Engine/Transmission (1998.5 - 2002) Boost gauge needle flutter?

[GDouglas]

I have been noticing for the past week that my boost gauge has developed a fluttering that makes the needle seem blurry. It flutters for about a range of 1. 5 psi while going down the road under boost. I am planning on pulling the valve cover in the morning and checking valve clearances even though I only have 75k miles. My theory at the moment is maybe to tight a valve clearance on a intake valve or a broken valve spring. The engine still runs flawlessly and with full powerr and a max of 20 psi just like it always has. If I don't find any thing mechanical I might borrow my buddies boost gauge that he hasn't gotten around to installing yet on his '03 and see if it is just a gauge problem.



Right now I have a hard time believing that my AutoMeter boost gauge might be at fault, but I am not ruling it out as a possibility.



I will report any fix I come up with just in case someone else might have run into this problem.

 

[csevers]

While there

If you are gonna pull the valve cover and have not adjust your valves I would go ahead and do it, I did mine about a month ago and they were all at the top end of the spec for checking them. I would bet that the guage is going Tot ta's up, I have an Autometer gauge and I don't think they are high end guages but they work.



Craig

 

[TSRAM]

After I installed my guages my boost needle bounced really bad too. I did some reading and found that if you crimp the rubber hose just a dab with a zip tie just enough to flatten the hose a bit the bounce went away.

The bounce came back about a month ago and then the needle quit altogether that afternoon. The hose had popped off of the barb on the head. pushed it back on and it's been fine since.

 

[GDouglas]

I have been running this boost gauge for about a year now and the needle has been rock steady so far until now. Maybe while I have the valve cover off I might just get around to installing the set of 275 injectors I have had for a few months now.

 

[Sticks]

:--) :--) :--)

 

[illflem]

My bet is your gauge has gone bad. Sort of like a track bar, it has too much play in the needle. You can pick up simple water pressure gauge from the hardware store for under $10 to verify if the gauge is indeed the problem. Some folks trade their fuel pressure gauge for boost to isolate the problem.

 

[GDouglas]

Problem solved folks! After checking valve clearances and finding all valve springs intact, I borrowed my friends uninstalled boost gauge and it was rock steady. Time to order a replacement gauge today.



As far as the valve clearances at 75k miles, the most variation was +/-. 002" from the nominal . 010" for the intakes and . 020" for the exhaust.



Unfortunately, time constraints at this time prevent me from installing the 275's right now.



Thanks for all the replys.

 

[Rockcrusher]

I took my boost gauge off my old truck on which is was rock steady, but vibrates like crazy on my '02. Probably need a vibration isolator or crimp the hose a bit.