62Ranchero200
Famous Member
Background: A DUI was part of my 250 w/AL head from the beginning, and had been running for about a year when the issues started. The DUI was custom curved for my engine and ran extremely well when it ran. I've put only about 2,000 miles on this engine since it was new a year ago.
About a month ago, on a Saturday afternoon as I was getting into the Ranchero, GF in the passenger seat to go to a local cruise-in, the Ranchero started, but ran very roughly. After a wrong turn looking at the power valve and diagnostic testing, I finally determined that a faulty DUI module ($50) was to blame. The module was diagnosed by elimination as there is no at-home test you can perform on an HEI/DUI ignition module - the voltage to the DUI, ground, coil, and magnetic pickup all tested within spec. After I replaced the module, the Ranchero ran well again for a month.
Last Saturday, again the Ranchero failed to start. This time, I did as much diagnostic testing as I could, replaced the module (another $50), but the Ranchero still wouldn't start. Replaced the coil as well (although it tested within limits, 0.7 Ohm primary 7.8 KOhm secondary) (another $50), to no avail.
The magnetic pickup tests within spec - 1040 Ohms, generated .5 - 1.0 V when the distributor is rotated - but that's significantly more trouble to replace - have to pull the distributor, pull the gear, pull the shaft out the top. I don't own a press so pulling and reinstalling the gear would be a PITA.
Two failures within a month, and $150 in parts so far, and the Ranchero is still not running ...
So I'm switching to a more traditional MSD / DS II setup. The DUI is too unreliable, too difficult to troubleshoot, too difficult to repair, and parts are too expensive.
Thanks
Bob
About a month ago, on a Saturday afternoon as I was getting into the Ranchero, GF in the passenger seat to go to a local cruise-in, the Ranchero started, but ran very roughly. After a wrong turn looking at the power valve and diagnostic testing, I finally determined that a faulty DUI module ($50) was to blame. The module was diagnosed by elimination as there is no at-home test you can perform on an HEI/DUI ignition module - the voltage to the DUI, ground, coil, and magnetic pickup all tested within spec. After I replaced the module, the Ranchero ran well again for a month.
Last Saturday, again the Ranchero failed to start. This time, I did as much diagnostic testing as I could, replaced the module (another $50), but the Ranchero still wouldn't start. Replaced the coil as well (although it tested within limits, 0.7 Ohm primary 7.8 KOhm secondary) (another $50), to no avail.
The magnetic pickup tests within spec - 1040 Ohms, generated .5 - 1.0 V when the distributor is rotated - but that's significantly more trouble to replace - have to pull the distributor, pull the gear, pull the shaft out the top. I don't own a press so pulling and reinstalling the gear would be a PITA.
Two failures within a month, and $150 in parts so far, and the Ranchero is still not running ...
So I'm switching to a more traditional MSD / DS II setup. The DUI is too unreliable, too difficult to troubleshoot, too difficult to repair, and parts are too expensive.
Thanks
Bob