factory tach/boost unit

[channer]

Hi all


My factory tach has gone haywired... and probably needs to get re calibrated.


question... if the factory tach is bad, does that also impact the factory boost gauge.  I am trying to figure out if the factory boost gauge is still working properly or not... or I may have a vacuum leak somewhere.  With just a light throttle, 2 or 3 bars light up on the boost gauge... but nothing moves on the aftermarket gauge.


I remember with a vacuum leak, the factory boost gauge would light up pretty quick with any sort of throttle response... but I can't remember if the needle also moved on the aftermarket boost gauge.




thanks... dave

[SuperSix]

There's carbon resistors on the back of the module that fail with age. The only way to get them to be close to accurate is to get them repaired/recalibrated - Casper's is the only company offering this service, I believe.
http://www.casperselectronics.com/cart/index.php?route=product/product&product_id=120

[Steve Wood]

they are separate, but it would be nothing short of amazing if either one worked at this point in time.

[Scoobum]

Fix the brakes yet Dave? Retiring soon. Got time on my hands...

[daveismissing]

Fix the brakes yet Dave? Retiring soon. Got time on my hands...

*LIKE*

[TexasT]

I sincerely hope you aren't using the stock rpm and boost gauges to gather meaningful info. The weren't accurate when the cars were new and are even worse now with their age. You need a tach and a decent boost gauge along with a scanmaster if you plan to do meaningful racing. If you don't have these I can almost guaranty a problem that will cost you much more than these three things will cost upfront.

[Scoobum]

Daveismissing and Scoob have hinted at something he needs even more.

[channer]

I sincerely hope you aren't using the stock rpm and boost gauges to gather meaningful info. The weren't accurate when the cars were new and are even worse now with their age. You need a tach and a decent boost gauge along with a scanmaster if you plan to do meaningful racing. If you don't have these I can almost guaranty a problem that will cost you much more than these three things will cost upfront.

I've got a scanmaster and autometer boost gauge. 

At idle... the factory tach show almost 2400 rpms, and when I step on it... I see red as the RPM maxes out. The factory boost gauge lights ups like crazy. 

I checked all vacuum line and they seem tight.  Autometer boost shows a better reading than the factory guage when I did a couple of highway passes.

I was thinking about taking the sending the factory tach & boost unit to Caspers

thanks all.

[channer]

Daveismissing and Scoob have hinted at something he needs even more.

Well...  My brakes did give up in the spring.  I tried swapping a couple spare accumulator that I had... but it kept on blowing fuses.

I was thinking about taking the car to you (Brad) or Dan... but i didn't think it was safe to venture very far...  so I bought bought a new GM master & booster and swapped everything over. 

I googled searched and noticed some people weren't bleeding the brakes after the swap... which is what I did.  I didn't feel like crawling under the car & bleeding the brakes... though I did buy new calipers & wheel cylinder.   the brakes feel a little soft for my liking... but better than the PM. 

right now, I may need my head gaskets replace... but the engine needs to be taken out because I got head studs.   Trying to find someone now.

dave

[Steve Wood]

If the studs used on the engine have the ends machined for a allen wrench, you don't need to pull the engine...

[Scoobum]

Dave...you parts whore. Get the car in one of your garages and I can come out and help you re and re the heads...and bleed the brakes. Order a new fuel pump from Jack...prolly how you popped the heads. Grab a 255 from him. Please tell me you have a chip from Eric...and not some outdated POS from 1923.

[earlbrown]

.

[TexasT]

Just double nut the studs to get em out. Get the new style for the new install. Pulling the engine can spiral into while I'm here syndrome . Not productive when you want to drive the car.

[Scoobum]

Dan and I can have an engine out and sitting on a stand in under 90 minutes. While it's out you can clean and paint the engine bay...remove the AC shield to get at the plugs nice and easy...and you can get a proper swing on the torque wrench for the head studs. And you won't blow your back out leaning over the fenders. You can clean and paint the engine and make it look real purdy. Pull the pan...inspect the bearings...cle an the pan...and pull the timing cover and have a looksee.

[TexasT]

Sounds a lot like "while I'm here" syndrome to me. Ninety min doesn't equal ez. Each to their own. I'm sure my son and I could have one out in that amount of time too, doesn't mean I'd pull one to change a head gasket.


I like to wrench as much as the next guy but spending an additional 90 minplus whatever more to do this cleanup and such just doesn't fit into the schedule. I'd rather be driving it.