I have a '99 7.3 diesel with 96K miles. I am the original owner. I have maintained the truck myself and changed the oil every 3K miles along with routine maintenance. I have regularly used Stanadyne to keep the injectors clean, and always change my fuel filter every 7500 miles. I don't have any modifications. At 94K miles the the truck began to idle very rough at startup. No problems in starting, just a rough idle and it smokes A LOT. (white, sometimes grayish blue smoke) It seems to do better after it warms up. It feels to me like it is missing or skipping. When I give it some throttle, the skip seems to go away. This continued to get worse and I took it to the dealer who told me I had a bad bad fuel sending unit and it needed to be replaced. It cost me $700 bucks. When I drove it away it seemed to be better but the next day, it was right back to the way it was before. I took it back. Then I was told I needed a new injector and glow plug. They charged me $1300 to replace one injector and one glow plug. I got screwed. The truck ran better for about a week and the problem returned. I took it back to the dealer who told me that with the age and miles on my truck that I probably had either another bad injector or glow plug that has since gone bad. I was pissed when I found out they did not change all the glow plugs. The truck and also started to surge / shake through all gears and the shudder seemed to go away when I would give it some throttle. The dealer said I need to have the tranny serviced again. After servicing the tranny the dealer told me they found a lot of clutch material in the bottom of the pan and that I needed a new transmission and that was part of the problem. I said no thanks and have continued to drive the truck. 2K miles later the problem has continued to get worse. It now shakes violently through all the gears at a low RPM. When I give it throttle it improves. I took it back and had the transmission replaced. With a new transmission, the truck is continuing to get worse and the dealer says I need to replace the injectors / glow plugs. I don't believe it and I am not going to continue to be a victim. I do believe it could be a fuel problem but I have never had any water in the fuel bowl when I changed the fuel filter. It is like the truck is suddenly not getting fuel at about 1200 rpm's and it misses and smokes. If I have the truck in park and rev the engine up it seems run great. If I get on the trottle really hard it pulls great and seems to be getting plenty of fuel and doesn't seem to be missing or skipping. I have been reading through all the posts and come up with a few things to check:
1.) Cam Position Sensor
2.) Replace all the glow plugs ( just because)
3.) Check the under valve cover wiring
4.) IPR

All the symptoms I have been having seem to be different from anything else I have found on this site so I would like to ask for any suggestions or ideas you all might have or additional things I might need to check.
Thanks.

 

Hello, and welcome to FTE.

First off, I should say, lets keep that truck away from the dealer.

Second, is your SES/check engine light illuminated when it starts to shudder?

The folks here will get you fixed up right if you are willing to get your hands a little dirty.

 

Lisa pretty much summed things up. Stay as far away from that dealer as you can. You've wasted thousands of dollars for nothing.

First question, does the Check engine light (also known as CEL or SES) come on? We need to know if you're issue is throwing any codes.

 

3x do not go to the dealer. Sounds like they are throwing parts at it (and very expensive ones too.) Like Chris and Lisa asked, are you getting a check engine light? Post where you are located and maybe someone can lend a hand.

Welcome to FTE!

 

Seems to be a fueling problem is my impression. could be injectors, wiring, or hp oil systems involved. got access to a scanner? again, ligts, codes, smoke details, etc. these all make a difference when we are thinking about your problem. i say fueling because it starts to clear with throttle. if it were tranny or something wrong with a rotating part, i would expect it to get worse on throttle (again my impression). Let us know where you are, maybe someone with a scanner is close. Scanner will let us check things like duty cycles and pressures in the HP oil system and some diagnostics on the injectors among plenty of other things. btw, don't take your truck to the parts store to get codes scanned. those cheap scanners don't work to well on these diesels.
Welcome btw

Chad

 

No. The Check Engine Light has not come on.

Thanks for the big Welcome and no, I don't mind getting my hands dirty!

 

No engine light. That's surprising.

DAI where are you located?

 

I am located in Gainesville,GA. 50 Miles NE of Atlanta.

 

Usually fuel delivery problems like a failing fuel pump will not throw a code or illuminate the check engine light. Hopefully, a member close to you can stop by to lend a hand.

 

Ok, I don't know a whole lot about these things, but wouldn't a failing fuel pump be intermittent through the power curve and not just at low rpm's? It seems like I've got plenty of fuel when I put my foot in it.

 

I had myself convinced we were looking at a sensor failure/IPR.

Now I suppose like you say focus on looking at bad fuel pump/clogged fuel pickup, restricted fuel line...

 

There seems to be plenty of fuel to the filter/bowl. Anything after the bowl that may be preventing fuel from reaching a particular injector that I might need to check?

 

No CEL can often be a fuel related issue, but the symptoms are opposite of yours. Fuel issues usually show up under load or heavy throttle, not at idle and clear up at high rpm's.

Lots of possibilities here, so we'll just have to work our way through the cheap tests first so you don't have to throw any more money after nothing. I am concerned about a possible injector o-ring(s) issue since the dealer has presumably already checked for codes & such on their computer.

First, lets start with the very basics. Engine oil is full, not past due for a change, and of the proper weight and rating? Fuel filter and air filter not needing a change? (no offense meant, we have to ask)

Are you burning or using any oil between changes? If so, how much in how many miles? Is there any signs of oil in the bottom of the fuel filter bowl? Does your problem only occur when the engine is cold, hot, or all the time? Do outside temps seem to have any effect on the issue? Is it always the same, or sometimes is it worse than others?

First free check: If you unplug the ICP sensor and then start the truck, do any of the symptoms change? (ICP is the sensor on the front inboard side of the drivers head)



Just unplug the electrical connector when you would expect to have a problem at idle and see if there is a difference.

 

Chris, no offense taken, I've done all the basics such as oil & filter change, oil level is good, new fuel filter, etc. As a matter of fact, when I changed the fuel filter last time, I evidently did not get the gasket back in place correctly and as a result had fuel all over the engine compartment. The pressure at which the fuel was squirting out and the volume makes me think that it might not be a fuel supply issue unless it is between the bowl and the injectors. I am not having to add any oil between changes, but I do have oil in the valley. That is another dealer horror story that has yet to be fixed. I will try the suggestion you made and post back the results tomorrow. Thanks.

 

You are pretty close to these guys: http://powerstrokehelp.com/

The are located in Buford down the street from ya.