A different starting mystery

After putting in the starter relay a couple years ago, I have never had a problem with my 85QV starting. And last fall, I replaced the fuse panel and have had nothing but sweet driving ever since. Three weeks ago, I moved my cars around in my garage to put the QV just inside the doors as I knew I would be driving it next. It was all normal and I shut it down. Normally, I do disconnect the battery, (my switch has been repaired) but this time I did not. However, when I got in this afternoon to take it out to wash it in prep for some use this week, I turned the key, it cranked strongly, and cranked, and cranked... Nada, no spark seems to be getting to the plugs. It had not been touched since the last time I shut it down.

I have checked the gas, there is at least a quarter tank (by both the gauge and by trip meter). I tried pushing the accelerator to the floor and holding it there while cranking...nothing. I left it for a half hour thinking perhaps I did flood it. Still nothing.

I have put the battery charger on it since I did a lot of cranking (I did not overdo or leave it turn too long each time). It registered 12.2 amps when I attached it. Like I said, it was turning over just like normal. I'm leaving on the charger but dont have a clue what to do next other than call my mechanic (who is an hour away).

Again, nothing has been touched since its last start and before that, immediate with the turn of the key.

Any ideas on what might be the problem or what I (a very inexperienced mechanic) might try or do?

 

Thanks for the input. My garage is not next to my house so I cant try some things at the moment. But in terms of information, I really did not smell raw gas when I opened the engine compartment. So perhaps it is a fuel delivery problem. I'll try the tap on the fuel pump in the morning. If that does not work, obviously I'll go from there.

 

It is more an more looking like an ignition problem. I have rapped on the fuel pump, checked the fuses. The battery was fully charged this morning. At least I think so. It registered 12.9 amps with all the bars (on the indicator light) at full. I gave it a go and the same as yesterday. The starter turns strongly but nothing catches.

I smelled the tailpipe after and there was a definite raw gas smell, so it does seem that the fuel pump is working. I waited an hour and took off the cold start blue electrical connection, and still no start.

I'm not sure I know how to test for spark. And if I find there is no spark, I would still need to engage my mechanic for further diagnostic and repair. So it looks like arrangements will have to be made in the morning.

Nothing left for it today but to close up the garage and go watch the F1. Hopefully there will be at least one fcar that runs great.

 

Guys, Thanks for all the input. I actually was waiting to post to try and say it had been solved, as on monday morning I had the car hauled to a bosch electronic specialist. Its the guy who installed my new fuse panel last fall. He is considered the local engine whisperer.

Well, Dante still ain't talking. Of course the mechanic left it sit two days, then yesterday began looking at it. At my rather plaintive call this morning he said he has checked all connections but has yet to find the problem. I presume that means there is no spark. He said he will give it the "maximum" today but I am worried that he has left it too late for us to get a part if needed this week.

We are registered (and paid up) to attend a big rally through the Bordeaux vineyards this weekend with 150 classic cars. And you are required to show up in the car you registered with and I may be left behind in more ways than one.

So Ok. Any ideas or possibilities that I might pass along?

 

So, I got a call around noon from my mechanic. He said he got the car running again but asked first if I had an alarm system. I said not to my knowledge after 4 years of ownership nor from anything received from the prior owner. There are no buttons or lights or procedures that I have ever used to turn on or off anything other than the ignition swith after hundreds of starts and stops.

He said he found an "extra" wire that had somehow disabled the electrical system sending the spark. When he cut/removed it, it started immediately. Since I have been traveling all day and only spoke to him briefly and with great relief that the car runs, I do not know exactly where the wire went from or to what it was connected.

So would an 85 QV have a built in alarm system? It has never once exhibited itself before, and why now? And if it did not, why is that wire there or what does it do to disable the electronics? These are of course rhetorical questions in the end for me. I'm just glad it was not something major. But it still leaves behind a mystery.

I will go pick up the car tomorrow afternoon and try to find out something more specific and pass it along. I'm just glad my engine whisperer was able to get Dante to purr again.

 

Thanks Wade. Yes, my shop manual with wiring diagrams was in the car. But I really dont know until I see him tomorrow what he used or found exactly. At some point, he did realize that the wire he eliminated was not supposed to be there or required.

But what is still a question is why after 4 years with me, this should suddenly be activated. I'll try and find out as much as I can tomorrow and report back.

 

Ooops, Wade. I meant to add that I would take in the schematic of the ignition system and try to have him show me where things were done.

But also, I note reference "83" on your image which refers to "key operated antitheft and ignition system". You said there was no OE alarm, but what about the antitheft part? Is there a OE antitheft system tied to the ignition and might that be what he has referred to?

 

When I picked up my QV, I brought along the ignition schematic that Wade posted. I showed it to Phillip, the mechanic, and he said he tracked down the problem by isolating the electronic control modules on Fig 1, page D1.

He said first he disabled one bank and then found there was spark in the other bank. When he disabled the second bank, there was no spark from the other module so that told him the problem was in the first module. As he looked at the connections and traced the patterns on the non functional module, he noted that there was a wire in position 7 which did not seem to be on the schematic. It is listed on the sheet as "ignition key". For whatever reason, he felt it was not correct and disconnected it. The engine fired immediately. So the car works but whatever was in position 7 of one control module is now not connected. So for me the mystery continues but now the car starts and runs perfectly, as it did the day I parked it.

I wish I had a more concrete reason for what went wrong and now why it is fine. Whatever gremlin was there is gone. And eliminating the wire does not seem to have affected any other system/function. That's why he asked if I had an alarm. It is somehow connected to the ignition key but we dont know why the wire was there or what it connected to, or why it worked for years as it was, and why did it stop, and why does eliminating the wire make the car normal again.

I'm just glad he eliminated the problem of course. At least I'll be on the road in the morning to the rally, 22nd curcuit Cadillac, a tour of the wine region around Bordeaux. There are 150 cars participating. The objective is to somehow tie cars to particular wines. Hmmm, dont know that there is any sangiovese grapes in the Bordeaux wineries. But should be great fun now that I am back on the road.

Wish I had more concrete info but an intuitive mechanic at least figured out the solution.