too much fuel

[DThibault]

I finally got my 91. 5 finished. While I was waiting for the paint to dry, I did some engine upgrades. I did a few things at once so I don't know what had the most effect on my new problem. I've had a Banks kit in it for at least ten years including a new wastegated turbo housing I think 12 cm, an upgraded intercooler, a 3. 5 exhaust, and turned the pump up a little, the truck ran great but of course I wanted more. So I bought a Denny T stage II pin, some SDX 5x14 injectors, a 366 gov spring and put them all in. The engine started right up and hazed a little while I looked around for leaks etc and when I took off in a cloud of black smoke. The truck ran great but too much smoke and the EGT's climb quickly. The power increase is tremendous but I want to decrease the EGT's and smoke and make it a little safer for other drivers who may not watch the pyro. I'm thinking my injectors are pushing too much fuel and was looking at others . Where do I start to calm it down? What does bumping the timing do? Any suggestions considered.

 

[Bob Beauchaine]

If the hot side was part of the Banks it is probably a 14 cm. With the Banks I/C you have an Inter cooler that flows plenty of air. If you did not add oversize plumbing from the I/C outlet to the Cummins intake you have a restriction there. If you are running the stock cold side turbo (H1C) with you might not be moving enough air. You can look at my sig and see that I've got a similar setup. I can create smoke when I want but I can also control that smoke. In short I think you are not moving enough air for the injectors you are running.



Bov

 

[RWherley]

I had a similar issue with my 93 after adding a BD fuel pin to my +40 injectors and turned up fuel pump, I fixed it by changing my turbo, intercooler, intercooler tubes, and intake horn. Look at "total air system upgrade" to see what I did.

 

[HHhuntitall]

The smoke is unburnt fuel. You're best bet is to back the fuel down a little and readjust the AFC valve to the Denny II pin is not working so quickly. It needs to build some boost before it gives it so much fuel, otherwise, it's going to smoke like that, and the EGTs will go off the chart if you lug it on bottom end.

 

[DThibault]

Thanks, Huntitall, that' kind of what I was looking for. The younger folks on the farm say "more smoke the better" but I get uncomfortable with it. I did a search on the AFC but the info that came up was for a 2nd gen, Where do I get the info to adjust the VE AFC, Thanks agaiin

 

[HHhuntitall]

Ahhh, check on here for pump tuning. The AFC is the air diaphragm on top of the pump. When you pull the four bolts, the cone shaped rod that controls the fueling rate under boost. Turning the coned rod adjusts where the fuel begins. Turning it to where it has to build more boost before letting the fuel rod move outward (down the ramp of the coned rod) will keep it from smoking quite so much. It's gonna smoke when you hammer on the throttle regardless, just due to injector/pump calibration setting where you have it. With the 12cm housing, it's as good as you can make it for bottom end, until you upgrade the compressor wheel or go to twins. You can go to the 14mm housing to help lower egts, but it's going to smoke even worse on bottom end and not spool as quickly. That's my preferred housing on the 1st gen, and with the 366 gov spring, perhaps you need to do that and keep it above 1500 rpm. That will extend the life of your transmission, too. You may even consider some smaller injectors, or backing the pump down some. The carbon it dumps in the oil is not good for longetivity... . or fuel mileage!!