460 Ford Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
304 Posts
Discussion Starter #1
So I bought a pair of these cyberdyne fuel pressure gauges
http://store.summitracing.com/partdetai ... toview=sku

Anyways, they have been a complete pain in the a$$ because my mechanical gauge reads between 9 and 11 psi without the engine running, just the fuel pump is running, causing the pressure creep. well, the digital gauge almost always reads 6 psi. when the actual pressure reaches 11, it reads 7. I know the mechanical gauge is right because I checked it against another brand of gauge and it is spot on between them. I've changed grounds, added grounds, rerouted wires, and to top it all off, when I went to turn off the annoying as hell low pressure flash on one of the gauges, I start to turn the little screw adjuster in the back, and the thing BREAKS OFF. I'm ready to get something different
 

·
Registered
Joined
·
2,185 Posts
Electronic gauges

A lot of these fuel pressure gauges use pressure transducers that rely on engine ground for sensor ground, and ground through the NPT thread on the sender itself.

If you use teflon tape and create electrical isolation (or partial electrical isolation), you create a problem.

Additionally, if the engine is not WELL grounded, and/or if the gauge portion of the system is not grounded to the exact same point as the sender portion of the system, the differences in electrical potential on the ground terminal will cause enough variation to create error in the measurement. Try grounding both sides at the same place and see if the results don't agree better.

Well, perhaps you can't now...if something broke off, but if you can...try it.
 

·
Registered
Joined
·
2,227 Posts
Almost too long ago to remember, I lost an engine because of the sloooow response of an electric oil pressure gauge. I won't use electric gauges, on important functions, because of that.
 

·
Registered
Joined
·
1,979 Posts
Don't use Teflon tape, Use Teflon paste and use it sparingly. Make sure the threads are clean on the engine side too..... Make sure the engine is grounded VERY well.

If need be use and ohm meter and measure the resistance from the sender body(ground) and the negative battery terminal. The resistance should be ZERO....... If all of this checks out then I'd say send it back, it's bad.... I don't like the automotive electric stuff for the main reason is that it's cheap......

The industrial electric stuff is awesome and rock solid reliable, BUT almost 4-5 times the price of the auto stuff too......

Even with saying all of that I'll probably throw some electric gaugeas in my pickup, just because they are easier to install and plumb up to the a-pillar gauge pod.....
 

·
Registered
Joined
·
304 Posts
Discussion Starter #6
I've had good luck with the Autometer electric street rod series gauges I put in. they seem just as quick as any gauge out there IMO.

I think I'm just going to return the cyberdyne's and spend the money and get something good. It just sucks I need to buy 2 :shock:
 

·
Registered
Joined
·
313 Posts
I've got the Automoeter UltraLites and they are spot on as well.



The a/f gauges are run off of my LC-1's analog 2 channel and output 1 - 0V representing 12 - 16 AFR. Poor mans AFR guage :) Verification of AFR comes from the AEM and an LM-1 that doesn't stay in the car.
 

·
Registered
Joined
·
313 Posts
Re: Tac

smjrhp1 said:
:?: How's it, that the RPM is showing approx 1200 and the other gages are indicating it's not running?
For one reason or another thats where it sits when you kill power to it, turn on the key and it goes to 0 - when not running, been that way since I got it out of the box.
 

·
Registered
Joined
·
1,979 Posts
Re: Tac

smjrhp1 said:
:?: How's it, that the RPM is showing approx 1200 and the other gages are indicating it's not running?
Just about all tachs will do that. They are receiving NO voltage when powered down so they don't know where to go....... It's common....
 

·
Registered
Joined
·
1,718 Posts
Re: Tac

smjrhp1 said:
:?: How's it, that the RPM is showing approx 1200 and the other gages are indicating it's not running?
Yeah.....it's normal. Walk around the pits and look at all the tachs......I doubt you'll find any GOOD ones at zero with the ignition off.
 
1 - 12 of 12 Posts
Top