S-type Electrical guide.

[J44EAG]

This is becoming a most interesting thread and one that would make a good article for the magazine.

Having read the link, there would appear to be certain similarities in function to some diesel fired blown air heating systems which I have encountered on small yachts and motor boats. Eberspacher, Webbasto and Mikuni being typical makes.

These units have proved to be reliable as long as fuel and filtration is kept in tip top condition. I`ve found that fuel with a high moisture content always causes problems. Any water droplets within the fuel cause the heaters to carbonise, clogging jets and combustion chambers with excess soot. If continued to run in that condition, the coking continues to build to a point when the unit is quite simply unable to function. A strip down and clean out then becomes necessary. Often an ecu re set is needed.

Fuel dryer additive is available from most typical motor accessory outlets. "Dry Fuel" is one such product made, I think by Wynns. Cost around £6.00 a bottle. The formulation allows minor amounts of water to combine with the fuel and allow it to burn without causing the carbonation issues. Large amounts of water that may have accumulated in a fuel tank should obviously be drained off.

Fuel should sparkle in a glass container when examined. Cloudy, dull looking fuel is indicative of the fuel having a high moisture content.

Wet fuel causes untold corrosion and blockage issues. On the engine side, fuel injectors operating with poor quality fuel will again be subject to a degree off blockage and more importantly nozzle erosion being a common problem which can require reconditioning of nozzle tips and needles. This deprivation is again a problem that I frequently encounter on neglected marine craft. Lack of use seems to exacerbate the issue.

I often regard this type of heater as being akin to "a blow torch in a box". Great whilst they are running well but rather expensive to sort out when the go wrong.

Thanks for that link, Doug. Very useful material.

Mike

[jeff1954]

My thanks also to Doug.
Loads of good posts and info on that link. I'm going to try pulling the fuse that operates the F.F.Heater whilst the engine is running and this sometimes (acording to the link) resets the unit.

Apparently low fuel can cause the heater to"lock out" after 3 attemps to start. When I purchased the car 3 years ago from a main agent the fuel level was very low. So maybe this is the problem as it has never worked in my 3years of ownership.

The other solution to the problem is to take it to a Jag or Webasto agent to have the fault cleared.
I'll keep you posted.

Jeff.

[J44EAG]

The other thing to consider is that if the heater were to have picked up a nice big dollop of water (usually caused by empty tank condensation or leaking tank fuel filler cap o-ring seal) then it would obviously fail to start up. Similar effect to having a carburettor float chamber full of water.

Mike

[daven]

Fuel Fired Heater (FFH)

Lots of interesting points in this topic, checking my notes there are some conditions that will prevent the heater from running and should be checked prior to further fault analysis.

1, The Heater will not run if the Climate Control is turned off
2, The Heater will not run if Battery Voltage is below 10.2 volts
3, The Heater will not run if the Low Fuel Light is on
4, The system operates if ambient air temperature is below 5c and the coolant temp is below 87c.
5, The Heater will only run when the engine is running

The information I have states the following:

During automatic heating operation the glow plug functions as the flame sensor to monitor flame condition. In the event of no flame condition a restart is initiated.
If the no flame condition persists, fuel delivery is stopped and the heater enters an error lockout with a timed shutdown of the combustion air fan to cool the heater.

I hope this helps

Dave

[jeff1954]

Thnks for that info Dave.
I think it's locked out. Iv'e tried pulling the fuse ect but to no avail.The next step is to take the car to a Webbasto agent and get them to unlock it!
Having said that it hasn't been all that cold here in sunny Stocport for the last week so it's hard to tell if it should fire up anyway.

Jeff.

[daven]

Jeff

Once you have checked the basics I would then look a bit deeper, ie check that fuel is been delivered to the heater, this is fed by a different line than that of the Engine so can easily be overlooked.

The Heater can normally be reset by removing the power supply to it.

Have a look at www.webasto.com where you will find that they provide service information for their Heaters.

Regards

Dave

[jeff1954]

Sorry about this late post.
Thanks for the reply Dave. I contacted a Webasto Agent in Manchester ( twice actually) but I didn't get anywhere with them. As the weather is now warming up you tend to forget about such things as I have done for the past 3 years. Maybe it's a job for the main agents ------ Ouch!

Jeff.