tewquick2c

When i shut the car off all the guages go to there bottom but the oil pressure gauge goes way down....

pengaru

just replace the sender and gauge with a sane aftermarket one.



sometimes you can fix the stock one, but it really isnt worth the trouble.



I had a stock one get all fucked up kindof like you are describing, it would rest below 0 when the car was off but it would read really low too (not like yours), what happened on that one was the needle had shifted on the axle due to the wire going to the sender falling off and shorting to the chassis. When it shorted temporarily the needle pegged but the axle tried turning it further than it's limits, making it slide inside the needle so when it returned to 0 the needle was showing below 0. It also bent the pin that is on the bimetallic strip in the gauge due to trying to bend beyond the limits it was deisgned for, I ghetto fixed it but it still didnt work quite right and it now sits in the basement in a box somewhere after I learned just how junky the stock stuff was.



with your problem, it sounds like the wire going to the sender is shorted to ground, pegging the gauge when theres current, and it's shifted it just like mine. So you can probably find the short and fix that, but I fear your gauge is probably damaged due to the shorting causing the bimetallic strip to deflect too far bending the pin and turning the axle inside the needle. Check the wire @ the sender, if it's connected properly, pull it off and check for continuity through the sender (multimeter, continuity buzzer / resistance check, one wire on ground, other on the terminal of the sender) if you find there is continuity then your sender is shorting internally. Make sure you're doing this with the car off (0 psi), it should have no continuity with 0 psi (infinite resistance).



I hope you decide to just get something aftermarket though troubleshooting and solving the problem can be satisfying regardless if you're into that, just be aware the system you're trying to fix is a shoddy one when working perfectly.

tewquick2c

Is there a guage/cluster kit you know of thats good for our cars?

tampaFD

guys i am browsing the 2nd gen site to learn some. i have a fd and where the stock oil sending unit goes, upper left side rear, the greddy elec unit does screw right in. dont know if it is the same but for what it's worth.

13BAce

Thanks for the confirmation.

Rob x-7

hey Peng- any idea how a aftermarket electronic oil gauge works?

pengaru

the gauge or sender?



the sender is usually a simple electromechanical setup like your fuel level sender, variable resistor, lever driven by a plate that deflects from the pressure. Resistance changes with pressure, gauge displays basically the resulting voltage (sometimes translation is necessary when it's not a linear relationship). They wear out eventually (remember the hand controllers for slot cars? mine used to wear out eventually over the area the wiper covers most often, like a TPS) but they are more reliable and consistent throughout their lifespan.





the gauges can still use a bimetallic strip, others use (electro)magnetism, some are quite advanced and use microprocessors so you can calibrate em to senders that have a non-linear resistance:whatever relationship, whatever being pressure, fuel level, temperature, etc. You can also get a LED gauge which IMO is a better choice than any analog gauge that uses a bimetallic strip as a motor for the needle. Or the ultimate, an LCD connected to a microprocessor + analog to digital converter.



One of the nicest things from my point of view about a simple variable resistance sender is you can actually test it with a ohmmeter if you doubt your gauge, and alot of these senders have published resistancesi (or whatever) tables online so you can confirm the real value with just the resistance reading, no gauge needed. You don't have this stupid heated element taking relatively large amounts of current to function as a sender either.

Rob x-7

I see you have done the reasearch, it would be interesting to know

what methods each brand used. You are going to run some kind of

set up thru a computer with a LCD screen correct?

pengaru

Yep, I am working on such a project, most of the data will be coming from the haltech e6k in already digital form, but there are still things like oil pressure and fuel level which the e6k knows nothing about. For those inputs I'm using a general purpose analog to digital converter just like the e6k itself uses for it's inputs, it connects up to the parallel port on the computer responsible for rendering the gauges on screen (and communicating with the e6k via the serial port).



The reason I had to look so far into the oil pressure sender is I tried using the stock one for the LCD gauge project, and that was a complete disaster given the design of the stock sender. Every other off-the-shelf sender I've bought and tested has been the more sane variable resistance type, I have yet to test the FD oil pressure sender which might be simlar to the FC one (ick) or might be 'normal', which would be nice since it's the correct japanese pipe thread type needed for our engines, eliminating the need for an adapter which is usually necessary with the off-the-shelf units (NPT).



I've actually got most the e6k stuff all hammered out, I intend to sell this as a product eventually but there have been some setbacks with other aspects, mostly hammering out hardware support for peoples laptops, particularly the graphics hardware. Laptops are a bit of a pain in the *** in the hardware support area. Feel free to PM me if you're interested in the e6k lcd gauges, I'm afraid it doesnt really help anyone with a mostly stock car who just wants some decent gauges though. The e6k is really needed to make it worthwhile at this time.

Rob x-7

Im sure you also know the adaptor block gives you 2

places for a gauge, so one could be oil temp if you desired it.