engine woes

[gkrcr882]

alright , our friend has a Syclone where when he reaches max boost the wastegate opens, and the engine shuts down to idle speed. also he lost all oil while going down the road, yet theres no hole in the oil pan. yes, this is the 400,000 mile syclone, and apparently it didnt throw a rod, but hes not going to sell it, he just wants us to check it out. i think it may have somthing to do with the computer system and the wastegate actuater, but i thought id ask the pros. thanks!

 

[GM TURBO]

Re: engine woes

Rear main. Oil filter lines.

 

[gkrcr882]

Re: engine woes

we'll be sure to check that. hes letting us take the truck home to try to figure out whats wrong, and if we get it fixed we get to keep it for a week, so any input is appreciated.

 

[Syclone#892]

Re: engine woes

Hey whats your name? I know a few people that go to that school just wondering if you know them.

Oil Leak could be pretty much anything, oil line at turbo, oil drain line, oil cooler lines, front/rear main seal, oil pressure gauge sender, etc. If it leaked it out quick then pour 5 quarts in and start it up and see what it does.

If you need any help let me know I'm a couple miles away.

 

[gkrcr882]

Re: engine woes

thanks for the input. I think the oil thing will be an easy one to fix, but the main concern is the high boost to idle issue. I think it may be because of overboost, and the computer is overcorrecting. if so, how can the wastegate be adjusted so its within the proper margins, as this is a stock truck. also, can a clogged cat cause the overboost problems? thanks!

P.S.- my name is Jeff H, sorry I cant tell my whole name, being an online board and all

 

[TYTILIDIE]

Re: engine woes

If your going to idle @ WOT, it sounds like a tranny issue. Its hard to say, give more details. Is there oil in the pan or is it all gone? DId you keep driving it this way? Ive overboosted to 17.5 PSI and my truck never did that. The ECM is supposed to cut off fuel not bring it to idle. Is there tacvh flutter?

Mike

 

[supersports10]

Re: engine woes

sounds like you should come to the april 2nd wrench session, at my house in wi, to get it figured out


theres gonna be 5-7 of us there so getting it cured shouldnt be a problem. :tup:

SS:tup:

 

[dgoodhue]

Re: engine woes

If the engine completely shuts off for a sec or two at full boost its probably overb oosting and that is th enormal ECM reaction. The vacuum lines are most likely leaking. At 400K miles it probably need all new vacuum lines even if has replacements.

As for losing oil, it has to be either burning it or leaking it, it has to go somewhere.

 

[bezerk]

Re: engine woes

As for losing oil, it has to be either burning it or leaking it, it has to go somewhere.

people can steal it too.

 

[gkrcr882]

Re: engine woes

thanks for the help everyone. I was doing some troubleshooting at school with our Mitchell On Demand program, and it has to be overboost. so I should check vacuum lines? I also printed out the driveability and diagnostics PDF from Sportmachines.net and looked through it. how hard is it to adjust the wastegate for an overboost situation? we will have the truck for a limited time to diagnose,reapir, and play with before we have to return it. thanks for the help!

 

[cloneman315]

Re: engine woes

400,000 was that right

 

[gkrcr882]

Re: engine woes

Almost half a million miles on the clock! :tup:

 

[critical]

Re: engine woes

My truck had similar problems when I bought it. The first time I floored it, the truck pulled like hell, then fell flat on its ass. A hard studder under boost usually accompanied any attempt to get into the power band. Take a good look at the boost solenoid. That was my problem. It was covered in oil,and looked really bad. I replaced w/ a new one, but even that did not help much. So I disconnected the hoses to the controller, and used a hardware store needle valve instead. SHAZAAM!