Wastegate Solenoid Question

[dieseldaver]

I lost boost from my turbo, and can move the wastegate with my hand while my '94 6.5TD is idling, so I figured it was the solenoid. I went to the dealer, and they tell me they have 2 different wastegate solenoids for the truck, one with a little vent thingy, and one without, but they couldn't tell me which one was the correct one. They did tell me to go have a look at mine, and it's the one without the vent, but I was just wondering what the one with the vent was for?

I'll be able to put it on tomorrow morning. It was raining here tonight, and the garage is full of my other crap...

[Barry Nave]

Make sure you have at lest 20 in. at the pump.
Sounds more like a pump issue ;)

[rjschoolcraft]

The one with the vent is likely for an EGR equipped truck.

One other possible failure scenario is a failure of the actuator itself. I posted info on this in the post "Significant improvement in towing performance!" (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=005059) The rod broke off where it attaches to the piston inside the actuator.

[moondoggie]

Good Day!

You might want to do a search

[MTTwister]

Are we talking the wastgate solenoid -( which I gather is the electronic control for the vacuum - or the 'vacuum can' on the turbo ?

[moondoggie]

Good Day!

[DickWells]

Dieseldaver: If you can easily move the actuater rod on your wastegate while the engine is ideling, then you probably don't have a solenoid problem. Check the vacuum lines for leaks and check the vacuum that the pump is making at idle. My pump on my 95 Sub. always reads about 20 at idle at about 750 ft. elevation.
I've been running without a wastegate solenoid for almost a year now (24k miles) with good boost control. I run at around 5 psi at 75 mph solo on a flat and about the same at 60 mph while towing. On a climb, I can see up to about 15 psi while towing. Whenever I used to lose boost with the solenoid hooked up, I would see the EGT climb rapidly. If I backed off and came back onto throttle and got a downshift (and) got boost back, then the EGT would plummet back down.
I have Kenedy's boost control and a large SpearCo IC, so 15 pounds, tops is not of much concern to me.
Why no wastegate solenoid? Well, I've had two of them quit working and when I simply jumped the little plug-un vacuum connection at the solenoid with a piece of neoprene hose, I got my boost back and had no more related problems. I don't know why I don't have runaway boost, and at this point I don't care. I always have the SES light on, of course. I always throw a code 78 (wastegate solenoid fault). I just live with it.
Moondoggie knows his stuff with thes issues, but I'm too old and electronically illiterate to understand his expenations. I can't wait to get my mechanical IP in there next summer so that I can (maybe) get a few thousand on the old gal without a hiccup or stall every once in a while.
Dick Wells

[ucdavis]

My rig has no EGR, but has a small sponge cover over a vent, if that's any help.