kevin Dubois

ok so i'm heading to a friends house to fix her cabriolet, and of course my car breaks on the way there. i was on the highway doing about 60 when all of a sudden the tac falls to 0 rpms (it was still in gear), and my WB02 display and AFC display both turn off immediately. my guess is that the reference sensor went bad, turning off the DME, which turned the WB02 display and AFC (Which were both running off of one of the DME switched powers) off. i spent about an hour trying to fix it after i managed to drift down the hill, off an exit and to a legal parking spot on the side of the road (amazing luck...). i checked the DME relay and i don't think that is the problem because the fuel pump will turn on. also the starter will turn the engine, but obviously no spark. i do have fuel pressure at the fuel rail.

any other ideas?/?


oh and i checked the fuse for the DME and it was ok.

Danno

No spark, eh? Check the obvious and easy stuff first. The distributor cap and rotor.

Then check the speed/ref. sensors. One easy test is to swap sensors. Pull them out and reverse their positions (don't forget the figure-8 spacer on the speed-sensor). Reverse the connectors then try again. This will obviously work only if one sensor is bad.

kevin Dubois

ok i figured out what went wrong. once i got the car home i had a few more tools at my disposal to diagnose the problem. well, the first thing i did was take my DME relay bypass wire and tried that. sure thing it fired right up. problem is the DME relay. so i took apart the relay to see what is going on in there, and sure enough, a lead was split apart. it looks like it actually burnt apart.


so now i suspect that maybe i had to much current draw off the DME relay causing it to burn the lead. the burnt lead is the pin 30 master power source thing, before it gets to the actual switch. i will take a picture asap.

so i must caution everyone using the zietronix wideband O2 off of pin 18 on the DME itself. i also have the apexi S-AFC running off of the same wire so i think that is the reason for drawing more then the 15A the relay can handle. but anyway, i think it might be safer drawing your switched power for the WBO2 from the radio and putting a little bigger fuse in the box. i would hate to see this happen to anyone else because it could be extremely dangerous if your relay burns up and turns your car off while your in traffic (which is exactly what happened to me).

Darius Juca

SO wich is better ..draw off the radio or DME? DANNO?

Chas

Wire your own source from the fuse box and make a fuse for it...I would not wire ANY peripheral devices off of the DME pins...especially a WB02...that sensor draws tons of current, especially when warming up.

It's cake to pull a fused wire back from the box, and you can build the circuit (like an op-amp) to use any switchable ignition source (like the radio) to turn the circuit on and off....that's what I did for my WB02

Mike1982

I am about to get a wb02, I have the gauge already but where would I hook the gauge into the wb02? Do I just connect it to one of the wires or what? Any advice would be great.

Chas

What gauge are you talking about?

kasturbo

bump, curious to see other opinions.

Bri Bro

The DME power from the DME relay is not fused. If you use the DME power lead you should always add a in-line fuse. By the sound of the fault, there was a short in one of the devices and the weakest link, the DME relay melted and broke the path. The DME relay supplies power to the idle controller, fuel injectors and the DME on pin 87 of the relay and there is no fuse to any of these devices. Pin 30 of the DME relay connects directly to the hot side of the battery.

The WB device has a heater and can draw 2 to 3 amps of current. The DME relay has never been noted for its robust design and adding more power load isn't the best path to take. Use the radio power, at least it has a fuse.

kasturbo

What color is the radio power wire? Red?

Bri Bro

Green/white is radio power.

Mike Murcia

I'll second Chas. Looking over the WB thread, I can't believe that Zeitronics suggested using the DME power to drive the sensor. With all the current required to initially heat that WB, you need a separate fused lead.

kasturbo

does the radio have to come out to get to it?

Bri Bro

Not sure the comment that the heater pulls tons of current statement is correct. The controller will limit the current to the WB as it warms up. The nominal current to the heater in normal operation is 10 watts which is less then 1 Amp.

Assuming the controller operates to the WB spec. a -40 degree startup should have a current draw of a little over 3 amps with it steadily decreasing as the sensor warms up.

Mike Murcia

Did the kit come with a fuse or manual? If so, what is the suggested fuse?