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Experiences with an HES

How to tell if the HES is bad

If the bike cranks but won't start, and you have no spark and you have no spray from an injector, then the HES is bad.
This can be checked in just a few minutes, by pulling one plug and then one injector.
In other words, the only common cause that can kill both spark and injection is the HES.
And furthermore, if you have either spark or injection then the HES is fine.

Another symptom of bad HES, sometimes, is that the tach needle jumps around like crazy while cranking.
 
Well we...My bride and I.....just got home last night from a 2100 mile road trip to Virginia Beach after the Finger Lakes Rally in New York.........great ride and no issues......glad the repair was done before we left
 
If the bike cranks but won't start, and you have no spark and you have no spray from an injector, then the HES is bad.
This can be checked in just a few minutes, by pulling one plug and then one injector.
In other words, the only common cause that can kill both spark and injection is the HES.
And furthermore, if you have either spark or injection then the HES is fine.

Another symptom of bad HES, sometimes, is that the tach needle jumps around like crazy while cranking.

What happens if one of the Hall sensors is bad but the other is good?
 
Teflon aircraft wire and hi temp heatshrink is the fix.
Hall sensors should be replaced if you really want to 0 time.
Trouble is, the Hall sensors are obsolete now. Honeywell (Airpax) 2AV54 are no longer made.
Hard, if not impossible to find


When you replace the wire harness, are you still using part of the original wire near the connectors and sensors? If so, dont they have the same bad insulation issues?
 
When you replace the wire harness, are you still using part of the original wire near the connectors and sensors? If so, dont they have the same bad insulation issues?

No, the actual wires coming from the hall sensor have the high temperature rating. The problem is the cable that was added by Bosch to make the assembly.
 
Thanks for clearing that up. I have an 03 RT with just under 20K. I have no idea if there was a cut off point with the harness problem.
 
Top sensor bad = no spark signal
Bottom sensor bad = no fuel injection signal

Can you tell me where you get that info?
I have believed, from observations on my own bike, that failure of either HES sensor kills both spark and injection.
From that I had guessed (only a guess) that the only reason for two sensors was to get more pulses and finer control at low RPM.
I've never been able to find any official reference to clear this up.

If necessary I'll disconnect one sensor and see what happens. Have you done this?
 
Can you tell me where you get that info?
I have believed, from observations on my own bike, that failure of either HES sensor kills both spark and injection.
From that I had guessed (only a guess) that the only reason for two sensors was to get more pulses and finer control at low RPM.
I've never been able to find any official reference to clear this up.

If necessary I'll disconnect one sensor and see what happens. Have you done this?

Ditto, can't find anything in writing. If I have to I will rig some switches.
 
Can you tell me where you get that info?
I have believed, from observations on my own bike, that failure of either HES sensor kills both spark and injection.
From that I had guessed (only a guess) that the only reason for two sensors was to get more pulses and finer control at low RPM.
I've never been able to find any official reference to clear this up.

If necessary I'll disconnect one sensor and see what happens. Have you done this?

Not directly but learned it by testing the sensor assy. (I have a rotational tester) before rebuilding and comparing that to the client complaint. IE: no spark or no fuel.

Also Dana Hagar writes about it in the Hall of Wisdom on ADV Riders.
 
Teflon aircraft wire and hi temp heatshrink is the fix.
Hall sensors should be replaced if you really want to 0 time.
Trouble is, the Hall sensors are obsolete now. Honeywell (Airpax) 2AV54 are no longer made.
Hard, if not impossible to find


Not if you search the web. Just got two........from China!
 
Teflon aircraft wire and hi temp heatshrink is the fix.
Hall sensors should be replaced if you really want to 0 time.
Trouble is, the Hall sensors are obsolete now. Honeywell (Airpax) 2AV54 are no longer made.
Hard, if not impossible to find


Are these ones that you have redone? They look great. Do you have instructions about how to do this?
 
I am not contradicting GSAddict's comments at all, but,

Top sensor bad = no spark signal
Bottom sensor bad = no fuel injection signal

On my 1997 R1100RT, it started running terrible. I had an odd vibration that I though could be drive line but it stayed engine side. It started, oddly enough, better than usual, no cheater lever needed.

So at times I think I'm a smart guy and I know how stuff works and read the codes. Kept getting the BDC HES code every time. Changed it with a known good used one. I have a very limited riding season and didn't want to wait for a new one. Well, bike started like before, need the cheater for a block or two, vibration gone, horsepower and fuel economy much improved.

In the process of taking the whole works apart, I found the dreaded crappy wires. I also looked at HES signals with a frequency meter. BDC still read but definitely different than the TDC. Checked the good used HES same way, both frequencies the same.

My assumption was that the Moronic used the BDC signal for an algorithm to determine RPM, timing etc., same as a lot of engines need a crankshaft position sensor and camshaft position sensor to be synchronized. I've seen some engines use two camshaft position sensors on the same camshaft gear, 180 degrees apart.

With comments on this post, I think my experience was one sensor going bad and not completely toast yet. I think my assumptions that the Moronic needs to see both sensors synchronized is probably me thinking too much.
 
On my 1997 R1100RT, it started running terrible. I had an odd vibration that I though could be drive line but it stayed engine side. It started, oddly enough, better than usual, no cheater lever needed.

So at times I think I'm a smart guy and I know how stuff works and read the codes. Kept getting the BDC HES code every time. Changed it with a known good used one. I have a very limited riding season and didn't want to wait for a new one. Well, bike started like before, need the cheater for a block or two, vibration gone, horsepower and fuel economy much improved.

In the process of taking the whole works apart, I found the dreaded crappy wires. I also looked at HES signals with a frequency meter. BDC still read but definitely different than the TDC. Checked the good used HES same way, both frequencies the same.

My assumption was that the Moronic used the BDC signal for an algorithm to determine RPM, timing etc., same as a lot of engines need a crankshaft position sensor and camshaft position sensor to be synchronized. I've seen some engines use two camshaft position sensors on the same camshaft gear, 180 degrees apart.

With comments on this post, I think my experience was one sensor going bad and not completely toast yet. I think my assumptions that the Moronic needs to see both sensors synchronized is probably me thinking too much.

So far everything points to what I have learned so far. I welcome someone proving that wrong.
The Motronic pinouts simply read S1 & S2 - not much help
The ignition system is "wasted spark" so it would stand to reason the injection would use the other; BDC sensor.
 
Sensor 1: spark
Sensor 2: fuel
With bad HES wiring, you can (and almost always will) get both spark and fuel (if the result of the insulation degradation is a short between the wires). Unfortunately, there is no telling when the signal will actually arrive at the motronic because of the short ("Hey! was that the ignition pulse or the fuel pulse??"). You can also have an open in the wire, but that can still cause erroneous signals because the wires sometimes short together.
 
Top sensor for spark, bottom sensor for fuel?

Not directly but learned it by testing the sensor assy. (I have a rotational tester) before rebuilding and comparing that to the client complaint. IE: no spark or no fuel.
I guess your setup has a variable speed motor driving a notched pulley into a fixtured HES from customers, with the HES connected to your oilhead. Cool. Much more conclusive test than just observing HES signals with VOM or scope.

I guess your "or" means you observed some HES units kill spark only and others kill injection only? If so, I retract my statement (that both would be killed if either sensor is bad).

Also Dana Hagar writes about it in the Hall of Wisdom on ADV Riders.
If you mean this excellent article..:
http://users.rcn.com/dehager/service/oilhead_hall_sensors.pdf
...I have read it many times and found no reference to different usage of the two sensors. But maybe he posted otherwise to ADV and I didn't see it.

I was glad to know Dana Hager when he was writing that and other great oilhead articles.
 
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