The Misfire Struggle (1.6 FSI - BAD)

xhuli

Member
Thank you guys for your support!

As promised, I'm here to report back and share with you the issues I've come across.

- 17912 - P1504 - 35 - 10 Intake Air System : Leak Detected
SOLVED : I knew I had an air leak somewhere and decided to blow some air on the engine. First I removed the Mass Air Flow (OEM 057 906 461 A) (G70) and sealed the Intake Air Duct (OEM 8Z0 133 356) with a latex glove. Next I blown some air with my mouth onto the engine bay Oil Filler Pipe (OEM 036 115 302 Q) and heard bubbles popping from underneath the car. I guessed it was the engine oil and a few seconds later I saw oil pouring on the ground. I went underneath the car and I saw where it was coming from. The leak happened to be in the external Oil Filler Pipe/Oil Dipstick (OEM 8Z0 115 302 N). The pipe was melted in the lower area which had created some big holes. I didn't have the replacement part so what I did is I removed the damaged pipe and sealed it completely for the time being. It's been two days now and the error code hasn't come back.

- Radiator Fan (OEM 8Z0 959 455 C) (V7) - Not turning on

KIND OF SOLVED : On several occasions when the engine was reaching 90° to 110° C I was expecting the fan to run and it never did. At first I thought the Control Unit for Radiator Fan (OEM 8Z0 959 501) (J293) was faulty so I decided to go further and hardwired the Radiator Fan directly to the power plug connector (T2J) which plugs into the Control Unit and the fan was running ok. I decided then to do an Output Test on the HVAC module via VCDS and everything was running/testing like it should and the Radiator Fan would actuate by VCDS commands. The engine has never overheated since I bought the car so maybe it's either I never hear it when it comes on or the engine is not enough warm to activate the fan. I guess I have to keep an eye on this on he future. I let it be for the moment.

- Air Conditioning not working
NOT SOLVED : When doing some work underneath the car I noticed the Refrigerant Hose (OEM 8Z0 260 707 N) was melted on the outside and I guess all the fluid has leaked. When activating the Air Conditioning on the lowest temperature in the Climatronic Unit (OEM 8Z0 820 043 D 5PR) (E87) there was not cold air and the fan was not turning on either. Before I fill the circuit with refrigerant fluid I will replace that hose. I forgot to check the Air Conditioner Pressure Sensor (OEM 8E0 959 126) (G65) and the Air Conditioner Compressor (OEM 8Z0 260 805 A) (N280) to see what is going on.

- High consumption
NOT SOLVED
: Before I repaired the air leak on the Oil Filler Pipe my consumption was like 7 L/100km (around 40 UK mpg). Now, after the air leak repaired, I'm running like 8 L/100km (around 35 UK mpg). My guess is the car needs some km before the ECU (BOSCH MOTRONIC MED7.5.11) adapt its fuel trims. Correct me if I'm wrong here. Is there a way to reset it? My two coolant temperature sensors are working ok and the car in about less than 10 minutes warms up already at 90°C in the Instrument Cluster.

- Misfire issues
NOT SOLVED : I noticed that I still had some minor misfire issues. Every now and then, especially on cylinder 3 (the one with less compression), a misfire would occur, it's like 1 or 2 per 5 min cycle. It's day and night compared to before but I wanted to report that. I never had the Engine Management Light (EML) come on since I changed the 4 Ignition Coils. The car pulls very well and feels very smooth across RPM ranges. But time to times there would be some tiny tiny gaps/holes/void when accelerating it's very very small and almost indistinguishable but I feel it's there (Misfires ?). Also when I start the car the first few seconds the car sounds like a diesel and then back to normal, I don't know if it's normal or not but it's weird. My idle too it's not perfect, it revs between 650 to 720 RPMs and time to times there would be small vibrations, the needle too would oscillate a tiny bit. This would happen even when a misfire is not occurring, again weird issue. I also did a graph monitoring test in VCDS on the Accelerator Pedal Position Sensors (APPS) (G79 & G185) alongside the Throttle Valve Drive Angle Sensors (G187 & G188) and Mass Air Flow Sensor (G70), all seem to be working well.

Now, said all that, the car feels like day and night compared to before addressing the huge misfire issues. From tomorrow on my wife will finally get her car back but I will still be monitoring those issues closely.

So I'll get back to you as soon as I have some news regarding my issues.
 

Attachments

PlasticMac

Member
I get that dieselly, rattly (I describe it as tappety) noise, for a few seconds, on start up too. I believe it's the valve lifters, which are hydraulic, and need to get the oil up to pressure, then they go quiet. Sounds like a plan ...
Mac.
(1.6 FSI, 50,000 mls /80, 000 kms. 43 - 44 mpg).
 

Andrew

A2OC Donor
Keep up the good work and excellent reporting.

A few simple things

Yes at startup it does sound like a diesel, perfectly normal, in fact I had a 'new' passenger who immediately commented "Oh, it's a diesel" as well as other people commenting it sounded "rough when you started it".

I can honestly say in the 10 years of owning my FSI I have never heard the radiator fan! I am not deaf! I get the impression it is almost redundant, enough air flow on the radiator when moving to keep equilibrium. Possibly there for hot engines idling in stationary traffic and very hot days. I suppose it might be so quiet to be inaudible to me.

Your idling speed is too low. I will check in the coming days but I am fairly sure that my FSI idles at a steady 800 rpm.

I have the impression the 10 minutes for the dash temperature to reach 90°C is a little long, but again I will check in the coming days, after all ambient temperatures in the UK must be not that much different to you.

Andy
 

xhuli

Member
Ok so that rattly/tappety/diesel noise on the first few seconds of the engine startup seems to be normal thenas described by @PlasticMac, @Andrew and other members on the forum reports.

I might have exaggerated when I said 10min for the dash temp sensor to reach the 90* C mark. In fact it’s faster than that, I just was in the safe side.

For the minor misfiring issues, I only changed one Injector maybe the other three are about to give up? Or maybe, as @A2 Louis said in the beginning of this thread, the HPFP might not operate 100% perfectly.

Anyway, as I need the car to be drivable, I will live with that for the time being. I’ve spent too much money on this already so I’ll leave it be for the moment. On the next oil service (10 000km) I will consider again replacing the 3 remaining Injectors, HPFP and others parts that I already have in my possession (such as the Oil Pressure Sensor and the Thermostat).

I’ll keep you posted no matter what.

Julian
 

kp 115

A2OC Donor
Ok so that rattly/tappety/diesel noise on the first few seconds of the engine startup seems to be normal thenas described by @PlasticMac, @Andrew and other members on the forum reports.

I might have exaggerated when I said 10min for the dash temp sensor to reach the 90* C mark. In fact it’s faster than that, I just was in the safe side.

For the minor misfiring issues, I only changed one Injector maybe the other three are about to give up? Or maybe, as @A2 Louis said in the beginning of this thread, the HPFP might not operate 100% perfectly.

Anyway, as I need the car to be drivable, I will live with that for the time being. I’ve spent too much money on this already so I’ll leave it be for the moment. On the next oil service (10 000km) I will consider again replacing the 3 remaining Injectors, HPFP and others parts that I already have in my possession (such as the Oil Pressure Sensor and the Thermostat).

I’ll keep you posted no matter what.

Julian
It may be useful to treat the engine to a flush with Wynn’s engine flush before the oil change
as I’ve found over the last 30 years of Audi ownership it keeps helps them pump quickly up to pressure & run quietly .
 
Ok so that rattly/tappety/diesel noise on the first few seconds of the engine startup seems to be normal thenas described by @PlasticMac, @Andrew and other members on the forum reports.

I might have exaggerated when I said 10min for the dash temp sensor to reach the 90* C mark. In fact it’s faster than that, I just was in the safe side.

For the minor misfiring issues, I only changed one Injector maybe the other three are about to give up? Or maybe, as @A2 Louis said in the beginning of this thread, the HPFP might not operate 100% perfectly.

Anyway, as I need the car to be drivable, I will live with that for the time being. I’ve spent too much money on this already so I’ll leave it be for the moment. On the next oil service (10 000km) I will consider again replacing the 3 remaining Injectors, HPFP and others parts that I already have in my possession (such as the Oil Pressure Sensor and the Thermostat).

I’ll keep you posted no matter what.

Julian
The sound your getting on start up will get much better almost none existent when you put fresh new oil in, at least thats what i'm experiencing and the sound, if it happens, only lasts a second or two.

I changed my Thermostat housing because it had a tiny crack in it and there was no difference in the time it takes to get to 90 and from what your saying less than ten minutes sounds right to me.

If i've missed it apologies but have your tried using an injector cleaner like Wynns Gold? It defornately makes a difference. Looking forward to more updates when you get there. 👍

 

Andrew

A2OC Donor
Hi,

I did some timings today for the dash temperature to reach 90°C with my FSI. Came to the conclusion 10 minutes is perfectly normal, nothing wrong with yours.

I will include the results, just to put them on record for other FSI owners if interested now or in the future.

Test route of slow 20mph for 1.5 miles,with some stationary pauses, while I exited my village, then free flowing main A road at 40-60mph. Ambient temperature 7°C. Engine not entirely cold at start, but previous experience suggests residual 35°C after a short 1.5 mile run 5 hours previously. Climate unit on Auto.

Temperature (°C) Elapsed Time (Minutes, Seconds)

60 ______________6,30
70 ______________7,10
80 ______________8,15
90 ______________9,45

Times rounded to nearest 5 seconds and very subjective as to when the needle was in line (while glancing down and keeping eyes on the road!). First timing is when needle moved from 60°C.

Andy
 
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@xhuli What a great thread, I'm getting interested in an FSI, this is giving me some confidence.

A couple of questions if I may, how did you clean the intake manifold etc. i'm guessing hard work. And how is it running now?

We stayed in Strasbourg, on the Route Du Polygone, for a few days last year, really enjoyed it. It is a lovely City.
 

Quill

Member
Ok so that rattly/tappety/diesel noise on the first few seconds of the engine startup seems to be normal thenas described by @PlasticMac, @Andrew and other members on the forum reports.

I might have exaggerated when I said 10min for the dash temp sensor to reach the 90* C mark. In fact it’s faster than that, I just was in the safe side.

For the minor misfiring issues, I only changed one Injector maybe the other three are about to give up? Or maybe, as @A2 Louis said in the beginning of this thread, the HPFP might not operate 100% perfectly.

Anyway, as I need the car to be drivable, I will live with that for the time being. I’ve spent too much money on this already so I’ll leave it be for the moment. On the next oil service (10 000km) I will consider again replacing the 3 remaining Injectors, HPFP and others parts that I already have in my possession (such as the Oil Pressure Sensor and the Thermostat).

I’ll keep you posted no matter what.

Julian
Hi, Terrific work. I found that when I replaced the G28 crankshaft position sensor the start-up rattle became much quieter. It's a pig of a job though so not one to do in a rush. It's just possible to get access by removing the inlet manifold support bracket, PCV/oil separator and disconnecting the inboard end of the driver's side driveshaft. Be careful, it's very easy to round-off the support bracket or G28 fixings by using the wrong Allen key/Torx/spline tool. Also, although your car is pulling well, for anyone who is experiencing poor torque at low speed it's worth changing the camshaft position sensor.

Regards
Quill
 

Nye

Member
Ok so that rattly/tappety/diesel noise on the first few seconds of the engine startup seems to be normal thenas described by @PlasticMac, @Andrew and other members on the forum reports.

I might have exaggerated when I said 10min for the dash temp sensor to reach the 90* C mark. In fact it’s faster than that, I just was in the safe side.

For the minor misfiring issues, I only changed one Injector maybe the other three are about to give up? Or maybe, as @A2 Louis said in the beginning of this thread, the HPFP might not operate 100% perfectly.

Anyway, as I need the car to be drivable, I will live with that for the time being. I’ve spent too much money on this already so I’ll leave it be for the moment. On the next oil service (10 000km) I will consider again replacing the 3 remaining Injectors, HPFP and others parts that I already have in my possession (such as the Oil Pressure Sensor and the Thermostat).

I’ll keep you posted no matter what.

Julian
Great posts. Have you made any progress on the misfire? I ask because I too have a P0300/P0303/P0304 flashing EML, even after putting in new ign. coils, sparks on 3&4 and a new camshaft sensor. I don't know what to do next. I am intrigued by the HP fuel pump solution because that is what I'm considering.
 
Have you tried stripping the Loom back off the coils. I have just done this on my 1.4 Petrol and found 4 broken wires. I stripped each one right back to the main part of the loom connector the wires were broken on cylinder 2 and 4. I got some heat shrink sleeve and a heat gun to repair them then new black wiring tape to re-do the loom back. Not had a misfire code since beginning of Jan and runs a lot smoother. I have been struggling with misfire issues since I got mine now looks all resolved.. Hope this helps. Graham
 

Nye

Member
Have you tried stripping the Loom back off the coils. I have just done this on my 1.4 Petrol and found 4 broken wires. I stripped each one right back to the main part of the loom connector the wires were broken on cylinder 2 and 4. I got some heat shrink sleeve and a heat gun to repair them then new black wiring tape to re-do the loom back. Not had a misfire code since beginning of Jan and runs a lot smoother. I have been struggling with misfire issues since I got mine now looks all resolved.. Hope this helps. Graham
That's an intimidating sounding job but I'm getting desperate so I may give it a go. Could you tell how your wires had broken? Were they frayed or over-stretched or chewed or...?
 
That's an intimidating sounding job but I'm getting desperate so I may give it a go. Could you tell how your wires had broken? Were they frayed or over-stretched or chewed or...?
It sounds hard but really easy to do. Just take the plugs off the coils undo it from the clips and follow the wires back to just under the header tank. All you are doing is undoing the black wire protector off the loom so you can see all 4 wires that go into the plugs. If you undo it all you might see split wires so you can see the copper in the wire that's where the problems are EXPOSED wires...
 
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katalin21k

New Member
VW Golf MK4 1.6 Fsi 110 bhp engine code BAD. Got same problem on cylinder 3 and same like you xhuli spent over 1,5k euro till now trying to fix the car. Ive make it to run a bit better but is not a fix. I don't know what to do more and here is an inspiration . You changed alot more pieces than me and idk maybe we find what is the problem with this engine type. Also PM you @xhuli
Thanks guys and hope is not a problem if i'm here since is other car but same engine, same group, same parts used.
 

nod

Member
VW Golf MK4 1.6 Fsi 110 bhp engine code BAD. Got same problem on cylinder 3 and same like you xhuli spent over 1,5k euro till now trying to fix the car. Ive make it to run a bit better but is not a fix. I don't know what to do more and here is an inspiration . You changed alot more pieces than me and idk maybe we find what is the problem with this engine type. Also PM you @xhuli
Thanks guys and hope is not a problem if i'm here since is other car but same engine, same group, same parts used.
good luck with the hunt for the misfire, i'm sure you've tried the easy stuff like swapping coil packs. as mentioned above definately check the wiring to the coil pack, its easy for the insulation to get split near the connector if the coilpacks are levered out without disconnecting, then they short out and misfires occur.
 

katalin21k

New Member
good luck with the hunt for the misfire, i'm sure you've tried the easy stuff like swapping coil packs. as mentioned above definately check the wiring to the coil pack, its easy for the insulation to get split near the connector if the coilpacks are levered out without disconnecting, then they short out and misfires occur.
Yes done that first, and i think is beyond that probably bent valves or worse broken segments. Also i didn't scan it in last 2 weeks after i've changed more parts, i'll do it when i can, still working 12h shifts and i need the fk car to work. You ment to check how many missfire goes with each cylinder and the amount of fuel that each injector spit?
And to be worse i think i have a vacuum leak and after 3,5k rpm engine strugle to put power and shake like gives power than cutson and on. To get it better i've removed the airflow meter sensor and it gets enough air but still shake a bit after 5k rpm.

I'll share a part of the message to xhuli:

All coils changed (with beru and all work fine).
All spark plugs changed with iridium ones.
Distribution changed with all filters and oil.
Engine mounts changed( got a broken one) and the anti balance one.
High pressure pump changed.
Both lambda probes the front one and the other after catalyst converter plus the exhaust nox temperature probe.
Air flow meter sensor replaced. With airflow meter jack off engine takes as much air he think it needs car work smoother on highway but keep the problem when it need power to move like when u stop on a traffic light. But the check engine light is off most of the time. Sensor is not broken but it cuts air.
Vacuum sensor replaced ( i still think i've got a leak). after 3,5-4k rpm it makes a fuss and is like gives power it shuts give again and so one car is bouncing.
I'll buy some injector cleaner today and changed gas filter yesterday again just to be sure (it remain the fuel pump and tank original it may have some waste in there).
In all the time i've been using 99+ gas (98+ on manual and in my country Romania they sell only 99+ and 100+).
What i have notice is that when u turn on the climatronic the shake of the engine is lower and without the jack from airflow meter is smooth almost like the car i been driving 9 years.
I don't know what to do now spent like 1,5k euro trying to fix the car, her value is like max 2,5k so soon i'll be in the position to throw cash for nothing.
For now ill go try the injector cleaner , premium gas 100+ , the airflow meter off and i put it on if the check engine for 100km and test it. At this time we just test all the things we can think.
A friend told me to buy some product that u can put in the antifreeze tank and can help if u got a leak into the cylinder but on mine cylinder 3 i did not found any oil (car maybe lose 300 ml oil in 1 year).

Did you do a smoke test to check if u got any leaks ?

In worst case scenario a mechanic told me i've got even bent valves or worse broken segments witch it make me think to sell the car :(

thanks for reply guys
 

PlasticMac

Member
Hi, suggest a compression test (spark plug out) on each cylinder (you hold a special pressure gauge on each cylinder) to check for mechanical damage, such as bent valves, broken piston rings, scored cylinder bores etc. That will narrow down the areas you need to investigate.
Any warning lights in the instrument cluster when the engine is running? If not, check that they all are on when you turn the key, but before the second turn to start the engine. Take a pic of the dash before and after, for us to see. I recommend a scan with genuine VCDS (free version and ebay lead will do) Generic scanners do not support VW specific codes. Good luck.
Mac.
 

katalin21k

New Member
@PlasticMac
I've did the pressure test a month ago when i've started to investigate the car. Cylinder 1-2-4 got 14 but cylinder 3 got 11 and i believe it need 12-15.
As warning light the check engine is almost always on, today even with airflow meter sensor off it got back on when i tried to move the car from a small ramp and for first time the battery light turned on check alternator. Turned off the car turned back on no light, guess now my alternator is broken.
I will try to scan with vcds again tomorrow. This car is only problems. (i cannot move free because of corona blockage and if cops pull me over they give me 500-5000 eurofine if i move without a good reason)

update: i will check the wires again tomorrow after i came back from night shift and sleep. (did a month ago when they were fine).
 
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