I picked up myself a good inexpensive mini-regulator from Grainger the other day for $14. Its a regulator made by Dayton, a reputible company. Can't beat that price compared to some of the kits they sell. I hooked up the T fitting for my boost guage right up to the inlet side with a pipe nipple and used the same barbed fitting I already had for the boost guage T to tie it into the MAP sensor hose. Simple, Cheap, Easy.

This is the regulator I found. Its the prefect size to hide under the hood. http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?xi=xi&ItemId=1611777835

I had a new guage handy to set it at the desired pressure with my air compressor. This is where I get a little confused though.

I set the pressure at 23 psi and took it for a ride to see if the triggered the overboost and I was supprised to see it come on at under 20 psi on my boost guage? I'd never really paid attention to when it came on before. If I'm that deep into the pedal I'm usually focussed on the road. Is it possible that my truck just goes off below 20 psi? or do you think my boost guage is off?

To check when the light came on, I thought of keeping the regulator connected to the MAP line and hooking up my air compressor to it, then slowly increasing the pressure until I got a check engine light, but I wasn't sure if that was a good idea or not... could I hurt anything if I was fooling the computer into thinking that I had 20 psi of boost at idle?

Comments welcome.

 

It is possible that your boost guage is off. Mine quit reading properly for no apparent reason. You could also check your connection to the boost guage to see if it is sealing well. A very small leak at the guage connections would result in a dramatic difference in the displayed boost.

I don't think it would hurt anything to fool the truck. Difuser makes a plug that you can put into the electronic side of the MAP sensor to make the truck think it is receiving full boost all the time. You'd essentially be doing the same thing with your test, fooling the truck that is.

 

I'll probably end up doing both. See exactly when that light comes on, and check for leaks on the boost guage. I hope not. That little hard plastic line was a $&%@# to run.

It better not be the boost guage either. I'll raise hell. That little thing is expensive. I saw your post on the bad guage though, and mine is an autometer too. Never had a problem with their stuff before though, and I've gots LOTS of automete guages on my 66 Nova.

 

I talked to Autometer and they seem to think it's bad, given everything I checked. So, I called the place where I bought it, and it should be replaced no problem.

 

That's good to hear. Nice to see they stick by their products.