Electromotive HPV-1 question

Curtis

Curtis

Well-known member
Run into one I can't figure out? Any help would be appreciated.

I can only get my Electromotive to advance to about 39 or 40 advance instead of the 60 it is supposed to be capable of reaching. Additionally at higher rpm it backs out 2-4 degrees seen watching with the light. Zeroed out it does light tdc as it should and the intial seems pretty close to what I dial in.

Changed batteries, ran new grounds, wired around the switch, ect but could not change anything so finally decided it was the unit itself. I changed out the whole HPV-1 unit for my spare. But no change. Still behaves the same.

Any ideas? Noise issues couldn't cause this could they? Voltage? I'm really at a loss as what to try next. Really hoping somebody says "oh yeah that happened to me once and this is how I fixed it".
 
Curtis,
I'm sure you already re-checked your mechanical TDC against the trailing edge of the 11th tooth as it aligns with the center of your 1/2" sensor. What is your initial idle rpm. The system holds the initial setting up to 1,000 rpm, then begins adding the advance you dialed in between 1 and 3k. If you set your initial advance at an rpm greater than 1k you loose some of the advance you wanted between 1 and 3k. Reset your initial at an idle below 1k and see if you get your 60 total back. Do you really get away with 60 degrees of total advance?

Thanks,
Keith
 
Curtis,

On you trigger wheel, how far before TDC is the index (skipped teeth). Is it possible that it is close to the 40° mark?

I had a simular issue with a Miata, index was at 25° and couldn't get more than 25 advance. Moved it to 75° and problem went away.

John
 
Thank you John and Keith.

With everything set at zeroe I have exactly zero advance so that is right. (and it is 11 teeth out)

With 20 degrees "initial" plus 19 degrees "3000" I can get the 39 degrees I want up to about 4500 rpms. The only way I can get it to stay at 39 as I rev higher is to set the high "8000" add at +8to10 degrees. While this should advance me to the high 40s, it instead just sticks me at 39 and keeps the unwanted retard from happening. The rev limiter has even gone goofy on me and kicks in at 4K when set at 6 but does turn off. So this is how I will go to Hallet (Hprod). As long as nothing changes I have exactly the right timing, just arrived at the wrong way. I am going to try to call Electromotive this week and see if they have any ideas.

For reference the car is an Alfa and it's a real 50s style Hemi chamber. Literally half a sphere so the burn is incredibly bad. Stock advance setting is 41-43. Until a recent piston design success 41-43 or was required by the traditional popup pistons, which screw up the chamber even more, as well. So I'm actually excited to only run only 39 now!

Thank you again for your replies.
 
This sounds dumb, but... is it set for 4 cylinders? The rev limiter thing made me think of that...

and yeah, an Alfa piston is something to behold. Tradeoff is that the head is enormous, and
those runners are huge, with great entry angles.

'Course, an Alfa main bearing is smaller than my rod bearings...

A different way of going fast, but they do go.

t
 
One other comment:

Might not be in spark box, rather try another timing light. I've had funny things happen with inductive pickup lights, particualarly those that had knobs on back to set advance...internal circuits just can't flash fast enough...

Just a thought.

Bob L.
 
Another thing to keep in mind when you're using a timing light, I believe on these is it fires on both the compression and exhaust strokes so it may be sending double signals to your timing light.
 
Curtis":15awjmdj said:
The rev limiter has even gone goofy on me...
Click to expand...
Curtis-
Have you tried it without the rev limiter "on"? At my first Runoffs I had an Electromotive external rev limiter go "bad" - it made the ignition run at TDC. Took awhile to figure out what was wrong, but when we unplugged it, everything went back to normal. Probably not related to the problem you're having, but a thought.

Brian
 
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