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Audi 100 5cyl cold start problem



 
 
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  #1  
Old February 1st 06, 11:45 PM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

Got a major problem here kindof i think. Got a 1991 Audi 100 with a 5
cylinder 2.3 litre fuel injected engine.
you can crank it for ages and it will fire once or twice or sometimes
not fire at all and just keep cranking. This only happens when the
engine (water) is cold. If I spray ether into the intake manifold it
fires continually until I stop spraying but still will not start. I
have removed two of the fuel lines going to the injectors and there is
no fuel pumping up them but there is on the cold start fuel line. Im
not sure if thats normal or not. but if i push up the lever thingy
behind the air filter then fuel pumps very slowly up all the injector
fuel lines. help help help!!!!

Ads
  #2  
Old February 2nd 06, 12:54 AM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

My initial idea is to say the fuel injection relay might not be working the
contacts wear out regularly (100k) and often don't give enough power to the
pump, if it is working full on you should hear the pump kick in when you
turn the ignition on for a couple of seconds before you start it. I had a
similar problem on 100 CD similar engine set up 2226cc one. The relays are
about £20 from german and swedish if I remember rightly, however it is
possible to check this by actually bypassing this relay (not adviseable
normally but just for test purposes, I ran my car on a wired switch for
about two weeks until I managed to get a new one) as it's a safety feature
to kill the pump once the engine is not "firing" rev check. You can use a
suitable thick bit of wire between the sockets for the terminals once you
work out after taking out the relay which ones are required to hard wire
together. With the ignition on only you will hear the pump in the tank
working. If it fires with this you need a new relay. IS the spray from the
cold start very strong? The cold start is on a relay that bypasses the fuel
distibutor if I'm right and will drain any pressure in it, or the fuel valve
in the regulator is sticking. I assume you have not played with the mixture
setting or dropped anything into the plate that regulates the fuel air
mixture etc.

Give me a mail back if that doesn't help.

PAul
"sealdogfish" > wrote in message
oups.com...
> Got a major problem here kindof i think. Got a 1991 Audi 100 with a 5
> cylinder 2.3 litre fuel injected engine.
> you can crank it for ages and it will fire once or twice or sometimes
> not fire at all and just keep cranking. This only happens when the
> engine (water) is cold. If I spray ether into the intake manifold it
> fires continually until I stop spraying but still will not start. I
> have removed two of the fuel lines going to the injectors and there is
> no fuel pumping up them but there is on the cold start fuel line. Im
> not sure if thats normal or not. but if i push up the lever thingy
> behind the air filter then fuel pumps very slowly up all the injector
> fuel lines. help help help!!!!
>



  #3  
Old February 2nd 06, 01:15 AM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

I will try bypassing the relay but when i turn the key to on I can hear
the fuel pump going and fuel is definately pumping, though im not sure
how strongly. When cold starting are the 5 injectors supposed to be
working or is it just the cold start injector that goes until it starts
up properly? also can i just take out the cold start injector and turn
it on and see if it sprays?

  #4  
Old February 2nd 06, 01:17 AM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

I also forgot to mention that the car does start every three days or so
and once it starts and warms up it runs fine. you can turn it off and
restart it but when it cools back down it wont start again for a few
more days at least.

  #5  
Old February 2nd 06, 01:22 AM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

I also forgot to mention that the car does start every three days or so
and once it starts and warms up it runs fine. you can turn it off and
restart it but when it cools back down it wont start again for a few
more days at least.

  #6  
Old February 2nd 06, 01:31 AM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

Okay cheap fix,

go and buy a new rotor arm for the distributor and if that fixes the problem
contact bosch uk and get a new distributor. The shaft bearings wear out and
the rotor arm contacts the contacts and heats up so much it blows the
resistor as it cools and warms it contacts. If this is happening it is
usually shown up as a crack in the dark brown resin they cover the resistor
with. Have a look at it. You should also be able to rock the rotor shaft
left to right if it is warn. Does this make sense?

Paul
"sealdogfish" > wrote in message
oups.com...
> I also forgot to mention that the car does start every three days or so
> and once it starts and warms up it runs fine. you can turn it off and
> restart it but when it cools back down it wont start again for a few
> more days at least.
>



  #7  
Old February 2nd 06, 01:37 AM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

Makes sense but the engine is sparking perfectly without fail, unless
the distributor tells the injectors when to fire? but when its cranking
there is no fuel going up the injector lines from what i can tell, no
fuel coming out of the metal round thing that all the fuel lines bolt
into. (except for the cold start)

  #8  
Old February 2nd 06, 01:43 AM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

Just thought of something else. Are all of the wires connected especially
the idle valve. They could be corroded check them just pulling them off and
refitting a couple of times might help.

The rotor arm actually usually actually works the other way it will start
when cold but not hot, however I have had similar problems, I still think it
might be the fuel relay. Don't forget that once it gets going it has to keep
up the pressure and that takes more power to do so, so still try the bypass
that I suggested mine also had the cold start issue. Just tapping the relay
sometimes was enough during cranking to get it to start. If this has been
going on a while it is likely to have carbon deposits etc. You could always
take it out and take off the cover and have a look inside and see for
yourself.

By the way if it is make sure you buy the 5 cyl relaynot the 4 cylinder I
think there is an over rev cutout that will kill the engine at lower revs if
you get the wrong one.


PAul


"sealdogfish" > wrote in message
oups.com...
> I also forgot to mention that the car does start every three days or so
> and once it starts and warms up it runs fine. you can turn it off and
> restart it but when it cools back down it wont start again for a few
> more days at least.
>



  #9  
Old February 2nd 06, 01:49 AM posted to alt.autos.audi
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Default Audi 100 5cyl cold start problem

I have a Haynes manual with test procedures etc if you would like me to scan
it and mail it to you if what I have suggested doesn't help

Paul

Take out the spaces in the email address to email me directly
"pdpass" > wrote in message
...
> Just thought of something else. Are all of the wires connected especially
> the idle valve. They could be corroded check them just pulling them off

and
> refitting a couple of times might help.
>
> The rotor arm actually usually actually works the other way it will start
> when cold but not hot, however I have had similar problems, I still think

it
> might be the fuel relay. Don't forget that once it gets going it has to

keep
> up the pressure and that takes more power to do so, so still try the

bypass
> that I suggested mine also had the cold start issue. Just tapping the

relay
> sometimes was enough during cranking to get it to start. If this has been
> going on a while it is likely to have carbon deposits etc. You could

always
> take it out and take off the cover and have a look inside and see for
> yourself.
>
> By the way if it is make sure you buy the 5 cyl relaynot the 4 cylinder I
> think there is an over rev cutout that will kill the engine at lower revs

if
> you get the wrong one.
>
>
> PAul
>
>
> "sealdogfish" > wrote in message
> oups.com...
> > I also forgot to mention that the car does start every three days or so
> > and once it starts and warms up it runs fine. you can turn it off and
> > restart it but when it cools back down it wont start again for a few
> > more days at least.
> >

>
>



  #10  
Old February 2nd 06, 01:54 AM posted to alt.autos.audi
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Posts: n/a
Default Audi 100 5cyl cold start problem

manual though is not accessible tonight, its in the back of the garage
somewhere behind the car and I have to move the car to get at it and I've
had a drink so it will remain there until tomorrow, I only have 2 inches
either side of the car when I pull it out and I don't actually want to
scratch it!

Paul
"pdpass" > wrote in message
...
> I have a Haynes manual with test procedures etc if you would like me to

scan
> it and mail it to you if what I have suggested doesn't help
>
> Paul
>
> Take out the spaces in the email address to email me directly
> "pdpass" > wrote in message
> ...
> > Just thought of something else. Are all of the wires connected

especially
> > the idle valve. They could be corroded check them just pulling them off

> and
> > refitting a couple of times might help.
> >
> > The rotor arm actually usually actually works the other way it will

start
> > when cold but not hot, however I have had similar problems, I still

think
> it
> > might be the fuel relay. Don't forget that once it gets going it has to

> keep
> > up the pressure and that takes more power to do so, so still try the

> bypass
> > that I suggested mine also had the cold start issue. Just tapping the

> relay
> > sometimes was enough during cranking to get it to start. If this has

been
> > going on a while it is likely to have carbon deposits etc. You could

> always
> > take it out and take off the cover and have a look inside and see for
> > yourself.
> >
> > By the way if it is make sure you buy the 5 cyl relaynot the 4 cylinder

I
> > think there is an over rev cutout that will kill the engine at lower

revs
> if
> > you get the wrong one.
> >
> >
> > PAul
> >
> >
> > "sealdogfish" > wrote in message
> > oups.com...
> > > I also forgot to mention that the car does start every three days or

so
> > > and once it starts and warms up it runs fine. you can turn it off and
> > > restart it but when it cools back down it wont start again for a few
> > > more days at least.
> > >

> >
> >

>
>



 




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