I have been struggling to tune my 4.7l turbo as some people know already. Using SCT a srt4 2bar map and 47# injectors. No matter the amiunt of fuel pulled or added, when at idle or under throttle but out of boost I run pig rich. A/R around 10.0 rich. Ohm'd the injectors and all seem to be right on par. Volt meter'd the map sensor and it read around 2.5 v key on engine off. The person tuning it for me stated he tried everything and believes the computer isn't responding to the map signal. I've also had opinions that my injectors are too large for my application. My question, before I drop money on either a new comp or smaller injectors is what do you think? I'm at my wits end. A reprogrammed comp runs about $200 and new injectors, either 32# or 39# will be in that ball park as well or ahould I take it to a dyno place. Will they be able to deduce the problem? I checked for vacuum and exhausts leaks and fixed minor ones I found and stillno change. Need help!

 

Adding a turbo to a computer controlled FI engine has a lot of consequences - it used to be somewhat easier a number of years ago. Adding a turbo changes the whole combustion and firing algorithm that's used by the OEM computer, so if you don't have the appropriate program installed, you're going to be into an uphill battle in my opinion. There's probably nothing wrong with the MAP and the OEM program just isn't able to use it properly in the new configuration. The MAP can be altered by adding a home-made circuit to lean things out somewhat, but I wouldn't take a hit & miss approach in fixing this problem, I'd want to get a good overview on the whole situation & see what my options might be. If I was doing this, I would first get some advise from an engine shop that has current experience with that engine type. I'd rather pay a few hundred for good advise and a good implementation plan than to pay for a whole bunch of hardware (like wrong injectors) that will end up sitting in my garage.

 

I noticed that without a tune, my stock ECU "learned" to correct for the new #39 injectors within a few days. It still goes rich during WOT pulls, but they are barely noticeable during daily driving.

 

I just checked on Ebay and they are selling an EMS 8860 with a starting bid of $350

I was looking forever and not one showed up on Ebay!!! I ended up buying mine for $1400!!!!

The 8860 can completely control fuel injection and ignition. You could literally have nothing but a chassis with an engine on top and run it with this computer.

http://www.ebay.com/itm/EMS-8860-Seq...#ht_500wt_1156

 

I had a lot of trouble tuning the 50lb injectors. Unless you are running more that 15psi of boost, I would stay with the #39 injectors. They were much easier to tune, it took a week to ge the A/F ratio correct for the 50lbs injectors to idle.

 

welcome back blown