SPONSOR AD

Support our Vendors! | Advertise Here

Topic: More My 79 Vette - Tach and Fuel QTY

in Forum: C3 General Discussion

Already a Member?
Login
Not yet a Member?
Register for Free!

More My 79 Vette - Tach and Fuel QTY (1/8)
11/19/12 7:53pm

GoodyT

Lifetime Member
Send Private Message

New Port Richey, FL - USA

Vette(s):
1979 Yellow L-82 Auto - SOLD 1994 1992 White ZO7 6 Spd - SOLD 1998 1978 Silver Anniversary L-82 4 Spd - SOLD 2006 1979 Silver L-82 4 Spd - 18,451 miles 1 owner car, found having been in storage 20 years. Purchased in 2010.

Joined: 4/2/2005
Posts: 31

Afternoon,

First thanks for all the great ideas and info reference tires for my 79, invaluable help.

Now I have a different issue, I figured that I would have several gremlins with this car after it was sitting so long.

Fuel QTY - I thought that it was near empty as it showed very low on gauge, went out and bought 5 gallons for it and gauge moved a little. Took it out for a very short drive to the gas station and decided to get more fuel, and to my surprise it only took 2.5 gallons and was full while gauge reads 1/4. I think "maybe" sender in tank may be stuck after sitting so long? any other ideas before I tackle that lovely job.

Tach - Noticed when Eng off Tach reads "Zero" but when Engine starts it reads 600/800 for a few seconds and then off to 3800 RPM and just sits there. No movement when I press gas pedal and when I shut the engine off it goes back to Zero.

Thanks for any advise,

Goody T.

______________

G.T�

Quote

Our Sponsors help support C3VR

Re: More My 79 Vette - Tach and Fuel QTY (2/8)
11/19/12 8:13pm

tonytheroofer
Former Member
Send Private Message

Rochester, NY - USA

Vette(s):
1980 L- 82 fully restored and upgraded.

Joined: 6/12/2012
Posts: 95

It could be the tach filter ,under the hood it is located in front of the dizzy attached to the manifold and may even look like it is part of the back of your carb

______________
1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI

https://www.c3vr.com/member_uploads/16001_16100/16019/resized201331973928r.jpg

Quote

Re: More My 79 Vette - Tach and Fuel QTY (3/8)
11/20/12 1:38pm

Adams' Apple

Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 20129

Fuel sender may be stuck, but it could also be the bladder has collapsed, and is holding the float down. You mgiht be able to look down in the tank from the filler with a bright light(no matches, please) and see the float, or the bladder.

Tach acting strange like that is probably either the tach filter, as mentioned, or the circuit board on the back of the tach itself. Thumbs Up

______________

Joel Adams
C3VR Lifetime Member #56
My Link

(click for Texas-sized view!) NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Quote

Re: More My 79 Vette - Tach and Fuel QTY (4/8)
11/20/12 6:11pm

Case75
Former Member
Send Private Message

, - Canada

Vette(s):
1975 Corvette 383 stroker w/Patriot 190 heads, Eagle stroker kit, Comp 279TH7 cam, DUI distributor, Edelbrock 7116 intake, Edelbrock 1806 carb, Hedman Hedders, TH400 w/TCI Breakaway 2400 stall, Transgo 1-2 shift kit.

Joined: 6/19/2012
Posts: 230

This is what a tach filter looks like: http://www.ebay.ca/itm/NOS-75-76-77-78-79-80-81-82-83-84-85-86-87-88-89-CORVETTE-TACHOMETER-TACH-FILTER-/251182281396?pt=Vintage_Car_Truck_Parts_Accessories&hash=item3a7ba172b4&vxp=mtr

I only post this as a picture. Not trying to make a sale for anyone. Smile

One wire goes from your distributor to the tach filter and the other wire from the tach filter goes through the firewall. Try unplugging both ends of the tach filter from their connections and plugging the wire from the firewall directly into the distributor bypassing the filter. If the tach acts normal, you have a bad filter.

______________

�

Build Date: May 7, 1975. 383 w/267 RWHP/310 RWTQ

Quote

Re: More My 79 Vette - Tach and Fuel QTY (5/8)
11/20/12 6:36pm

GoodyT

Thanks for the troubleshooting info on the Tach, bypassed the filter and on start tach showed normal and then went to 3800 and stayed there. Sounds like card might be bad, I guess it's time to look at all the cards as with this long storage they may all have some issues. Thanks again.

______________

G.T�

Quote

Re: More My 79 Vette - Tach and Fuel QTY (6/8)
11/21/12 9:15pm

daveo76
Former Member
Send Private Message

Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 857

I was going to vote for the tach circuit board, too. I had weird tach issues too (but a bit different from yours) and a new board solved the problems. (Still have my original filter) As far as vendors go, I had good luck with Wilcox for that particular part. They have good how-to vids on you tube, too.

______________

1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Quote

Re: More My 79 Vette - Tach and Fuel QTY (7/8)
11/22/12 12:12am

GoodyT

Thanks for that, found Willcox last night and they do have good stuff. I also found on their website a nice little troubleshooting procedure for a fuel qty issue very similar to mine.

______________

G.T�

Quote

Re: More My 79 Vette - Tach and Fuel QTY (8/8)
11/22/12 10:49am

lukesvette

Lifetime Member
Send Private Message

HOWELL, NJ - USA

Vette(s):
1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.

Joined: 5/18/2004
Posts: 6812

Definitely sounds like the tach board. After you replace the board with the ignition in the run position and engine not running, make sure the tach reads 0 rpm. if it doesn't, you may need to re-zero the tach. A little tricky in the dash and much easier if on the bench. I believe it involves removing the needle, applying 12V to 2 specific studs on the back of the tach, and then carefully putting the needle back on - just pulls off and presses on - don't over do it when pressing back on.

Good luck!

Paul

|UPDATED|11/22/2012 7:49:57 AM (AZT)|/UPDATED|

Quote

Our Sponsors help support C3VR