When Boosting Lose All Power

HBWaterfowler · Jan 13, 2009

Hello,

I just (yesterday) put an MAFTranslator on my 1G Laser, and the GM MAF is mounted between the I/C and TB and my BOV is venting.

The car idles great, and also good during non-boosting RPM. The problem is, as soon as I see boost (1psi) if I don't shift, then the car will feel like someone took it out of gear (complete power loss). It will only get up to 3-4psi at the most, and I have held the gas down when it did this a few times and it never recovered, but I did hear some wissle/hissing noises outside during this symptom.

I think it could be two things, but I'm still a newbie:

1-The Dejon upper i/c pipe that fits the GM MAF between the TB and i/c does not match up well with the intercooler very well (a rubber hose is used as a reducer to match up with the i/c. So I think it could be that I can re-do the hose clamp and see if that helps.

2-I'm venting my BOV into the atmosphere and it seems like air is coming out of the BOV at idle, low rpm. So maybe the BOV is opening when it shouldn't? I don't know. I'm hoping it's just the hose that's leaking.

One person at my friends shop mentioned it could be a fuel cutt, but I don't think so personally.

Thanks!

I'm trying to get this finished ASAP! so if you have any questions, let me know and I will be more then happy to check things. I also have a Scanmaster for data logging and should be able to get you some information from that.

Pekkle · Jan 13, 2009

Sounds like boost leak.

210 dsm · Jan 13, 2009

you cant be cutting on fuel because your not even getting boost, theres only fuel cut if your pushing TOO much air and the fuel system cant deliver it. your not pushing in air from boost at all. and i dont really understand your situation with the Dejon tool part ,but it dosent really matter because my opinion on it is the same ether way, get it on right! ... all your pipes should fit perfect in all the couplers. from the turbo outlet to the throttle body. if you doubt it from sealing in any way then fix it. as for the BOV theory, it sounds correct according to your symptoms but the questioin is. is it really staying open?...

well theres only ONE thing for you to do and it will answer both #1 and #2 in your original post. like homeboy said do a boost leak test. doing that will for tell you what the problem is or isent.

No_Skillz · Jan 13, 2009

210 dsm said:
you cant be cutting on fuel because your not even getting boost, theres only fuel cut if your pushing TOO much air and the fuel system cant deliver it. your not pushing in air from boost at all.

As a matter of fact, most cases of fuel cut are from boost leaks and a massive leak could cause little/no boost. Air is being pushed past an airflow sensor but is not reaching the motor. Since with a turbo application the intake is pressurized, there is a huge amount of air lost. The ECU thinks this air is still reaching the motor and cuts the fuel because it thinks there is too much boost.

live4my4g63 · Jan 14, 2009

boost leak test to make sure all pipes are on, if your only getting 1lb then its not getting anymore boost to the motor. check the j pipe and intercooler pipes

210 dsm · Jan 14, 2009

live4my4g63 said:
boost leak test to make sure all pipes are on, if your only getting 1lb then its not getting anymore boost to the motor. check the j pipe and intercooler pipes

this pretty much summarizes everything i just said

210 dsm · Jan 14, 2009

No_Skillz said:
As a matter of fact, most cases of fuel cut are from boost leaks and a massive leak could cause little/no boost. Air is being pushed past an airflow sensor but is not reaching the motor. Since with a turbo application the intake is pressurized, there is a huge amount of air lost. The ECU thinks this air is still reaching the motor and cuts the fuel because it thinks there is too much boost.

so in short terms, boost leaks = BAD :notgood:

HBWaterfowler · Jan 14, 2009

The part about the Dejon I/C pipe, is where it meets with the intercooler.

The size of the dejon pipe is diffrent then the size of the intercooler outlet, and they offer a rubber hose ment to use like a collar to match the hose that connects the two.

I wasn't to happy with how it was arranged. But the pipe was held on very tight, I could not move it at all, so I figured it was fine.

As for the BOV, I'm not sure if it's staying open. It seems to be working fine, it's just the that it's not being recirculated. It seems to not be fully closed at idle or pre-boost.

Thanks for the comments!

:laser:

SupremeDsm · Jan 14, 2009

Make sure that you got the GM Maf set up past the BOV!!

HBWaterfowler · Jan 14, 2009

I do

Jpierre655 · Jan 14, 2009

I bought a maft and installed it in the same location and my car it would crank and idle fine but would not rev past 1500rpms then die down and rev again. i moved the mass before and after the turbo same problem i even tried another mass, same problem. so i called slowboy which is were i purchased it and they said to send it back. Something was wrong with the software or something they said but when i got it back it worked great.

Definately check boost leaks first i also have had a boost leak in the past that every time i got on the gas over 30% as soon as boost started the car would fall on its face. also check to see if the mass is turned the right direction

dsmfa9nutter · Jan 14, 2009

Get a good silicone reducer (siliconeintakes.com) with t-bolt clamps to ensure a good seal. Make sure the maf is aligned correctly when you put it back on.

viperlp01 · Jan 14, 2009

Your running rich. It is not a boost leak. I mean the only leak you can have on a maft setup is your intake manifold. I bet money that your settings are off and you are running pig rich at wot... You need to tune it alittle better.

210 dsm · Jan 14, 2009

but before you do a good tune you need to get your "base" tuning done correctly which is the AUX and BASE dials in the GM translator.its just to calculate for injector size, use the chart that came with the translator. also make sure the four MODE switches are set for your setup.
and yes make sure the internal divider in the actual maf if as vertical as can be and in the right direction of flow.

viperlp01 · Jan 14, 2009

I know your running rich because i have a wideband and im having a problem tuning mine right now and it falls on its face at boost. Just an excuse for better gas mileage

No_Skillz · Jan 14, 2009

viperlp01 said:
I mean the only leak you can have on a maft setup is your intake manifold.

My thoughts were that since the OP is a self-proclaimed newbie, his couplers on the GM-MAF are not tightened correctly. Also, don't forget the TB and its plethora of connections and seals.

I would definitely suggest look into your suggestion of running rich after a full BLT is completed.

HBWaterfowler · Jan 15, 2009

Well it was a boost leak.

When I was test driving my car originally, it was holding boost. As I drove back and forth to work, it seemed to get worse. I couldn't see that a hose after the MAF had slipped off.

So I took all the piping off and re-did it all with more time to check everything good.

It's holding boost good. I only went up to 15psi to be safe because I need a tune still. But the problem is gone. The power seems the same if not a little less, but the next step is tuning it. I was thinking of richening it 10% idle, mid, WOT to be safe (richer then leaner).

I know, stupid hose.

The problem is, the Dejon tool kit for that MAF comes with some way to short hoses and I'm on the very minimum on where I clamped everything down. I think if I had about 2 more inches on each hose, It would all fit better and have more room to clamp it all down in the right place.

Thanks for all your comments.

The base tune (AUX=0, BASE=2, 450 injectors) seems to be better then the stock MAF was doing.

I bought a 3" MAF from the junkyard to make sure that wasn't the prob (not sure what car the 3.5" came out of). It made no difference.

Thanks again.

HBWaterfowler · Jan 15, 2009

dsmfa9nutter said:
Get a good silicone reducer (siliconeintakes.com) with t-bolt clamps to ensure a good seal. Make sure the maf is aligned correctly when you put it back on.

Good call, that's also on the to-do list.

HBWaterfowler · Jan 15, 2009

210 dsm said:
but before you do a good tune you need to get your "base" tuning done correctly which is the AUX and BASE dials in the GM translator.its just to calculate for injector size, use the chart that came with the translator. also make sure the four MODE switches are set for your setup.
and yes make sure the internal divider in the actual maf if as vertical as can be and in the right direction of flow.

The 4 dip switches are set correct for a 3" MAF.
1-off
2-off
3-off
4-off

I did install the MAF with the divider vert too, thanks for the reminder.

HBWaterfowler · Jan 15, 2009

No_Skillz said:
My thoughts were that since the OP is a self-proclaimed newbie, his couplers on the GM-MAF are not tightened correctly. Also, don't forget the TB and its plethora of connections and seals.

I would definitely suggest look into your suggestion of running rich after a full BLT is completed.

Yeah, you were all on the right track for the most.

I do need better couplers, and tighten it down better.

The TB is a rebuild with new seals and all that, and I got the TB area all on lock down. The upper I/C that connects to the intercooler is nicely done now too.

I need to drive it around some more, but it seems great.

I still have the stock air meter and intake pipe on too, so once I can replace that with new one... I should be seeing a lot more flow.

Thanks DSM hommies :thumb:

With this shitty economy, I don't know when I will be able to get the intake pipe and wb02 all done. I can start data logging other stuff until then.

Everyone have a good day.

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