Engine misfiring??
Posted
#1622504
(In Topic #222091)
Old Timer
Please help guys the sun is out and my cabriolet needs some cruising
Regards Dean
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Posted
Local Hero
Bad plugs,
Bad Wires, Cap or rotor, and
Timing.
What do Divorces, Great Coffee, and Car Electrics all have in common?
They all start with GOOD Grounds.
Where are my DIY Links?
They all start with GOOD Grounds.
Where are my DIY Links?
Posted
Regional Host NE
mate
Do not know a lot but willing to help if possible
1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF
1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF
Posted
Old Timer
Engine misfiring??
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Posted
Old Timer
I also had a misfire on my GTi which many years ago which turned out to be a dodgy plug lead (which was only a few months old). Might be worth swapping leads with a spare set just to rule this out.
Nut & Bolt Resto Complete (Mars Red GTi original): https://vwgolfmk1.org.uk/forum/index.php?page=topicview&type=misc&id=projects%2Fyour-mk1-golfs_2%2Fpistolpete-s-mars-red&start__keyed=
Nut & Bolt Resto in Progress (Lhasa 16v): https://vwgolfmk1.org.uk/forum/index.php?page=topicview&type=misc&id=projects%2Fyour-mk1-golfs_2%2Fpistolpete-s-lhasa&redirected=1
Nut & Bolt Resto in Progress (Lhasa 16v): https://vwgolfmk1.org.uk/forum/index.php?page=topicview&type=misc&id=projects%2Fyour-mk1-golfs_2%2Fpistolpete-s-lhasa&redirected=1
Posted
Old Timer
Engine misfiring??
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Posted
Local Hero
I had a misfire caused by a bad wire, but it took a spare set to find it, as the Plug Sets I bought (bosch triple plats) had 1 bad plug in the first set, and 3 bad ones in the second, add to that a bad wire in the mix I had the original bad wire, and 2 bad plugs so I made it progressively worsen. I got my Ohm meter out and found that 2 of the Plugs were open. Still was doggy, and even the Switch to NGK plugs caused me an intermittent miss…. When my Daughter got home with the other car I swapped Caps and Leads and presto…it was a race car…. I then swapped leads over one at a time and found the bad one….
Another thing to look for is Carbon Tracking, that can cause a miss. Take a Blanket (dark one or do this after dark) and with all lights around the engine off. Start the car and see if you have sparking fairies dancing about…
I have seen it on Wire Sets that the metal plug end was shorting out to the head, as well as cracks in the diz that had gotten water soaked.
What do Divorces, Great Coffee, and Car Electrics all have in common?
They all start with GOOD Grounds.
Where are my DIY Links?
They all start with GOOD Grounds.
Where are my DIY Links?
Posted
Old Timer
Re:
Thanks briano for your reply I really appreciate you taking time out to council me .it appears to be getting worse but then seems to get a bit better ?? Very strange. Can you educate me .I had the timing set to the right degrees by my tuner .if you recall I was boasting how I got 106.9bhp on the dyno .he set it then and it's not been touched since then ? So how could it be that .? As it was running well after the dyno then developed this fault? I'm not doubting your expertise mate .I know that you know your stuff .I'm just trying to understand how it could have "moved" timing ? I am hearing you about the leads but dont have a spare set unfortunately. So would have to buy a new set .including plugs etc .so il have to do that .could it be a fueling issue? As foot down its worse at set off but as the rev range rises it happens less and less until almost nothing at the top of the rev range ???? Such a royal pain in the bum, as it's just passed its mot only failed on 1 ball joint, which I thought was brilliant for a 29 year old car. I got both done obviously with new wishbones ball joints the lot ….Briano1234 said
Check your diz advance, sounds like your diz if vacuum advanced has a leak or that you have a vacuum leak somewhere.
I had a misfire caused by a bad wire, but it took a spare set to find it, as the Plug Sets I bought (bosch triple plats) had 1 bad plug in the first set, and 3 bad ones in the second, add to that a bad wire in the mix I had the original bad wire, and 2 bad plugs so I made it progressively worsen. I got my Ohm meter out and found that 2 of the Plugs were open. Still was doggy, and even the Switch to NGK plugs caused me an intermittent miss…. When my Daughter got home with the other car I swapped Caps and Leads and presto…it was a race car…. I then swapped leads over one at a time and found the bad one….
Another thing to look for is Carbon Tracking, that can cause a miss. Take a Blanket (dark one or do this after dark) and with all lights around the engine off. Start the car and see if you have sparking fairies dancing about…
I have seen it on Wire Sets that the metal plug end was shorting out to the head, as well as cracks in the diz that had gotten water soaked.
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Posted
Local Hero
I have a similar issue, never really gotten to the bottom of it. I recently took the chance to refurb (paint) the pulleys when the water pump was replaced, I painted them black and highlighted the timing marks, and also painted on degree markings at 10 deg, 20 deg, 30 deg etc so at least I can check it better now.
Posted
Old Timer
Engine misfiring??
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Posted
Local Hero
Posted
Old Timer
Engine misfiring??
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Posted
Old Timer
Engine misfiring??
Sent from my SM-G950F using Tapatalk
Posted
Old Timer
Engine misfiring??
Sent from my SM-G950F using Tapatalk
Posted
Local Hero
The choke would richen the mixture. It might be that's slipped too, except they don't really "drift" that much over time unless there is a fault with the carburettor. In any case, my tool of choice to check mixture is a wideband lambda probe. A garage/mechanic will probably have this kit.
Posted
Old Timer
Engine misfiring??
Il get it checked regardless mate
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Posted
Local Hero
Deano777 said
Does the fact the choke makes it run well .not suggest it's running lean?
Yes but the question is, if it were professionally set up, then something has changed and its now running lean, what's broken?
There isn't a single fixed point at which the mixture, or timing, MUST be set. There's an acceptable band, within which the car will run without misfiring or other issues, and outside, it will be noticeable. Within the band, you won't be able to tell from your own senses but it will show on instruments eg timing light, mixture (gas analyser, lambda sensor) or power output on a rolling road.
Its quite possible to measure the relevant stuff and put the car "in the middle" of that sweet spot, or (deliberately) on the rich side, or on the lean side, etc. If your car was set up nicely but on the lean side - quite appropriate to do for a daily driver - then a small change could make it misfire.
Also bear in mind, a Mk1 Golf is old-school compared to a modern car. The ignition and mixture isn't controlled by a computer with a map, its all done with mechanical physical things which wear out over time. And there's no monitoring or feedback available from the car eg you can't read off misfire events or knock sensor events, fuel trim, etc etc. And definitely no "closed loop"!
Posted
Old Timer
Engine misfiring??
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Posted
Old Timer
Engine misfiring??
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Posted
Old Timer
Engine misfiring??
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