensor that's under the hood, yes leave it plugged in.

A small word of warning. I don't think the barometric pressure wire on MY car was black. (the '92's may be different..) BUT I do remember that the wire I thought was pin # 16 at first was black.. I then re-checked it against the diagram (The same one at the bottom of the website Mike posted about) and I had the wrong wire. I had counted from the wrong end. You may want to check yours again. Just make sure that you're looking at the plug the correct way, and count it again.. Kinda like carpentry.. measure twice, cut once!!

Look at the bright side.. 17 psi, and no fuel cut!!

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

Did the mod this weekend, among a few other mods, using the 10K pot and a 32K resistor. I believe the wire was green with a yellow strip... 90% sure anyway. Mod worked good... I could adjust it from .91V to .86V or so. I didn't leave it that low until I finish the fuel pump rewire that I'm in the middle of. Gavin, do you have the voltmeter set for dc volts (not the one with the ~ over the V, the other one). Set it for like 2V or something (not less then a volt). When I get to the track (Cayuga) this weekend I'll put the race gas in, and start upping the boost and see what happens I mounted the pot pretty cool in the car too Anyway good luck, let us know if there's any more trouble.

Later....

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Mike Jackson
92 Laser RS-T
-Set For Stun-

Gavin,

For orientation remember the image of the pin-out on the DSFCD page is of the ECU! Not the connector! If looking at the face of the connector it would be the mirror image of the image from the DSFCD. This should help you find the correct wire, and explains why Steve counted from the wrong end

Later....

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Mike Jackson
92 Laser RS-T
-Set For Stun-

Yep, that WOULD explain it.. (DOH!)

Anyone know what pin #21 does??

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

that's the Crank Angle Sensor connection.

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90 Talon AWD TSi
"Pressure is building up!"
90talon@wildmail.com

Thanx Dennis.. hmm.. in car timing adjustment??

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

OOOOOHHHHHH!! DOOOOOHHHH!!! Now that I know that I have to look at it as a mirror image maybe things will wotk out better eh. Just for further references though does anyone know the colour of the wire? I'll give it a try again tommorow. Thank's again guys!!!

90% sure it was green with a yellow strip on my car... I can check fro sure tonight for ya.

Later.....

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Mike Jackson
92 Laser RS-T
-Set For Stun-

I just undid this mod and my a/f ratio went from .85V (with 0 ohms on the pot) to .90V. Now I can turn the boost up a little more This mod combined with the Mike J (or Al Blaha) style MAF mod just made things too lean even with no adjustment (0 ohms). I think that resistor we added to the extra lead of the pot gave some default offset value so it leaned the a/f ratio by its self. Anyway if you've modded you MAF and you still have this exact mod and are running too lean... just undue it. Dennis & Steve... you listening?

Later...


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Mike J

-Quadcylla-
92 Laser RS-T, FWD

Vortex Racing
http://www3.sympatico.ca/robin.jackson2/HomePage.htm

[This message has been edited by Mike Jackson (edited February 28, 2000).]

Hmm.. thanks for the tip. I actually undid mine a while ago, BUT instead of completely removing the wire, I just joined them where the pot used to be. I wonder if the extra length is enough to give the extra resistance... Hafta check that out..

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1992 Eagle Talon Tsi FWD
Superiority after 60'..


ICQ # 9622983
www3.sympatico.ca/steve.kinnaird

Hey Mike I'm done screwing around! I'll have to make an appointment with you sometime when I'm free so you can do it . I'll let you know well in advaance. Thank's

Sure mon

Later...

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Mike J

-Quadcylla-
92 Laser RS-T, FWD

Vortex Racing
http://www3.sympatico.ca/robin.jackson2/HomePage.htm

How are you guys doing???

I got a 1G, 2.0L NT. I did removed the two tubes (Lower part of the MAF, No lower honeycomb on NT) and I was running lean, 0V...
Have a look at this page; http://www.lks.net/~ghislisa/DSMMod.htm

I did temporary rectify this condition by removing the vacuum line from the fuel pressure regulator to the intake manifold. The end result was more fuel pressure (extra 10 PSI)in the fuel rail. After this, the Air/Fuel Gauge reading became similar to what they were before the MAF mod. I'm in the process to install a 10K pot to the temp sensor in order to fool the ECU (Remember, my car is a NT, adding it to the barometric sensor will lean it more)

BTW;1G NT car have 37 to 39 PSI of fuel pressure in the fuel rail with vacuum at the fuel PSI regulator and 47 to 50 PSI without vacuum.
1G Turbo have 32 to 34 PSI with vacuum and 36 to 38 PSI without.

Any of you ever tried to swap your Fuel pressure regulator for a NT (I don't know if they fit but I would think so) In order to "Sweeten" the Air/Fuel mix???

Ghislain

Why didn't you just drill a larger and larger hole in the back of the one tube that is blocked off until you had a good a/f ratio? If you ended up losing your idle it would be easy to plug that tube back up. Just a sugestion for you NT guys.

Later...

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Mike J

-Quadcylla-
92 Laser RS-T, FWD

Vortex Racing
http://www3.sympatico.ca/robin.jackson2/HomePage.htm

Actually, what I did was to drill all four plastic "Rivets" out so I could put it back I winter time... I should be going back to the summer MAF configuration soon.

The next step will be to try to cut the area out to match the air outlet of the air can. Again as a "Back-up" I will make a "Restrictor plate" that I could be put in if the Air/Fuel mix is way too lean and can't be compensated for or when winter comes...

I'll see how the pot works... ;~0

Thanks for the tought.

Ghislain.

[This message has been edited by Ghislain (edited March 02, 2000).]

When were you running lean? At idle or cruise or wot? Hos was your idle after taking that section out...rough?

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Mike J

-Quadcylla-
92 Laser RS-T, FWD

Vortex Racing
http://www3.sympatico.ca/robin.jackson2/HomePage.htm

Have a look at the "NT MAFs" in the NT Forom for the ansewer.