Audi 100 2.5TD runs for 5 seconds then cuts out..

pxr5 · 16-12-19, 06:50 PM

Ive this early straight 5 cylinder believe its a AAT engine, this car has been standing for some time, I start it up every 3/4 months but now it starts up & dies after 5 or so seconds,

Ive a good flow of fuel to the pump. Ive fiddled with all the electrical connections but no luck so far.
I'm really stuck with this, can any one suggest whats wrong? thanks

Sandro · 16-12-19, 07:05 PM

Does it come with immobilizer?

pxr5 · 16-12-19, 07:13 PM

I assume it has, the key fob has a button, but ive never had to blip it to start the engine before.

tractor Dave · 16-12-19, 07:26 PM

Change the fuel filter

pxr5 · 16-12-19, 07:31 PM

fuel is free flowing at the pump......

tractor Dave · 16-12-19, 07:40 PM

Ok, you may be seeing fuel flowing but from my experience with tractors this is classic fuel starvation symptom. I could be wrong but it's worth a try. The modern fuel now has some bio diesel added which actively attracts moisture. If left for a long period a black mould grows in the fuel/water mix and slowly builds up. It then clogs the fuel filter. Bio diesel was first introduced into red diesel a few years ago and many people who lay up their classic tractors over winter have discovered the hard way about this. You can get an additive that kills the bugs but some have found this eats their seals away!

pxr5 · 16-12-19, 07:48 PM

Ive rigged up a clean can of fuel with a low pressure pump, the pipe out of the filter head gushes fuel, Im sure its no that.

tractor Dave · 16-12-19, 07:58 PM

Maybe fuel pump then

pxr5 · 16-12-19, 08:48 PM

This has the pump witch is controlled by an ecu, airflow meter etc, Im hopeing some one will chime in with "its a bad connection at XYZ component ( I know wish full thinking!)

steveb · 16-12-19, 08:58 PM

Is it fuel injection ? if it is try bridging the fuel pump relay, it sounds like it is running on the cold start injector but no fuel once it starts ?

16-12-19, 08:58 PM	#10
steveb Senior Member Classic Audi Club Member Join Date: Jul 2008 Location: West Berkshire Posts: 1,155	Is it fuel injection ? if it is try bridging the fuel pump relay, it sounds like it is running on the cold start injector but no fuel once it starts ? __________________ [FONT] '76 Leyland Princess 2200 HLS '79 Scirocco storm '84 WR '89 coupe quattro '01 A2 1.4 TDI SE '14 A3 1.4 TFSI COD [/color][/size][/font]

16-12-19, 07:05 PM	#2
Sandro Grown up member Join Date: Feb 2011 Location: Chelmsford Posts: 651	Does it come with immobilizer?

16-12-19, 07:13 PM	#3
pxr5 Newbie! Join Date: Nov 2019 Posts: 14	I assume it has, the key fob has a button, but ive never had to blip it to start the engine before.

16-12-19, 07:26 PM	#4
tractor Dave Senior Member Classic Audi Club Member Join Date: Apr 2018 Location: Wales Posts: 1,157	Change the fuel filter

16-12-19, 07:31 PM	#5
pxr5 Newbie! Join Date: Nov 2019 Posts: 14	fuel is free flowing at the pump......

16-12-19, 07:40 PM	#6
tractor Dave Senior Member Classic Audi Club Member Join Date: Apr 2018 Location: Wales Posts: 1,157	Ok, you may be seeing fuel flowing but from my experience with tractors this is classic fuel starvation symptom. I could be wrong but it's worth a try. The modern fuel now has some bio diesel added which actively attracts moisture. If left for a long period a black mould grows in the fuel/water mix and slowly builds up. It then clogs the fuel filter. Bio diesel was first introduced into red diesel a few years ago and many people who lay up their classic tractors over winter have discovered the hard way about this. You can get an additive that kills the bugs but some have found this eats their seals away!

16-12-19, 07:48 PM	#7
pxr5 Newbie! Join Date: Nov 2019 Posts: 14	Ive rigged up a clean can of fuel with a low pressure pump, the pipe out of the filter head gushes fuel, Im sure its no that.

16-12-19, 07:58 PM	#8
tractor Dave Senior Member Classic Audi Club Member Join Date: Apr 2018 Location: Wales Posts: 1,157	Maybe fuel pump then

16-12-19, 08:48 PM	#9
pxr5 Newbie! Join Date: Nov 2019 Posts: 14	This has the pump witch is controlled by an ecu, airflow meter etc, Im hopeing some one will chime in with "its a bad connection at XYZ component ( I know wish full thinking!)