Hi,

 

I recently got my first VW era skoda and its been a nightmare....

 

Currently popping fault codes rather frequently - P0106 a lot and recently P0170...

 

I have replaced the MAP sensor but no difference. Given the EPC light is also coming on sometimes I am thinking I must have a manifold leak - is taking the inlet manifold off hard to do - is there a guide somewhere?

 

Anyone got and thoughts or advice?

 

Cheers

 

Frogz

po170? that's short term fuel trim isn't it?

 

a manifold vacuum leak is a possibilty yes, but normally this would give a corresponding increase in idle speed too... it's worth checking the earth ring terminal on the back of the cylinder head for corrosion and seciruty before going to the effort of removing the intake manifold, random faults like that are far more likely to be electrical related

Is the first code this:

 

http://wiki.ross-tech.com/wiki/index.php/16490/P0106/000262

 

And does the second relate to running over-lean or over-rich?

 

Please list all fault codes as the complete code and we'll try to help.

^^whs

 

the fault code itself doesnt help you much without the full definition, it could be short to ground, open circuit, implausible, out of range etc etc

Hi,

thanks for the thoughts - I will look at the earth.

fault codes are:

p0106 - manifold absolute pressure / barometric pressure circuit range / performance problem

and

P0170 - fuel trim bank 1. - trim level is high presumably trying to compensate for an over lean condition.

What do people think?

regards

Frogz

Edited 21 December, 201312 yr by Frogz

Removal of the manifold is not particularly complex, some of the fastenings are tricky to get at, the two that hold the EGR pipe to the manifold are a nuisance since you have to work by feel alone, you can leave the throttle body attached to the wiring loom so you don't have to re-adapt it, just remove it and swing it out of the way still plugged in.

 

While you have the manifold off check all the vacuum hose connections which run under and behind it, particularly the big one to the brake servo and don't forget the EVAP valve pipework, it's also a good opportunity to clean out that EGR pipe and the EGR valve itself and give the manifold itself a really thorough internal clean.

Haynes manual will also give you torque settings etc...............I hope you've got a copy!

 

As for those fault codes could also be carp on the lambda sensors (there are two of them), what fuel do you use & when was the fuel filter last replaced???

Hi,

 

I have not replaced the fuel filter and do not know when it was last done - I think I have one so will replace that. I am using 98 ron (v-power) fuel.

 

I'll have a crack at the manifold - looks like 6 allen bolts hold it on...

 

Thanks everyone - I let you all know if I sort it.

 

regards

 

Frogz

Edited 22 December, 201312 yr by Frogz

A few months back I bought a 1.4 16V to fix up and these are the things I would suggest.

 

It had air leaks in the following places:

 

Throttle Body to Inlet manifold (the AUB engine does not have a gasket there, but the BBZ version should)

Inlet Manifold to Brake Servo Vacuum Line (Plastic pipe had perished, allowing for air leaks)

EGR Pipe to Inlet Manifold plate (This should have a metal gasket, but was omitted, as the EGR system is often removed and cleaned to fix Carbon build up as a result of prolonged 95 octane use)

EGR Valve to EGR Pipe (at the front of the engine bay, two bolts which need to be torques equally and appropriately, again with a metal gasket)

EGR Valve to Exhaust manifold (another gasket here, but any leak will be due to inappropriate torque-ing of the two EGR bolts)

 

So id check out a few more first before diving right in and pulling the Inlet manifold off.

 

I would also suggest starting the car, With the MAP sensor plugged in lightly rev the car just a few blips of the throttle up to id say no more than 3k revs.

 

Then with the engine still running, unplug the sensor. With it unplugged, attempt to rev the car in the same way as before, 

 

Does it rev in the same way? or seem to have no power and not want to rev?

Does it stutter?

Does it even idle or Stall?

or is it the Same as before?

 

If it is the same as before, it would be worth attempting to prove the wiring loom is ok. I don't know how you are reading the fault codes, but my generic Reader has a "Real time measurements" section. Go into the equivalent and look for IAT (Intake Air Tempreture) they are part of the same sensor, and if there was a Wiring issue then it could effect both sensors. Alternatively if you have VCDS just go into measuring blocks 003 and look at the 2nd value, it should be in the range of 240 - 420 mbar.

 

May i also ask, where did you get the replacement MAP sensor from?

 

I hope I have helped

Hi,

Thanks for the advice.

 

Not yet taken manifold off and symptoms still there having changed fuel filter and done a tba. I have checked the throttle body gasket and the erg pipe connections.

 

What I have noticed is that the engine management light cmes on just as the engine gets up to temperature - i.e. seems to be related to a component getting warm - it took longer this morning being very cold than yesterday afternoon when it was relatively warm.

 

cheers,

Frog

Possible issues with the crank position sensor or the cam position sensor, these are both Hall effect triggers and are known for breaking down when hot. Have you read the codes when you get the CEL?

One thing to bear in mind is, the information from the lambda probes is ignored until the engine (and they) have warmed up and so can be believed and their output (S1) used to regulate fuelling levels, all these bits of information are combined to make up the final injection "squirt" period - and that will affect the fuel trim adjustment - maybe not relevant in this case, but worth considering while chasing a needle in a haystack!

One thing to bear in mind is, the information from the lambda probes is ignored until the engine (and they) have warmed up and so can be believed and their output (S1) used to regulate fuelling levels, all these bits of information are combined to make up the final injection "squirt" period - and that will affect the fuel trim adjustment - maybe not relevant in this case, but worth considering while chasing a needle in a haystack!

 

That's a very good point, especially if the car is using a little oil and doing lots of short trips the wideband Lambda probe can soot up yet not give readings outside the normal range and therefore not get flagged by the ECU.

To check fueling get an obd2 reader and look at your short term and long term fueling, it typically has a range of +25 and - 25. High either way may give you an indication however - 10 or 10+ is fine, this is a running total but take it after say a 20mm drive ltft is a running average of the stft which constantly fluctuates they are to trying reach a target afr reading in partial throttle.

As above when coolant is say greater than 70c the o2 sensor is then used under 70c it is ignored and this could also be your problem.

If it doesn't idle too well then it's probably the O2 sensor.

Lastly log the map sensor it's typical range is 0-5v or - 20psi to say 5psi but it won't ever go past 0.2 psi typically. 5psi is just what it happens to go up to.

A dodgy map sensor, coolant sensor, exhaust on exhaust or manifold leak (though would have to be bad to moderate), o2 sensor, vacuum leak, I don't think clearances would be an issue. I have seen one way valves incorrectly fitting if it has air vacuum box this is used If it has a pump to heat up the cat, also sometimes the cat emissions warm up pumps fail.

Does it has an idle control valve as such?

Tbh I'd be surprised if it had a wideband sensor probably narrow.

Of course it's wideband Lambda, all Euro IV cars have wideband, narrowband is for the second post-cat sensor.

It also has no idle control valve, just a stepper motor throttle body which handles everything.

MAP reading is from 0-100 kpa. Jeez ajs, I'm old but IMPERIAL on a Czech car with a German engine and Italian engine management?

Didn't know it was euro iv, most cars I worked on have narrow band on both o2 sensors. I'm sure all s2000 for example are euro iv compliant yet 2005 onwards only have wideband.

I worked/designed on the machine to automate/manufacturer of the new Cummins euro 6 engines thstywill be appear in trucks soon, it'd just a lot of filters and probes bit of a joke.

Haha I know get my units mixed some times, but I always switch to psi from kpa in tables when tuning cars.

Thanks for the thoughts above. I have narrowed down the symptoms. It appears to be consistent as follows:

• Drive the car from cold
• just as the engine temp gets up to normal (needle bang in the middle of the gauge) there is a very brief stumble and the engine light comes on as does the epc light.
• Car continues to drive fine
• I can cancel the engine light whilst still driving (using Bluetooth obd and 'Torque' - really nice android app) and it does not come back on. The EPC light goes if I turn the engine off (whilst still rolling ) and restart it.
• It is then fine to the end of the journey
• The fault code is p0106 - absolute manifold pressure problem
• Idling is not totally smooth - feels like occasional misfire but its not bad.  

I have cleaned the throttle body (did not disconnect it) and the egr valve and pipe. I have replaced the fuel filter, oil and air filters and plugs..

This is driving me nuts!  I originally thought it was a MAP sensor issue - have now changed twice and have a good OE unit in now  and same problem with all three sensors. I then thought of a manifold leak somewhere but if this was the case I would have thought the lights would come on pretty much straight after cancelling them. If it where the lambda / O2 sensor again I would have thought the problem would persist.

Is there some sort of transient power drop as the car gets up to a particular temp; does the egr valve suddenly open causing a transient pressure change in the manifold?? As you can see I am clutching at straws.

 

Anyone any thoughts?

 

Cheers

 

Frogz

Edited 30 December, 201312 yr by Frogz

Thanks for the thoughts above. I have narrowed down the symptoms. It appears to be consistent as follows:

• Drive the car from cold
• just as the engine temp gets up to normal (needle bang in the middle of the gauge) there is a very brief stumble and the engine light comes on as does the epc light.
• Car continues to drive fine
• I can cancel the engine light whilst still driving (using Bluetooth obd and 'Torque' - really nice android app) and it does not come back on. The EPC light goes if I turn the engine off (whilst still rolling ) and restart it.
• It is then fine to the end of the journey
• The fault code is p0106 - absolute manifold pressure problem
• Idling is not totally smooth - feels like occasional misfire but its not bad.  

I have cleaned the throttle body (did not disconnect it) and the egr valve and pipe. I have replaced the fuel filter, oil and air filters and plugs..

This is driving me nuts!  I originally thought it was a MAP sensor issue - have now changed twice and have a good OE unit in now  and same problem with all three sensors. I then thought of a manifold leak somewhere but if this was the case I would have thought the lights would come on pretty much straight after cancelling them. If it where the lambda / O2 sensor again I would have thought the problem would persist.

Is there some sort of transient power drop as the car gets up to a particular temp; does the egr valve suddenly open causing a transient pressure change in the manifold?? As you can see I am clutching at straws.

 

Anyone any thoughts?

 

Cheers

 

Frogz

 

It sounds like this is happening when the engine makes the transition from closed loop to open loop, which indicates an air leak, have you checked the brake servo vacuum pipe, these commonly split and allow air into the manifold causing the MAP sensor to complain that there is too much air in the manifold when the throttle is shut.

I would also suggest double checking the EGR flange at the Inlet manifold. this is what the part looks like

 

 

It bolts on underneath the throttle body, but above the gearbox. All it takes is for it not to be torqued down appropriately and will distort at temperature and will allow for an air leak.

 

If I recall correctly, the EGR system does not come into operation until the engine is up to temperature too. So if you have a an air leak on the exhaust side of the EGR valve, when the EGR valve opens it may also allow for extra unmetered air.

 

This is the part of the EGR pipe which connects to the EGR Valve (it is Inlet side)

 

 

I would strongly suggest you check the places which I suggested in the earlier post, as well as the Brake Servo vacuum Lines like Sepulchrave said.

 

 

These engines tend to have alot of EGR issues, and people sometimes strip parts off to clean carbon out, but may not refit it properly (not saying you did but someone may have), causing further breathing issues for the car. I feel it is more likely that someone has done this instead of having a poorly torqued down the inlet manifold.

 

 

Only other thing is if there was a Wiring Loom issue with the MAP sensor, again that would not be detected until it was at temperature and went into closed loop operation.

have you checked the charcoal canister purge valve and all it's hoses... the open/closed loop thing doesn't make a lot of difference to the running or vacuum in the engine, the fuelling will be running closed loop within 30 seconds of starting when at idle irrespective of coolant temperature.

Thanks for the new suggestions and I will check these (but not sure where the charcoal canister is!).

 

What I do not get is that all of these things would persist while the engine is up to temp - why wouldn't the light come straight back on if there is a leak at the EGR  pipe or a wiring fault - but once it has come on and then been cancelled it stays off. Or am I missing something here about how it works?

 

Cheers again

 

Frogz

have you checked the charcoal canister purge valve and all it's hoses... the open/closed loop thing doesn't make a lot of difference to the running or vacuum in the engine, the fuelling will be running closed loop within 30 seconds of starting when at idle irrespective of coolant temperature.

 

Mine doesn't go onto closed loop for quite a while, you can see exactly when it happens from the average mpg in the trip meter, it's very noticeable.

yes that is right, there is a warmup enrichment phase the engine goes through gradually decreasing as the engine coolant temperature rises. but the actual mixture propogation is still closed loop under the control of the oxygen probes.. in response to another poster on here the map sensor doesn't magically switch on when the engine is upto temp, the ecu constantly uses it as the main source to determine engine load, it also acts as a barometric pressure sensor BEFORE the engine is started..

 

there is obviously something very subtle going on here with the op's car, it's more than likely an electrical fault rather than mechanical, possibly a loose or corroded connection somewhere... but without the full fault code definition it's anybodys guess

 

edit: just remembered, you can see the full closed loop status in a binary readout in vcds, it's channel 1 in measureing blocks, i think it's the 2nd to last digit on the right, 1 for closed, 0 for open loop

silly question but is there a flexi joint in the exhaust between the 2 probes?

i had this years ago on a mk3 golf similar issues and found leaky flexy and worn manifold to downpipe o ring seal

silly question but is there a flexi joint in the exhaust between the 2 probes?

i had this years ago on a mk3 golf similar issues and found leaky flexy and worn manifold to downpipe o ring seal

 

To answer your question yes

 

 

Photo taken of my Old Fabia 1.4 16V AUB