1G running better with no maf why?

[fncrazy]

Hello everyone, I have been looking for a couple or days now for the answer to this question maybe you can help me out so here it goes..... I installed a front mount with 650 injectors and ecmlink v2. the ecm was just repaired by the awesome guys at ecmlink. the car was running great then it started to have idle surge. After trying blt, changing my tune etc... nothing helped. The car was running full rich and surging. o btw did find a leak and fixed it still no better... I decided to go back to stock injectors, it did idle a little better but still rich and surging. So I went back to my stock ecu... and guess what no better, then I tried my 1g maf ( was running 2g) no better. So in a nut shell I have tried 2 known working maf off a 2g and one 1g that was working on my car with zero problem and no change still full rich and surging. Then I tried just for fun to unplug the maf..... Finally the reading start dropping to like 13.8, throttle is responding great. Then and only then are my reading dam near perfect. I do one day soon want to go to SD but for now I just want to drive her while it is cold here and before the snow starts. So my question to all who respond is Why does it run so much better without the maf pluged in, Two any known fixes, Three Is it safe to run without maf since that seems to be the only way it runs right. But most important I want the right fix. Thanks in advance.. I do have some old logs if that will help. One more this with out maf plugged in it idles around 1000 and has a ever so slight phantom miss.

 

[steve]

Put the parts you really want to be running back in and post some logs. Not old logs that might show what the current issue is or might not.

 

[fncrazy]

these are the logs with the set up I want to run. the oldest two is from when it was running good.

 

[fncrazy]

Im thinking back and this all started when I tried to see how it would run on a hacked 2g maf map. Since that I have been playing hell trying to get this straight. Any advice would be great. I would get more logs but at the present time the car is at a friends house 45 mins away. I just want to get it back home to be able to do live logs and start moving in the right direction.

 

[steve]

The all the logs are missing key information. You don't have throttle position, battery, closed loop, or short term fuel trims in any and less in the running good logs.

In the -02 log your ISC is run all the way to zero and you still not down to the set idle speed. Since your not logging enough I can't say anything about the O2 not cycling. Having to pull 30-40% of the air out with MAF Comp isn't good.

The -08 and -10 logs is almost idling but same problems with the log. At least the ISC is unstuck. Again the MAFComp is out of whack and your airflow/rev agrees.

If your 2G MAF is hacked find a good unhacked one. The stock MAF's in general are well quantified by the factory and if you have to do much with the comp it's usually a sign of other issues.

Have you checked your base fuel pressure lately. it looks like the car ran better with the -26.6 global than the current -31.6 but MAFComp will screw with the fueling since you're playing games with the airflow.

 

[fncrazy]

wow ok thanks for the info I will try to get better logs. Steve your the man. I will check the fuel pressure also. thanks again... I at lease have some where to start and I guess its putting the ecu with ecmlink back in. I will be back with more info for this issue very soon. And will keep you posted cause I want to put resolved on this and maybe it will help out the next guy.

 

[fncrazy]

Ok mark this one resolved... I found after, the boost test I must have pulled the intercooler line off behind my bumper.

 

[steve]

It happens. Take a look at the MAF and those MAFComps now that it's running again.

 

[fncrazy]

I will do!!! redid all the intercooler pipes with a small tapper and hair spray. I will be driving it home this weekend... then I will be putting the 650 back in, ecu that has ecmlink back in, and the 2g MAF. In your opinion @steve do you think the 650 are going to make a big difference? Or do I just stay with the stock 2g ones I have in there now. Thanks

 

[steve]

With the stock turbo the 450cc injectors are enough. As long as they have fresh insulators so they aren't boost leaks you could leave them in.