Allyn wrote:
if your vacuum (between throttle body and valves) just 'goes away' suddenly, i'm likely to think the issue is more of an air delivery issue. of course this only applies if the vacuum drop comes before the rpm drop. for this to happen, the vacuum loss would have to be unmetered, and LARGE (i.e. audible suction noise).
I can hear no vac leaks and I cannot tell if the vac drop causes the rpm drop or the drop causes the drop in vacc.
aside from this (and provided power loss comes before/during vacuum loss), it could be some sort of fuel issue that only happens on a cold start. a few causes come to mind:- fpr sticking
I does seem similar to the time the fuel pump died. I want to check the wiring to the FP this weekend. I hope its not another FP going out. Not much fun to replace.
- isv sticking (in this case sticking shut, but occasionally sticking and swinging open, causing your vacuum drop). test by removing the isv, checking for free motion. clean with carb cleaner and lubricate with a high grade oil.
Thats one I did not think of. Good idea.
- dpr on its way out (not properly responding to the larger currents it sees on a cold start). test by watching dpr current - especially helpful if you can watch it while the problem is there. use an analog meter if possible, or at least a fluke with a fast updating bar graph.
I had trouble with the DPR from the start. Even at Cincy last year I had several people look at the car, but never did get it set right. Even after changing the O2 sensor. (Yes I was getting frustrated)
hth Al----- Original Message ----- From: "Julie Macfarlane" <juliemac57@hotmail.com>To: <scirocco-l@scirocco.org> Sent: Thursday, January 13, 2005 9:47 PM Subject: More symptoms of the poor runningEngine 2L 16v Electrical: 88 16v harness Fuel CISE Engine starts well. One crank and operates.Low rpm and rough idle. I had to open the air bypass screw a few turns to idle at 950-1K.Problem. Power loss. Vac drops from 18" to 0 rapidly, almost stalling. Fluttering the pedal can keep the car running.The idle feels "buzzy", a rough edge to the running. (poor desc I know)Keeping the idle abve 1500 for a few secs will cause the rpm/vac to drop again.Only fluttering the pedal will keep the engine running.This will last for a minute or 2. The engine then will run correctly for the rest of the trip home.I checked the plug wiring and replaced the fuel filter. It seems to be intermittent.Any help appreciated! Julie Macfarlane "Its not just a car! Its an adventure!" 1981 MKI 2L 16v w 2Y Amsterdam NY _______________________________________________ Scirocco-l mailing list Scirocco-l@scirocco.org http://neubayern.net/mailman/listinfo/scirocco-l
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