Golf MK4 GTi Misfiring: 16804
Discussion
Hi Guys
I just popped to have a look at a MK4 Golf GTi that has come for sale locally as spares or repairs.
The owner admits that it has a misfire and the EML light is on. I first plugged in my cheap handheld scanner and the only code that appears is: 16804: Catalyst System Bank 1: Efficiency below threshold.
I then started the car thinking it just had a small misfire; no, it sounds awful, engine bouncing all over the place and sounded so bad I turned it straight off.
The fault code would suggest a faulty catalyst or o2 sensor.
Now I am not doubting the var requires this but would / could this cause such a bad misfire!!??
Thanks
I just popped to have a look at a MK4 Golf GTi that has come for sale locally as spares or repairs.
The owner admits that it has a misfire and the EML light is on. I first plugged in my cheap handheld scanner and the only code that appears is: 16804: Catalyst System Bank 1: Efficiency below threshold.
I then started the car thinking it just had a small misfire; no, it sounds awful, engine bouncing all over the place and sounded so bad I turned it straight off.
The fault code would suggest a faulty catalyst or o2 sensor.
Now I am not doubting the var requires this but would / could this cause such a bad misfire!!??
Thanks
TROOPER88 said:
Hi Guys
I just popped to have a look at a MK4 Golf GTi that has come for sale locally as spares or repairs.
The owner admits that it has a misfire and the EML light is on. I first plugged in my cheap handheld scanner and the only code that appears is: 16804: Catalyst System Bank 1: Efficiency below threshold.
I then started the car thinking it just had a small misfire; no, it sounds awful, engine bouncing all over the place and sounded so bad I turned it straight off.
The fault code would suggest a faulty catalyst or o2 sensor.
Now I am not doubting the var requires this but would / could this cause such a bad misfire!!??
Thanks
2.0 or 1.8 engine? The 2.0 do seem to have a habit of killing cats around 100k miles and aftermarket ones still set the light even if under mot limits. The coil packs also tend to fail, I just popped to have a look at a MK4 Golf GTi that has come for sale locally as spares or repairs.
The owner admits that it has a misfire and the EML light is on. I first plugged in my cheap handheld scanner and the only code that appears is: 16804: Catalyst System Bank 1: Efficiency below threshold.
I then started the car thinking it just had a small misfire; no, it sounds awful, engine bouncing all over the place and sounded so bad I turned it straight off.
The fault code would suggest a faulty catalyst or o2 sensor.
Now I am not doubting the var requires this but would / could this cause such a bad misfire!!??
Thanks
TROOPER88 said:
It is the 2.0 GTi
Would this be ht leads/plugs or coil packs?
They had a garage take a look and apparently they said it was the leads or plugs but I have my doubts
its a simple system, a coil pack in one for all 4 , then leads as usual to the plugs. The coil pack plastic breaks up and lets in water, short term fix is something like araldite but better to replace it, takes about 20 mins , it's mounted on the front of the engine next to the gearbox.Would this be ht leads/plugs or coil packs?
They had a garage take a look and apparently they said it was the leads or plugs but I have my doubts
If it's the azj engine the plugs are well hidden and the leads could be damaged if pulled from the plugs by the lead only.
Normally it would store a misfire code aswell as the 16804 if the coil was an issue The 2.0 all seem to burn a little oil so I suspect that kills the cat overtime. Aftermarket cats enough to get through an mot around £100 but expect to still Get the error code after a while.
Hi Guys
Well I purchased the Golf and picked it up this eve.
It drove ok, bad misfire but I knew about this.
Lots of fault codes to be honest: 16804, 17704, 17925, 16684, 16685, 18058, 17978, 16705
I think most are misfire relates or things affected due to the misfire.
I have ordered plugs, leads and a coil and will set about getting this done this week. Looks like the inlet manifold has to come off in order to access the plugs and leads??
Well I purchased the Golf and picked it up this eve.
It drove ok, bad misfire but I knew about this.
Lots of fault codes to be honest: 16804, 17704, 17925, 16684, 16685, 18058, 17978, 16705
I think most are misfire relates or things affected due to the misfire.
I have ordered plugs, leads and a coil and will set about getting this done this week. Looks like the inlet manifold has to come off in order to access the plugs and leads??
TROOPER88 said:
Hi Guys
Well I purchased the Golf and picked it up this eve.
It drove ok, bad misfire but I knew about this.
Lots of fault codes to be honest: 16804, 17704, 17925, 16684, 16685, 18058, 17978, 16705
I think most are misfire relates or things affected due to the misfire.
I have ordered plugs, leads and a coil and will set about getting this done this week. Looks like the inlet manifold has to come off in order to access the plugs and leads??
Assuming it's an azj engine I'm told that all plugs can be changed without taking the manifold off, using flexi joint socket set. Not done it myself though. That said you have a whole host of error codes there, including Ecu/immobiliser and dash wiring issues. I'd check all of those connections firstWell I purchased the Golf and picked it up this eve.
It drove ok, bad misfire but I knew about this.
Lots of fault codes to be honest: 16804, 17704, 17925, 16684, 16685, 18058, 17978, 16705
I think most are misfire relates or things affected due to the misfire.
I have ordered plugs, leads and a coil and will set about getting this done this week. Looks like the inlet manifold has to come off in order to access the plugs and leads??
HI chaps
I called at Euro car parts this morning and picked up HT leads and plugs. Unfortunately they did not have the ignition coil in stock so I’ll pick that up tomorrow.
This is the engine:
I removed the air intake pump and then loosened the inlet manifold.
I was then able (very tricky) to removed and replace the 4 plugs and leads.
I put it back together but unfortunately the misfire is very much still present.
Prior to beginnng the job, I deleted all fault codes and none have re-appeared.
As I say, I’ll pick up a new coil in the morning and try that.
What do you guys think?
Probably the coil or could it be any number of things?
Many thanks
I called at Euro car parts this morning and picked up HT leads and plugs. Unfortunately they did not have the ignition coil in stock so I’ll pick that up tomorrow.
This is the engine:
I removed the air intake pump and then loosened the inlet manifold.
I was then able (very tricky) to removed and replace the 4 plugs and leads.
I put it back together but unfortunately the misfire is very much still present.
Prior to beginnng the job, I deleted all fault codes and none have re-appeared.
As I say, I’ll pick up a new coil in the morning and try that.
What do you guys think?
Probably the coil or could it be any number of things?
Many thanks
TROOPER88 said:
HI chaps
I called at Euro car parts this morning and picked up HT leads and plugs. Unfortunately they did not have the ignition coil in stock so I’ll pick that up tomorrow.
This is the engine:
I removed the air intake pump and then loosened the inlet manifold.
I was then able (very tricky) to removed and replace the 4 plugs and leads.
I put it back together but unfortunately the misfire is very much still present.
Prior to beginnng the job, I deleted all fault codes and none have re-appeared.
As I say, I’ll pick up a new coil in the morning and try that.
What do you guys think?
Probably the coil or could it be any number of things?
Many thanks
Did you get anywhere with this? coil pack would cause these issues I called at Euro car parts this morning and picked up HT leads and plugs. Unfortunately they did not have the ignition coil in stock so I’ll pick that up tomorrow.
This is the engine:
I removed the air intake pump and then loosened the inlet manifold.
I was then able (very tricky) to removed and replace the 4 plugs and leads.
I put it back together but unfortunately the misfire is very much still present.
Prior to beginnng the job, I deleted all fault codes and none have re-appeared.
As I say, I’ll pick up a new coil in the morning and try that.
What do you guys think?
Probably the coil or could it be any number of things?
Many thanks
Hi
The leads and plugs did not resolve it so picked up a coil.
I was hopeful when I looked into the current coil and whereas the other 3 plug connection points are clean, number 1 was dry and brown/black.
Unfortunately the coil is not the issue.....
I spoke with a local garage who said that I would now have to remove the inlet manifold completely (is there bolts on the back??) and do a compression test on each cylinder.
If compression is good, then it sounds like an injector/wiring to the injector.
Does this sound the best approach?
I put an inline spark tester on lead number 1 and there is a spark. Plugs to cylinders 2,3 and 4 were white and number 1 was dry black.
Any ideas anyone???
Thanks
The leads and plugs did not resolve it so picked up a coil.
I was hopeful when I looked into the current coil and whereas the other 3 plug connection points are clean, number 1 was dry and brown/black.
Unfortunately the coil is not the issue.....
I spoke with a local garage who said that I would now have to remove the inlet manifold completely (is there bolts on the back??) and do a compression test on each cylinder.
If compression is good, then it sounds like an injector/wiring to the injector.
Does this sound the best approach?
I put an inline spark tester on lead number 1 and there is a spark. Plugs to cylinders 2,3 and 4 were white and number 1 was dry black.
Any ideas anyone???
Thanks
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