I just recently got studs and 190cc injectors with stock nozzles installed with AN 6 fuel lines from the secon filter to the heads. I noticed on my way home that when i let off the go pedal, the injectors pulsse width stays at 0 till I slow down to 55mph. Then they start goin again and jump around a lot, occasionally back to 0 and the engine sounds like its missing a lot and gets real choppy until i hit the gas again. Then, if you rev it in neutral, the rpms hang for a second and drop back down to normal. The truck runs great and has plenty of power. My buddy said his buddy had this issue with his obs 7.3 when he swapped a super duty hpop in it but he's not sure what it was. Ive also seen that it could be the icp valve isn't tuned for my injectors. At the moment, it is not tuned. Could this be my issue and is it safe to drive?

 

Could be your ICP but typically when you change injectors in the 6.0 or intoduce air into the HP oil system on anything HEUI it will take it a few miles (50-100) to get all the air out of the oil system. Same thing with your buddys 7.3. It should start to clear up. If it keeps acting funny you'll have to plug a laptop into it to it and see what's going on with your sensors. We're did you get your injectors from?

 

Theyre from warren diesel. Ive put a good 200 miles on it since they were installed. I have the edge monitor and from what I've read, my icp is good along with everything it monitors. Im wondering if its just that its not tuned and doesn't know to compensate for the larger injectors.

 

It might be a tuning issue some times certain injectors take specific tunes to run but mostly on the 7.3. Your not running any kind of tuner? It might also be your FICM.

 

I havnt had the funds yet to do tuning and I figure id just have the injectors installed while I had it in for studs. And the ficm voltage checks out good to but ill be gettin a 58v ficm at the end of october along with tuning

 

Have you asked the shop that installed them to check it it out? They should be able to tell you exactly what's going on, without my laptop hooked to it it's kinda like shooting in the dark. That's about all I can tell ya. Your HPOP and fuel psi are not low are they?

 

I havnt asked because he is a good distance away and I dont have much extra time due to work. But from what it seemed, the guy at the shop checked everything. He said the fuel pressure was lower than before I'm guessing because of my fuel lines, but it wasn't to low. I'm not sure about the hpop though. Im guessing I can tell by the icp voltage? If so, my edge insight says its fine.

 

The ICP voltage is just the sensor, you either gotta have a gauge or a scan tool with ford software on it to see the actual HPOP pressure. Fuel psi is one of the most important things on the 6.0 IMO I'd invest in a gauge. Anything less than 45psi needs to be addressed for the longevity of your injectors anyway. A fass or airdog system is a wise investment with aftermarket injectors. Its not uncommon for a weak stock pump to run fine with stockers than act funny with something wanting more fuel, It might just be filters too or a weak FPR spring.

 

He did say fuel pressure was above that. But I'll be ordering an airdog at the end of the week. If that doesn't slove it, ill head over to a shop and get it checked out. Im just baffled because it sounds great until I let off. And only while its in the 40-55 mph zone.

 

Get that thing tuned, can't believe you're even driving it with 190's on stock tuning.

I've heard of erratic RPM when in neutral or park and revving it up with big sticks too. I wonder if he welds the spill ports on his 190's.

Definitely get it custom tuned ASAP.

What's the point of the big fuel lines coming from the filter to the heads? That's larger than 3/8 line and everything behind it is still really small? Have you done the blue spring upgrade? What is your fuel pressure now? Do you even have a fuel pressure gauge? You should.