2000 7.3 psd question

**wrenchjunkie** · July 28th, 2019

My truck is a 2000 7.3 6 spd ZF 4x4. It has 1999 AB injectors (because I had them), 1.1 AR compressor housing, .84 turbine housing, Banks power elbow, 4" exhaust, Banks 6 gun, Superchips tuner (for the speedo correction) and a cold air intake, all stock fuel system, 4.11 gears and 40" tires.

The problem I'm having is painfully narrow power band. A typical 2nd or 3rd gear pull from 1000 rpm acts like this. There is no boost until 1200 rpm, 2-4 psi by 1500 rpm with heavy black smoke, smoke clears by 1700 rpm as the boost passes 10 psi, by 2100 rpm the boost races to 15-18 psi and it feels strong, by 3000 rpm boost is 27-28 psi and the truck feels like it defuels, absolutely no smoke, boost falls off and it feels like it ran out of fuel, momentum may carry it to 3200 rpm. During this whole 3-4 seconds EGTs shoot up to 1000-1150 degrees pre turbo and fall off a little at 3000 rpm.

70 mph in 6th up 395 around Parr shows about 1750 rpm, mild black smoke, 1150-1200 egt and 12-15 psi
70 mph in 5th up 395 around Parr shows about 2300 rpm, no smoke, 800-850 egt and 19-22 psi.

Best mpg 16.8, worst 14.2 but I haven't towed more than a few miles with about 4000 pounds and just locally.

What I would like is either a little more rpm (4000?) or more boost, 10-15psi at lower rpm (1000-2000).
I love it on the freeway but driving around it kinda sucks. As it sits I baby it up to about 1500-1600 so as not to smoke out the place then step on it for 2 seconds until it falls on its face at 3000-3100 rpm and I grab the next gear. If I short shift it, it just smokes and is really lazy.

**3rd Petal** · July 29th, 2019

Doesn’t sound too terribly differently set up than my 7.3. I run a 99 7.3, zf6, 39’s with 4.30 gears, stock AD injectors, SCT tuner, 1.0 AR compressor housing, non wastaged 1.0 exhaust housing, 4” downpipe to 5” exhaust, water/meth injection, and a few misc fuel mods

Below 1500 you aren’t gonna build much boost. I also don’t see the need to rev it to 4 grand. When towing I run mine from about 1750-3000, and I never have any issues towing about 7k

These truck de-fuel at around 25 psi unless your chip programs that out, or you have “boost fooler” relief valve in the MAP sensor line. But with ab’s it’s possible you are just running out of fuel....

No codes?? Have you had anyone with an AE scanner or similar run a live test on your icp pressures and ipr duty cycle?

**wrenchjunkie** · July 29th, 2019

I guess I'm just too used to gas engines. Mainly I wanted a wider power band. I'd be happy with more boost at a lower rpm just to kill the smoke and wake it up a little. The EGTs get a little high when it smokes so I don't lug it and downshift instead, then I run out of power past 3000.
Correct, no codes. Engine seems happy, just lazy down low and shuts off up "high". High in quotes because the 302 in my early bronco used to see 7800 on occasion.
I'm thinking about getting Auto Enginuity because there are 3 7.3s at the house now and I'm planning to add a "tow only" rig

**3rd Petal** · July 29th, 2019

Smaller compressor housing will probably get boost up a little quicker, and one of the “wicked wheel” or equivalent aftermarket compressor wheels. But I don’t think you are building good boost under 1500 no matter what you do.
If you have multiple 7.3s, use the stock height one for towing. You can pull a lot with a lifted truck, and look good doing it, but at the end of the day a stock height truck is way better as a tow rig

A side note with the zf6, probably applies to most transmissions really, is to try not to be pulling a heavy load uphill under full power in 6th. I blew up 6th in mine once, from pulling too hard uphill. Still had plenty more power to give, but the overdrive gear couldn’t handle it. I’ve heard of a few other people doing it too. So I try to pull hills in 5th when towing now, even though I don’t really need to downshift to make the hill