Engine/Transmission (1998.5 - 2002) Intermittant Loss Of Boost

[cwsoules]

Twice in the past few days when starting off towing I have lost boost pressure. My truck has 101,000 miles on it and has towed a 10. 4K 5th wheel for 49,000 miles. The first failure came on departing from a RV park but after about 5 minutes of towing the boost returned. A few days later after towing for a while I stopped for diesel and shut off the engine, when starting off again there was no boost. I left the engine running and rapped the turbocharger with a tool and I got boost back.



The inner cooler hoses were tightly atttached. Besides a loose innercooler hose would not reconnect restoring boost.



The Dodge diesel mechanic measured the fuel transfer pump pressure and found it to be low. He believes that this is the cause of the intermittant loss of boost, and the turbocharger is OK. I certainly hope so as I cancelled the change out of the turbocharger and approved a new fuel transfer pump.



The mechanic thought that if a bearing is going bad in the turbocharger and the turbo would not turn, it is unlikely to allow the turbocharger to start up again and work OK for several more days.



Any comment?

 

[Timbeaux38]

Is your truck throwing any codes? Sounds like an Injection pump. .

 

[cwsoules]

No there was not check engine light. The mechanic said the low transfer pressure would restrict the flow thru the injection pumps. He thought the injection pump was OK.

 

[nps]

If the truck is running and you have good EGTs (high enough to drive the turbo) then the LP could not cause a loss of boost. Also I don't believe hitting the turbo would cause it to come back on after a boost loss.



Given that you don't complain of anything else other than a loss of boost pressure reading (no low power/excessive smoke/lagging) then I would suspect your gauge is sticking or the boost line is plugged.

 

[cwsoules]

I thought about the gage being bad, but when I had no boost the truck developed very little power and my EGT went very high when I tried to accelerate. I had an event years ago before I had gages when an inner cooler hose blew off. The truck had very little power then and this led me to believe the lack of boost pressure on my gage was accurate as the engine developed little power. Once boost came back the engine developed normal power. I did not check my exhaust so I can not tell if I was smoking badly when I had no boost.



When I have boost the EGT is running in the normal range and the power seems normal. In the mountains going up a grade the EGT rises to 1250 while the boost gets up to 18. At 1250 I back off on the throttle to keep EGT at or below 1200.



My real concern is that we are heading for South Carolina and are now in Phoenix heading East. If the turbocharger dies we will be 2 miles from nowhere.

 

[nps]

Well, that's a bit different description. Sounds more like your wastegate is sticking open and dumping all your boost. Would also explain why rapping on it would make it start working. If it's under warranty get DC to change the turbo. If not, then j hook it closed and the problem should not reappear, although you may get an overboost code and the resulting defuel if you get too high of boost.



on edit - see you have a EZ so an overboost code should not be a concern. Have you already j hooked it?

 

[RDHamill]

I had a similar thing some time ago, my MAP sensor was NFG.

Once replaced the truck worked great.

good luck

 

[cwsoules]

Update

The new transfer pump did NOT solve the problem. I have more power but have had to tap my turbocharger with a wrench twice in the past few days to keep on heading East to Columbia, SC. When I get there I'll look into replacing the turbocharger. All I need to do is successfully complete my tow. Currently we are in Tow, TX with alot of USA left to cross.

 

[TGibbs]

Sounds like the wastegate, turbo is still good I bet. The j-hook will get you to 26 psi boost (which is where the turbo is the most efficient) and it should also stop your no boost problem.

 

[LostTrucker]

I would have to agree, it could be the waste gate on the turbo or it could be your pacbrake stuck on. I have seen alot of exhaust brake problems, not just pacbrake brand. :{

 

[NoSeeUm]

I would have to agree, it could be the waste gate on the turbo or it could be your pacbrake stuck on. I have seen alot of exhaust brake problems, not just pacbrake brand. :{

This was my first thought also. But in my case this will only happen to me if I have the cruise and the exhaust brake on at the same time. No way can I even get to 50 mph with out pegging the EGT. I doubt you could do it with a trailer in tow.



If it were me I would still check it though, as an option, because it might not be sticking all the way closed. As an example, some where in a TDR thread I read where I guy had his engine torn down searching for a problem (by a dealer) when it turned out to be a bad hose on his Pac Brake.



Jim

 

[cwsoules]

What is a J hook and how would I use it? Just about daily I have to rap the turbocharger to get it to provide boost. Sometimes it when I start off and other times it happens when I decelerate and boost drops low in slow traffic. My smart box is also on when I use the exhaust brake, but I can not see how it would affect the boost.

 

[cwsoules]

I just looked at another post about the J hook. It talks about a boost of 30psi. The highest I have seen in my truck is 18psi without exceeding 1200 EGT. My truck seems to have good power, but with a J hook would I get alot more power?

 

[BManuel]

Not more power, just a lower EGT.

 

[cwsoules]

Thanks, but I still have no idea of what a J hook is or who sells them. A google search leads me to fishing hooks and clothes hooks. Can you tell me who sells J hooks?

 

[NoSeeUm]

Thanks, but I still have no idea of what a J hook is or who sells them. A google search leads me to fishing hooks and clothes hooks. Can you tell me who sells J hooks?

I can't really recomend a J-Hook plus or minus. Never used one. I am just trying to ease your frustration.



But I did do a search here on TDR using the search function. If you want to do that search for "J-hook" (use the quotes), and you will get alot of hits.



Check here for a TDR thread



Check here for a vendor that might sell them



Good Luck;

Jim

 

[cwsoules]

Thanks Jim. The J-hook vendor xdescription says that it is for 2001 and up cummins diesels. My truck is a 2000.



I'm still not certain what is wrong and would hate to replace the turbocharger and not have it solve the problem. i assume the waster gate is a part of the turbocharger on it's discharge side.

 

[NoSeeUm]

Hm... .



Give them a call. Don't quote me on the year, but at some point the waste gate actuator mounts on the turbine casing then switches to be mounted on the compressor housing. If they know this they can probably get you what you want.



You if it were me, and in your case, I would just take off my turbo and have a look at the waste gate and or the waste gate actuator. I mean that may not even be your problem.



At any rate, be certain that you want to disable your waste gate if you decide to go with a J-hook.



Jim



Jim