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Hard start/extremely hard warm start.

1K views 7 replies 4 participants last post by  fuzzman 
#1 ·
Ok, so I'm new here but I've done some lurking and reading I'm not a big Ford diesel guy I've been in the military for 6yrs and I'm a diesel mechanic with the Army so I have some general knowledge and some really useful tools.

2007 XLT crew cab 6.0L Auto-trans 153,xxx miles
So, here's the issue...I bought the truck a little over a month ago and when I went to buy it they said it hadn't been started in a while, so when we went to start it; the truck has a very hard start with some excess smoke which didn't seem off if it hadn't been started in a while. When I took the truck down the road it sputtered and jerked and acted a fool till it was warm about 10 minutes of Ohio winter driving, then it cleared up and ran fine! Since I purchased the truck its the same thing warms up and its fine...I tested the FICM and i get a constant 48v with koeoff and cranking test. Now yesterday I took my truck into work, and put it on the lift changed the oil and the fuel filter/separator filter. And, while I was looking just to see if I had any random oil leaks or anything I should be concerned with, on the drivers side where the engine meets the trans I found oil residue. I also plugged the truck up to our Solus Pro. and got a P2291

So, my question is, can all of these problems be caused by the STC fitting or do you think there are other underlying causes? The truck currently has no mods,no programmer, nothing changed from factory except usual wear and tear items.
 
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#2 ·
Almost sounds like injector stiction, because the 6 liter uses heui injectors the oil supply is vital. any oil imperfections can affect them. because of how the head is tilted (on a stock truck) when listening with a stelthascope the rear cylinders will sound worse as they collect more of these imperfections. I had a similar issue, ford quoted me for a full set of injectors.... that would fix the issue but not on my budget.
 
#3 ·
Well see while I was scanning I did a buzz test using the solid pro and it check good on all I went through and checked duty cycle of injectors and shut them down and turned them on one at a time to see if there was a big difference or if it was the same and there was a big different when any one was shut off. The only thing that leads me to believe its a leaking STC fitting is that there's a little oil coming off the back side of the engine area.
 
#4 ·
with the stc leaking you will see a decrease in oil pressure but if that was your issue you would see more of an issue when up to temp (thinner oil) not cold (higher pressure)
The duty cycle is checking the electrical integrity of the solenoids (but it sounds like you are doing a cylinder cut out test), with the injectors being indeifferent, its more likely a problem on the oil side of the injector.
 
#5 ·
You can try Rev-X or Archoil 9100, both of which have shown to have an effect on stiction. Look for a YouTube video, the sound of stiction is very distinctive and you will know if you have it.

I see in the title that you mentioned extremely hard warm starts. If the truck is having problems when completly warm or hot, STC is a possibility, especially if you can start if after 20 minutes or so.

Good Luck!
 
#7 ·
yes after about 20-30 minutes the truck will start back up and run fine I think I have a combination of 2 different issues but the rough running when cold is the least of my issues right now. the persistance of the truck not wanting to start when its warm is getting worse. So, I'm thinking either STC or Dummy plug/stand pipe. Is there any way to test to see if its the STC fitting?
 
#8 ·
do you have a monitor? that will help narrow things down a bit...
sounds fairly likely that you are looking at a problem with your STC. you can check for leaks with compressed air. you take out your ICP sensor and thread in a fitting to that spot to hook up an air compressor. then you run 100 psi or so of air through your engine and listen for air leaks. the location of the sound helps you narrow down the location of the leak...

valve cover area - injector orings, standpipes or dummy plugs
back under the turbo - hpop (high pressure oil pump) or STC

im pretty sure you can just tear it down and then apply air with things open and relly zero down on the real culprit.

do a search here for high pressure air test and you will get the idea.

with your background this shouldnt be to hard to handle!
 
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