Ford Powerstroke Diesel Forum banner

Could I have a vacuum problem???

2K views 14 replies 5 participants last post by  Joe Johnson 
#1 ·
The reason I am asking about the vacuum problem is that when I use cruise control, I have to push hard on the brake to disengage cruise, where before it would take I light touch of the pedal. Here is what I have posted in other posts and what I have done. PLEASE help as we are trying to get back to Texas and that is an 1,100 mile journey and we want to get this thing right before breaking down on the side of the road.

NYC 350, SixString, and others. Well, the test on the FICM showed 48.6 when the key was turned on, then 48.2 when cranking and then 48.6 when running. Now that I have started and tested in, here is what I have found, some new symptoms. I took it on the highway and the acceleration is GREAT, but still, when I level off, I have a slight miss and then when I engage the cruise you can feel it more. So, I bring it back to house and let it idle and hit the pedal to jump it to 2500 rpms and there is a small puff of black smoke, no white. And I have also put a pry bar between the gas pedal and drivers to burn more of the fuel off, and now when I get it initially level out at 1500 rpm with the pry bar, the rpms will raise to about 1800 rpms then drop to about 1400, and it seems to cycle like this when I leave it set up like this. The reason I am trying to burn off some of this fuel is the Ford tech I had originally talked to told me that I should double the dose of the Power Services in my fuel when I filled up so I did it. But now I am wondering if this might be the problem, so I am about to go add more fuel to it as well. So, up to this point, I have replaced the fuel filters, oil & oil filter, air filter, upgraded the fuel spring to the Ford blue, checked the FICM, and replaced the batteries. How would one check the injectors if someone says it might be an injector?
 
See less See more
#2 ·
As as the cruise control goes, it should actuate off of your brake light switch, which should be behind the brake pedal looking at the firewall.

As far as your injectors being bad, I can't speak for that other than what you said your symptoms were. I have double dosed with PS before and not had these issues. Granted it was on a full tank and yours may not have been.

Generally when you have injector issues you will get a lot of black smoke both at idle and running down the road if it is over-fueling. The best thing you can do, is get a good quality scanner such as an Auto Engenuity or Snap On or a Ford Scanner. That is going to tell you a lot more than just mechanical tests.

However, with the surging you are talking about, I would try to disconnect the electrical connector at the turbo that controls the variable vane and see if you still get the same surging. If it doesn't happen, then you may want to look into cleaning the turbo as well, which, while not a hard job to do just takes a little time.
 
#3 ·
I read thru your other posts and I'm confused by your issue.

You have a slight miss/shuddering problem at 1500-2000 rpm? Is it a miss or shuddering or more of a racing rpm issue?

The miss/shuddering issue could be from a few things. I would try having the trucks PCM/FICM updated to the latest programming though. I've had trucks before that have had this same miss/shudder issue that a PCM/FICM update took care of it. There are quite a few TSB's on issues like this. For 100 or so bucks it's worth a shot.

I don't think it's a vaccum issue though. These trucks don't use vaccum for the cruise like older trucks do. It's all electric nowadays.
 
#4 ·
Miss

Roary & Justin,

Roary, where is the plug to unplug the turbo? Can I run it on the highway without this electrical connection to test it for about 8 miles? As I said, when I get to about 65 mph & even up to 75 mph and level out on the speed, then I can barely feel the miss, but once I put the cruise control on, I can feel it better.

Justin, the missing/surging while in Park is as follows: I can put a pry bar between drivers seat and gas pedal at around 1500 rpms, and then you can see and hear the motor going up about 150 rpms from where I set it back down to around 1500 rpms, and it keeps cycling like this. As for the miss on the road, when I get to about 65 mph & even up to 75 mph and level out on the speed, then I can barely feel the miss, but once I put the cruise control on, I can feel it better. As for black smoke, I only get a small cloud of black smoke if I let the truck idle and then have the some rev the motor up to 2500 rpms or so. I was told that if it was the injectors, then I would see white smoke as unburnt diesel fuel.

To all, thanks for the help but any advice would be appreciated.

I will try anything at this point
 
#6 ·
Try what roary said and see if it changes. The plug is right on the front of the turbo. It goes to the solenoid that controls the vanes in the turbo. What year is this truck? Does it have the boost gauge in the dash? Do you see the boost fluctuating with your surge?

It's kind of hard to tell if your talking about just a surge problem or and actual miss/shudder. There 2 different things really.

If it's only a light shudder when youre revving it up not under load, and it's just a slight shudder when you're driving, I would try getting it reflashed. What RPM's is it most noticable at when driving? RPM's are more important then actual MPH as far as trying to narrow it down. Try lugging it in lower gears and see if you can't get it to do it. I bet it does it then also, and is probably most noticable when keeping it between 1500-2000 RPM, especially when under load like pulling a slight hill.
 
#7 ·
Justin, it is a 2004 and yes, the range is about 1500 to 2100 rpm when out on the highway when I feel this miss/shudder, but it is less noticable if I leave cruise off and fluctuate the gas pedal. You are also correct about it being noticable when going uphill, so therefore I do not want to pull anything until I get this thing straightened out. Others say it might be a stuck injector or two, but wouldn't I be seeing white smoke? Another concern is that with a stuck injector, would it not be missing consistently, because I can be at several stop lights and it idles great, and then another stop light it might idle a little rough, so it is not consistent. Can I run the truck for about 8 miles without the plug on the turbo? As for the surging, like I said this happens when I have the prybar between seat and pedal and set at about 1500 rpms, it will then fluctuate the rpms up and down within about 200 rpm difference. Please, everyone jump in and let me know your thoughts.
 
#8 ·
It could be signs of a pending injector issue. Depends what parts of the injector is acting up, if it's more of an electrical fault or a mechanical fault with the injector.

I really wouldn't sweat it if it's only intermittent like that. I would really try the reflash and see if it doesn't take care of it.

The reason I'm suggesting this is I had a truck that did the exact same thing. It had all the same symptons your describing. Had it reflashed and it smoothed out. There have been alot of updates to the programming on these things, especially if it hasn't been updated recently.

You could run the truck with that turbo plug undone, but I don't think that's your issue. That problem would cause a very noticable engine racing. It would be jumping around RPM's when your driving, like you were mashing off and on the throttle consistently.

Try and get the thing reflashed. Ford is usually pretty good about doing it, it runs about $100 bucks here in MD.
 
#9 ·
Yes, you can run it unplugged, but you will have very little acceleration and a LOT of black smoke plus you will throw codes so be aware of that. What oil (brand and viscosity) and filters are you using? Just curious mainly but that could play a part in it as well if it is HP oil related.
 
#10 ·
Roary, I had Rotella T 15w-40 put in the the Motorcraft oil filter. The gentelman who sold it to me was not sure when his dad had changed the oil last. This is an 2004 with 234,900 miles. I know my 7.3 diesels, I could get 500,000 miles easily as I maintain my trucks very intensely. How could I check the HP oil pressure? I have one guy telling me it might be an injector or two thst is stuck closed, but here is my thoughts. I can run the truck in town and be at several stops lights at idle and the truck runs fine, but then every once in awhile I will come up to a light and then it idles rough. So, would this still be a sign of a stuck closed injector or what else? I will try the turbo test, remove the egr and look inside to see if it is wet, check the FICM again, check the ICP sensor too. If I have to replace the ICP sensor, do I need to use Motorcraft? Thanks, and this is open to all as well to comment on.
 
#11 ·
Justin, it is going to get reflashed today as I am sure it hasn't been reflashed anytime recently. I did unplug the turbo and ran it down the road, here is what happened, no acceleration, but no signs of smoke neither. I will let you know how it is after the reflash and hopefully this will straighten it out. The guy told me that his father had the batteries unplugged for about 2 weeks last year when we was having issues with his alarm system which shorted out and would not allow the truck to start until he removed the alarm system. Could this 2 weeks have caused any reflashes to be null and void? It is gettting reflashed today for sure though, already have my appointment set up.
 
#12 ·
Reflashed

Okay, it is flashed and it seemed to run a little better. I then let Ford change the oil to Rotella T5-10w30 and it seems to have helped it even more and that was just 10 miles from the dealership. I am trying to decide if I should chance pulling a little 14' car hauler with me to Texas now, as we are trying to make it to Texas as our daughter had her baby. This truck has put our dates back quite a bit, but I would like your opinions. Thanks
 
#13 ·
Well at this point, I think I would put the car hauler on behind it, load it with whatever you are planning to take, and then take an hour or two drive and try to pull some grades with it. Since you have put all this other money into it, a couple of hours worth of fuel and time is cheap compared to peace of mind.

While you are doing this drive, I would try to monitor everything that you could. If you don't have gauges or something like an Edge Insight, I would highly recommend it just so you know what your truck is doing. Plus during the 1-2 hour drive you would have some base lines to compare to the readings you will get on your drive to Texas. It may be enough that if you start having problems you will catch it before it becomes disastrous.

Just curious, what part of Texas? I'm just N. of Dallas.
 
#14 ·
Roary, we are now in Deer Park, TX on the Southeast side of Houston. I have some excellent news. I stopped by one of the tractor shops and talked to a real diesel mechanic rather than the young Ford techs who couldn't help at all. These diesel mechanics advised me to go get my oil changed to Rotella T-5 10w30 and also add 3 ounces of Lucas Diesel Injector cleaner to each 10 gallons of diesel. He told me that within 50 miles of doing this that I would feel the sticking injector performing better. In fact, he said, drive your truck with the car hauler after I got the oil changed and add the additive and he was confident that my problem would be solved by 500 miles. He is so right, because now my truck is running so smooth and he advised me not to buy the PowerServices as he considers it junk and after using his method, I have to agree with him now. So, we made it to Texas with no problems and the truck runs so smoothly. Thanks to everyone who replied.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top