175/146's or 200/30%'s?

[Big Bore]

Or one failed ICP sensor throwing your timing down the drain when it goes best guess.

Is there a way to prevent that from being a possibility in the tuning?

 

[Chvyrkr]

I dunno if a tuner would have control over the default tables or not.

If not though, with a "big oil" system putting out more than the PCM thinks it should have for any given IPR setting, the timing would become advanced I'd think. As 3000 ICP and 2.0 ms of PW, and 2000 ICP and 2.0 are two different volumes of fuel, the timing would be just as different.

Makes sense to me anyway.

I'd bet alot of trucks that didn't live with large injectors on weak rods had something in addition to tuning wrong with them.

 

[Big Bore]

I know that when I took the Termies off the truck and put the stock pump back on, a bunch pf my problems went away. My new tuning for twin pumps is going to be totally different.

 

[Chvyrkr]

Did you change toons at the same time?

 

[Big Bore]

Did you change toons at the same time?

No. However the rest of my problems went away later when I changed them. Before you ask, the tunes were written specifically for twin pumps by someone who was supposed to have been the expert tuning those pumps, and in fact had live tuned the exact setup that was on it at the time. I'm confident I know exactly why they didn't work properly, and how to remedy the issue.

 

[Marty]

I would listen to whatever Dave (Golfer) says about injectors.

He alone has more experience with 7.3L injectors then probably everybody in this thread combined. Excluding Tim @ PIS - as I don't know who you are.

 

[Tim @ P.I.S.]

Thanks Marty, I think......

I do sometimes forget that not EVERYONE is wanting to go race their truck. In the chance that someone is wanting to gain economy or build a strong pulling truck, with a stock'ish turbo, the 30% nozzles will do the job. But you will never get the full benifit of the 200cc of fuel with that nozzle. The PW will cut back way to soon to give a good "top end", imho. I personally like the 30% nozzle for 160cc injector.

 

[Marty]

LOL yeah, I see the injection systems information in your signature and since I don't really know you I couldn't lump you into the rest of us who might do injectors 3-4 times a month.

 

[Gearhead]

with HEUI delay times factored in, at 3000 rpms all the fuel past 3.2-3.5 ms (with typical timing factored in) commanded is just late injection and only makes a difference in power output if you are running nitrous and able to burn the fuel that late ATDC.