Low MAF Readings!!! This is killing me

[GetBoosted84]

Hi guys,

I'm having extremely low MAF readings on my current GT2860RS with a AEM Dryflow 3" cone filter running PES T28 software. I'm only getting about 10 psi at WOT out of my GT2860RS with no major boost leaks. Only getting 10 is more than likely being caused by my shitty Synapse wastegate but I have a Tial on the way to solve that issue.

I am having real trouble getting more power out of the setup. I checked for boost leaks and corrected one that I had but that didn't help me.

Block 032 is showing:
At Idle,-10-10% = -1.1
Partial Throttle,-10-10% = -4.6

Here is some of the information i just pulled from blocks 003 and 031 in second gear:


The PES file calls for a oem A4 MAF to be used in conjunction with a 2.75" ID housing (TT225 housing meets the requirement) and I am using that exact setup.

What are some things I can look at?
* Exhaust leaks? (I have a small leak somewhere in the exhaust)
* Get a different less restrictive air filter (AEM filters down to 1 micron)?
* Something else?

Please help me

[mike-2ptzero]

Its going to read low if you can only make 10psi. IIRC another member had the same issue with that same WG and ended up going to a Tial.

[GetBoosted84]

Its going to read low if you can only make 10psi. IIRC another member had the same issue with that same WG and ended up going to a Tial.

I will be so happy if it is just a fault of this crappy wastegate. Their BOV is awesome but their wastegate is junk IMO.

Is there anything else I can check until I receive my replacement wastegate?

[mike-2ptzero]

I will be so happy if it is just a fault of this crappy wastegate. Their BOV is awesome but their wastegate is junk IMO.

Is there anything else I can check until I receive my replacement wastegate?

I would just wait till you swap out the wg.

[GetBoosted84]

ok I'll wait and see what a tial gives me for my MAF readings.

That timing # from block 003 is really worrying me. I was assuming that my degrees of timing would be somewhere less than 13-14 under WOT. 30 degrees of timing does not look safe at all unless I am reading it wrong.

[mike-2ptzero]

ok I'll wait and see what a tial gives me for my MAF readings.

That timing # from block 003 is really worrying me. I was assuming that my degrees of timing would be somewhere less than 13-14 under WOT. 30 degrees of timing does not look safe at all unless I am reading it wrong.

Well the timing is high because your not producing any boost or load on the maf/engine. Thats also why your 02 readings are still lean. Everything is related to the fact that your not producing any real boost. You can log block 002 and see what your load readings look like.

[GetBoosted84]

Ok that makes sense. Guess I'll just keep it out of boost till my replacement WG comes in.

Thanks again Mike. I'll post up my results once I get the replacement on there.

[GetBoosted84]

Ok, the new results are in...

I'm still not hitting over 200 g/s on my MAF after installing the replacement wastegate. I am hitting ~17 psi now but still don't have the MAF readings that I was expecting.

What should I try next?

[mike-2ptzero]

Why do you think your going to hit 200 g/s with the PES software and running just 17psi? Their tune is not rescaled for the larger maf so the g/s readings are always going to be on the low side.

Try logging block 002 so you can see what the load readings are at now. You might also what to turn up the boost a bit, 20-21psi is normal boost level for a pump gas street tune.

[Poopie]

you're running a larger ID maf so its supposed to a bit on the low side. like mike said, bump up the boost to 23is psi. Everything looks great so far. 3.6k rpm to 5.6k rpm in 10 seconds is pretty solid for 4th gear.

[GetBoosted84]

Why do you think your going to hit 200 g/s with the PES software and running just 17psi? Their tune is not rescaled for the larger maf so the g/s readings are always going to be on the low side.

Try logging block 002 so you can see what the load readings are at now. You might also what to turn up the boost a bit, 20-21psi is normal boost level for a pump gas street tune.

I was looking for 200 g/s because from my research I have found that others are hitting that with their GT28 setups so I was thinking that mine should also. Tony @ PES recommended running with the oem a4 sensor and a maf housing that is 2.75" inside diameter so that's why I'm running with that currently.

I'm waiting on another guy who is running the PES software to get back to me on what his MAF readings are also. Biketsai where are you :-)?

As far as the boost is concerned, I'll crank it up a little bit today so that I can see where that puts me and I'll make sure to log block 003 to compare from my prior run and I'll also log block 002 so I can see what the load readings are.

you're running a larger ID maf so its supposed to a bit on the low side. like mike said, bump up the boost to 23is psi. Everything looks great so far. 3.6k rpm to 5.6k rpm in 10 seconds is pretty solid for 4th gear.

Car is feeling pretty good and I am happy with the lambda values I am seeing. I wish I could have gone a little further with it but at 5.6k RPM in 4th I am going a bit fast.

I'm a little concerned about the timing although it is looking to be much improved from before. Not really sure where those values should be for me though so I guess it might just be me being paranoid.

I'll take the boost up a notch today and post my results.

[bassed]

Keep us posted Chris. Things are looking good though, which make me smile.

[GetBoosted84]

I'm so glad to finally be able to hit more than 10 lbs of boost consistently. It feels much better.

Gotta hit the track to see what kind of 1/4 mile time I am getting.

[Poopie]

different maf sizes and sensors will really screw up your timing maps. The timing the last log looks almost perfect so it looks like you got the right combo. What are your timing corrections? that should be block 20

[GetBoosted84]

different maf sizes and sensors will really screw up your timing maps. The timing the last log looks almost perfect so it looks like you got the right combo. What are your timing corrections? that should be block 20

Ok cool. I'll take a log of block 020 tonight and post my results.

[GetBoosted84]

I am thinking that my cylinder retard is pretty high (judging by the recommended cylinder retard listed here).

Other than that it is looking pretty good other than the fact that even when I turn up the boost it won't go above 17-18 psi so I am going to try another boost controller and see how that goes.

Got the latest logs:

Run 1:



Run 2:



Thoughts/Opinions?

[mike-2ptzero]

Yes your CF readings are very high. Your requested boost seems to be pretty high at low rpms, almost has that "k03 or K04" chip tune look to it.

[biketsai]

Chris, when I block 115 and 20, which values out of the 4 do you want me to select? Im also gonna make a video when I do my 3rd gear log on Thursday night. Sorry about the delay.

[GetBoosted84]

Yes your CF readings are very high. Your requested boost seems to be pretty high at low rpms, almost has that "k03 or K04" chip tune look to it.

Ok I'm glad I'm not crazy. Sucks that the readings are higher than they should be though.

I did notice that too with the specified boost coming on so much faster than actual but I wasn't really sure what to make of it.

Is this something I can fix with lemmiwinks or do I need to give PES a call and ask them what the heck is going on with their file?

P.S. - I fixed my boost issue, I used a different (simple ball valve) boost controller and got the boost to hold at 20 psi, spiking to 21 psi in 3rd gear.

[biketsai]

Ok I'm glad I'm not crazy. Sucks that the readings are higher than they should be though.

I did notice that too with the specified boost coming on so much faster than actual but I wasn't really sure what to make of it.

Is this something I can fix with lemmiwinks or do I need to give PES a call and ask them what the heck is going on with their file?

P.S. - I fixed my boost issue, I used a different (simple ball valve) boost controller and got the boost to hold at 20 psi, spiking to 21 psi in 3rd gear.

I really wonder how your turbo compares to my T28

[GetBoosted84]

I really wonder how your turbo compares to my T28

Betcha your requested vs. actual boost looks like that too since you are not hitting full boost till ~4k rpm. Once you have the logs we can confirm that but I'll bet your in the same boat.

Chris, when I block 115 and 20, which values out of the 4 do you want me to select? Im also gonna make a video when I do my 3rd gear log on Thursday night. Sorry about the delay.

When you log on vad mobile, it will log all 4 values... not just the two you can select to display on the screen so you can pick whichever ones you like. No worries about the delay. I have been working out some kinks in my setup in the meantime.

[mike-2ptzero]

At 20-21psi you should be seeing 140-150 g/s readings. Since your a 2001 the ecu is really using the maf to set timing by looking at the load readings and low load readings will cause the ecu to run more timing, the ecu is also using the 02 sensor to help it spray the right amount of fuel to hit the target AFR. So you might want to try a new maf sensor or a slightly smaller maf housing.

[GetBoosted84]

At 20-21psi you should be seeing 140-150 g/s readings. Since your a 2001 the ecu is really using the maf to set timing by looking at the load readings and low load readings will cause the ecu to run more timing, the ecu is also using the 02 sensor to help it spray the right amount of fuel to hit the target AFR. So you might want to try a new maf sensor or a slightly smaller maf housing.

I have a 3" ID MAF housing that I can try out. As far as the MAF goes, I only have a TT225 MAF sensor as a spare laying around (unless I can use that one) so I'll have to pick one of them up if the other 3" ID MAF housing doesn't get my timing readings down.

I'm still running the stock primary o2 sensor that has never been replaced also so could it be something I should think about replacing also with the MAF?

I'll double check my MAF readings tomorrow at 20 psi to make sure they are around 140-150 g/s also.

[biketsai]

Betcha your requested vs. actual boost looks like that too since you are not hitting full boost till ~4k rpm. Once you have the logs we can confirm that but I'll bet your in the same boat.



When you log on vad mobile, it will log all 4 values... not just the two you can select to display on the screen so you can pick whichever ones you like. No worries about the delay. I have been working out some kinks in my setup in the meantime.

So I dont need to select the two values in block 003? It will automatically do all 4 if I dont select anything? And that is what you want right?

[GetBoosted84]

So I dont need to select the two values in block 003? It will automatically do all 4 if I dont select anything? And that is what you want right?

Yep. I normally only select the two values so I can watch them on the screen if I am looking at the values instead of logging them like the long term fuel trims on block 032. I'll take whatever logs you got also .

[Poopie]

I don't think the tune was meant to use an N75 valve so you can ignore the desired boost values. Your timing correction is huge though. You are basically retarding any type of advanced timing the ecu is requesting. Maybe try disconnecting the maf and see how the load looks based off the map sensor.

[GetBoosted84]

I don't think the tune was meant to use an N75 valve so you can ignore the desired boost values. Your timing correction is huge though. You are basically retarding any type of advanced timing the ecu is requesting. Maybe try disconnecting the maf and see how the load looks based off the map sensor.

Gotcha (still have the n75 looped so it's not involved with the setup). I can try disconnecting the MAF tomorrow morning and do another log of block 002 and 020 to see what it does for me.

Tomorrow I will try to swap out the MAF housing also to see if that gets be a better result also.

[GetBoosted84]

Got the newest results without the MAF on the car in 3rd gear at 20 psi.

Looking better (minus the zeros for the MAF :-P).

Data:


Graphs:


So I am guessing I am going to need a new MAF judging by the better results?

[mike-2ptzero]

Yes you need a new maf, the timing CF looks much better. Notice now that your maf is unplugged your engine load readings are back up to normal numbers. How does the car feel compared to before with the maf plugged in?

[GetBoosted84]

Yes you need a new maf, the timing CF looks much better. Notice now that your maf is unplugged your engine load readings are back up to normal numbers. How does the car feel compared to before with the maf plugged in?

Ok I just bought a brand new MAF so that should help out my situation. As far as how the car feels without the MAF, it feels stronger but when I idle it is sporadic. Haven't checked my lambda so I can't say whether it is running rich or not without it (I imagine it is though).

I guess I'll wait till the replacement MAF comes in before I try out the larger MAF housing to see if that improves things a little more.

[mike-2ptzero]

Well a larger maf housing will make it worse, so you dont want to do that. You almost want to use a slightly smaller maf housing, so that your readings get higher and the ecu knows more air is going thru it.

[GetBoosted84]

Oh good point. I could try out the OEM MAF housing 2.75" OD so probably 2.50" ID (considering the TT225 MAF is a 3" OD and a 2.75" ID) to see if that helps.

Once I get the replacement MAF I will see if I can rig up the 2.75" OD OEM MAF housing to my 3" intake setup.

[mike-2ptzero]

Well try the new maf in your TT housing first.

[GetBoosted84]

Yeah, thats my plan. If all looks well with the TT225 maf housing then I'm not messing with a good thing.

[GetBoosted84]

Hi guys,

I bought a new MAF just in case but it looks like a can of MAF cleaner may have fixed my MAF issue. Still looks like I have a lot of correction on my cylinders but the MAF numbers are way higher now.

Here is a quick log I took this morning:

[biketsai]

I need to pick up some MAF cleaner myself.
Chris I will most likely be running the logs tonight, ill keep you posted.

[Poopie]

is it me or does it look like the afr is lean then jumps to rich? what is 100% injector duty cycle in terms of on time?

[GetBoosted84]

is it me or does it look like the afr is lean then jumps to rich? what is 100% injector duty cycle in terms of on time?

I noticed that too. Looks like it's getting to 14.3 so it's still not going over 14.7. I ran a couple other times also and at no point does it ever get over 14.7 which is good. Not sure if I want it to be that close to going lean though.

Aaron, what block can I get the injector duty cycle from? I can take a log of that today also.

[Poopie]

i don't remember man. its related to injector on time. mike posted up info a little back ago. maybe you need a new fuel pump or bump up the fuel pressure.

[mike-2ptzero]

Well its hard to see the change seeing that there is 1.21 seconds between readings. He would need to log less blocks to get a better reading or just log using a wide band unit.