New Boost Guage Not Working...

[JRussell3176]

Hi All,



I just installed a new Autometer boost guage (0-35psi) and it doesn't seem to be working properly. I used the threaded port located on the manifold, just under the intake.



The guage didn't move when I first started the truck (which I thought was odd). Then as I started to drive and floored it the boost guage seemed slow to react and only made it to just under 15psi. When I let off the throttle the guage was VERY slow to return and never went back down past 7psi... even at idle. I've checked my intake system/intercooler piping and can't find any leaks there (the boots are all brand new and not old).



Any ideas on what it could be?

 

[Philip]

Check and see if you have a kink in the line to the gage. If not contact Autometer and get a RMA on the gage.



You will not show boost till there is a load on the engine. Thats why you don't see boost at idle. 15 PSI is normal for a stock engine.



Welcome to the TDR.



Go to the user control panel and set up a signature line showing you truck spec's. That way we can see what you have without having to ask. The user control panel is located in the discussion forums drop down menu.

 

[JRussell3176]

Thanks Philip.



I checked for a kink and everything looks fine. The only thing I did notice is that I might have over-tightened the compression fittings and crushed the ferule. You think that could cause the gauge to act like this? Does anyone know if you can normally buy those ferules locally (Home Depot, etc)?

 

[Philip]

Any good parts store should have ferrels. A crushed line will do the same thing as a line with a kink. Showing pressure after the engine is shut off means a bad gage or crushed line.

 

[JRussell3176]

Ok, I found some ferrels from another autometer guage set that used the same plastic tubing and installed those in place of the crushed ones. I made sure not to crush them this time, but the guage works exactly the same!



It seems to work but very roughly. There are no small and/or precise movements of the needle. If I floor it the needle will jump suddenly to 12-14psi and then suddenly drop back down. The odd thing is, the guage never goes under 6psi now. Idling, driving normal, slowing down it still reads 6psi.



There can't be too many defective ones coming from autometer, but I don't know what else it could be.

 

[JRussell3176]

Oh, I also forgot to add the guage never went back to "0" when I unhooked the lines and re-installed the new ferrels.

 

[HRDROKN]

Yep... the gauge would appear to be faulty... . and just too add, you would not normally see any boost at idle. The greater the load, the more fuel and higher the boost.



My truck was originally getting 13 psi :{ I turned the full fuel screw in 1 turn and got 18 psi I changed injectors and now have 29 psi under full load Oo. And we're not finished yet... .



And when I would free rev the motor with the stock air cleaner... 0 psi, after installing a AFE... . 2 psi.

 

[JRussell3176]

Thanks wrknrott, that info helps a lot.



Your truck sounds sweet. Are you running the stock-size (3'?) exhaust still with all those fuel mods? If so, how are the EGT's under heavy load?

 

[HRDROKN]

I have a 3" downpipe into 4" the rest of the way... With the set up as it is I have hit a max of about 1100 degrees.

 

[JRussell3176]

Well, I got the new gauge and it works great. My max boost is around 19psi and I guess that sounds on par with the minor mods I've done so far (and given my elevation).



Now I'm off to destroy this little collar on the full power screw! Oo.