100% IDC then fuel cut??

[turbo23]

I've had this car for a month or so now, and have been slowly fixing issues, so far I've changed the capacitors in the ecu, fixed all the boost leaks. reset all the tuning stuff in the safc and the maft. car runs tons better part throttle, had to put 10% in the low adjustment on the translator to get the fuel trims down. the only problem I haven't figured out is under WOT the car seems to have a load based issue. in 1st gear car runs great until 6300 in secind till about 5200 and 3rd till about 4800. Basically the car acts as if it hits fuel cut.. did a few logs the other day and found that the IDC was going to 100% and as soon as it gets to 100% the injectors shut off. The logs showed 0.00ms and 0% IDC at WOT ??? everything looks great up till this point. no knock, AFR's look good. kind of lost, I know it doesn't have any boost leaks up to 30 p.s.i. the timing is dead on.. not sure what to try next. seems to be an ecu issue, maybe? the 100% IDC doesn't worry as much as why the ecu is shutting them off right after.. thanks.

 

[toofast82]

The stock fuel map is extremely rich at 9.4:1. Lean it out some and you will free up some idc, which will get you out of fuelcut most likely. It is designed to occur at 100%idc as protection

 

[turbo23]

I treid that, puts it right into about 20 counts of knock.. I didn't know the ecu was suppose to do that.. the car is said to have a 255 in it, But i have not check that at this point. I have a set of 850's in the back seat I could put in there, I haven't yet becasue I wanted to make sure the issue wasn't else where. think I should put them in there and see what happens.

 

[toofast82]

The safc or maft will not be able to really control the 850cc since they "hide" aiflow which causes timing to increase. You may want to drop boost a pound or if you have a 1g, try lowering timing a degree or two via cam sensor. It's all a compensation game. Tell me a little more about your setup as far as year, what turbo, etc.

 

[banishedmunk]

set the maf-t to 450's close it up and tune it out with the safc that way no timing corrections are being made due to inputs from the maf-t

 

[toofast82]

You need to get a custom chip set up for those 850cc you have and just choose one of your "piggyback" options and sell the other. Thats funny though, i actually had the same thing a few years back(safcii, maft, keydiver). Let me say, multiple piggybacks arent the way to go.

 

[turbo23]

The maft and the afc are all zero's, so the timing is all stock as of now.. the cas is a 1g tsi, big 16g,3" exhaust, maft with dejon hard pipes, nothing real special. has an hks exhaust cam also. I've played the "compensation" game before with another car.. I was thinking the same thing, set it up for 850's at the translator, then start with the base timing backed off 3 or 4* and add or subtract based on knock sensor readings. its not the right way to tune, but at this point I don't have an option, and I'm farily confident I'll be able to make it work ok.

 

[turbo23]

I forgot all about getting a chip, farily sure a customer of mine would hook me up withh one also I'll looke into that. Anyway though, the ecu is meant to shut the injectors off at 100% IDC?

 

[ArticNemesis]

Anyway though, the ecu is meant to shut the injectors off at 100% IDC?

That's the point of fuel cut. To keep you from adding anymore air without your injectors being able to add fuel (super lean condition!). It's a protective measure to keep you from melting anything.

You aren't going to be able to tune for the 850's through a piggy back without a chip. With the maft and afc settings at 0, you are dumping a ton of fuel into the motor.

As already stated, your timing is advancing way to far when you dial back the airflow settings to account for the 850's, hence why you are getting knock.

 

[turbo23]

I only leaned it out 5%. how big of a timing difference does that make?... anyway I'll figure it out, thanks for your help.

 

[knochgoon24]

Do you have a wideband?