7A starting issues

[8690q]

Hi,

Not an S2 but I know there's some good guys on here so thought it might be worth an ask.

I'm now the owner of the 80 quattro avant that Nogin and co converted from v6 to 7a power. See the work here - http://www.audi-20v.co.uk/myquattro5.htm

In the 2 weeks I've had the car it's had a new power steering pump, spark plugs, rotor arm and a distibutor cap.

Power steering pump was leaking when I bought it so just put a good used one on I had lying around.

The spark plugs etc were put on to try and cure a starting issue. it didn't work.

When cold the car will turn over a few times before it catches then dies. a few repeated attempts at this gets it running though albeit very reluctantly. When warmed up it turns over for ages before starting. Once started when warm it idles fine.

The car seems down on power. It stinks of petrol when warmed up. It also seems reluctant to rev back up after changing gear.

I've also noticed that a few times when trying to start the car it seems to stop like the starter has jammed or something. When this happens the engine feels like it's rattling around the engine bay !

Any help with these problems will be much appreciated.

[sidrick]

Sounds like a compression issue

[UrS4boy]

Not that familiar with the 7A (BTW too bad they didn't convert the V6 to AAN or ABY) but the starting and restarting and fuel smell issue(s), sound to me like you need to investigate the Fuel Pressure Regulator. Here is some FPR info that covers the 3B, AAN, ABY and ADU with a little bit of 7A info.

http://forums.quattroworld.com/s4s6/msgs/21108.phtml

[djh]

Good site for the n/a 20v 7a engines

http://20v.org/

[andyg plym]

i had the same starting problem on my old 2.3 10valve ng coupe,it was related to the exhaust,it was choked up (wouldnt rev or take a load) and lambda iirc.

[andy10v]

Could stick up the emissions results from the MOT in case any people can read anything from that?

[mcandmar]

It almost sounds like you have a few different issues going on as the symptoms dont really point me to one thing. I would start with basics and make sure ignition timing is right, and the throttle position sensor and idle switch are all working properly. Also since this car has been converted to a 7A make sure the fuel pump primes when the ignition is switched on, not sure about V6 cars but ABY/AAN etc only turn the pump on when the ECU sees the engine turning over.

Smell of fuel and hydro locking as you describe could be faulty injectors. The shitachi injectors in these engines are prone to failing and when they do they piss fuel out all the time, it would be worth pulling the fuel rail out and running the pump to make sure they are ok. Just dont get sprayed in the face while doing it. Its also not uncommon for the fuel pressure regulators to tear inside leaking fuel into the intake though its vacume pipe, both can make it very hard to start as it floods itself.

[UrS4boy]

.... Its also not uncommon for the fuel pressure regulators to tear inside leaking fuel into the intake though its vacume pipe, both can make it very hard to start as it floods itself.

This is where I was going with my FPR suggestion.

[andy10v]

Little update.

Sucking on the fuel pressure regulator vacuum line and it holds vacuum against your tongue.

Removed the fuel rail complete with injectors, they do not appear to leak, cranking the engine over with the injectors spraying into cups and they all seem to spray fuel, and a similar quantity.

Fitted another fpr anyway.

If the isv is unplugged the car dies.

The throttle switch clicks, and the idle changes if it is unplugged.

Checked timing, flywheel, cam, crank pulley all line up, dizzy points to 1.

It is strange as sometimes it fires straight up perfectly, sometimes not.

[djh]

teeth missing off the dizzy gear? still sounds timing related.

[andy10v]

Dizzy was appeared ok when new engine was fitted, has not been checked since though. It did come with a dizzy with broken teeth in the boot.

[andy10v]

More info in case it sheds any light

I seem to remember that this car had similar problems with the engine I blew up after just 2 hours. Laughing I think there was some talk then of the fuel lines getting too hot as they were maybe on the opposite sides from the V6/I5.

In my very short experience there was also an awful stench of fuel which I put down to the fact the engine was about to give up on me. In the set up of the first 7A used I did notice the crankcase breather was not back into the air manifold, i.e. just a vent under the bonnet. If any fuel is getting past the rings then this would likely cause something like this to happen. Not sure if it is set up like this still with the new unit.

Is is running rich?

The old unit would not idle when cold but that might just have been the first (and only) time I had started in the cold Laughing I.e. had to catch it on the throttle when I picked it up.

Best of luck with the car and hopefully you get these wee niggles sorted and very glad it lives on.

[andy10v]

Car is also running an atmospheric vent catch tank. There is also a blow from the exhaust at the downpipe.

A brief history

Car was converted from v6 to 7a, the 7a then died (catastrophic bearing failure), another 7a engine was swapped in.

The fpr, alternator, ps pump, dizzy, flywheel, throttle body were removed from the dead engine and fitted to the new. The throttle body has since been replaced with another as it has a chunk missing from the bit that goes into the intake boot.

[andy10v]

What are the symptoms of a clogged fuel filter?

[mcandmar]

Sounds like you covered a lot of stuff today. How does the car run when driving, does it feel normal / smooth running? Basically are your problems only start/idle or does it just not run right all the time?

Out of curiosity try putting a fuse into the fuel pump relay and see if makes any difference, might help rule out a sensor or two.