Archived Turbo with low boost. Need help!

[Ramtuf1]

The same thing happened two weeks ago and took to dealer. Reading only about 10 to 12 PSI on the boost gauge. Tech says that waste gate stuck and was going to order new turbo kit. He also indicated computer had code set of over boost condition also. I indicated not to order kit as the turbo/waste gate kit over $2000. 00. He did indicate that turbo was working for him at the time I had it in.



It worked for a week or so and now low boost again. Fluctuating between 10 to 14 PSI but no 23 or 24 PSI which I normally see (stock engine) when I pull my camper and get into it.



Since I'm paying the bill now and not warranty, can I monitor the vacuum signal to be sure it is getting a signal and if so, get a waste gate separate from a turbo kit? Is there anything else I can do to check the waste gate for sticking condition? New at this as I have always had it to dealer for service under warranty. Appreciate any help I can get. Heading to Charlotte, NC in a month with camper.

 

[tp0d]

If you have a boost gauge, disconnect and plug the wastegate fitting, and use your right foot as a wastegate. This will let you know if you have a boost leak, or exhaust leak rather than a wastegate problem. Do you hear any hissing from the engine compartment under load? When you have low boost, do you also have high EGTs? if theyre low, your computer is sensing the overboost and going into limp mode. You may need to get a boost fooler. . (sorry i`m not much on 24v's)



good luck



-j

 

[p-Bar]

you can buy the waste gate from Gale Banks

 

[Graphic man]

i would also look at the MAP sensor if it is bad it could give a over boost and de-fuel the truck and inturn you will see low boost on your gage, and it may or may not set a code



Scott

 

[Ramtuf1]

If you have a boost gauge, disconnect and plug the wastegate fitting, and use your right foot as a wastegate. This will let you know if you have a boost leak, or exhaust leak rather than a wastegate problem. Do you hear any hissing from the engine compartment under load? When you have low boost, do you also have high EGTs? if theyre low, your computer is sensing the overboost and going into limp mode. You may need to get a boost fooler. . (sorry i`m not much on 24v's)



good luck



-j

With regards to hissing under the hood, the answer is no. I have had instances where the inter-cooler hoses have parted so I'm familiar with that. If I disconnect the vacuum, should I see the boost go back up to the normal range under a load or what should I expect to see and how should I test that condition?



My EGT's seem to be normal. I put my foot into it while towing and didn't notice any high temperatures.

 

[Ramtuf1]

i would also look at the MAP sensor if it is bad it could give a over boost and de-fuel the truck and inturn you will see low boost on your gage, and it may or may not set a code



Scott

Can I test the MAP sensor directly or should I look to see if there has been a code set.



I'm in the process of picking up a service manual for the truck as I have waited long enough. I usually do my own maintenance but since this has been under warranty, I haven't worried about it.

 

[Ramtuf1]

The turbo just starting acting up as I mentioned in my first post. I'm looking for a good approach to diagnose this thing before heading south with the truck/camper. My only indication that the waste gate is sticking is what the tech said and I don't have a lot of confidence in his trouble shooting ability.



I think I'm going to see if the boost exceeded code is set tonight when I get home. welcome any other suggestions and thanks for the above replys.

 

[Graphic man]

Boost Voltage (MAP)

0 -- 1. 045

6 -- 1. 48

10 -- 1. 75

15 -- 2. 05

18 -- 2. 27

20. 5 -- 2. 44



Hope This Helps



Scott

 

[Ramtuf1]

Appreciate the MAP reference voltages. What is best way to measure? Put DVM in line and measure dynamically while under load on road? Or is there a static test which can simulate these?

 

[Graphic man]

i just hooked up a Volt meter to the Map and went for a drive and watched the boost gage



there mey be other ways to do it, but thats what i did



Scott

 

[Ramtuf1]

I read the codes and the only code indicated was P1693. I'm going to check out the MAP sensor and in reviewing another post, I see the same information from Scott "Graphic Man" on this issue. One responder indicated he used a regulator to create a variable signal to the MAP sensor and read the corresponding voltages. I have the set up with which to do that.



If the tech who worked on my truck with the first occurence of this condition was right about the waste gate sticking, I'm wondering if it would be obvious if I remove and inspect the unit.



Any one have information on the P1693 code in the meantime??