Cold start problems.
 

Hi. I have problems with starting my 87 944 NA when the engine is cold. Where I live the outside temeperature never gets below zero Celcius. The car starts only from second/third try even if it's pretty warm outside.
Recently I've replaced the AFM and tested it, it works fine. Also Oxygen sensor is ok. I've installed a new water temperature sensor, cleaned the injectors, got good sparks. And the most important I've put a low mileage engine from 1987 924S. The problem was the same even with the old engine, looks like there is not enough fuel supplied or the fuel pressure is too low. What could be the problem ? DME faulty? speed reference sensors? Fuel Pump? Thanks for any help.

Same issue on 2 motors leaves the only things left is the pump/relay. Otherwise I would suggest the FPR and/or the temp sender.

Dal

fuel pump check valve.

Ok, what's FPR? and which temp sender ? where is fuel pump check valve located ? Another problem that I have is when the car is warm enough and when I press fast on gas all the way to the floor it would go up to 3000 rpms and then stop there or when I step on gas slowly until it gets 4000 rpms and then step on it all the way to the floor it would drop to 2500rpms instead of increase. What causes the problem? Thank you.

FPR = fuel pressure regulator. there is also a dampener, i believe.

check valve is IN the pump. requires replacement of the pump.

could all be fuel pressure problems. i think you ought to test your fuel pressure and flow rate. check also for vaccum leaks.

Where is the fuel pressure regulator located ? How can I check it ? Thanks

The fuel pressure regulator is located on the fuel rail. Both it and the damper have vacuum lines running to them and they are both located at the each end of the fuel rail. Follow the fuel lines running from the tank and you will find them. All symptoms suggest low fuel pressure which is more than likely the fuel pump or regulator as everyone already mentioned. When are the drag races? Might just have to come help you personally! :-)

thank you, you can see the schedule here :
<a href="http://www.pomonaraceway.com/2006/schedule.html">http://www.pomonaraceway.com/2006/schedule.html</a>

I've been to every major track in the country, Pomona and Indianapolis are definitely the best. Let me know if you need more help with your car. I am guessing a weak fuel pump, but it's just a guess. Good Luck.