code 78 and 87 with turbomaster installed..

[mobilevet]

Got a code 78 and 87 the other day. There was no change in performance. I've had the turbomaster installed for several years, but never had any codes so I never bothered with a boost fooler.

Can someone give some insight on :

1) if I need to go to the trouble to do the fooler?
2) Ignore the 78 codes?
3) Why now, not for the last few years?
4) Why the 87 code?

Thanks!

[JohnC]

87 is a trans code.

Check the wastegate to see if it is free. If it is getting hard to move that could account for the change. Or, did you change the exhaust or air filter?

You could have been getting one code off and on for a while and the other other code finally lit the light.

If you can't find anything, clear the codes and see which one (if any) comes back.

[mobilevet]

Thanks John,

I'll check the wastegate to be sure it is still moving free... no changes on any filters or exhaust parts recently... the 78 code was first and then the 87 when I checked them... don't know if they typically are sequential as to the occurrence???

I checked them by jumping the lead and watching the flashes... is there a way to clear the codes without a reader?

thanks

[JohnC]

The codes always display in numerical order.

IIRC, to clear the codes you hold the accelerator and brake down together for 5 seconds while the codes are being displayed. Pull the jumper out while still holding the pedals down, then release the pedals. I think it may display code 12 when the codes clear, but I also recall it was a little temperamental.

[mobilevet]

great! thanks.

[mobilevet]

ok... cleared the codes (nice) and got some more lights yesterday while out... only the 78 code this time...

still no change in performance.

checked the turbomaster and it moved freely

????

[JohnC]

Under what conditions does the light come on?

If you're not towing or otherwise loading the engine, you won't notice a change in performance.

[mobilevet]

No, not towing... just running down the interstate about 65 mph (rpm's about 2.2k)... doesn't seem to come on as much (at all?) when running down county roads (55 mph)...

[mobilevet]

Ok, we now have a power loss issue. I'm still getting the code 78 off and on, but now at even lower speeds (55mph).

Also, this time I checked, there was a code 85 (last time it was 86), guess this is a trans code also, so it may be a red herring in terms of the 78.

A few days ago I noticed that when on cruise and going up a hill after the down shift there wasn't as much "pull" as normal. Today, it happened again and then I realized that even when accelerating through the normal 1st and 2nd gears when it it 2k rpm I was getting black smoke (same when down shifting on a hill - it would jump to 2.5k rmp and have no appreciable power increase).

So, with the code 78, black smoke, and power loss that seems to me to be a turbo boost issue... HOWEVER... I am running with the turbomaster so this can not be an electrical or vacuum issue.

So, what is it?

I removed the intake side of the turbo and the turbine spins freely and smoothly.

What's my next step? pull the turbo? if so, what am I looking for?

[mobilevet]

Ok, I checked the cross over pipe for leaks, it looks fine - no rust at all. So I pulled the turbo. I did notice a lot of soot on the wheel-well and some on the valve cover area. After off, I split it and checked the wastegate - looked fine and worked fine... the turbine spun freely and no slack. The base where it sits on the exhaust manifold looked like it very well could have been leaking. I think I know what might have happened: about 6 mo ago I had to remove the turbo to fix a cracked valve spring. When I put it back together, I assumed that it needed a gasket between the turbo and exhaust so i made one with some felpro gasket material.. i think that over time the heat just torched the gasket i made and that made the connection very leaky... it was very easy to remove the nuts/bolts which might have been because it was loose (from loss of the gasket).

Let me know if you think this makes sense or if I still need to be looking for a problem... in the mean time I'll be putting the turbo back on...

[mobilevet]

turbo back on... short test run.. smoked at first, but then I think it stopped was getting dark at the end so I'll have to try again tomorrow.

(also, there was a ton of soot in the air box [snorkel removed] and filter was black [will get a new one asap])

[mobilevet]

no smoke, power back, no SES... 60 mile round trip today interstate and back roads... thanks for having a great forum.