Fuel smell when shut down
11-01-2007, 02:11 PM
#16
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Location: Milwaukee, WI
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Yeah, I have the feeling the pressure test is going to tell you something here.
Now that I think about it, my car did seem to be more susceptible to killing when it was at idle. So I, too, was doing things like keeping the revs up at idle thinking that if it *was* my FPR, then a higher duty cycle on the injectors would help keep the fuel pressure in the rail down closer to what it should be and give the injectors less opportunity to stick closed. That was just my theory, though.
Now that I think about it, my car did seem to be more susceptible to killing when it was at idle. So I, too, was doing things like keeping the revs up at idle thinking that if it *was* my FPR, then a higher duty cycle on the injectors would help keep the fuel pressure in the rail down closer to what it should be and give the injectors less opportunity to stick closed. That was just my theory, though.
12-12-2009, 10:20 AM
#17
Drifting
Thread Starter
Better late than never on thread closure I say... I began to hear a hiss-like sound after shutting the car down that lasted for several minutes. Not real loud, you had to be paying attention. I listened with the stethoscope and it seemed to come from the fuel damper. Pulled the vacuum hose and sure enough a few drops of gas. Replaced the damper and hard start/fuel smell problem fixed. For grins, I vacuum tested the diaphragm on the bad one and it was a very slow leak at 20 in vacuum. Now I'm waiting for FPR to fail since it is original with 245K miles....
12-12-2009, 01:52 PM
#18
Burning Brakes
nice one ,Solutions are so useful when diagnosing a no start.
. I was guessing damper as i read through the thread because I read a Bosch trouble shooting guide last week. That was the failure Bosch suggested.
Glad you found it eventually .Took me 7 weeks to get my S2 started and I am still not sure why it failed to start.
http://fc3spro.com/TECH/FAQ/pd.html
. I was guessing damper as i read through the thread because I read a Bosch trouble shooting guide last week. That was the failure Bosch suggested.
Glad you found it eventually .Took me 7 weeks to get my S2 started and I am still not sure why it failed to start.
http://fc3spro.com/TECH/FAQ/pd.html
12-12-2009, 04:39 PM
#19
Drifting
Thread Starter
What got me was how slow of a leak could result in this condition. I had vacuum checked the FPR and damper when I started chasing it 2 years ago and didn't measure any leakage but maybe I did judged too quickly...
12-12-2009, 08:07 PM
#20
Burning Brakes
I think mine was a combination of dirty plugs ,poor electrical contacts ,sticky injectors and running the tank really low. probably brought up a load of water .
The thing that finally got it started was definitely cleaning and heating the spark plugs in the oven
The thing that finally got it started was definitely cleaning and heating the spark plugs in the oven
12-16-2009, 09:22 PM
#22
Mike - my 93 Tip is now giving a whiff of fuel too. I had a mechanic drop the tank and all the lines from front to back are new, but I'm at a loss - where is the 'fuel damper' ? TIA, as they say.
12-21-2009, 09:06 PM
#25
Drifting
Thread Starter
The 968 factory shop manual indicates that no fuel damper is used at all, it only has a fuel pressure regulator which appears to be located at the aft end of the fuel rail. I found the 968 FSM here:
http://www.cannell.co.uk/Manuals.htm
http://www.cannell.co.uk/Manuals.htm
12-22-2009, 05:11 AM
#26
Burning Brakes
sorry only just seen this. The working link was in the previous post.
http://fc3spro.com/TECH/FAQ/pd.html
Mike your link doesn't appear to be working however I find it very surprising that Bosch wouldn't use a fuel damper on the 968. How else would you damp out the fuel pump pulses at idle and low revs ?
12-22-2009, 03:18 PM
#27
Drifting
Thread Starter
Here is a screen shot of the Fuel System Diagram. Maybe the 968 uses a different fuel pump that doesn't require the external damper?
Last edited by Mike C.; 03-02-2010 at 05:13 PM.
12-22-2009, 05:15 PM
#28
Burning Brakes
mmmm looks like they don't use one. maybe it is incorporated in the pump itself ? I think the 968 must use the latest Motronic fuel system which has a pulse-free pump and works on lower pressure. Is the pum external or in the fuel tank?
looks like they don't use one. maybe it is incorporated in the pump itself ? I think the 968 must use the latest Motronic fuel system which has a pulse-free pump and works on lower pressure. Is the pum external or in the fuel tank?
