quattro v1.0

Ok, so Im risking the embarrassment of going to another gathering and having to crank my car 15 times before it starts - while convincing everyone that it's really ok, really. See?

Again, the car is an MC2 with full MAC14, QLCC chipped. Runs absolutely beautiful once its started, doesn't like to start cold OR hot all of a sudden.

I had suspected the cold start valve since the system pressure did not seem to be bleeding down. (hard wired the fuel pump and primed the sh*t out of it and still no-start) Also I thought that the CSV assisted hot starting / WOT enrichment as well - someone correct me if I'm wrong.

I pulled the CSV tonight and cycled through 'starting' the car - about 6 cranks about 4 seconds each. Not a single drop of fuel came out of the CSV - I mean it didn't even make the plastic baggy smell like fuel. Not so much as a fuel fart! When I cracked open the fuel fitting I did have fuel pressure at the CSV.

Im in Vegas but oddly enough do not gamble. So, should I just acquire a new CSV and go from there? (any modern mechanic would) Or do I start looking for reasons the CSV would not be triggered, and are they easy-to-check items, like sensors?

I cant pull a code from the MAC14 since I don't have the 'tool' nor do I have a fuel pump relay with the fuse-jumper. I know you can make a thing-a-ma-jig with LED's and a few wires, but thats reallllly a last resort for me.

Any ideas?

AudiSport4000

The CSV will only operate at a low enough temperature to my understanding. Even if its not working the car should still start (my 4kq did this, it had a faulty coolant sensor).
If the ambient temp is somewhat warm Id look elsewhere personally.

Others may disagree, but thats what I can see from the description.

Vac leaks?

Katman

I'm not sure having the fuel pump hard wired will help a hot start problem.

The problem is not fuel pressure when startign, but the fuel pressure when the car was sitting while still hot.

If the fuel pressure drops too soon after shutting down, the 'heated' fuel in the injector lines can vapourize. Bring the system up to full pressure again when going to start probably won't make the fuel 'unvapourize' again.

Remember that the fuel in the injector lines in not under direct fuel pump pressure as such, but is after the fuel distributor.

Best I coudl think would be to have the gas pedal all the way down when cranking, and hope that any vapour is displaced by fuel sooner.


However.. As you have hard starting both hot AND cold, I'm thinking that's probably not your problem.



I'd almost think that chasing the CSV is a false lead. I've had a 4k that had the CSV disconnected, and it still started OK in the winter. So it's not essential to start, but may help.

Really, you need to figure out what susbsystem isn't working right when cranking. (Ign, Fuel?) that stops it from starting.

Maybe post on the 5K/V8 forum too, as they may have more experience with that motor/CIS system?

quattro v1.0

I richened up the mixture at the metering head and she fired up like she used to. Gave it almost a full turn.

As an added bonus, I found that the car had only been running about 3/4 throttle at best. And some here would say this car was quick at that - Holy COW!! Since I had to remove the throttle cable to get to the CSV I marked the adjustment of the cable. Something led me to pull the intake boot off and take a peek. I had a buddy get in and put the pedal to the floor. I was shocked at where the throttle plate stopped. I made the new adjustment and the next ride I took was rather moving to say the least.

I still have the hot start issue as bad as it's ever been though and Im getting beyond flustered with it.

mtaudi

I haven't had time to look into it. I've had the injectors replaced, fuel pump, accumulator, fuel filter. Fuel pressure is good. When it's really cold it is a beatch to start. One odd thing I noticed is that if it sits in hot sun all day it is hard to start as well. I think going over the vacuum system would help even though I've had mine checked for leaks.

koselowiec

I would take apart your fuel distributer and injector lines, and then retune it. I had this same problem with my UrQ last week, and it was due for a good cleaning (65K on the car), and right now it starts up like a dream. BTW before I mess with the fuel mixtre, I would check the cold start valave. The contacts get easily corrided and become loose so it wont turn on.The only other thing that might be doing the hot start issue is that the car is running too rich and the engine is flooding, thus fouling your spark plugs. Like I said, my urQ had similiar problems so this is what I did.

AlekP

If you find a solution to your hot start issues please post it. I'm having the same problem with my UrQ. Starts right away when cold but won't budge when hot.