Mondial QV won't start

These are two different issues.

With regard to "no spark during engine cranking" -- can we assume that you had the threaded portion of the (removed) spark plug connected to engine ground during the test? There are very few single problems that can take out both banks of the DigiPlex ignition at the same time -- no power to the coils (so you seem to have already ruled that out), the RPM flywheel sensor not working, loss of common ground at the DigiPlex ECUs, etc.. If you have truly confirmed that BOTH banks have no spark during engine cranking:

1. measure the resistance between the two terminals of the RPM flywheel sensor when unplugged -- should be ~700 Ohms. If zero Ohms = replace RPM flywheel sensor; if resistance measures OK = go to step 2.

2. measure the AC voltage output of the RPM flywheel sensor during starter motor cranking (with it now plugged in) -- should be something like ~2V AC (IIRC).

With regard to "The fuel pump runs with the key in position II" -- are you saying that:

A. you had modified the system to intentionally make this happen so you know for sure that the fuel pump is working, or

B. The fuel pump (correctly) didn't used to run with the key in Position II (when the engine is not running), but now (suddenly) it does with the key in Position II when the engine is not running. If the behavior suddenly "changed", my guess would be that the center plunger in the fuel distributor is sticking so the plate in the airflow metering device is not returning to the rest position (which leaves the safety switch open). The test here would be to mechanically inspect the smoothness/motion/return of the airflow metering plate when the system is at zero fuel pressure (i.e., fuel pump off, and crack open the cold start injector fitting to ensure the fuel system is at zero pressure -- use a rag around the cold start injector fitting when opening to catch any fuel spray that might come out).

Good Hunting! How long was the engine not used during the repaint? Saw in your other thread that you had a 6 year period of disuse (was that the repaint?) -- regardless, this can be very troublesome on Bosch CIS injection as any debris/varnish/crude that forms downstream of the fuel filter can get dislodged (at any random time thereafter) and muck-up the fuel distributor or WUR.

 

A fellow owner here had a similareproblem after paintwork on his 3.2 mondi,

His theory was that the paint oven had made some contacts on the Fuseboard dry/brittle/warp.

Mine was in the same oven a few weeks earlier with no problems

 

Are you sure that the welder had disconnected the battery and all ECU before welding? Welding without doing this it is looking for for troubles if the welding is done with an electrical welder because it can fry the ECU (at least I was told from an expert).
Check for some paint on the ground connection too. If some paint has gone under a less than perfect connection you are going to have electrical problem.

I hope that you can solve soon.
Keep us updated.
Alessandro

 

Just a random thought, but how old is the battery? If it is 6 or 7 years old, it may not be holding a sufficient charge, and the voltage may be too low for the Digiplex units. I remember reading that they need at least 11.8V or more to operate properly. I could be wrong here completely, but if the battery is old, you might want to have it tested, and if it is not up to snuff, you might want to replace it.

 

I think the SEN-8D is electrically functionally equivalent to the Ferrari 119052 - the exception that the mounting holes may be a bit smaller - but can be drilled out to the correct Ferrari diameter.

http://competitionsystems.co.uk/uploads/mediacentre/20100526111207-sen_series.pdf

The SEN-8D is a Magneti Marelli part number but not referred to as such in the above link.

SEN-8D Magneti Marelli part number is typically priced less than the Ferrari 119052.

DRG
Jerry

 

No problem Dean -- glad that you got it sorted with minimal grief. No matter how "exotic" the beast, if the starter motor spins the engine, but it won't fire up, we always start at the same place: "gotta be no spark or no fuel -- so rule spark in or out first"

What about the other issue? -- is the fuel pump still (wrongly) running with the key in Pos II and the engine not running?

 

hi guys hope this thread is still active, my 84 QV just let me down for the 1st time in 10 years! no spark on either bank and no fuel pressure but i can hear the fuel pump, im going to check the crank sensor first and the earth to the ecu's. just slightly confused as to how I have both faults at the same time? suggestions? i will keep you informed,

 

crank sensors check ok at 700 Ohm trieda couple of additional earths and that didn't help, just called the auto electrician.....

 

I would look at the coils first...bad/burned contacts of the distributor wires that are going to the coils.
guido

 

very unusual...how are you measuring/determining this?

One thing that could cause both systems to fail simultaneously is a bad ignition switch (although the fuel pump would also not be running). When the key is moved to Pos III (start), it should still also be putting +12V onto the items of Pos II (run) -- which include the ignition and the fuel pump operation items. Measure the voltage on the yellow (IIRC) wires going to terminal 15 of the coils during starter motor cranking -- should be +12V (or maybe +10V since the high current draw of the starter during cranking will cause the battery voltage to droop some). If that's OK, but still no spark on both banks = suspicion has to fall on the flywheel RPM sensor. Even though you measure its resistance is OK, the real operational test is measuring the AC voltage between the two terminal while plugged in = should be ~2 VAC during starter motor cranking.

 

ok we have 12v across the iirc reducing to 10v on cranking, we have no output from the crank sensors while cranking, we do have output from crank sensors if we remove them and pass them by a metal trigger, the flywheel is still on and the crank is not broken so it must be the dowl in the flywheel that triggers the sensors, look like the clutch and flywheel and bell-housing needs to be removed, could be worse it could have been the crank that had snapped

 

Can't easily agree with this deduction. There are two dowels, so. if one fell out = you'd have spark on two cylinders in each bank. If both fell out, that would kill both banks, but I'm skeptical (as the pins have no relationship to the RPM sensor output). You can fairly easily remove one of the TDC sensors and confirm/deny the presence of the pins (2 pins 180 deg apart), before resorting to more serious disassembly. The RPM sensor (which senses the ring gear teeth) should still work (i.e., have a 2 VAC output when plugged in and cranking) even if the pins were gone. If you want to functionally test the output of the two TDC sensors, they should have an output of something like 0.1~0.2 VAC when plugged in during starter motor cranking.

 

ok i will take your advice, it is much appreciated! and look further, i will keep you informed, the sensor that was reading zero ohms had marks on the tip that look like a foreign body had hit it, i agree to loose 1 dowel would be very unusual to loose 2...,?