Timing not advancing - code 41 - HES maybe?????

[rayc]

OK, here goes. Sorry for the long post but I wanted to summarize how I've reached the current level of frustration
in hopes it might trigger some ideas.

When it started missing I checked to see if any fault codes were set but none were. Hoping it might not be electrical I changed the fuel filter
and for a few days it didn't miss a beat but then got more frequent. So I pulled the injectors and had them checked and cleaned.
All were good but the missing got worse and still no fault codes.
The plugs (new) and wires are good, I replaced the original coils and had the ignition control module
bench tested and it is good.
At this point the 'miss' had become permanent, the engine starts, idles poorly and the timing seems to not be advancing.
So hearing that the HES is a weak point I ordered and installed one of the 'new improved' versions.
Static timing was reset after the new HES was installed.
At the same time I pulled the ECM and sent it to people who rebuild them and they said is appears to be good.
After installing the new HES the only change is that now I get a fault code 41!
Using the 'non-scan' diagnostic test I get good ground on the black, 12v on red with ignition on, 5v when HES disconnected and 0v when connected which leads to the conclusion
that the HES is bad! I guess it is possible that a new HES would be defective but I would be surprised.

So now my questions: Is there a way to confirm that a HES is good or not? Would the Elanscan program show this?
There is a second HES in the CAS, on the upper back side which connects with two wires to the ignition control module but I don't see it referenced anywhere.
The wires are not open or grounded but I don't know how it can be tested. I heard that these 'never fail' but is there a way to test them and can they
be replaced if bad?

Any and all comments or suggestions welcome.
Thanks, Ray

[wayne]

You seem to have already covered most of the things that I would have thought about.

Just a thought.... You mentioned after changing the fuel filter things seemed to improve for a short while.
Have you looked at the fuel pressure regulator or fuel pump?

When you say the timing does not seem to advance. Have you checked this with a strobe? (may need to put it into service mode).

Also if before you changed the HES you had no codes but after you had a code 41. After I changed to the new style HES I had problems getting the pins to lock into the new plug. You could try putting the old one back and see if the code goes away.

How are the vacuum hoses? any holes in them? I believe that there is one on the back of the plenum that can come off and is very difficult to see. I seem to remember using ty wraps to secure mine in position.

Sorry this may not be very helpful but worth a try

[rayc]

Wayne, Thanks for the input.

Fuel pump and pressure are OK.
WHen I got the fault 41 after changing the HES I did suspect the new connection but it is good. The correct voltages are read after the connection.
One thing we did not do was watch the timing (not in service mode) with the strobe after changing the HES. We only set the static timing in service mode but will try that to confirm if it is really advancing or not. THanks!
The vacuum lines appear to be good. Removing the one behind the plenum causes the idle to get worse so I don't think there is a leak.

Ray

[Peter_W]

Ray,

I've received code 41 twice in the past. The first time replacing the CAS fixed it (this was before Lotus came out with the separate HES). There are threads on LEC where wear issues with the CAS itself (as opposed to the HES) were the cause.

The other was related to the seating of the memcal in the ECM - obviously a longshot in your case as you've had the ECM checked out.

Pete