Is This MAF bad?

[GeoTalon91]

After working on and off on the 91 1G Talon. I finally got it too idle a bit smoother, however I have a few questions, that perhaps a few of you can help me with.

First, I am curious if this MAF is bad, seeing as how the cardboard insulation is lifting off. (See Pic)

Should I leave it alone? Look for another MAF? Or take the Cardboard insulation off? For now all I did was just flatten the cardboard back up with my finger and left it in there.

The idle used to be very rough, but I changed some vacuum lines, and injector o-rings that were leaking. In the process I broke off one of the bolts that holds the fuel rail to the head, the one that is closest to the throttle body. Any ideas on a fix for this or should I leave it alone for now? I checked all injectors and o-rings with the car on and none of them are leaking so the seal is good (this may change once I boost though).

I also added a new boost gauge and an NSX Manual boost controller. While I was at it I adjusted the BISS and set the idle for about 900-800 RPM. (I still need to set the timing on the car).

At this point my main concern is the MAF, any thoughts on this?

Thanks

 

[Bojangles465]

i would just take the card board out, that wouldnt mess up the mass airflow signal or anything, it would actually let more air in if you think about it, allowing more air into the engine, or if you wanted to, you could do the 2g maf swap

 

[ChiTownHussla]

2g maf is a great upgrade. Look into it

 

[GeoTalon91]

From what I've read before, I'd have to upgrade injectors to install the 2G MAF.

I have a 3" GM MAF in case I decided to go with a translator at a later time. For now I want to get the car up to par wit the 1G MAF, seeing as to how Holidays are here it will be another couple of weeks before I have more cash to drop into the talon.

So removing the cardboard from the MAf would not be an issue then? I was thinking it would mess up the airflow or the air Charge temp signal.

If removing the cardboard causes no significant issue to the MAF then that is exactly what I will do tomorrow.

 

[NHerron]

If you actually got your idle to sit at that RPM (800-900) then you screwed up the auto idle system royally and effectively canceled out any effect the IAC motor once had on the engine. You may now experience hard starts depending on the weather and other problems.

The correct way:
1G BISS Adjustment

 

[GeoTalon91]

What would lead you to believe that I did not adjust the BISS as per the VFAQ guidelines in the first place?

 

[Bojangles465]

it wont make that big of a difference tbh im running 450 cc injectors with a 2g maf, it will make it a LITTLE bit lean, but not much, it wont make that much of a difference if you just slapped a 2g maf on temporarily until you got either 550 cc injectors or dsm link

 

[GeoTalon91]

What would be a safe boost setting on a 2G MAF with 450cc injectors?

I was contemplating going the 3" GM MAF along with MAFT translator route, but the 2G may be a cheaper route.

 

[NHerron]

What would lead you to believe that I did not adjust the BISS as per the VFAQ guidelines in the first place?

Welp. You said you got the idle to sit at 800-900... and VFAQ shows no such spec..?

FSM calls for 750+/-100 but when setting the idle you adjust for 750.

 

[pauleyman]

it wont make that big of a difference tbh im running 450 cc injectors with a 2g maf, it will make it a LITTLE bit lean, but not much, it wont make that much of a difference if you just slapped a 2g maf on temporarily until you got either 550 cc injectors or dsm link

You looked at your fuel trims? You should not run 450s on a 2g mas.

 

[GeoTalon91]

Welp. You said you got the idle to sit at 800-900... and VFAQ shows no such spec..?

FSM calls for 750+/-100 but when setting the idle you adjust for 750.

*Exactly*

1G Manual 750+/-100=650 or 850

I'm at 800-900 idles fine between both when engine warms up, call it 850..

Besides, technically you can adjust the BISS to sit at any RPM you like 750 would be ideal of course, but that does not mean many other do not have it set between 650-900.

 

[NHerron]

Okay, if you say so and the idle automatically jumps from 750 to 850 after ungrounding then I guess that's normal and you won't have any problems.

Just lettin ya know.

BUT no you cannot *set the idle where you like*. Maybe you don't understand the VFAQ quite right. Only with tuning software such as DSM/ECMlink can you properly alter the default idle.

The ECU looks at the engine RPM along with other inputs and judges if that is an acceptable RPM considering the other sensors such as intake air temp, coolant temp, if A/C is on, if power steering is clocked all the way to the left or right, etc. If the idle is too low or too high for a given situation, it commands the ISC motor to bypass more or less around the throttle plate, thus effecting idle. That's normal operation.

Now if someone adjusts the BISS to bypass enough air to bring up the idle to 900RPM, the ISC is now waaaay out of range and is basically totally closed, TRYING to bring the idle down. If you were to play with the BISS with nothing grounded, you will notice it effects the idle, but only for a second then the computer snaps back to it's desired RPM by adjusting the ISC. If you keep adjusting the BISS you will eventually get out of the ISC motors range rendering it totally useless to controlling idle. That's because the ECU itself wants to keep the idle AT 750 and will never change it's mind unless persuaded by changing it's operational parameters deep within the ECU. ECM/DSMlink can do this.

The BISS is not like setting idle on a carbureted engine. All it's for is to keep the ISC smack dab in the middle of it's adjustment range for maximum flexibility for each daily situation.

 

[GeoTalon91]

Okay, if you say so and the idle automatically jumps from 750 to 850 after ungrounding then I guess that's normal and you won't have any problems.

Just lettin ya know.

BUT no you cannot *set the idle where you like*. Maybe you don't understand the VFAQ quite right. Only with tuning software such as DSM/ECMlink can you properly alter the default idle.

The ECU looks at the engine RPM along with other inputs and judges if that is an acceptable RPM considering the other sensors such as intake air temp, coolant temp, if A/C is on, if power steering is clocked all the way to the left or right, etc. If the idle is too low or too high for a given situation, it commands the ISC motor to bypass more or less around the throttle plate, thus effecting idle. That's normal operation.

Now if someone adjusts the BISS to bypass enough air to bring up the idle to 900RPM, the ISC is now waaaay out of range and is basically totally closed, TRYING to bring the idle down. If you were to play with the BISS with nothing grounded, you will notice it effects the idle, but only for a second then the computer snaps back to it's desired RPM by adjusting the ISC. If you keep adjusting the BISS you will eventually get out of the ISC motors range rendering it totally useless to controlling idle. That's because the ECU itself wants to keep the idle AT 750 and will never change it's mind unless persuaded by changing it's operational parameters deep within the ECU. ECM/DSMlink can do this.

The BISS is not like setting idle on a carbureted engine. All it's for is to keep the ISC smack dab in the middle of it's adjustment range for maximum flexibility for each daily situation.

I applaud your explanation as I have learned something new today!

Will go and set the BISS again and see if it will stay at 750.

Originally I was very concerned with the fact that the cardboard from the MAF was falling. Only one person on this thread has told me to take the cardboard off as it would have no ill effects on the engine.

Can anyone else confirm this? I want to be sure before I take the cardboard off and then run into a bigger problem.

Thanks

 

[NHerron]

No problem, that's one thing that will throw things off so it's good to double check it.

Sorry I can't be of help with the cardboard, but FWIW, I've never seen that during my time on Tuners and certainly not on my 2G MAF. Is it glued down to anything? Does it look like a factory thing? If that was stock I'm sure I would find something in a quick search but I didn't find anyone with the same question. So for some reason you have cardboard jammed in there...

 

[undefined0000]

What's the big deal about the idle? Am I going to get flamed for running an 1100 idle? Lol.

 

[ChiTownHussla]

I don't recall that on my 2g maf but I rly think that you are ok if you take it off

 

[LouieAWDTSi]

I don't remember having cardboard in my 1g maf when I had my 92 awd tsi so I'd guess take it out. You could always throw it back in if it changed anything after you have taken it out. gLuck!

If you are looking for a cheap 2g maf, PM me...I have an extra.

 

[NHerron]

What's the big deal about the idle? Am I going to get flamed for running an 1100 idle? Lol.

Haha, well not if you get it done correctly...wouldn't be a bad idea for the winter months

 

[Spanky_DSM]

What's the big deal about the idle? Am I going to get flamed for running an 1100 idle? Lol.

RIGHT!!! haha,


I run my idle at 1000.

Its just more pleasing to my eyes to me

 

[undefined0000]

That and having poly/solid mounts makes it a lot less shaky. 750 with a BSE would probably be a 10 magnitude earth quake

 

[GeoTalon91]

No problem, that's one thing that will throw things off so it's good to double check it.

Sorry I can't be of help with the cardboard, but FWIW, I've never seen that during my time on Tuners and certainly not on my 2G MAF. Is it glued down to anything? Does it look like a factory thing? If that was stock I'm sure I would find something in a quick search but I didn't find anyone with the same question. So for some reason you have cardboard jammed in there...

Its more like attached but not glued just kind of layered on top and it looks like it was factory made, either that or someone really took there time to cut it out perfectly.

I've tried searching for something similar to this and could not find anything on it either.

Need to try and set the BISS again. I set it and at time it will sit nicely at 750-800RPM then it likes to sit at 1000 and on the next red light it will sit at 750 once again.

Also, the car is stuttering at about 3000 RPM under boost, may be a bad fuel filter not sure yet though.

If I ease on over 3000 RPM it will climb nicely up to 5000RPM but if I gun it under 3000RPM it feels almost like fuel cut and I'm only only boosting 10lbs according to the Prosport gauge, the stock guage says 14 but I dont trust it.

I think the cardboard on the MAF may be the root of a few of my problems.

I don't remember having cardboard in my 1g maf when I had my 92 awd tsi so I'd guess take it out. You could always throw it back in if it changed anything after you have taken it out. gLuck!

If you are looking for a cheap 2g maf, PM me...I have an extra.

If I take it out I'd have to tear it from the middle. Its almost like soft cardboard/sponge material. IF anything I would say it would be there to absorb heat but I dont see how that would make sense.

 

[NHerron]

Remember when the car first starts up it idles high for a bit. I can't remember how long it's normal but after some time it settles. And don't forget about coolant temp, it should be warmed up.

Another option to try is just buy a used stock 1G one off the classifieds, they're certainly cheap enough

 

[GeoTalon91]

Just got back from work a few days ago.

Took out most of the cardboard from the MAF the rest is glued to the Honeycomb part of the MAF. Hopefully I did not mess anythign up!

Adjusted the timing to 5* BTDC. Set the MBC to about 9PSI. And "tried" setting the BISS.

On initial start up the car revs to about 1500RPm then dies, no problem had been doing this before I removed the cardboard as well. So I think this issue is related to something in the throttle body perhaps.

After the car is warm the idle stays at 900RPM

Before I had set the timing the car would bog anytime it saw boost over 3000 RPM now it pulls very hard and feels like its making great horsepower at the 4000 RPM range, I have yet to floor it past 5000 RPM.

 

[NHerron]

Try a boost leak test and spray real good around the intake manifold. Sounds like you have a good sized vacuum leak. Or if you can't do a BLT, run it and spray brake cleaner around the IM. If the idle raises then you've found the leak. But that's really not the best test, plus it's hard to tell on some leaks.

I bet once it warms up to op temp it gets back to normal right?

 

[9secSLC]

What he said^ and take that cardboard out!