audi 90 poor cold start......

[johnboy]

hi there people!

ok i have got a 1989 audi 90 2.2 5 cylinder,and it is not a great cold starter! is this a normal thing with these?

things i have already done and tried:-

1)fuel filter changed

2)distributer cap + rota arm change

3)new plugs

4)new air filter

5)checked cold start injector and seems ok

6)fuel pump checked and is working ok(but dont hear a prime noise when turning ignition on is this also normal for this model as in manual it said it is normal?)

once the car starts which starts on the 9th maybe 10th turn over it runs and goes great, and when the car is warm it starts fine but as soon as it goes cold again same thing?

is there any body out there that has had the same problem? or knows anything else to check ect?

cheers in advance

john

[amanda]

either isv or plug leads/ plugs..... what ones have you got in?

[msh]

amanda... As he said, "once the car starts which starts on the 9th maybe 10th turn over it runs and goes great" - this means, isv is good If it would be stucked, he's engine would be prone to stall until it's get warm. And plug leads also isn't case

johnboy - how did u checked cold start injector?

[BW2309]

try swapping your fuel pump relay. These are a common failure and sometimes struggle to operate constantly enough initially to prime the system. If this is the case u would normally find the engine is being starved a bit at very high load to. Failing that, the fuel pump may be running fine fine with sufficient pressure but they have a non return valve built in to them that can stick. This allows the fuel to run back from the metering head and so takes a while to get forced back up before having to build up to the 80psi required for start up. If u connect a fuel pressure guage to it, run the car then switch off and leave guage connected. Check the pressure after 10, then 15mins. I'll find the holding pressure from my manuals and let u know what it should be.

[msh]

How I like this "western" way how to repair car - replace whole car until it's fine

BW2309 do u know, what happens if this non return valve [actually, hydrotransformator] fails? This is what actually happens with my car - I'm cranking my engine, it start's for half second, then it stalls, I'm still cranking, after 3-5 secs it's finally running. And, also, ticking sound from place, where is fuel pump assembly located [B3 sedan] - from hydrotransformator.
If fuel pump sound can't be heared, it means nothing. It can also mean just fuel pump in very good condition - I can't forget, that british don't drive with their cars - at last when u look on unbelievable mileage for 20 year old and older cars and u can't believe it's not fake If someone would say "my 20 years old audi have 200-300miles on clock", yeah, it's avarage LHD mileage for 10 years Because on my 20 year old 3A was main bearings gone, I would presume it has 500k kms or more in past Whatever, I just wanna say - I have fuel pump, that can be heared not only with engine off, but also while it's iddling and car is stopped and radio isn't turned on And this is too fckin common sight of B3's - it looks to me that half of injected B3's have very loud fuel pump Here in latvia, of course, not UK. And if author of the topic wants verify, does he's pump is running or not, there is some simple ways, how to do it. One of them - disconnect incoming fuel hose from injection head [I have there 17mm bolt], dry it, then turn ignition on and look - is there fuel or not, and how much. U can also try to crank, for very short moment. Only after that this bolt must be tightened with brains - this head is made of aluminium My favourite way - tighten, then theck, if it doesn't leak fuel, if it does, tighten it a bit more.

Btw - is this common sight - KV engines in B3 for britain? Looks like for germans there was only NG for 5cyl 10v [excluding rare PS 2.0 10v engine]

[BW2309]

Not quite sure what you're getting at here - I agree, no noise from pump is no bad sign. You can't hear mine running at all. I was suggesting changing a very cheap, even with second hand, relay purely as it is so cheap and easy. Not suggesting changing the pump, I am very much against just swapping all bits on car but you NEED to know if the car's holding fuel pressure with a fault like this. Then systamatically move on to next item to check. Idea of allowing fuel (if it's working) to spray all over the engine is not for me!

[msh]

Remember - if all is working well, except fuel pressure, engine for first time will start, but only for half a second or less Remove fuel pump relay of your 7A and u will see the same thing

About spraying fuel - there is two things - first of all - Audi made it's engines from steel, aluminium and some other stuff, that withstands fuel And also, fuel quickly evaporates - there it was, after 15-20 secs there isn't anymore. And second - engine? It's just little fuel pipe, not the one which are used by firefighters The only thing that gets fuel is air filter box. And if I'm checking nozzles, only thing that gets fuel is right wing or front bumper

[BW2309]

Yes, I agree but not speaking of poor fuel pressure, I'm on about fuel delivery rate. If fuel returns to tank the air drawn in to metering head and fuel lines through the injector nozzles has to be expelled before pressure can build up so there is often not enough pressure to start at all, even for the few seconds you get if pump itself worn or the relay knackered. Once the fuel reaches the engine the car strats fine as the pump is strong.

[msh]

But there is anyway some drops of fuel left in nozzles, which is enough for engine for some "fires" I may film how my cold 3A is starting, but, unfortunately, I'm afraid I wouldn't be able to do it - after overhaul glitches of injection have weakened And, btw, don't forget - he have K-Jet, and, just like my KE-Motronic, main thing for start isn't fuel delivery rate, but pressure - don't forget K-jet is working on twice pressure as your 7A And hydrotransformator consists of membrane and springs - how do u think, what this thing is doing there?

[20vcqdriver]

The Cold start injector is controlled from a sensor in the back of the head or block (it's been a while). This decides for how long the cold start injector operates for depending on water temp. If possible connect a lamp to the valve and see how long the injector fires for when starting from cold. It may be running for too long and flooding engine or not at all. Most of the problems with these are with it flooding and many leave this injector permanently disconnected. Especially those with Ur quattros!!