Where's my Euro 328's frequency valve fuse or relay?

That is an oxygen (lambda) sensor (not a relay), and, yes, typically they do unscrew, but they can be difficult from the rust/corrosion.

A euro 328 would not have a "frequency valve fuse" (more correctly termed a "protection relay fuse") unless it was added as part of the federalization. We haven't seen many (any?) examples of federalized 328, but on 308QV, the euro fuel distributor is such that you can't add a frequency valve exactly like the US version so they did something a little cheesier where they added a valve in a manner to change the control pressure (rather than change the lower chamber pressure). Can you post a photo of "where the lambda and microp. are" and the fuel distributor area?

And have you confirmed the ignition is all working OKish?

 

The "silver" ECU is the MicroPlex ignition ECU. The Neutronics Lambda Computer is an aftermarket addition running your added FV -- can't tell from the photos how your FV is exactly plumbed into the system. If you had an added protection relay with a fuse, it would be the thing that supplies +12V to the Neutronics ECU. They typically look like this:
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but, if you can't find it, another thing you can do is just try to confirm/deny if +12V power is reaching the Neutronics ECU -- if your protection relay fuse (if so equipped) was blown, the result would be no +12V power to run the injection ecu (even on a stock system).

If you have the schematic for the Neutronic ECU, and can scan/email/post it, I'd be glad to see if there are some multimeter measurements you could make to see if it's working.

 

Incidentally, the car will still run with the fuse blown in the protection relay, but it will run like crap - gutless and with some farting and spitting (similar to what you're experiencing, or so it sounds). I got my '88 3.2 Mondial cab for cheap because the prior owner couldn't figure out why the car ran so poorly - he thought the engine was toast. After getting the car home I went looking for the relay, found it in the right side trunk cubby and saw that the fuse was blown because water had contacted the relay (leaky aerial). Replaced the fuse et viola - car then ran perfect.

I hope you find a similarly nice and easy fix. For starters, I'd check you've got powere to your microplex ecu as suggested above, and clean all the connections in the vicinity.

Good luck and persist!

 

The good news is that on a 328 (MicroPlex) they changed the "pickup" architecture such that, if either pickup fails, both banks lose ignition so the trouble has to be either coil + power module, coil wire, dist cap/rotor, Microplex ECU itself, or some other more subtle downstream wiring issue on the dead bank (hopefully one of the first three).

Not that surprising But are you saying that you've confirmed that this is the situation (i.e., no physical buzzing/vibration of the FV when engine running)?

 

Exactly...as this is the primary difference (in the ignition system) between a 328 and a 308QV. Personally, I'd visually and electrically verify the condition of the cap, rotor and wires (including the coil wire) on the "dead" bank. If all tests "OK", I'd suspect the "power module", which really is the coil driver. A quick test would be to swap the modules from bank to bank and see if the problem moves.

Although I've seen all of the likely problems that Steve describes, the most common culprits (in order) have been:

-An open coil wire
-The carbon contact in the distrubutor "toasted"
-A burned through rotor
-Coil driver blown
-Open coil

David