1.6 FSI bad running and catalytic converter glowing red

shaun5

Member
Ive got a 1.6 FSI which isn't running correctly. I bought it with a misfire / bad running thinking i could get it running right and save it from the scrap heap.

First thing i found was a split EGR pipe, i fitted blanking plates as i didn't have any brazing rods to weld it up. The car ran much better but still at low revs it misfired and spluttered.

The fault codes i had were 16788 EGR system range / performance P0404
17439 Intake manifold tuning valve (N316) set point not reached P1031

Looking at the inlet manifold / fuel rail i could see the plastic arm had snapped so i knew i was going to have to remove it!!!

Ive changed the sparkplugs / serviced the car (fuel and air filter) still no different.

I removed the inlet manifold and injectors, gave it all a good clean. I watched a You Tube video showing how to clean the injectors so cleaned them and it appeared to work, they showed a good spray pattern. I repaired the arm and refitted everything.

I started the car and it was still the same from low revs. I held the revs at 3-4k for about 30 seconds to see if it cleared, i went to look under the bonnet and noticed the catalytic converter was glowing red hot. Now has anybody else experienced this?

Researching why it was glowing red hot appeared to point at to much fuel going into the exhaust because of misfires. A blocked catalytic converter was another possibility.

Ive had the engine running for a bit and its showing no fault codes!!!

Has anyone had this problem or got any ideas what wrong?
 
I'd have a look at the measuring block for exhaust gas temperature and see what that's reading - I've never noticed my catalyst glowing red? It would be interesting to see if this is because you've blanked the EGR - the FSI uses the EGR to reduce exhaust gas temp for purging Nox etc when running in stratified - that's my theory anyway!!
 
The egr on my missus car is blanked at the moment and does not glow red but her car is running fine with no misfires, only fault is biometric sensor which is in the inlet

Sent from my SM-G950F using Tapatalk
 
Good to know, I don't think your car will drop into stratified without the barometric / MAP sensor though.

The other quick check for the (blocked) Catalyst is putting your hand over the end of the exhaust - you should have a prominent flow from the exhaust (always good if you've another car to compare against)
 
Topsie;289367 the FSI uses the EGR to reduce exhaust gas temp for purging Nox etc when running in stratified - that's my theory anyway!![/QUOTE said:
You're on the right track but this is my theory -

Air is mostly made up of nitrogen (around 80%, and the rest oxygen) When combustion temps are high enough and in combination with the abundance of nitrogen, the dreaded oxides of nitrogen (N0x) are produced.
By diverting exhaust gas into the cylinders via the EGR valve, the flame is quenched and combustion temps lowered, resulting in less NOx

Cheers Spike
 
You're on the right track but this is my theory -

Air is mostly made up of nitrogen (around 80%, and the rest oxygen) When combustion temps are high enough and in combination with the abundance of nitrogen, the dreaded oxides of nitrogen (N0x) are produced.
By diverting exhaust gas into the cylinders via the EGR valve, the flame is quenched and combustion temps lowered, resulting in less NOx

That's how I understand it - I know in stratified mode EGT's rocket - which is expected when running a Lambda of ~3, in cycle the FSI introduces exhaust gas in homogenous mode for ~2 seconds to reduce EGT and purge the stored NOx. With no exhaust gas to recirculate it stands that EGT will remain high, at least until the upper limit (whatever that may be?) is reached and the engine returns to homogenous mode.

The real question is will this cause the Catalyst to reach high enough temperatures to cause it to glow...

You could disconnect the MAF sensor and see if the catalyst still glows? The engine will not drop into stratified mode without the MAF sensor.
 
Thanks for all the suggestions, i will try to do some of the things that have been suggested this weekend.
 
Hello, one question.

How many revolutions per minute does it have to have the 1.6 fsi with the engine at operating temperature?
Mine has 600 rpm, I think they are very few, right?

Greetings,
 
I've had a failed catalyst on my first MGF, ages ago.
The engine would not rev up, the exhaust was largely blocked.
I dismantled the catalyst and gave it a good shake, with each flange pointing down alternately. Broken pieces of matrix came out. After refitting, the engine revved up to 7000 rpm again. Even if the MIL light would not come on ("Euro 2" generation of engines with only one lambda probe, before the catalyst), I still bought a new catalyst after.
 
A quick update, not good news for me.

I disconnected the MAF and the cat still glowed and the engine ran rough.

I decided to buy 4 new injectors which i fitted tonight but the car still isn't right. Im starting to give up with it.

Im gunna put my works Snap on Solus on it to see if there are any fault codes (no engine light on and my basic fault reader doesn't show any)

Please someone help me. MOT is due in December and if it isn't fixed by then then it will be going to car heaven.
 
A quick update, not good news for me.

I disconnected the MAF and the cat still glowed and the engine ran rough.

I decided to buy 4 new injectors which i fitted tonight but the car still isn't right. Im starting to give up with it.

Im gunna put my works Snap on Solus on it to see if there are any fault codes (no engine light on and my basic fault reader doesn't show any)

Please someone help me. MOT is due in December and if it isn't fixed by then then it will be going to car heaven.

Could the Cat be blocked (It happens)?

Steve B
 
i disconnected it from the downpipe and ran the engine (very loud obviously) but it made no difference.
 
i disconnected it from the downpipe and ran the engine (very loud obviously) but it made no difference.

Sorry, just clutching at straws.

High exhaust temperatures are also caused by a lean mixture, is there something that could be causing a lean mixture, leak on the air intake side?

Just another straw to clutch at?

Steve B
 
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