1g maf 16g 510 cc fuelcut

hollandeclipse · 10-08-2008, 04:48 AM

These are my mods:

Evo 3 16g@17 psi
Evo 3 manifold
S-AFC
510 cc injectors
255 lph walbro
3" turbo back system
FMIC

My hi settings were first - 10 % through the range after logging I noticed 23 knocks! when boost comes on. So I try to richen things up. My hi settings turned to -5% and still 7 knocks and tima back to 11. Then I tried to richen it further up but at -3 % at hi but then I hit fuelcut.

My 1gmaf is stock. should I replace this for a 2gmaf or get bigger injectors or can I just screw the 1gmaf fully open?

JayRolla · 10-08-2008, 08:35 AM

Boost leak test. I was able to get 18psi on a 1g maf no problem. I bet you have a boost leak. I would also get a wbo2 so you can tune a lot safer.

hollandeclipse · 10-09-2008, 12:30 AM

thx for the reply I will test it for boostleaks. Did you also had the 510 cc injectors in it and what were your AFC settings?

4G63_Attack · 10-09-2008, 11:04 AM

I would have to say that you MIGHT be over running your mas/maf

JayRolla · 10-09-2008, 06:32 PM

I dont remember the settings, I had 550's in. The injectors dont madder though. The ecu doesnt care about them, it cuts fuel when the maf pulls in too much air. When you have a 16g at 17psi and a boost leak, the turbo pushes harder to hit the set boost which will make the maf see 20+psi which will cause fuel cut. I had fuel cut at 11psi on a 2g maf with a major boost leak on my old setup.

Stapl3 · 10-09-2008, 10:17 PM

Agreed. Your mas is seeing all this airflow that isn't making it into the engine because of leaks inbetween. Boost leaks absolutely kill the performance of DSMs in every aspect, from WOT to gas mileage to idle.

I'll eat my hat if that MAS is being overrun at only that PSI on a 16g.

hollandeclipse · 10-10-2008, 04:45 AM

My mileage is very good and the performance till 5000 rpm is also very good. Max torque is 300lbs at 4000 rpm. My concern is that for a good fuelmixture I have to set the AFC to zero and setting the AFC to zero causes fuel cut. When you have 550 cc in it you can set your AFC to say - 7% so the maf will see less air and therefor will not go into fuelcut. I was just wondering at what HZ readings the stock maf will go into fuelcut, and if just unscrew the screw will help the maf to go not into fuelcut.

I will test for boostleaks tomorrow. My piping is completely new from turbo to throttle body. The only weakspot can be the Bov which is an HKS sqv. For safety I will also test all the connections to the fmic etc.

hdoerr · 10-10-2008, 05:12 AM

From the looks of your tuning I would say that you are dealing with phantom knock. Your process is correct, if you see knock then you should add fuel which in turn causes you to get closer and closer to over running the maf. Solving phantom knock can be an extensive process that could require a head rebuild or something as simple as getting an after market knock sensor that isn't so sensitive.

hollandeclipse · 10-11-2008, 01:29 AM

The knock only occurs when the boost comes in at around 3500 rpm. First I had 23 knocks ( afc -10) but after setting the AFC to -5 I have now around 8 knock so I don't think it's PK.

To get my mid and high fueltrims at around 100 % I also had the correction set to -5.

el guapo · 10-11-2008, 01:59 AM

do the boost leak test if thats good check into an eprom ecu if you have dual valve springs that could maybe show some knock a wideband o2 would realy help with tuning though.

dsm-onster · 10-11-2008, 04:09 PM

Definately do a boost leak test. But You lcould verywell be overruning your maf. Mine always do at close to 30lb/min. . .

hollandeclipse · 10-12-2008, 01:57 PM

After testing yesterday I noticed that the bov is opening under pressure from 13 psi on, so I have to work on that. I also noticed that my Hz reading on the AFC are above 2000 from 3800 rpm full boost on so defenitely boostleak through the wastegate. What I don't get is thew low correction settings on the AFC. lo settings has to be set to - 5 % and high settings to -3% which I can imagine because of the boostleak at the bov. After fixing the bov I will post another reply if the problem is solved.

JayRolla · 10-12-2008, 09:31 PM

If you have a stock 1g im very surprised its leaking. If you crush the BOV you will beable to hold 24+psi on the stock 1g bov.

dsm-onster · 10-12-2008, 09:38 PM

I am suprised, as well. If you do the "dodge garage" mod to the 1g valve it will hold over 30psi. . .

JayRolla · 10-12-2008, 10:10 PM

Quote:

Originally Posted by dsm-onster

I am suprised, as well. If you do the "dodge garage" mod to the 1g valve it will hold over 30psi. . .

The one or two times my car luckily had no boost leaks, I tested too 30psi and my crushed bov didnt leak at all. Same on my bros car.

hollandeclipse · 10-13-2008, 03:01 AM

I have a SQV bov sorry for not mentioning this earlier.

JayRolla · 10-13-2008, 09:23 AM

Get a stock 1g bov, you will never need another one.

hollandeclipse · 10-18-2008, 04:33 PM

I did a boostlek test today and first everything seems alright untill I removed the rubber maf hose and I discoverd that the hose was not connected good at the bottom and there was a big hole in it what explained my lean mixture. Also I discovered a small leak at the throttle body elbow.

After test driving the car there is no knock anymore with my hi-settings at -5 and also no fuelcut anymore. Thx for cooperation.

Now I can go further with the tuning. Future mods will be a maf upgade to or GM with a MAFt or the new MAFT pro with speed density.

airmail96 · 10-19-2008, 08:15 AM

if you want to go speed density you could look into DS-MAP. Thats what I run and I LOOOOOOOOOOOve it.

hollandeclipse · 10-29-2008, 02:10 PM

Today I did the following mods to resolve the problems I had and it worked:

1. Installed an AFPR and set the fuelpressure to 45 psi
2. Installed a 2g maf from a Pajero 3.5 L
3. Installed a 2,5 inch trottle body elbow

Then I had to set my AFC to 0 at low trim and at hi trim I have put it to +2. The results are very good. No more knocking and full boost from 3000 rpm.

Thx every one for helping me out.