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Fuel Heater

G

Guest

Guest
Hi,
I think I have a problem with my fuel heater. Symptoms are the glow plug light does not come on when I turn on the ignition. Up until this morning, I have only had the car a month, it has started fine. I assumed it was just the bulb. Today we have a frost and the car has been outside, it is usually in the garage, it took a lot of cranking before it started.
I started to investigate the fuel heater system. As far as I can tell there should be a fuse and relay in the under bonnet fuse box. I have the fuse and it is fine but I do not have the relay! There is not even any wiring in the socket it should fit in. This has confused me as it is a UK car so I assume it should be fitted with a fuel heater.
Am I looking in the right place for the relay? Any suggestions as to what I should check next?
Thanks
Ian Rubie
Hampshire UK
96 HDJ80
 
The fuel heater is nothing to do with the glowplug light. The heater
is a separate assembly that sits on the top of the filter. It contains
a vacuum switch and a small heater element that comes in to operation
when the fuel is waxy because of cold. The car should start without
it. If you have it there is a 2-way lead from the top of the filter
plugged in to the loom before the relay box. You do not say your car
model for more help, some of the 80's dont have glowplugs, they have
an inlet heater instead.
Regards, Clive.
On 1/22/06, Ian Rubie <[Email address removed]> wrote:
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Thanks Clive,
I do have a two way lead on top of the filter. I have checked and I am
getting 12V at the connector. Is there a way of checking the heater is
actually working?
Sorry, it's a 1996 UK Spec VX with 24 valve engine.
I can not see any glow plugs, I assume they should be some where near the
fuel injectors if fitted.
Regards
Ian Rubie
Hampshire UK
96 HDJ80
 
There is a way of checking the vacuum switch, do you have any sort of
a manual for the car? I am not sure of the cut-in date but you may
have the inlet heater instead of glowplugs.
Regards, Clive.
On 1/22/06, Ian Rubie <[Email address removed]> wrote:
 
I have a Haynes manual. I was following the diagnostics in here when I
discovered I don't have a fuel heater relay or even wiring for it in the
fuse box. This is what lead to my original question. Now I am even more
confused. I don't have a heater relay but do have 12v at the heater!! This
is assuming I have identified the heater correctly - next to the priming
pump button on top of the filter.
I can not carry out the diagnostics in the Haynes manual fully as I don't
have a hand held vacuum pump.
Regards
Ian
----- Original Message -----
From: "Clive Marks" <[Email address removed]>
To: <[Email address removed]>
Sent: Sunday, January 22, 2006 11:15 AM
Subject: Re: [ELCO] Fuel Heater
There is a way of checking the vacuum switch, do you have any sort of
a manual for the car? I am not sure of the cut-in date but you may
have the inlet heater instead of glowplugs.
Regards, Clive.
 
On further checking I can not see anything vacuum related on the filter
assembly. I have an electrical connector at the bottom, which I assume is
water level warning. An electrical connector at the top, which I assume is
the heater and two fuel pipes. No other connections are visible.
Am I looking at the right parts? The Haynes manual says the heater and
vacuum switch are both in the fuel filter adaptor.
The fact I don't appear to have a relay or vacuum switch is making me think
either I am loosing it (highly possible) or I have a different system
fitted.
Regards
Ian
----- Original Message -----
From: "Ian Rubie" <[Email address removed]>
To: <[Email address removed]>
Sent: Sunday, January 22, 2006 11:28 AM
Subject: Re: [ELCO] Fuel Heater
 
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That sounds very much like the heater, I cant understand why no relay,
The relay, from memory, is powered from the ignition and power sits on
the vacuum switch. when the switch pulls in it powers the heater. All
I can think of is that someone has wired yours direct, not too serious
as the vac. sw. will still be doing it's job.
Regards, Clive.
On 1/22/06, Ian Rubie <[Email address removed]> wrote:
his
 
Another thought. With the temperatures that we are having in the south
you will not be needing a fuel heater. Diesel sold at UK pumps during
the winter has an anti-waxing additive in. This is enough for our
climate right now.
If you have an inlet pre-heater then your voltmeter will be low
for 2-3 minutes after you start the engine, and then a bit higher for
10 mins. or so. This is noticable.
Regards, Clive.
On 1/22/06, Clive Marks <[Email address removed]> wrote:
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Ian,
The switch and the heater are one unit.
Regards, Clive.
On 1/22/06, Ian Rubie <[Email address removed]> wrote:
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't
 
Clive,
Thanks for all your help. Maybe it not starting that well this morning was
just one of those things. It just seemed an odd coincidence that it was the
first time the car had had frost on it and it was the first time it had not
started instantly. I was cranking it in 15 - 20 second bursts. It fired at
the forth or fifth attempt. I was also mentally linking to the fact I have
no glow plug light. Seems I put two and two together and got five!!!
My voltmeter is low for the first couple of minutes, I assumed this was the
batteries charging after the startup.
Regards
Ian
----- Original Message -----
From: "Clive Marks" <[Email address removed]>
To: <[Email address removed]>
Sent: Sunday, January 22, 2006 12:06 PM
Subject: Re: [ELCO] Fuel Heater
Ian,
The switch and the heater are one unit.
Regards, Clive.
 
Ian

I've got the same engine as you. As others have said you don't have
glow plugs (not much room for them in a 24v head, and no need on a
direct injection engine anyway), but by the sound of it you do have an
air pre-heater screen. This isn't in the Haynes manual, but it's a box
about 5" square that sits above the turbo forming the start of the
crossover pipe to the inlet manifold, and has various electrical and
vacuum pipes dotted around it. On mine there are two exhaust gas
recirculation thingies, looking a bit like mushrooms, next to it.

Supposedly it improves emissions when starting a cold engine, but
personally I think Toyota were sponsored to fit it by battery and
alternator manufacturers as all it does on mine is consume huge amounts
of electricity for about 2 minutes, as the exhaust fumes from mine
immediately after a cold start are pretty noxious!


However I'm fairly certain your problem is nothing to do with fuel or
air heating, as mine starts absolutely instantly in all weathers with no
"wait for it to heat anything up" time. (My glow plug light comes on for
maybe 1/2 a second, but never stays lit.)

I think it's far more likely that you have air in your fuel line, or
fuel starvation. You can test this by seeing if it is possible to work
the pump on top of the fuel filter: if it has no resistance for a few
strokes, then builds up, and the engine starts easily once pumped, then
fuel starvation is the problem.

If this is the case then you'll have to work out why: when it happened
to me (in a VW) it was due to a poor seal at the top of the fuel filter
causing air to be drawn in. Have you changed the fuel filter recently?
Or alternatively is it very old?

Christopher Bell
Devon, UK
1996 1HD-FT

Hi,

I think I have a problem with my fuel heater. Symptoms are the
glow plug light does not come on when I turn on the ignition. Up until
this morning, I have only had the car a month, it has started fine. I
assumed it was just the bulb. Today we have a frost and the car has
been outside, it is usually in the garage, it took a lot of cranking
before it started.

I started to investigate the fuel heater system. As far as I
can tell there should be a fuse and relay in the under bonnet fuse box.
I have the fuse and it is fine but I do not have the relay! There is not
even any wiring in the socket it should fit in. This has confused me as
it is a UK car so I assume it should be fitted with a fuel heater.

Am I looking in the right place for the relay? Any suggestions
as to what I should check next?
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Christopher,
Thanks for your reply, I'll check the pump after it's been standing for a few hours. I have only had the car a month and do not know when the fuel filter was last changed. I am slowing working through it changing all fluids and filters. I will be fitting a new fuel filter in the near future.
If like mine your car has no glow plugs, what is your glow plug light indicating when it comes on for its half second? Mine has never lit at all.
Regards
Ian
----- Original Message -----
From: Christopher Bell
To: [Email address removed]
Sent: Sunday, January 22, 2006 1:32 PM
Subject: RE: [ELCO] Fuel Heater
Ian
I've got the same engine as you. As others have said you don't have glow plugs (not much room for them in a 24v head, and no need on a direct injection engine anyway), but by the sound of it you do have an air pre-heater screen. This isn't in the Haynes manual, but it's a box about 5" square that sits above the turbo forming the start of the crossover pipe to the inlet manifold, and has various electrical and vacuum pipes dotted around it. On mine there are two exhaust gas recirculation thingies, looking a bit like mushrooms, next to it.
Supposedly it improves emissions when starting a cold engine, but personally I think Toyota were sponsored to fit it by battery and alternator manufacturers as all it does on mine is consume huge amounts of electricity for about 2 minutes, as the exhaust fumes from mine immediately after a cold start are pretty noxious!
However I'm fairly certain your problem is nothing to do with fuel or air heating, as mine starts absolutely instantly in all weathers with no "wait for it to heat anything up" time. (My glow plug light comes on for maybe 1/2 a second, but never stays lit.)
I think it's far more likely that you have air in your fuel line, or fuel starvation. You can test this by seeing if it is possible to work the pump on top of the fuel filter: if it has no resistance for a few strokes, then builds up, and the engine starts easily once pumped, then fuel starvation is the problem.
If this is the case then you'll have to work out why: when it happened to me (in a VW) it was due to a poor seal at the top of the fuel filter causing air to be drawn in. Have you changed the fuel filter recently? Or alternatively is it very old?
Christopher Bell
Devon, UK
1996 1HD-FT
Hi,
I think I have a problem with my fuel heater. Symptoms are the glow plug light does not come on when I turn on the ignition. Up until this morning, I have only had the car a month, it has started fine. I assumed it was just the bulb. Today we have a frost and the car has been outside, it is usually in the garage, it took a lot of cranking before it started.
I started to investigate the fuel heater system. As far as I can tell there should be a fuse and relay in the under bonnet fuse box. I have the fuse and it is fine but I do not have the relay! There is not even any wiring in the socket it should fit in. This has confused me as it is a UK car so I assume it should be fitted with a fuel heater.
Am I looking in the right place for the relay? Any suggestions as to what I should check next?
____________________________________________________________
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systems are scanned for acceptability of content and viruses
 
Ian
| Thanks for your reply, I'll check the pump after it's been standing
for a few hours. I have only had the car a month and do not know when
the fuel filter was last changed. I am slowing working through it
changing all fluids and filters. I will be fitting a new fuel filter in
the near future.

Good luck, hope it points to the problem

| If like mine your car has no glow plugs, what is your glow plug light
indicating when it comes on for its half second? Mine has never lit at
all.

Maybe mine has delusions of grandeur, or some sort of electronic
psychosis or something! It mentions it in the handbook, and I spent a
little while puzzling over it, but I gave up worrying once I twigged
that I didn't have any glow-plugs. Maybe it would pause to preheat
something in very cold weather, but the coldest I've experienced since I
bought the truck is -9C and nothing changed then. One of life's little
mysteries, and so long as the engine starts I'm not bothered.
CB
By the way I've converted this email to plain text as Julian prefers
that (it uses less space on his server than HTML).
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Ian,
I think Christopher is on the right track. I have the same engine
and it starts a dream, even in Russia in Feb., when it was fairly
cold. As well as the priming pump check, make sure there has not been
an in line filter put in by a previous owner, they clog up that much
faster, although I would expect that to result in rough running.
Regards, Clive.
On 1/22/06, Christopher Bell <[Email address removed]> wrote:
 
Christopher,
Does your truck have a fuel heater relay in the under bonnet fuse box? I do
have the air pre-heater thing.
I will definitely be investigating air leaks.
Clive - does your glow plug light flash on like Christopher's ?
Opps - sorry Julian.
Ian
 
Mine has the same glow time as Christopher's- about 1 sec. and then
starts as LC should :)
Lubo
96 HDJ 80 24 valves
On Jan 22, 2006, at 3:14 PM, Ian Rubie wrote:
 
Lubo,
Can you please check if yours has a fuel heater relay in the under bonnet
fuse box. Mine is marked on the cover but not fitted in the box. With both
your and Christophers glow light flashing on and mine not it sounds like
that this might be my problem, especially as normally it starts fine and it
was only a cold morning that brought the problem on. Since the initial
start this morning it has been fine all day. I am directing my attention
back to the fuel pre heater vacuum switch unit.
Thanks
Ian
 
It looks like relay and it's beside the fuse box
Lubo
On Jan 22, 2006, at 4:19 PM, Ian Rubie wrote:
 
Ian
I don't have a fuel heater relay, just an empty slot, but I do have a
fuel heater fuse. Dunno what to make of that! I appear to have
electrical dooberries both on top of (?heater?) and underneath (?water
sensor?) my fuel filter.
I truly don't believe your problem is electrical though, as I can't
visualise something that would put enough heat into the fuel that
quickly without vapourising it! And if the fuse is 20A the circuit can't
be carrying more than around 10A, delivering 120 watts max. That's way
less than the glow plug systems I've seen on other cars, where each plug
drew at least 20 amps.
Anyway a direct injection diesel with a huge starter motor like ours
shouldn't need glow plugs or heated fuel in our climate.
CB
|
| Christopher,
|
| Does your truck have a fuel heater relay in the under bonnet
| fuse box? I do have the air pre-heater thing.
|
| I will definitely be investigating air leaks.
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Electronic mail messages entering and leaving Arup business
systems are scanned for acceptability of content and viruses
 
'Evening all!
I got rid of my fuel filter nine months ago and hence the heater (I fitted a Racor as recommended By Craig & Dana), plus the intake heater and EGR valves three years ago. It has made no difference to the starting or (visible) emissions in the UP.I. temps. The glow plug light still comes on momentarily when the ignition is selected to 'on'.
As Christopher observed, the intake heater takes quite a lot of juice initially on a cold morning. I have noticed the initial post start-up voltage is much healthier without it, even when the Webasto has been running for a while.
Again as Christopher says, I am certain your problem is nothing to do with fuel/intake heating. I think the 24 valve motor should start easily at very low temps (assuming no fuel waxing) without all these devices; it might rattle and smoke a tad though!
Good luck
Dermot Allen
'97 1HD-FT
Norfolk
 
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