i was seeing 32-35psi before last night with my truck, but after installing the latest version of the van aaken V5 my gauge will not read a spec over 20psi, but the truck makes SO much more power up top.

I am thinking that the previous owner tapped the gauge somewhere that has it reading the boost signal from the ECM. Which in turn would now only read 20psi because of the built in boost fooler of the VA box. The reason i am thinking this is because the gauge will quickly pull up to 20psi and instantly just stop and sit perfectly on 20 without any fluctuation.

Is this possible? If so where can i find a signal for boost that is not affected by the boost fooler so I can tap into the correct source

 

I take it this is an electric boost gauge? Still don't understand how this is possible, though!?!?

 

Right behind the MAP sensor I believe is a plug. Remove the plug and hook your gauge to it (your gonna need an adapter). Be careful though. There are two plugs. One is for coolant and the other is for boost. If you undo the coolant plug, don't worry cause it won't dump coolant everywhere. Just be sure to seal it back up. I've been pulling my boost signal from there for 4 years now without any problems.

 

this is my only thoughts as to why my gauge only reads 20 as compared to 32 before the VA went in...

maybe ill disconnect the box tongiht after work and see if the boost goes back up to normal...it should because it was pulling more than 20 when i test drove it to test my lower I/C boot to make sure it was tight...came back and installed the box...now 20psi max

 

i bet its fun to get to because i had a hard time connecting to the MAP sensor for the box, what kind of adaptor am I going to need and where can i get to it.

first thing i need to do is trace the boost gauge wires to see where the other guy is pulling the signal from to see if this could be the issue

 

where are you pulling your boost signal from? there are several options including the port behind the MAP sensor, get a boost fitting from Piers that replaces on of your intake bolts, tap the airhorn. if it's a mechanical gauge, it sounds like the boost fooler in the box isn't working and your ECM is in control.

 

i dont know where its pulling the boost signal from. its an electronic guage not mechanical, the previous owner installed it so I have no clue.

I cant see why the gauge would read 32-35 psi up until i installed a van aaken box last night with the built in boost fooler. Now that the truck has a bosot fooler installed, the gauge will read NO MORE than 20...its impossible to get it above 20 now.

i will have to trace the wires tonight from the gauge and see if I can find where he is pulling the signal from.

 

It definitely sounds like the boost gauge is tapped into the connector wiring that goes on the MAP sensor. Once you put the VA boost fooler on it, the tapped point is now behind the fooler and reading the clamped voltage level. Find the tap point and move it to the connector that goes right on the MAP and you should then be reading true pressures.

Jim

 

I'm not sure if different model years are different on 24v's but I can say for sure on my 98.5, the port BEHIND the MAP sensor does NOT have manifold pressure, it is a coolant port......however, the 3/4" NPT port in FRONT of the MAP is manifold pressure......this is where the Piers adaptor threads in.....I just used a few reducer pipe bushings screwed together to adapt down to the correct size......

I agree with rfcom's diagnoses....makes sense...

 

CTD NUT, your right. It is in front of the MAP sensor. It's been a while since I looked at it.