I have a 99 with 270K miles on it. Over the past few months, noticed that when I start it in the morning it idles a little rough. Also, if I don't let the truck warm up for at least 5 minutes, it has problems accelerating. If I let off the gas when it does this and pull over to the side of the road and sit until it warms up, then it runs fine, but if I don't let off the gas and keep trying to accelerate the truck will die and it won't re-start unless I let it sit for a while. These symptoms are worse the colder it is outside. If it's hot outside, it doesn't have this problem.

I have the AE code reader and these are the diagnostic codes i'm getting.

P0472 Exhaust Pressure Sensor Low
P1212 Injector Control Pressure lower than desired
P1247 Turbocharger Boost Pressure Low
P0340 Camshaft Position Sensor A Circuit (Bank1 or Single Sensor)

KOER Cylinder Contribution test
P0284 Cylinder 8 Injector Circuit Contribution/Balance Fault

What do y'all think this might be? Where should I start to try and diagnose this problem. I've searched this forum but haven't had much luck finding a solution. Any suggestions will be greatly appreciated.

 

One more thing, i've put a new air and fuel filter in but this didn't help.

 

Time for injectors.

 

All of them? One of the codes referred to the #8 injector, so should I just replace that one.

Any suggestions on the best price/value where to buy injectors?

 

Does it start hard at all? I agree with injectors,but hot shot secret or revx might be an option since it clears up.

 

Poppet valves are SHOT.

No sense replacing just one...and #8 will ALWAYS show up, even when brand new.

 

It starts right up, no problem. It just idles a little rough until it warms up. The biggest problem is when you try to accelerate before it gets warm. That's when it will not accelerate at all and will start losing power and die if you don't let off the gas.

 

So I guess the consensus is injectors? Nothing else to try before I drop that kind of money?

Thinking of upgrading to Full Force stage 1 injectors since I have to replace them anyways. Or should I go to stage2 or stage 3? I mostly use my truck to drive around town and up in the woods at the hunting camp. I may put bigger tires on one day, but probably won't go any bigger than 33 mudders. I also pull a travel trailer on occasion and a tractor now and then for planting food polts. So that being said, what stage should I go with. And if I do upgrade, should I buy a chip to go with the injectors to maximize the benefit (i believe I read that upgrading injectors are worthless if you don't put a tuner chip in with them).

Thanks for the help as I've only had a diesel for about 2 years but planning on running this truck for many years to come. I love pulling into a gas station and hearing "Hey man, is that the 7.3? Best engine ever made".

 

Before you order injectors check the poppet clearance. Pull the injector solenoid and you see the armature plate(square plate) and see what us the biggest feeler gauge you can get user it. A new injector has .004 a shot injector will be .002 are smaller

 

Mine and my sons did the exact same thing, hard start and run rough cold until the oil warmed up. Pulled the VC off and there was no oil spitting on 3 of the 8 injectors when the oil was cold. We replaced his injectors last week and mine next weekend. We went with stage II's and a chip. Made a world of difference with his truck in starting and fuel economy. I would stongly recommend replacing ALL the injectors, do it right the first time and you won't go wrong!

 

While I agree that if the injectors are shot they should all be replaced at once...why aren't we trying to diagnose these codes before going so drastic a solution?

Have you ever pulled your EBPV sensor tube off and cleaned it out, and inspected it to make sure there are no holes or cracks in it? That's free to do, and cheap to replace the tube. Also, pull your ICP sensor wire off and make sure it's not full of oil...if it is, you're likely going to need a new sensor.

Have you checked for boost leaks? It could be any of your six boots, or leaking up pipes (I have that problem on HIS Excursion). If you're still running stock boots, well, at 270k, I'm sure you need new ones. Clay at Riff Raff has all of them for something like $100. Your turbo may need to be rebuilt if it's still original...270k is a lot of miles. About $100 job if you DIY.

And CPS...well, heck, that's a $15-20 solution that takes 10 minutes to replace. DO THIS ASAP!!!

Once you've done all of that, then pull your valve covers and run the engine with them off to make sure all the injectors are spitting oil properly. That very well may be your problem, but all of those other things to check will need to be addressed whether or not you replace your injectors...so do them first!

 

OK. I will definately try these fixes before dropping the money on new injectors. I've put a new CPS in not too long ago, so doubt that is it, but will try all the other suggestions. Hope to get to it this weekend if I can find the time.

 

While having these codes present MAY be a concern for some, the original poster started off by saying that:

"I have a 99 with 270K miles on it. Over the past few months, noticed that when I start it in the morning it idles a little rough. Also, if I don't let the truck warm up for at least 5 minutes, it has problems accelerating. If I let off the gas when it does this and pull over to the side of the road and sit until it warms up, then it runs fine, but if I don't let off the gas and keep trying to accelerate the truck will die and it won't re-start unless I let it sit for a while. These symptoms are worse the colder it is outside. If it's hot outside, it doesn't have this problem.

Because the exhaust backpressure sensor problem (if there is one) won't cause hard starts, a rough idle, or poor drivability when the oil is cold.

A manifold pressure issue won't cause hard starts, a rough idle, or poor drivability when the oil is cold.

A camshaft position sensor (technically CMP per J1850 SAE specs) won't cause hard starts, a rough idle, or poor drivability when the oil is cold. It will either run....or it won't.

The injection control pressure code - well, that's up for debate on what is actually causing the problem. Please see below!!!

The only thing that has my curiosity piqued is that he says the truck will die and not restart if he continues to drive when the truck is cold. I'm wondering if he has a pick-up tube issue (crack or leak near the foot) or a low oil level issue as well because when the oil is cold it doesn't return to the pan very quickly and it will starve the high pressure oil reservoir....thus introducing air into the high pressure system and causing all sorts of problems. I have seen this on a few occasions. If the oil pump pumps the pan dry before the oil has time to return to the pan, then oil pressure goes away because the pump sucks air. As the oil warms and becomes less viscous, it is able to drain back to the oil pan fast enough to replenish the supply. When the engine is idling, the volume of oil usage is low enough NOT to pump it all out of the pan when cold.

 

Well, checking the oil level is cheap and easy!

 

I want to go ahead and try the easier fixes first as don't know what was done to this truck before I had it, so may as well go ahead and do it. Then, do the injectors after that if still having problems. I'll post back after I finish the easier fixes and will read the codes again and see where we are.

Thanks again for all your responses. I appreciate the help.