Blew a head gasket...

Rodney87GN

Well-Known Member
Joined
Feb 1, 2004
...a few weeks ago. At the time it happened so fast I didn't know what caused it...wasn't paying attention to the gauges or scanmaster. Just taking a test drive after finishing up installing a complete Autometer gauge set into a GNX style panel. I got up to 26 psi of boost (just to make sure the boost gauge works :biggrin: ) and that's when I popped the passenger side head gasket.

Fast forward to yesterday. I finally got everything fixed and running good. Primed the ALKY and set the boost controller on low boost...time to go for a test drive. I ease into the gas and get to about 6 psi. The green alky LED is NOT coming on! I bring it up to 10 psi, still no light.

Uh-oh, I think I just figured out why I blew a head gasket a few weeks ago.

Since the alky primed with the test button, I figured it had something to do with the MAP sensor. Then it just TOTALLY dawned on me....when I did my GNX dash conversion, the MAP sensor no longer gets its 5V or ground anymore. Razor even tells you this in the instruction manual.:redface: Unfortunately I installed my Alkycontrol kit a long time ago before I did the dash conversion, so I didn't even think about it.

I followed the directions in Razors kit to supply 5V to the MAP but took it one step further. Rather than run the wiring in the engine bay I did it inside under the dash. I ran a wire from pin C14 on the ECM to pin B (gray/blk) at the clear connector behind the glove box. This supplies 5V from the TPS gray wire to the MAP sensor. And I ran a separate ground for the MAP sensor from pin G (blk/wht) at the same connector behind the glove box. 30 minutes later, it works like a champ.

Sooo, chalk it up as a lesson learned...no one else's fault but my own. And for those doing an aftermarket dash with Razor's alky, don't make the same mistake I did!
 
Two more notes.. anytime a change is done to the car.. bring the boost down and work your way up. This applies to pretty much anything..

You may want to get an audible knock sensor.. those things can save you when your motor when your not looking.

At least you figured the problem and not go to 26 PSI to realize the same issue again.
 
Two more notes.. anytime a change is done to the car.. bring the boost down and work your way up. This applies to pretty much anything..

Thats what I normally do, but who woulda thunk a dash change can blow head gaskets...;)

But yeah I was more careful this time trying to find the cause. With the rash of bad Walbro pumps going around that was my first thought. I'm just glad it was an easy and free fix.
 
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