holy cow...

I doubt its your map sensor, or the PCM, or the fuel pump. Those injectors are probably just too big.

You could try a 3 bar map... I know quite a few SRT-4 owners that run them. Check modern performance if your interested.

 

The #39 injectors on 224 cams at 6,300 RPMs will fuel up to 14 psi of boost without running lean.

Unless you are pulling down more than 15psi of boost or more a 2-BAR MAP is all you need. I had significigant tuning issues when I went up to 50 psi injectors. It took about a week to work them out.

Good luck and keep boosting.

 

I'm going with injectors just dumping too much fuel.

 

I guess I'm just spoiled with an AEM. Even before the AEM I ran 1000cc injectors (95lb) and idled with absolutely zero issues. Stock injector size was 450cc (42lb). Even with the stock ECU and a SAFC I was able to tune the 1000s to idle like stock. I don't see why the jump to 47lb injectors is "too" much. Those things are barely bigger than my stockers. Guys that I race with run 1800cc injectors ( 171lb).

So, my first question is in the calculation for fuel. I think a 3 bar map sensor would be a good start. Trimming the fuel from there shouldn't be an issue, although I have no experience with a SCT tuner. What is frustrating is hearing people say "your injectors are too big". There is no such thing (relatively). Especially for a small jump to 47s. I would look into a different tuning tool. Or, get with Blown or Hahns and figure the limits of the SCT. Maybe its just in the tool and setup. I think an adjustable regulator is necessary with the fuel pump you put in.

 

yea I dont know, the stock injectors I took out were 19lbs and I put the 47#'s in. Our trucks have a closed loop fuel system, I was told the adjustable fuel regulator wouldnt work because there is no return line. I actually have one, ha.

 

If Mitsu's truck can trim the fuel down from 39s with the stock MAP, I don't see why yours can't trim down 47s with a 2BAR...

Either way it's more injector than you need, I'd drop down to a 39lb and see what happens.

 

The problem is the trucks ECU not cutting IDC's to compensate for the extra fuel being dumped by the larger injectors.

He's running speed density, so you cant just trick the computer to pull fuel like you would with a MAF setup. Either the tuner isn't able to control injector cycles, or the map sensor isnt functioning properly. Since he's on his 3rd new map sensor... I am saying its the ECU and thus injectors.

SCT doesnt have near the capabilities of MegaSquirt or the AEM stand-alone.

 

I have 60# injectors pushing closer to 70# and I haven't been able to get them tuned in due to the shear fact I don't get enough seat time. I also see boost so fast that we had to turn off my closed loop at just 1,500 RPM and now have to tune vac and boost. Another headache.