Wastegate problem - overboost/ ECU cutout

Quickstop [UK]

Quickstop [UK]

Combating adversyty.
I am now the proud owner of a 1992 white GMC (Saudi) Typhoon! Very pleased.

OK, the problem:

I messed around with the wastegate as the actuator appears to be sticking.

1) Drove car in the morning and the boost would cut out .

2) Later that day, tried to move actuator but it was stiff and appeared stuck almost.

3) Set it fully to the rear (wastegate open) and no problem with the ECU cutting out. Turbo took a little longer to wind up but it eventually got there though it did feel a little less powerful than I was hoping for.

4) Tried it with wastgate actuator closed (fully forward?). Power was not as good, but it still didn't cut out. I was expecting loads of power, quick response with quick cutout - not what happened at all.

What could be the problem?

Is it a vacuum operated wastegate or an over pressure wastegate?

Is the solenoid activated to close the turbo, or does the solenoid move the actuator? Where can I get detailed info on how to fix it?

I also need a MPH display for the dashboard / console. I have loads of questions now, but love my new car. Pictures to follow!

cheers,

Q
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: Wastegate problem - overboost/ ECU cutout

pat,

cheers buddy! Did you find a replacement wastegate that fits the stock turbo or did you go for an external wastegate?



Cheers for your help - keep it coming!
where are you? Am in UK.

Q
 
L

LandryPoole

New member
Re: Wastegate problem - overboost/ ECU cutout

Hello, I just bought a Typhoon, and am so happy I can't stand it, but it does have a problem, and I just read about it. When I step on it, the boost gauges peggs, and it acts like it has a terrible miss. It does not do the miss think under boost lower than pegged. DOes this sound like the W/G? If so, what do you recommend?
 
dirtdemon

dirtdemon

"mr. ghettowrench"
Re: Wastegate problem - overboost/ ECU cutout

army helo pilot said:
pat,

cheers buddy! Did you find a replacement wastegate that fits the stock turbo or did you go for an external wastegate?



Cheers for your help - keep it coming!
where are you? Am in UK.

Q
Click to expand...

the orig. WG is an integral-style , nothing to replace ... would have helped me also, then :squint:

external is an option, tought about it - but there IS a con : external WG cant be controlled by the ECM ... so when it knocks it knocks the hard way :rotf:

- im located in austria (the lil country next to germany *gg*)
 
dirtdemon

dirtdemon

"mr. ghettowrench"
Re: Wastegate problem - overboost/ ECU cutout

LandryPoole said:
Hello, I just bought a Typhoon, and am so happy I can't stand it, but it does have a problem, and I just read about it. When I step on it, the boost gauges peggs, and it acts like it has a terrible miss. It does not do the miss think under boost lower than pegged. DOes this sound like the W/G? If so, what do you recommend?
Click to expand...

fawk the stock gauge - its just an optical gimmick *lol*
get an aftermarket gauge (-30 to + 30 should do best, when starting lab on boost ;) )
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: Wastegate problem - overboost/ ECU cutout

any recommendations where I can get an aftermarket guage and how to fit it?
 
JSM

JSM

Active member
Re: Wastegate problem - overboost/ ECU cutout

If you remove the actuator does the flapper move freely?

Have you searched and found the proper wastegate adjustment procedure?

Do you have a scan of the truck running, driving that we can see?

Overboost cutout is due to the computer shutting you down. Bad news is each syty is only loaded with X # of those shutdowns, then the motor will blow up. I try not to find out how many X's are in each truck myself.
 
Flyin Ryan

Flyin Ryan

hated cuz he drives fords
Re: Wastegate problem - overboost/ ECU cutout

So basically what JS is trying to say above is keep your foot out of the gas until you get this issue resolved or else your motor will go Kabooom..

The "miss" feeling in boost is due to the ecm trying to save your motor by preventing too much boost to occur.. so what I would do is the following.. they are not in any special order by the way.

Check and replace all vacuum lines especially at the map sensor because vacuum leaks have been known to cause this common problem.

Has your exhaust been modified?
If it has and it's a stock stock turbo/wastegate truck which it sounds like it is..Then that is most likely your problem..the stock wastegate setup can't handle or has problems with handling the increased flow from what an opened exhaust or more flowing exhaust gives.. so it can't keep up which causes this issue. Once you have found this to be the problem do a search you'll find how porting the wastegate will resolve the problem or going external etc.. but that's a whole nother can of worms. .

If your unsure then you could possibly check this by disconnecting your wastegate solenoid(orange/black wire that plugs into your wastgate and sits in the front of the turbo useally)
The reason why I suggest this is because the electrical imput to the selenoid is to increase boost above the 8psi base pressure.. so basically if your exhaust is not the problem then you will only see 8psi of boost max. If it still rises too high then most likely you have too free flowing of a exhaust system for the wastegate or your wastegate isn't functioning correctly (stuck or sticking etc)

Check the wastegate out and the flapper.. try adjusting the wastegate some.

remove the WG rod from the flapper arm, you should have 7/8 pin covered by the rod, or preloaded. remember if your over boosting then you want to make it longer.

http://syty.org/old/d&e-code31.html

If you can't sort this problem out and need to drive the truck and you only got 8lbs of boost max when unplugging the boost solenoid from one of the steps above.. then leaving that unplugged would be a good idea until you get this fixed.. that way you won't risk running wot and killing your motor.

Also I might as well mention this so for any future problems you can dig into a bit more first.. http://www.sportmachines.com/maintenance/aldl.php
 
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