87 1.8gt Coupe Misfire

5potJacko · 15-02-18, 10:48 AM

I've recently acquired an 87 coupe gt with the 1.8 4 cylinder engine. It has a constant misfire and the previous owner told me this is on cylinder 4. Does anyone have any experience on these engine and if so anything obvious I should be looking for?

Its had a brand new dis cap, rotor arm, plugs and leads and it didnt fix it (again previous owner)

vagdream · 15-02-18, 11:09 AM

First thing I would do is to crosscheck the initial diagnosis and disconnect No.4 plug lead and see whether the misfire is changed in any way, if not then at least you have confirmed where to focus your attentions.

steveb · 15-02-18, 12:33 PM

A compression check would be a good way to proceed

M4rkp · 15-02-18, 03:23 PM

Honestly, I would discard anything the previous owner has hinted at such as new plugs, leads, dizzy cap etc.....

A compression check and leakdown check is a good way to start, if you get acceptable readings then go on to doing as vagdream suggests. I would be certainly looking at condition of plugs....get yourself a set of inline spark indicators, that way you'll be able to see if you have good spark on all four pots.

Of course, could be a fuelling issue - bad injector/seals - do a test to determine flow rates and spray pattern.

Steady and methodical...don't take anything for granted!!

5potJacko · 19-02-18, 01:40 PM

Solved this within 10minutes of investigation. Although the spark plugs were reletivley new, one wasnt working properly so £250 later and its running spot on! Cheers for all help

SwallownAmazon · 19-02-18, 04:24 PM

£250 for a spark plug?

vagdream · 19-02-18, 04:40 PM

£2.50 maybe for a W6DTC?

5potJacko · 20-02-18, 12:16 PM

Halfords prices!

15-02-18, 12:33 PM	#3
steveb Senior Member Classic Audi Club Member Join Date: Jul 2008 Location: West Berkshire Posts: 1,155	A compression check would be a good way to proceed __________________ [FONT] '76 Leyland Princess 2200 HLS '79 Scirocco storm '84 WR '89 coupe quattro '01 A2 1.4 TDI SE '14 A3 1.4 TFSI COD [/color][/size][/font] Last edited by steveb; 15-02-18 at 12:36 PM.

15-02-18, 11:09 AM	#2
vagdream Grown up member Join Date: Jul 2015 Location: Llandudno Junction Posts: 165	First thing I would do is to crosscheck the initial diagnosis and disconnect No.4 plug lead and see whether the misfire is changed in any way, if not then at least you have confirmed where to focus your attentions.

15-02-18, 03:23 PM	#4
M4rkp Grown up member Classic Audi Club Member Join Date: Feb 2013 Location: Sometimes Roberttown - sometimes Surrey Posts: 194	Honestly, I would discard anything the previous owner has hinted at such as new plugs, leads, dizzy cap etc..... A compression check and leakdown check is a good way to start, if you get acceptable readings then go on to doing as vagdream suggests. I would be certainly looking at condition of plugs....get yourself a set of inline spark indicators, that way you'll be able to see if you have good spark on all four pots. Of course, could be a fuelling issue - bad injector/seals - do a test to determine flow rates and spray pattern. Steady and methodical...don't take anything for granted!!

19-02-18, 01:40 PM	#5
5potJacko Grown up member Classic Audi Club Member Join Date: Dec 2013 Location: Bishops Stortford, Hertfordshire, UK Posts: 31	Solved this within 10minutes of investigation. Although the spark plugs were reletivley new, one wasnt working properly so £250 later and its running spot on! Cheers for all help

19-02-18, 04:24 PM	#6
SwallownAmazon Grown up member Classic Audi Club Member Join Date: Jun 2017 Location: Tonbridge, Kent Posts: 511	£250 for a spark plug?

19-02-18, 04:40 PM	#7
vagdream Grown up member Join Date: Jul 2015 Location: Llandudno Junction Posts: 165	£2.50 maybe for a W6DTC?

20-02-18, 12:16 PM	#8
5potJacko Grown up member Classic Audi Club Member Join Date: Dec 2013 Location: Bishops Stortford, Hertfordshire, UK Posts: 31	Halfords prices!