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ANYONE w/ knowledge on the 1G to 2G MAS conversion HELP!!!!!

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dsmtrance

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Discussion starter · #1 ·
I am on my second 2G MAS. The first one tripped code 13 (Intake Air Temp Sensor) and code 25 (Barometric Pressure Sensor) to start off with. Then it also tripped code 12 (Air Flow Sensor). Now ALL 3 of those codes are MAS codes (not only that they are the only 3 MAS codes listed in the code breakdown!). So I figured it HAD to be a bad MAS. Well, I replced the MAS with another 2G MAS and ALL the codes went away...for about the last day or so. Now I am again flashing code 13!!! So far that's the only one.

My question is...is there anything else that can trip those codes? Would'nt likely be another bad MAS would it? Is there any particular wiring that I should look at (either MAS related or AFC related?????). I have another post on here as well that may shed more light on this. It relates to this.....The car "bucks" HARD under any type of even slightly hard acceleration and my idle is either ALWAYS very high (2100-300orpm) OR it will constantly surge (1100-1500rpm) on me. WHAT THE HELL IS GOING ON!!!! Someone, anyone, please help if you can! THANKS
 
#4 ·
Do you have some type of heatshield around the mass to keep the hot air away from the engine and radiator fans? It might be possible that the constant high intake air temps could trip the intake air temp code. Hot air blowing on it from the radiator fans could cause erratic idle......also disconnect the battery for a few minutes to reset the computer and see if the code returns.
 
Discussion starter · #5 ·
No Shit? Not having a heat shield around the MAS could actually cause those problems? I did'nt think about that. I have heard that 1G's (especially 91's) have been said to get "unusually" hot under the hood compared to other year DSM's. Not that they run any hotter engine (coolant temp.) wise, they just let off more heat under the hood. I don't doubt it either. It seems like my 91 gets 2-3x as hot as my 97 GS-T or my 92 AWD ever did under the hood! Hell, maybe I should rig something up for the MAS to block some of the heat. Thanks for throwing that out there. Damned if it would'nt kill me if it was something as simple as that! Any other ideas are still welcome.

Just one quick thing. The S-AFC hooks up the same regardless of whether or not you are running the 1G or 2G MAS on your 1G car, right? Because I have had the AFC hooked up since my Blaha MAS and all I did was remove the Blaha and put the 2G MAS on. Just wondering.

And last of all, I have seen people posting their AFC settings (mostly for 2G's) and mine seem to me to be VERY much on the rich side compared to what I've seen. On the LOW settings I have like +20% at 1000rpm, +10% at 2000rpm, and then like +2-+4% from 3000-7000rpm. On the HIGH settings I have like -10% at 1000 and 2000rpm, and then gradually go from 0% at 3000rpm to about +8% at 7000rpm. Do those sound way too rich for my fuel setup (Walbro 255HP rewired, 660's, and the Spoolinup.com AFPR)??? The only reason they are so high on the LOW side at 1000 and 2000rpm is b/c that seemed like about as low as I could go to get any sort of reading on the A/F gauge (I did'nt want to be too lean at idle). Also, my FPR is set at like 36-38 psi as well. Is that too high? I was thinking maybe I should try like 30-32 psi??? Anyone have any insight for me? Unfortunately I have NOONE in my area to help me out with all this!!!
 
#7 ·
dsmtrance said:

Just one quick thing. The S-AFC hooks up the same regardless of whether or not you are running the 1G or 2G MAS on your 1G car, right?
Click to expand...
The same.

dsmtrance said:
Because I have had the AFC hooked up since my Blaha MAS and all I did was remove the Blaha and put the 2G MAS on.
Click to expand...
Car ran fine before right? For the error code check your wiring. All connections are soldered, right?!

dsmtrance said:
LOW settings I have like +20% at 1000rpm, +10% at 2000rpm, and then On the HIGH settings I have like -10% at 1000 and 2000rpm,
Click to expand...
With 660's and a 2g MAS I have no idea how +20% at idle even works without dumping raw gas out the tail pipe. Sounds rich to me, I would've bet closer to -20% And why are your Hi settings lower than your Lo settings for these low rpm ranges? That doesn't any make sense and can't be good. I think your bucking, surging and generally fucked up idle are simply your s-afc settings.

dsmtrance said:
Also, my FPR is set at like 36-38 psi as well. Is that too high?
Click to expand...
No, it's perfect. Leave it alone for now. Umm, wait a minute. Is that base FP with the vacuum hose attached or detached? For right now, disconnect the FPR's vacuum signal hose and set it at 37 psi. Stock, 1g, 5-spd. base FP. Then reconnect the vacuum hose.
 
Discussion starter · #8 ·
Hey Van....first, I've had the surging idle problem for as long as I've owned the car (about a year now). The TB and all it's sensors are the ONLY things that I have not changed at this point. As far as wire connections go I used aircraft environmental splices to connect the wires from the 1G harness to the 2G MAS plug. That won't work just as well?? Do I need to cut them and solder them instead? And FYI, the ONLY wires that I messed with were the ones on the MAS harness.

My AFC settings seem to be rich to me too. BUT, when I start to lean it out at 1000rpm on the low side the A/F gauge starts to barely even register (where as at +20% or so it will go from lean to stoich, following the idle surges...what I thought it was supposed to do). Am I wrong here? Should I try leaning the hell out of it (-10% to -20% or so) and take it for a drive?? What settings should I try to go with to start (any idea on a baseline to start from?)?

Lastly, my base FP was WITH the vacuum hose attached. I will set it at 37psi today with the hose off like you suggested and see if that does anything too.

ONE FINAL THING...I had my timing looked at and they said it was at 8-10 deg. Good, right? My question is, I SWEAR that it "LOOKS" like the cam gears are one tooth off from each other. That's just by looking at it though. I have an adjustable exhaust cam too FYI. How can I tell for sure if the cams are a tooth off or not?

Thanks for all the help!
 
#9 · (Edited)
Surging idle: BISS and ISC motor, check the FAQ's for set-up, testing info, etc.

About soldering: the vampire style connectors usually come loose and/or cause erroneous readings. With really low voltages and resistances like on the MAS sensors and O2 sensors, it truely is better to have them soldered. It makes for a much better connection with no increase in resistance or voltage drop and will stay put too.

Your AFC settings seem so rich to me, but every car is different. The 660 are like 46% bigger than stock and the 2G MAS is about 20% bigger/leaner; meaning more air for the same Hz count to the ECU. Just doing the math like that shows you should be at
-20% or so. -46% and +20%... Maybe you have a massive vacuum leak or does your Dejon intake have that extra intake port bypassing more intake air around the MAS? I would try and lean her out, at idle, in the driveway, just to see. You can always dial it right back up. :) You are correct about the bouncing O2 voltages at idle.

Yeah do the FPR adjustment right, and see if that helps any. If nothing else it will put it back to stock. Then once you get her ironed out you can try bumping the FP back up to 43 psi with the vacuum hose detached.

8-10 degrees advanced is ok. That's where I like mine.

You just need to line up all the timing marks to check if you are a tooth off. I think that I've seen a thread here that a few people have had good luck with the exhaust cam one tooth off. I don't know about that myself, but maybe try a search and see what was said.

I'd recommend that you get a datalogger asap. :)
 
#10 ·
Discussion starter · #11 ·
Just curious...is there anyone running the 2G mas on their car with a setup similar to mine that could maybe give me an idea on AFC settings??
My settings on the LOW side are like +20% (1000rpm), +10% (2000rpm), and then like +4% - +3% from 3000-7000rpm. On the HIGH side they are like -10% at 1000 and 2000rpm, 0% at 3000, +2% at 3500, +4% at 4000, +5-6% at 5000, +7% at 6000, and like +8% at 7000. Do those sound way off to everyone??? Just wondering.
 
#13 ·
I'm running a similar setup, although different turbo. I'm running a Frank 1, 660 injectors, Walbro 255 HP pump rewired, 2g MAS (all Honeycombs intact) and my AFPR is set to 48psi base(with the hose disconnected) to allow me to run 85% injector duty cycle to redline. My AFC settings in the high band from 5500-7k are about -17%. 20psi of boost on the street. My low settings are like -30% idle, -24% at 2500 RPMs, and -17% to 5500RPMs.

With the above setup, I've tuned to no knock, 26 degrees of timing max, and seeing about 1575 degrees EGTs at the top of 3rd.

Check your injector duty cycle/pulse width if you've got a logger. You may be still running pretty high duty cycles, even with 660s.

Get a logger, tune to knock and EGTs. O2s (for me at least) are useless. My O2s read around .80 at WOT with the above settings, on my '90 GSX.
 
Discussion starter · #14 ·
I have the money to get the shocks I've been saving for but should I go ahead and use the money to get the pocketlogger setup?? Will the pocketlogger setup answer all my ailing questions (idle probs., why I'm cutting out under throttle, etc)?! If so, then screw the shocks for now. :) I REALLY need to figure out how to get this thing running right first!!! AND SOON!

One other thing...it had been suggested that I get a heat shield for my 2G MAS. It was mentioned that the change in airflow (+ the temp) when the fans kick on could be disrupting the airflow and causing the MAS codes to trip. I have spal fans and noticed today that they do blow right on the damn filter when they come on and they blow hard too! Is a heat shield for the MAS filter a pretty good idea in this case? Could it possibly fix the tripping mas codes problem? Any ideas? Thanks for all the help so far guys. I REALLY appreciate it.
 
#15 ·
With the mods you have I bet you'd pick up a buncha power when properly tuned... Get the datalogger!!!
 
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#16 ·
dsmtrance said:
but should I go ahead and use the money to get the pocketlogger setup?? Will the pocketlogger setup answer all my ailing questions

Is a heat shield for the MAS filter a pretty good idea in this case?
Click to expand...
Yep, if not all of your questions, certainly most of them.

A heat shield and/or a cold air duct is always a good idea.
 
Discussion starter · #18 ·
OK...update!!!

I put on a new TB w/ sensors. It seems to have stopped the idle surging and seems to keep the idle rpm's constant at about 1150-1250 after it warms up (that ok?). I also made a "generic" :) but effective heat shield for the MAS filter and so far no MAS codes have reappeared. BUT I HAVE A NEW ISSUE...


Whenever I get on the throttle (EVEN JUST A LITTLE) I get this really loud "whistling" sond from under the hood. Just cruising it does'nt happen but the second I start to give it throttle it does. What the hell? Boost leak? Where? I've checked all my intake connections (all hoses and clamps). ALSO, for some reason I tripped code 43 (EGR, Cali only) on the way home yesterday. What the F*#@ is that all about??? I don't even have an EGR. It's been blocked off! Plus I bought the car in NY. It's not even a Cali car. HOWEVER, the TMO Stage II ecu I bought off the net may be a California model ECU (part number wise). I'm not sure. Could that be the problem? If not, what the hell will trip that code??????? And is it anything to be concerned about? I'm really lost on this one!
 
#19 ·
I get a whistling(maybe more of a high pitched whine) sound too...but only under full throttle...i guessed it was the turbo making it. I pressure tested my intake system and the only leak i found was a very small hisssing sound coming from where the throttle plate shaft goes through to the throttle cable on the throttle body. At $400 for a new TB i figured i could live w/ it...it was a very, very small leak. Check all the vaccum lines on the TB that you played with when replacing the TB for leaks. Pressure testing the intake system will reveal any leaks you might have. I'm not sure if the EGR has an electrical connection(i don't think it does) but if it does check to see if it is connected. Also check the vaccum lines that go to the EGR.
 
Discussion starter · #20 ·
MY BAD...I need to clear a few things up.

ALL emissions equipment on my car has been removed (which means ALL the vacuum ports on top of the TB have been capped off). This also means that the car does NOT have an EGR system anymore as well. The EGR has a blockoff plate on it on the intake manny. The car has also had the AC removed as well as the cruise control and balance shaft.


Now I have never tripped this code (43) before yesterday. And I have had the car for about a year. I am wondering if it because I "may" have a Cali. part # ECU. The TMO Stage II I bought off the net a couple weeks ago "may" be a Cali. part # ECU. I can't remember (although I think it is). Will this cause me to trip the EGR code? ANYONE know? I reset the ECU today (did'nt drive the car though) and the code cleared. Any help on this one would be appreciated.

Just one other thing I noticed today...my throttle % on the AFC does'nt go to 0% unless I give the throttle a good hard tap. If I barely touch the throttle the % stays at like .9-1.0%. I'm thinking that the spring on the TB is worn and is'nt letting the TB plate to close all the way. I don't think it's the throttle cable itself. Anyone with experience on this one? Just curious. It's not my main concern at this point. Thanks.
 
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