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Discussion Starter #1
Well, I think it's time to take my early 99 to a diesel mechanic for diagnostics. It's been starting very hard lately. I did check the GRP and GPs and they all checked fine as far as I could tell. This past week I upgraded my exhaust to a 4" downpipe into a 5" system to the end. I thought this was suppose to be a simple upgrade with no problems. Now that I've driven and towed with the truck, it just ain't doing right. It is shaking a lot more at idle, like it has a lumpy cam feeling. When I hit the 35-45mph range the truck really shakes bad; fourth gear in this range is horrible.. I thought a bigger exhaust was suppose to give me better response, but I feel it a bit more sluggish. My thought is that by doing the bigger exhaust I may have exposed an already existing problem:shrug: . So I guess I'll find a good mechanic and have them look it over and hook it up to whatever electronics they can.

Also now with the big exhaust, I see how crappy this XLE coded shifting is. Man I need to get a PMT1 PCM.

Any thoughts?

Thanks

Tim
 

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Senior Member
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Discussion Starter #2
Here's a pic of the 5" exhaust. The muffler is in the wrong spot when I layed it out here. But it is on correctly under the truck.

 

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Ok, I did a 5" straight pipe on my 7.3, had no problems with it whats so ever. I am going to assume you have checked all of your fluids and all that. Sometimes something as simple as low oil can cause those types of problems. Also check the HP resevour. It is the box dead center on the top front of the motor....long thin aluminum thing right up top. take the little motor cover off, and there will be a plug on the drivers side of that resevour. Take the plug out and check the oil level in there. It should be 1 inch or less from the top. That could cause some problems too. If that is leaking down, it will be hard to get going.
 

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OK, also with having the muff in place, it should create enough back pressure to where you should not see too much of a low end loss in power. I had a straight pipe and noticed a little, but nothing that created any problems.
 

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The turbo creates all the back pressure needed on a turbo diesel, the larger exhaust is all about lower EGT's and cool sound, should be little if any noticeable difference unless you had a plugged CAT. the Exhaust upgrade should be unrelated to your current problem.

Josh
 

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Tim,
Is it makin any boost when it does this?
 

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TDG Mafia - Booze Runner
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the change in exhaust should not have caused your problem. I noticed better miliage and towing when adding mine. It almost sounds like a UVC harness issue especialy at the speeds your talking about. I had that a couple of times when I had bad UVC harness then the last time was an injector going bad..... Find someone to do a injector buzz test and change out the UVC first if one injector is weak ( buy it from International if your can (cheaper)), then go for there, but the exhaust is not your problem.....
 
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