I have a 99 7.3, been well maintained and I love this truck. Problem being I have a rough idle.. truck runs good above that, in park its smooth, in gear it idles and the truck shakes lightly, however it is very annoying. Does appear to be lacking power slightly.. could just be used to my old edge evo. 230k and counting at the moment. Couple weeks ago on the freeway the truck did a "cough cough" brief moment of power loss, then completely fine.

The rough idle sound, almost sounds like a hiccup? like a rubber squeak, but it comes from the exhaust, kinda like the engine sounds like its rocking in the mounts. It comes and goes though, sometimes its smoothish, and sometimes its really squaking. But still, after an injector swap it runs so smooth its like a gas motor. So could be heading up the wrong tree.

I got a tank full of water a month ago and I believe it is all gone. I have changed 3 injectors as they did not pass CCT. Ford did the cps recall, Grey sensor I believe. brand new fuel filter, brand new oil as of last week.

I changed 1,3,8 injectors. the last one being 3 as of last tuesday. every time I change the ones that dont CCT it runs great for a week then back to crappy idle.. Injectors all buzz fine, no codes, HPOP puts out good pressure. I have no tuner at the moment, stock. Just have intake and exhaust. No fuel in coolant, and no fuel in oil. fuel filter was clean but changed it cause the gasket swelled. But on a brighter note, my DP tuner comes in tomorow

HOWEVER, this is my only indication that anything is wrong...



you drain the filter housing, turn key on, clean fuel comes out. run it for a few.... back to that. it appears air perhaps? and when I change an injector its fine for a few days. then back to square one. But this cloudy substance is always present.

Thanks! help my truck!

 

Hmmm... how did you get the water out of the tank, pump, lines, prefilter, rails (with deadhead), etc... or did it make it that far?

I saw this happen to me... right after I replaced the HPOP and installed the FRx. I introduced a lot of air in my oil and fuel by pulling all the parts out and it took close to 250 miles and parking for a day to get completely rid of the "gurgles". You might look at the FRx (link in my signature) to address things that can get trapped in the dead-end fuel rail.

If you removed the fuel tank to get the water out, did you do the hutch mod? You might be circulating an abundance of air and it's getting into the fuel pickup.

 

the truck still ran; never died. I pumped it out till it was all i could get, and Ive ran 9 or 10 cans of sea foam and heat through the tank to absorb the moisture. So Im fairly confident it is all removed, not too mention the 10 or so gallons ive dumped from the fuel bowl lol.

Ive been considering dropping the tank to do the hutch mod, but I want to make sure I am resolving the issue before modifying anything else to the truck. Though air intrusuion could be the issue.

after the new injector, it runs like crap for 10 minutes, then go and run it at 2600 for a few miles and shes runs so smooth, and idles fantastic! then 3 or 4 days goes by and it slowly goes back into its slump?

Im gonna keep driving on it, still very odd its reverted back to this problem once again

 

OMG... if it were my vehicle, I would have dropped that tank before turning the key. water collects on the bottom after it sits for a while and the first thing you pull are the remnants of water. The fuel rail has a dead-head issue - no place for fuel/air/water to go except through the injectors, with injector 8 getting the brunt of the air and I speculate 7 gets it on the other side. Since water is heavier than fuel or air, this adds a whole new dimension to where that would go. Agitation of movement and pumping would really mix that water up and send it on through. Your fuel filter has a small capacity for water, but I'm sure that's sufficiently nuked.

I'm not on expert on diesels, but I've heard many times from many sources that water in the fuel is very bad for a diesel. I would be far more aggressive in addressing this, but I invite more experienced members to share their thoughts.

 

Unfortunately when your half way to Seattle your options are limited to this situation. This morning however when I started it, the tach didn't respond for two seconds.

 

Ick... far from home and disaster strikes. No tach? CPS is highly suspect.

 

The tach is there, but it was slow to respond. I'm suspecting that the cps is causing my issues? It did hiccup on me a few times

 

It's cheap. It's fast. It's easy. Not trying one might send you through the briar patch, only to end up back at the CPS - with bandaids on all your appendages and a rip in your pants where you used to keep a wallet.

 

You've got to drop that tank and get it cleaned. A CCT test doesn't necessarily prove you have an injector problem. With dirty/polluted fuel, anything can cause an injector to act funny. What does your anti-freeze look like? Fuel or oil in there?

 

The fuel filter is very effective at keeping water out of the heads/rails - to the point that wet fuel can cause fuel starvation. BTW, the 'issues' with the dead-headed fuel rail are way overblown, save your money here...

It looks and sounds like you primarily have a fuel quality issue. The additives you've been dumping in the tank are now contributing to the problem. All these do is allow the water to get thru the filter and ultimately thru the injectors. This stuff is in the same category as radiator stop leak. If Red Dawn goes down and ya gotta get out of there, do what ya gotta do. Otherwise, pull the radiator - or in this case drop the tank - and do it the right way.

That cloudy fuel is a big, red flag.

 

I love to do things the right way so I'll drop the tank. Is there a special
Method of flushing the fuel out of the motor and why not? I just want it all out and done with. And I got my dp tuner today; horray. Antifreeze is green, oil is clean and not smelly.

 

There's only about 4oz of fuel in each head, given what you've already run thru there - don't worry about it.

I sure hope it clears up for you!

 

Lol at this point I hope so, but I'm committed to put whatever it needs to do it on the truck

 

Seems like we have a similar issue. I have seen it on may boards and in several threads here. https://www.ford-trucks.com/forums/1...sual-idle.html

Wish I could say We have a solution, but maybe we can work together. Take a look at whats been done on the other thread please.

 

I have solved my issue! I had a tiny fuel leak that was introducing air into the system. The fpr return line was the culprit. The hard line with the nut on it has a tiny rubber seal INSIDE the nut was trashed. Few bucks at ford my truck runs excellent. The smooth idle has returned. My truck always ran good in the throttle but that seal was my rough idle maker.

That seal is inside that nut. Make sure you tighten the nut down firmly; it actually seals the threading up against the fpr the rubber seals the line. I'm very happy.

7.3 return line seal - Google Search