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 Post subject: 1986 740 wagon stalling problem
PostPosted: Tue Oct 13, 2015 4:48 pm 
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Here is a little bit of the history;
The car stalls at the weirdest times. It is just like the key is turned off. Engine quits, dash lights come on.
It started two years ago. At that time it was the Radio suppression relay which burned out.
Six months later the same thing happened again.
This time I replaced the ignition control module. It worked fine for a year.
Next time I re-soldered the relay and it worked again for awhile.

Just this week I redid/checked all of the above and tested the coil by putting it on another car. Bad coil. It did not work at all on the other car.
New coil, car works fine again.
This time I also got a new knock sensor.
The knock sensor plastic cover disintegrated and one of the contacts was broken.
I also got a new (re-conditioned) distributor with the build in Hall sensor. It just arrived today.
Questions;
1; Any pointers for installing the distributor? What to look out for, what not to do?
2: The next test on my list is to test the wiring. Any suggestions how to go about that? Or is there anyone here in Lethbridge who can still work on the wiring of "real" cars.
Appreciate any feed back and help.
Thanks
Peter

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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Tue Oct 13, 2015 9:13 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Location: Lethbridge, AB
Hi Peter,

The knock sensor takes a standard junior power mini timer (aka Jetronic plug) - there should be lots in the JY. You can also get them new. These older harnesses sometimes suffer from disintegrating wire jacketing. Check out Dave Barton's website - he sells new and good used wiring harnesses.

Manually rotate the engine to TDC on 1 (line up the timing mark and check to see that the rotor points to plug wire 1. Remove the old distributor (they are sometimes frozen in place and may require a little tap with a hammer). Then rotate the new distributor without touching anythings else on the engine, and slip it into place. It will line up where it is supposed to be. You'll need a timing light to make sure the base timing is where it should be.

There is no on in town that would do a really nice job in my opinion. Would they use the proper GXL or TXL wire or just PVC jacketed stuff? Is it heat shrunk or did they use double wall with glue to seal the joint? Did they solder or crimp (both are fine if done properly). My advice is to DIY it and you'll be more happy with the result.

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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Tue Oct 13, 2015 10:00 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
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Location: Calgary, Ab
Being that this is a 740 you don't have to be too careful about distributor position: it's driven by the cam and it only slots into the cam one way, so it's impossible to put in wrong. It's also not going to seize into the back of the head like a block mount can do. There is a timing adjustment required after you're done but again this is straightfoward.

Wiring harnesses on earlier (pre 88) 740s is just as bad as any 240. I would say that among the many potential ground failures, the harness itself is a top contender to be your problem. There are a number of grounds peppered around the car - like, 12 or 13 of them - that you should really check. Remove, clean, and use a conductive cleaning paste like Tunerlube (you should be able to get some at a serious electronics shop) and don't stop until you get them all. Also, check your fuse box: I've had to replace a melted one that was causing all sorts of problems.


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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Wed Oct 14, 2015 2:26 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Location: Missing my garage in Sunnyside
Yes there's a good chance your previous repairs weren't from replacing a component but just adjusting the wiring harness when you did! Check the condition at the firewall connectors- if it's dodgy there it's will be in lots of other places. Rebuild yourself or find a good used replacement and swap it in a couple of hours.

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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Wed Oct 14, 2015 2:43 pm 
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Joined: Thu Oct 01, 2015 10:07 am
Posts: 9
swedishmeatball wrote:
Yes there's a good chance your previous repairs weren't from replacing a component but just adjusting the wiring harness when you did! Check the condition at the firewall connectors- if it's dodgy there it's will be in lots of other places. Rebuild yourself or find a good used replacement and swap it in a couple of hours.


Thanks for your reply. That's what I thought too. But each time before working or replacing anything I fiddled with the wiring and would try to start the car but it is usually after removing one part that it starts again.
Don't know if I am courages enough to replace a wirring harness. But it might seem that it will be neccessary. :-(

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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Wed Oct 14, 2015 2:45 pm 
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Joined: Thu Oct 01, 2015 10:07 am
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122_Canuck wrote:
Hi Peter,

The knock sensor takes a standard junior power mini timer (aka Jetronic plug) - there should be lots in the JY. You can also get them new. These older harnesses sometimes suffer from disintegrating wire jacketing. Check out Dave Barton's website - he sells new and good used wiring harnesses.

Manually rotate the engine to TDC on 1 (line up the timing mark and check to see that the rotor points to plug wire 1. Remove the old distributor (they are sometimes frozen in place and may require a little tap with a hammer). Then rotate the new distributor without touching anythings else on the engine, and slip it into place. It will line up where it is supposed to be. You'll need a timing light to make sure the base timing is where it should be.

There is no on in town that would do a really nice job in my opinion. Would they use the proper GXL or TXL wire or just PVC jacketed stuff? Is it heat shrunk or did they use double wall with glue to seal the joint? Did they solder or crimp (both are fine if done properly). My advice is to DIY it and you'll be more happy with the result.


Thanks for your reply, no I tried the junk yards, nobody had any.
Thanks for the advice on the distributor and the wiring.
Peter

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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Wed Oct 14, 2015 2:59 pm 
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Ugly Duck wrote:
Being that this is a 740 you don't have to be too careful about distributor position: it's driven by the cam and it only slots into the cam one way, so it's impossible to put in wrong. It's also not going to seize into the back of the head like a block mount can do. There is a timing adjustment required after you're done but again this is straightfoward.

Wiring harnesses on earlier (pre 88) 740s is just as bad as any 240. I would say that among the many potential ground failures, the harness itself is a top contender to be your problem. There are a number of grounds peppered around the car - like, 12 or 13 of them - that you should really check. Remove, clean, and use a conductive cleaning paste like Tunerlube (you should be able to get some at a serious electronics shop) and don't stop until you get them all. Also, check your fuse box: I've had to replace a melted one that was causing all sorts of problems.


Thanks for the advice.
Did check the fuses and relays. Took them all out and added the Tuner lube. Electric grease the guy at Napa called it. :-) Nothing seems wrong from the top of the box.

I found a wiring diagram online but it does not really tell where exactly all the ground connections are on the car. Do you know if there is a list somewhere?
Peter

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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Wed Oct 14, 2015 3:27 pm 
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Here's a link to one of the electrical sections from the 700/900 FAQ on Brickboard. The section on grounds is about halfway down. If you're going to do a harness replacement (I haven't) I would agree with Craig that Dave Barton is the place to buy one.

https://www.brickboard.com/FAQ/700-900/ ... sisGrounds

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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Wed Oct 14, 2015 3:58 pm 
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Joined: Thu Oct 01, 2015 10:07 am
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woodenshoes wrote:
Here's a link to one of the electrical sections from the 700/900 FAQ on Brickboard. The section on grounds is about halfway down. If you're going to do a harness replacement (I haven't) I would agree with Craig that Dave Barton is the place to buy one.

https://www.brickboard.com/FAQ/700-900/ ... sisGrounds


Thanks for the link, I will check it out.
Don't know if I have the guts to replace a wiring harness. Hopefully I will find something with ground wires.
Peter

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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Wed Oct 14, 2015 4:01 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Dec 21, 2005 8:40 pm
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Location: Calgary, Ab
A B230 engine harness practically falls into place: they even have yellow tape on the wrap to show you where the clamps or tie-downs go. All the plugs are pretty much impossible to screw up, though you have to be careful about the knock sensor and coolant temperature sensors: they can but should not be interchanged. Just be sure that the heavily shielded one goes to the knock sensor. I can't speak to Barton's harnesses as far as accuracy and details like the yellow tape, Volvoshredder has used one of Dave's earlier ones and helped work out some teething problems.


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 Post subject: Re: 1986 740 wagon stalling problem
PostPosted: Wed Oct 14, 2015 4:09 pm 
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Joined: Thu Oct 01, 2015 10:07 am
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Ugly Duck wrote:
A B230 engine harness practically falls into place: they even have yellow tape on the wrap to show you where the clamps or tie-downs go. All the plugs are pretty much impossible to screw up, though you have to be careful about the knock sensor and coolant temperature sensors: they can but should not be interchanged. Just be sure that the heavily shielded one goes to the knock sensor. I can't speak to Barton's harnesses as far as accuracy and details like the yellow tape, Volvoshredder has used one of Dave's earlier ones and helped work out some teething problems.


Thanks, you make it sound easy. :-)

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