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I have had my 159 TBI for nearly a month now and it's had a couple of niggley issues to sort out.

The most annoying issue for me is a misfire/lumpyness that occurs up to about 2500 rpm.

The car was purchased having just been fully serviced, cambelt replaced and spark plugs changed. Initially I felt this misfire from cold and it would gradually fade away as the car warmed up. Since yesterday the misfire has started occurring when hot too.

So ruling out the spark plugs, what could be causing this? Coilpacks? MAF? I have also purchased Multiecuscan and this showed no faults.

Thanks

Phil
 
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I'm leaning towards that too. I will take a look after work and see if there is anything immediately obvious. No engine lights or anything, infact today it was behaving like it was before, lumpy when cold but fine once warmed up. Very strange...

Love your videos btw :smokin:
 

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I’ve had a long term battle to sort the misfire on my 2.2

I went through a whole host of different causes, from MAF, new coil pack, checking for vacuum leaks, new spark plugs. In the end, it turned out to be a faulty injector. You would have never have been able to tell this purely from the error codes. If your car has a faulty injector then obviously there will be lumpiness, a lack of power and acceleration and poor mpg. However, this can be an expensive process. Do your error codes point to a misfire on a certain cylinder? If it’s multiple cylinders it could be the coil pack, but you can get diagnostics done to see if you have weak spark.
 
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Thanks Valinor. I'm going to start with the simple stuff first. I will inspect the plugs and make sure the right ones were fitted as the TBI can only take a particular NGK Iridium plug. Then inspect the coils. If all looks well I will look into the injectors, the car is luckily still under warranty but the trouble is it's a 3 hour drive from me!
 
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Had a look yesterday and I came stuck with the spark plugs, I have 2 spark plug sockets and neither of them fit into the wells. Is there a special socket to remove the spark plugs from the TBI?

The coils looked fine, no splits etc. I had noticed that whoever had topped up the oil had spilt some over the cam cover where is was pooling and I think a bit went down the well but nothing that would cause any issues.
 

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Assuming your cambelt was replaced by someone who knew what they were doing and used the right locks etc I would recommend this highly for the TBi (from experience) next: Autolusso - Injector Cleaning

Mine didn't have your misfire problem during my tenure but the TBi has known injector issues that could cause exactly the problems you're experiencing.
 

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Oil in the spark plug wells is also a common issue. This comes from a dried out head gasket joint. If I remember correctly, I used a 14 mm wrench for the spark plugs.
 

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Assuming your cambelt was replaced by someone who knew what they were doing and used the right locks etc I would recommend this highly for the TBi (from experience) next: Autolusso - Injector Cleaning

Mine didn't have your misfire problem during my tenure but the TBi has known injector issues that could cause exactly the problems you're experiencing.
You got there before me, injectors need to be checked on our machine and take it from there, ultrasonically cleaning them makes a big difference

Ned
 
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I will be picking up the correct spark plug socket this week so will be able to look at the state of the plugs then. If they all seem well it looks like I might have to get the injectors looked at :(
 
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Spark plugs inspected, they all looked fine however they were not torqued up much at all (barely finger tight) I assembled it all back and it was like driving a different car! No hesitation, no surging and no misfires. But unfortunately that didn't last long...

The following morning after starting and pulling away the car started surging (like a rhythmic pulsing on the throttle) whilst accelerating up to 20mph. After about a mile of driving it was all fine again. It misfired once after with half throttle on 4th gear from about 1500rpm.

This is really starting to get on my nerves now! I have MES and no faults have appeared. Can someone please guide me into what I need to be monitoring to find out what the fault is?

Thanks
 

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Spark plugs inspected, they all looked fine however they were not torqued up much at all (barely finger tight) I assembled it all back and it was like driving a different car! No hesitation, no surging and no misfires. But unfortunately that didn't last long...

The following morning after starting and pulling away the car started surging (like a rhythmic pulsing on the throttle) whilst accelerating up to 20mph. After about a mile of driving it was all fine again. It misfired once after with half throttle on 4th gear from about 1500rpm.

This is really starting to get on my nerves now! I have MES and no faults have appeared. Can someone please guide me into what I need to be monitoring to find out what the fault is?

Thanks
I feel like MES would be of no use for further diagnosis. IMHO you should try to find a professional with a "pico" scope and plug into coils and see what is happening with the ignition and ECU signal sending to the coils. Would not hurt to get a gauge and check fuel pressure but this seems like an ignition issue. Maybe a coil going bad and maybe I am wrong.
 
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I feel like MES would be of no use for further diagnosis. IMHO you should try to find a professional with a "pico" scope and plug into coils and see what is happening with the ignition and ECU signal sending to the coils. Would not hurt to get a gauge and check fuel pressure but this seems like an ignition issue. Maybe a coil going bad and maybe I am wrong.
Thanks, to be honest by the time I spend money getting a garage to diagnose the problem I may as well buy a set of coils anyway (especially if they find the coils are at fault). I'm leaning towards either coils or the MAF sensor.

I'm slightly disappointed that MES doesn't even have a misfire counter. I use to use VCDS on my Golf and that gave far more information and readings.
 

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Thanks, to be honest by the time I spend money getting a garage to diagnose the problem I may as well buy a set of coils anyway (especially if they find the coils are at fault). I'm leaning towards either coils or the MAF sensor.

I'm slightly disappointed that MES doesn't even have a misfire counter. I use to use VCDS on my Golf and that gave far more information and readings.
True that. MES is not a very versatile tool yup...unfortunately.

You should be able to check the MAF with MES though.
 
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True that. MES is not a very versatile tool yup...unfortunately.

You should be able to check the MAF with MES though.
Thanks Frosty, would that be the "Air quantity" parameter?

Since my last update I have put some injector cleaner into the tank and I don't know if it's just a placebo but the surging/misfire doesn't seem as bad... Really hoping it's not the injectors!
 

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Thanks Frosty, would that be the "Air quantity" parameter?

Since my last update I have put some injector cleaner into the tank and I don't know if it's just a placebo but the surging/misfire doesn't seem as bad... Really hoping it's not the injectors!
We can test and recondition your fuel injectors so you won't need new

Fuel injector issues are common on this engine

Autolusso - Injector Cleaning

Ned
 
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We can test and recondition your fuel injectors so you won't need new

Fuel injector issues are common on this engine

Autolusso - Injector Cleaning

Ned
Thanks, the car is still under warranty but with garage being a 3 hour drive away I'm trying to pinpoint exactly what's wrong with it before taking it there. Annoyingly as it misfires/surges worse when cold it would probably have to be left with them.
 

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Thanks, the car is still under warranty but with garage being a 3 hour drive away I'm trying to pinpoint exactly what's wrong with it before taking it there. Annoyingly as it misfires/surges worse when cold it would probably have to be left with them.
There are options here, we can do work on warranty and we can test and recondition the injectors if you send them to us

If it is that annoying this is quite simple to deal with

Ned
 
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