Steven.Hesterman

Need some help. I’ve got an 88 GTU NA, fresh rebuild, haven’t driven it yet, but while getting things put together, a new problem from two days ago. The car will not shut off with the ignition switch. I’ve pulled all the fuses on the interior block looking for back feed, no dice. Pulled the BTN fuse in the engine compartment, no affect. The alternator only has a single wire in, so I couldn’t of revered wires. This wasn’t happening over the last few weeks of running it.
The car will stop if I pull the EGI Comp and or the EGI Inj fuses....logical, kill fuel and kill computer. I’m learning toward the main fuse, but it seems to be stuck, it will not pull out, unless there is specific technique. I don’t want to break it. I guess it could be a bad ignition switch too.
when I turn the key off, other electrical things turn off I.e. radio, heater blower.
I’m at a loss, this project has kicked my butt...long story, but eventually I’d like to be able to drive the car occasionally.
also, yesterday my rpm gauge randomly quit working...haven’t had any issues until after I pulled the EGI fuses.
any help is appreciated, thanks in advance
Steve

Spider2k

main relay sticking?

mazdaverx713b

iTrader: (91)

My first guess would be the ignition switch is at fault. Does it power on and power down the car without the engine running?

Steven.Hesterman

it does, the ignition turns on/off the radio and gauges when cycled through

Kellis

iTrader: (4)

I doubt the main fuse is the issue, but its legs are physically bolted to the fuse block to hold it in place. There should be an 10mm on each side you have to remove to get it out.

ozoone le deuxieme

I have about the same problem. the car start great while cold. then when i want to shut it of everything stop exept injection and ignition. I mean you can hear there is still injection and ignition by the engine still running but the fuel pump is off resulting in a flooded car for the next start.

Spider2k

Either the switch has a stuck position or the main relay does.

ozoone le deuxieme

where is located the main relay? and do you need to take the steeringwheel of in order to take the switch cover off ?
btw car is a 87 s4 N/A

Spider2k

Main relay is under hood. Driver side inner fender next to the coils.

Can get to ignition harness just by looking under the dash.

ozoone le deuxieme

so i checked for the relay but there is nothing next to the coils. the only thing is a connector and the headlight.
as for the switch i dont have the 4pins connector and when the key is on start i have continuity bitween ST and B and IG1 exept for that every other position is fine on the switch

Spider2k

The coils closer to the firewall. Near the clutch master.

Continuity between B and ST would be turning the starter over.

ozoone le deuxieme

so continuity between ST and B is fine ? that mean my switch is good.

I only have 2 coils and they are just behind to the headlight.

Spider2k

how do you only have 2 coils?

there should be 4...

ozoone le deuxieme

thats not mine but mine look like that. there is only 2 coils behind the headlight where the blue wires are on the right

Spider2k

Well alright then. 2 coils and a dizzy. So many variations...

That gold box, top right corner by the clutch master is the main relay.

ozoone le deuxieme

Thank you i ll check it later today.

Is there many variation for the same year ?

Spider2k

Honestly I'm new to this scene. My 86 has a CAS and 4 separate coils. I guess they changed it on the S5.

ozoone le deuxieme

thank you for the help. ill let you know what i found

ozoone le deuxieme

ok here i am with my ignition switch good and my main relay good.
I dont know what to do and i still have injection and ignition after taking the key out of the switch.
Injectors are good i got them checked and cleanned 2 time.

Any lead anyone ?

mazdaverx713b

iTrader: (91)

It sounds like you have a backfeed in the that circuit. Its time to get out the wiring diagram and inspect the wiring and grounds for that circuit. Very likely a faulty ground causing the backfed voltage.