Car will not start when cold unless i put gas into the intake

[spaugh]

Ok I have a 91 TSI AWD it has a walbo 255 with stock fpr. When car has sat over night or just a few hours it will not start i have to take off the intercooler pipe and spray a lil gas into it, and it starts right up then it will keep starting no problem untill it sits for a few hours. Does any one know what might cause this. I am putting FIC 750cc in it this week and a 50 trim, its a brand new ETE32 mutt what do you all think of them it has the 360 bearing in it.

 

[ninjaneonturtle]

we had a porsche that would do that. we used to have to start it with starting fluid, then it would be fine until it sat for a while. if I remember correctly it has to do with the power supply for the fuel pump. does it turn on when you first turn the key? I'd test to see if it turns on when you turn the ignition on. you might want to do a rewire anyway.

 

[1stGenTSi]

It is either the o-ring at the top of the walbro is allowing fuel pressure to bleed back into the tank as it sits or it is very possible your coolant temp sensor wires have broken off or come unplugged. Check below the radiator cap and make sure all wires are securely connected. Without a temp sensor the ecu will think the temp is like -50* F and will DUMP fuel making it almost impossible to start. Get an AFPR for that 255 with a gauge on it and you will be able to see if fuel pressure is bleeding off.

 

[1stblackawdtsi]

Your fuel system is supposed to store fuel pressure in the lines to allow for starting after the car has sat. Your fuel pressure regulator could be leaking or the check ball in your fuel pump could be bad. Both of which wouldn't allow fuel to be stored in the system for extended periods of time, but the leaks would be slow and not noticable unless the car sat for a few hours like you stated. The way you test for this is to do a "deadhead" fuel pump pressure test. Which is best done by a qualified mechanic, because if not done properly you can destroy fuel lines, fuel pump, and or FPR.

 

[spaugh]

I can hear the pump running it is really loud. The temp sensor is messed up i think because my temp gauge starts @ 0 but after like 2 or 3 min it is all the way up.

 

[1stGenTSi]

You mean after 2 or 3 minutes of idling the temp gauge goes all the way to HOT? And as for the fuel pressure test the easiest way to do it is to use a T fitting that comes with most fuel pressure test kits. You install the T where the fuel filter would go since 1g's don't have a schrader valve on the fuel rail. Disconnecting the fuel filter is usually a p.i.t.a. though.

 

[spaugh]

Yes thats what I ment. I will try a presure test.

 

[-LA-]

I can hear the pump running it is really loud. The temp sensor is messed up i think because my temp gauge starts @ 0 but after like 2 or 3 min it is all the way up.

or it is very possible your coolant temp sensor wires have broken off or come unplugged. Check below the radiator cap and make sure all wires are securely connected. Without a temp sensor the ecu will think the temp is like -50* F and will DUMP fuel making it almost impossible to start. Ge

+1 on the ECT sensor. Really don't make any sense to say the fuel system, even though it might be letting fuel not stay primmed in the lines.

Once you turn your key and hear the pump, the lines are gonna be primmed. Thus letting fuel ready. I mean you could have 2 problems. One with the pump or ball valve letting it prime off, and the ECT.

But first things first. Let's get the ECT sensor working. Also, when your trying to start it, can you actually smell any fuel?

Have you tried to pull the fuel line off and see if it's actually getting there when your turning the key over?

 

[spaugh]

If i sit and crank it over and over i do smell fuel. I have not checked the lines.

 

[1stGenTSi]

Hold off on the pressure test I think your problem is related to the coolant temp sensor. Is your radiator full/thermostat opening? The only way I could see your car overheating in less than 5 minutes would be; Low/No Coolant, Bad waterpump, or the temp sender is flaking out. There is a one wire coolant temp sender that goes to the gauge in the car and a 2 wire sensor that goes to the ECU. The wires to the sensor and sender get very hot and brittle on a high mileage vehicle and will tend to break. Check these first.

 

[1stGenTSi]

If you smell fuel it is most likely too much fuel keeping your car from starting and not a lack of fuel.

 

[1stGenTSi]

Get the coolant temp stuff taken care of ASAP. Is it possible his 255 is overrunning the stock FPR before even getting the car started?

 

[ninjaneonturtle]

you're probably flooding the motor without an aftermarket FPR, the 255 makes too much fuel pressure so you have to turn it down or you'll run rich.

and I think he means that he just gets up to temperature quick, not overheating.

 

[AOsipower]

I can hear the pump running it is really loud. The temp sensor is messed up i think because my temp gauge starts @ 0 but after like 2 or 3 min it is all the way up.

Correct me if I am wrong but I dont thing the ECT has anything to do with whether or not your temp gauge is functioning properly. If your gauge isn't working right it is most likely your coolant temperature sending unit or the gauge itself. The ECT should have nothing to do with that the Coolant Temp sender is what sends info to the gauge.

 

[1stGenTSi]

Correct me if I am wrong but I dont thing the ECT has anything to do with whether or not your temp gauge is functioning properly. If your gauge isn't working right it is most likely your coolant temperature sending unit or the gauge itself. The ECT should have nothing to do with that the Coolant Temp sender is what sends info to the gauge.

By ECT he is referring to Engine Coolant Temperature. I think you thought he meant ECU in which case you are right.

 

[AOsipower]

No I know he means ECT. There is a difference between an Engine Coolant Temperature Sensor (ECT) and a Coolant Temp Sending unit. The ECT I believe affects A/F ratio because it tells the ECU how hot/cold the car is running. The Coolant temp sending unit is the one that relays info to the gauge. If you look in a manual (my comp skills suck or I would upload a pic) there is both a sensor and a sender, they are two different entities. The only reason I made the original post is because I didn't want the person to think that because his gauge was wacky his ECT was bad. Because they are not really connected.

 

[spaugh]

The only thing is if it was gettin to much fuel why would it start after i put more fuel into it. I have tried two custers and the the temp gauge done the same. None of the gauges work on the speedo. Like i said it was the same on both clusters and i have changed out the ECU.

 

[AOsipower]

Well at least for your temp gauge problem try checking your Coolant temp sending unit (not the same as ECT). If you tried two clusters its probably not the gauge unless by some weird chance they were both bad, but seeing as how thats unlikely I would try and check you Coolant temp sending unit and see if that helps your gauge predicament.

 

[spaugh]

Will do Does any one know if i can pick one of those up from a parts store or is it something i will have to order.

 

[AOsipower]

You could always call a few local parts places and see if they have anything in stock, before you drive over. And also price them out at different places so you can find the cheapest. I know my local Autozone had the ETC sensor (not what your looking for) in stock when I called.

 

[blueninteytwo]

my call is the ECT sensor too. my old vw fox had a bad ECT sensor, and it just wouldn't start in the cold. pissed me off too because it was getting everything, i could smell the gas, see the spark, and verify the timing...

The ECT is supposed to tell the injectors to richen the fuel mixture on start-up, and if it's failed to do so, the starting fluid is your fuel enrichment the gas vapors fail to atomize very well in cold weather so if you're getting no fuel enrichment, it might not be atomizing enough to start the car. but you can still smell the gas as it's being sent out the tailpipe unburned.