Engine/Transmission (1998.5 - 2002) turbo bark/surge???

[turbo lcc]

Since the cold weather my truck has been surging at higher RPM/boost. Now this morning I was starting up a hill about 25lb of boost and all of a sudden the turbo barked and boost dropped to 0lbs then started to climb again. The rest of the way to work the truck ran fine?????? Any ideas????

 

[Bob Wagner]

chances are you blew one of the boots off. check your clamps too

 

[turbo lcc]

I check the intercooler hoses. . all ok. . and it would build boost after it did this????

 

[tcourse]

Was truck warmed up? Mine does not respond to a lot of go pedal when it is cold.



TC

 

[Alan Reagan]

When it's nice and cold, these engines have to be warmed up some. The engine will surge and you'll hear the VP44 surging with it. The surge and then attemt by the engine to "right" itself probably caused the bark if you were under high boost. You might want to take it easy when it's cold until the temp gauge starts to move up before you do any hard acceleration.

 

[turbo lcc]

Is should have been warm at that point I drive 80miles to get to work and I was about 60miles into the trip. . It was very strange. . It was just like if I let off the go pedal all at once the floored it again???

 

[Car_nut57]

Maybe the waste gate blew open momentarily or the engine shut off for an instant. If the engine isn't running you don't have any pressure to operate the turbo.

 

[Alan Reagan]

I'm not sure how cold it is there, but you might have been close to having the fuel gel on you causing a slight disruption in fuel flow. Just a thought.

 

[turbo lcc]

I don't have a wastegate so I am sure that is not it. . and the weather is around 30ish. . That should not be cold enought to gel?? right??? Thanks for the feedback

 

[Alan Reagan]

Nah, it won't gel at 30.

 

[jconnolly]

Originally posted by turbo lcc

Since the cold weather my truck has been surging at higher RPM/boost. Now this morning I was starting up a hill about 25lb of boost and all of a sudden the turbo barked and boost dropped to 0lbs then started to climb again. The rest of the way to work the truck ran fine?????? Any ideas????

you may want to check your fuel pressure if you don't have a guage but you will have to watch it till it acts up. I have had several customers with failing lift pumps that were just like you turned of the key for a second. Not sure about turbo noise but could be same thing!!

 

[zman]

Well, a sudden drop in boost is probably one of two things - boost leak or lack of fuel. Given that your clamps/boots were tight, you don't have a wastegate, and this doesn't happen all the time; I'd guess it was a momentary lack of fuel. It could be the lift pump, the injection pump, or the EZ. I mention the EZ because it might be failing in such a way that the ECM is seeing an overboost situation and momentarily cutting back the fuel. You might check for codes. Also check all of your electrical connections to the above mentioned items.



When I'm in a high boost situation and have to let off the accelerator quickly and fully, I'll occasionally experience a turbo surge or bark. The turbo is actually spinning backwards when this sound is made.



So based on your comments, I'd say you are experiencing some sort of momentary defueling situation.



Steve

 

[KWIKKURT]

Turbo Icc,



Jconnolly's Idea of low fuel pressure is the most likely suggestion.



The 24V Lift pumps fail all the time.



I have also have seen a electrical Gremlin from the boxes and / or the fuel pumps spring up and never return.



When the lift pumps fail they will cause the engine to surge, Cough and Buck under load. I most commonly see this after installing a Fueling Box. The Lift pumps fail over a period of time so you don't notice the gradual power loss.



I test all 24V's when they come in for almost any repair or Performance upgrade unless they have less than 25,000 miles.





You want to check the Lift pump pressure at the INJECTION Pump and Under Full Load. I have a stack of pumps that supply 10 - 15 psi at idle and 0 Psi under load.





This condition will cause turbo to bark or Surge. The noise is the Air flow trying to reverse it's direction or to stall Compressor wheel. The Turbo is flowing at a high rate and all of a sudden the engine Doesn't want it due to lack of Fuel. This is even more pronounced with High Flow/ Performance Turbos. Although it does not reverse your turbo it is hard on some Turbo designs while other turbos can be surged repeatedlly without Damage.



Kurt

 

[turbo lcc]

Thanks for the replies. . I think I may have found the gremlin last night. It appears that the line to my fuel pressure gauge was loose and started leaking (spraying) diesel fuel last night. I thing that may have been the issue.



Thanks

Lynn