Author Topic: Rough idle after startup  (Read 1368 times)

April 01, 2022, 10:35:31 pm

unitedracing

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Rough idle after startup
« on: April 01, 2022, 10:35:31 pm »
So I've had the Vanagon on the road for a couple weeks and mostly all is good, however it's developed an issue I've never seen before. When starting cold or hot I get a rough idle AFTER the first couple seconds of running. It starts awesome cold or hot and will idle smooth initially... and then it gets rough. At first it would go away quickly but now it's taking longer. It could be an injector even though they're freshly rebuilt. I have a spare set I'll try this weekend to see if there's any change. Someone mentioned the fuel pressure regulator valve piston may be jammed. Any of you ever see this? Thanks!



Reply #1April 02, 2022, 02:03:28 am

fatmobile

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Re: Rough idle after startup
« Reply #1 on: April 02, 2022, 02:03:28 am »
 Do you have clear fuel lines?
Is there air in the fuel as you start?
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #2April 02, 2022, 08:34:33 am

unitedracing

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Re: Rough idle after startup
« Reply #2 on: April 02, 2022, 08:34:33 am »
Yes on the clear line, and there's no air showing. There's no smoke to speak of either. Its odd that it idles smooth for a few seconds and then gets rough.

Reply #3April 02, 2022, 09:25:02 pm

fatmobile

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Re: Rough idle after startup
« Reply #3 on: April 02, 2022, 09:25:02 pm »
Clear line to and from the pump?
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #4April 02, 2022, 11:30:45 pm

unitedracing

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Re: Rough idle after startup
« Reply #4 on: April 02, 2022, 11:30:45 pm »
I don't normally have one after pump, but did try that today.  No air seen. I did remove and check the pressure valve today and its fine. I have a spare set of injectors that I may throw in tomorrow to try. They are NA units, but nearly new. It will also give me a chance to have the current ones tested

Reply #5May 05, 2022, 07:22:50 pm

33B

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Re: Rough idle after startup
« Reply #5 on: May 05, 2022, 07:22:50 pm »
I've had rough idle after cold startup for a few seconds. It was the injectors not spraying right.
1987 Passat B2 (33B)- 1.6TD JR, Audi 80 b4 front suspension and power steering. 280mm brake discs with 54mm calipers front. Rear MK3 disc setup with golf mk5 calipers.

 

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