Noob needs some direction

[windsoreight]

I just traded my 85 Porsche 911 for an 87 corvette vert. It had a few bugs which I worked out except for 2. First my speedo would fluctuate mainly reading zero. Sometimes it would get so bad the would go back and forth between zero to highway speeds sending the lock-up converter into a fit. I was sure a speed sensor would fix it. I repaced it and at first it was still all over the place then it smoothed out and started working. I did notice that when I hit a bump or took a turn it would fluctuate that clear up. I smacked the top of the dash a few time and it caused no disturbance. So I am thinking a bad connection or wiring between the cluster and the speed sensor.

My other issue I think is vacuum. I have no cruise control. My heater blows mainly out the defrost and a little out the front vents. I do have vacuum going to the cruise control but it seems weak. I have checked the the vacuum lines at the intake. Where are the common areas I should check for vacuum leaks? Thanks guys.

 

[vetteoz]

My other issue I think is vacuum. I have no cruise control. My heater blows mainly out the defrost and a little out the front vents. I do have vacuum going to the cruise control but it seems weak. I have checked the the vacuum lines at the intake. Where are the common areas I should check for vacuum leaks? Thanks guys.

Is the one way check valve in place and working?
Line from intake runs to check valve.
Splits there ; side port to cruise and vac ball under drv side headlight
Rear port to plastic line that runs inside to the HVAC control.Vent only is default position indicating no vac inside
Is common for the plastic vac line to break off , line is inside the wiring harness on firewall behind dist and only has a 3" stub sticking out to the right angle connector shown in pic

 

[windsoreight]

The plastic line to the check valve is ok. I will check the lines coming from the check valve.

 

[C2C3C4]

The 87 vert I used to have had a hole in the vacuum line near the plastic ball in front of the driver's fender well. I clipped it off and luckily had enough left to reattach it.
That was several years ago and the new owner says it is still working fine.
Hope your problem is that easy to fix.
Here are a few tips I learned from a Gordon Killebrew class (Gordon was one of the factory trouble shooters). Buy the newer style plastic headlights. They weigh a lot less and will prolong the life of your headlight motors. Clean all your weatherstripping and coat it with dielectric grease and then wipe off. This will keep is supple and extend its life. There is a drain tube in the rubber bib around the gas cap. Make sure it is not full of spider web gunk. This will prevent the water that collects there during a rainstorm from being sucked into your fuel. You can also drill a couple of holes in the lower corners of the bib to help the water to drain. Don't buy an air foil for your throttle body intake. Waste of money and it does not improve horsepower or torque.

 

[windsoreight]

Thanks for the info. I fixed my cluster today. I pulled it apart to find a rebuilt cluster. It ended up being an opened up socket on the female plug at the cluster. I cleaned up the connections and tighten the socket up and all is good. Tomorrow I will hook a smoke machine up and see if I can find the vacuum leak. I have checked all the vacuum lines I can get my hands on and found no leaks.

 

[Curious George]

I just traded my 85 Porsche 911 for an 87 corvette vert. It had a few bugs which I worked out except for 2. First my speedo would fluctuate mainly reading zero. Sometimes it would get so bad the would go back and forth between zero to highway speeds sending the lock-up converter into a fit. I was sure a speed sensor would fix it. I repaced it and at first it was still all over the place then it smoothed out and started working. I did notice that when I hit a bump or took a turn it would fluctuate that clear up. I smacked the top of the dash a few time and it caused no disturbance. So I am thinking a bad connection or wiring between the cluster and the speed sensor.

My other issue I think is vacuum. I have no cruise control. My heater blows mainly out the defrost and a little out the front vents. I do have vacuum going to the cruise control but it seems weak. I have checked the the vacuum lines at the intake. Where are the common areas I should check for vacuum leaks? Thanks guys.

So how do you like the Corvette vs. the 911?

CG

 

[windsoreight]

I bought the porsche off a customer of mine for $2000. It was a drivable car but needed work. Second gear needed a syncro and it needed valve guides. It was going to cost me $4k in machine shop fees and parts to fix the car. I did not enjoy driving the car. It is very quick, the corvette could never keep up.If I were younger I would have kept it.

The vette is just more comfortable to drive. Not as fast and dosen't handle as well. I have more fun with the vette.