Little help please.

[REakin]

Hey all! Having some troubles lately with a goofy ticking sound in the engine. Usually between 10 and 20 lbs boost accellerating moderatly with a load. It starts to tick and the boost gauge bounces up and down about 5 psi. If you back out of the throttle she quits and you can push her on up to 30 psi no troubles. It will do it with out a load but I don't really need push it to that point.



I've tried advancing the timing a little seemed to make it better, but I don't want to go too far.



93' BTA- intercooler isn't plumed in yet

220 horse bosch injectors (what the guy at the pump shop called them)

Piers cam

Stock turbo with wastgated housing.



I can drive her without letting her do it, but it's annoying when your trying to merge onto the interstate pulling 6,500 lbs of mowing equipment. tick, tick, tick, tick!

 

[cerberusiam]

Check your waste gate and actuator and make sure it is alright. It sounds like under certain circumsatnces the wastegate is fluttering. Could be plumbing, sticking, or something else. Hope this helps.

 

[Paychk]

Originally posted by REakin

87 Chevy 4 door cab and chasis, 6BTA from a 93, ballanced, PDR cam, stock turbo with 14cm wastgated housing (blocked), 220 horse Bosch injectors, new pistons . 020" over

The sig line says WG is blocked, I would think the boost gage bouncing would indicate a leak some where in the pressure side of the turbo. I would check all the rubber boots and clamps, then the pipes themselves.

 

[REakin]

I guess it's possible for it to be leaking..... but would it sound like a ticking and then be able to hold at higher pressures? ... I guess I'll go check out my plumbing and be sure the waste gate is still closed off. I hope that's all it is.

 

[dpuckett]

How long has it been doing this? If it is a stock turbo, it may just be the normal fluttering of it, I've had a few that did that. Very noticeable with an open exhaust. Doesnt sound like a head gasket, though not many had heard of a bird chirping/ screeching being a blown HG, either. Have you checked your valve adjustments lately? New parts, new overhaul. May need fine tuning? Just a thought. ALsoi check the line coming in to the boost gauge and see if it is cut, crimped, etc. I had one come apart on me one time, and it made an awful racket inside the cab. (then-)Fiance thought it was gonna blow up.



Daniel

 

[REakin]

I adjusted the valves the first time I noticed it, still ticked. Tried again. still no change. Can't find anything wrong with the plumbing... . didn't think to check the gage though..... Guess it's next thing... . I wouldn't think it's the head gasket the engine's only got about 3,000 miles on it. But never the less.....



Hey, could an exhaust leak be intermittent? kinda sounds like a cracked manifold type tick..... Guess I could look at that too! never heard one that didn't just tick all the time though.

 

[dpuckett]

Check it out. Good excuse, er, uh, I mean, REASON for an ATS manifold. The manifolds are known more for shrinking than cracking on 12Vers, but it has happened. Check the gaskets for soot around them.



Head bolt retorque may not hurt, esp just after a rebuild/ upgrade.



-DP

 

[JLEONARD]

Speaking of soot around the exhaust manifold... .

will these seal back up with new gaskets? Or is that a losing battle?

Jay

 

[dpuckett]

Jay- normally if you sand them down- head and manifold, they will reseal. Now if stuff aint lining up just right, they will still leak. Careful of the bolt on the end, they like to break off in the head.



-DP

 

[MMiller]

Mine will do that with the stock turbo, loaded heavy, and low rpms. I first noticed it when hauling heavy 20,000 gross+ at 55 mph in over drive. Drop to 4th at 55 and the problem goes away, or run 65 and no noise. Boost guage flutters between 20-25 psi. The other day in high winds loaded 28,000, i noticed it when shifting if I short shifted it. If I let it rev up to near the governor before shifting then it was ok. My truck never does it empty.





This was talked about a while ago. I think(ie opinion) with plenty of fuel, and higher than stock boost numbers at lower rpms, maybe the turbo is stalling or stuttering, because the air is not getting away from it fast enough. The engine running slower rpms, the valves only moving so fast will only let so much air in. Coupled with the fact that the truck can't accelerate as fast the air flow is much more choppy, not as smooth.



Does this make sense? Is it possible to be pushing to much air when loaded at low rpms? Pastor, what do ya think. Hey Ron you tow with big turbo, granted you have 24V head. Anybody else?



Michael