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I have recently installed the TeamRush upgrade along with the MSD-6A & MSD TFI coil. I also have the Howell TBI system on my 83 CJ7/258. It's running great except that the engine is knocking once it's at or above 180 F. The vacuum advance is connected to ported vacuum on the TBI. My vacuum guage showed 0 in Hg at idle and a maximum of 20 in Hg before it comes down as the throtle opens even more. This matches the manifold vacuum at 20 in Hg at idle. Do I need different springs for the centrifugal advance? I think it is advancing too much because I have backed the timing down to 2 dbtdc and there's still some knocking (but there is a slight improvement). I have written TeamRush before about possibly using MIG welder tips in the vacuum advance line to limit the advance, but I didn't have a vacuum guage to know what I was talking about. I know I've got to be close because it runs and sounds great until the coolent temp reaches 180. Just looking for a little help here.

Jeepgator
1983 CJ7/258/T-999/TBI/TeamRush/MSD

 

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/wwwthreads_images/icons/tongue.gif At 180 degrees your spark CTO switches from manifold vacuum to ported vacuum.....are you running the stock smog stuff?/wwwthreads_images/icons/tongue.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.
 

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This is an easy one...

HOWELL SPELLS OUT IN CAPITOL LETTERS IN IT'S INSTRUCTIONS THAT THE VACUUM ADVANCE ISN'T USED WITH IT'S FUEL INJECTION SYSTEM ON THE 258.
Manifold Absolute Pressure (MAP) sensor submits vacuum readings to the computer, and the computer compensates for the vacuum advance.

It's on the web site also.
(Unfortunately, I lost the Howell web site address in a server crash about a month ago...)

Disconnect your vacuum advance, and plug the vacuum port it went to.

I've had this question at least a half a dozen time on private email in the last 30 days...
Must be a bunch of those Howell EFI systems on Jeeps now...

So Many Cats, So Few Recipes...
 
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