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The Volvo is DONE! Well, as "done" as one of these projects gets. The tach failed and the engine quit running, we think at the same time. After digging around it turns out that the tach signal from the MSD had failed which meant that there was no tach readout but more importantly the EZ-EFI had no tach signal so it couldn't trigger the EFI meaning the engine can't run. I found a temporary work around but it puts the EFI in limp-home mode and dead rich so that's not a long-term solution.
I ordered a new MSD (I plan to send the old one back to get the tach signal fixed) and installed it which made the engine run properly but still no tach readout which Dick really wants. I tried several possibilities but was left scratching my head until Hot Rod Magazine ran an article on Red Line Gauge Works fixing the "old tach with a new engine" type of issue. They replace the old guts with modern electronics which makes all tachs work with multi spark ignitions and high output alternators both of which can mess up a tach and both of which we have in the Volvo.
I called Red Line and it turns out that our issues were exactly what they fix, even with a factory VDO tach. Dick agreed so I sent the whole dash pod (that's how they like to get them) off to them and about 3 weeks later it came back. I installed it today and......absolutely no reading. It turns out that I had knocked the tach signal wire off the back of the gauge pod when I hooked up the speedo cable so that was a quick fix. I hit the key and VROOMMM, lots of RPM. It was obviously reading MUCH too high, maybe as much as double. After another session of head scratching I remembered that I had installed a Dakota Digital Universal Tachometer Interface when I was trying to make the original set up work. I found that and jumped the signal input wire (the tach signal wire from the MSD) to the signal output wire (that's the one that plugs into the dash pod), insulated the ground and switched 12 VDC that fed the tach interface, hit the key and everything is groovy! I could hook up the hand held EZ EFI readout and see if it agrees with the VDO but it certainly has reasonable readings now with cold idle at about 1,000 RPM - it settles down a bit once warm.
Dick is a bit under the weather right now but we'll make arrangements to get it back to him in the near future.
I ordered a new MSD (I plan to send the old one back to get the tach signal fixed) and installed it which made the engine run properly but still no tach readout which Dick really wants. I tried several possibilities but was left scratching my head until Hot Rod Magazine ran an article on Red Line Gauge Works fixing the "old tach with a new engine" type of issue. They replace the old guts with modern electronics which makes all tachs work with multi spark ignitions and high output alternators both of which can mess up a tach and both of which we have in the Volvo.
I called Red Line and it turns out that our issues were exactly what they fix, even with a factory VDO tach. Dick agreed so I sent the whole dash pod (that's how they like to get them) off to them and about 3 weeks later it came back. I installed it today and......absolutely no reading. It turns out that I had knocked the tach signal wire off the back of the gauge pod when I hooked up the speedo cable so that was a quick fix. I hit the key and VROOMMM, lots of RPM. It was obviously reading MUCH too high, maybe as much as double. After another session of head scratching I remembered that I had installed a Dakota Digital Universal Tachometer Interface when I was trying to make the original set up work. I found that and jumped the signal input wire (the tach signal wire from the MSD) to the signal output wire (that's the one that plugs into the dash pod), insulated the ground and switched 12 VDC that fed the tach interface, hit the key and everything is groovy! I could hook up the hand held EZ EFI readout and see if it agrees with the VDO but it certainly has reasonable readings now with cold idle at about 1,000 RPM - it settles down a bit once warm.
Dick is a bit under the weather right now but we'll make arrangements to get it back to him in the near future.
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