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Eggy smell, lack of power, running hot .....

6K views 9 replies 7 participants last post by  novaguy08 
#1 ·
Oh dear - maybe time for a new Catalytic converter on my new Astra :(

Had a look at the last MOT and the emissions were a bit high as well.

When I'd been giving the car a bit of welly, I'd get the dreaded eggy smell. Car ran fine when cool but when warmed up was a bit lumpy and lacked power.

Did an oil and filter change and also put new plugs and leads on it and wow what a difference. The old plugs looked in reasonable condition but obviously it wasn't burning the fuel properly.

So if your car has an eggy smell and isn't going quite as it should, try an engine service first and see if it helps before forking out on a new cat.

Now I've got a car that feels like it should power wise, no eggy smell and all for the sake of £25 :D
 
#2 ·
I would be a little bit cautious on doing this, you may just be curing the symptoms and not the problem itself. If the cat was blocked/broken up then obviously this is going to cause lambda readings etc. to be affected, which would affect fuelling specifically, which i'm sure you quite well know, can knacker the plugs if too much fuel is injected, causing the poor running, and eventually leads to the same result later down the line.

You may well be right and have cured the problem by changing the plugs etc. but you said it was running hot, something a knackered cat can cause, and not so much spark plugs/leads.

Don't get me wrong, not trying to sound a dick, just a little idea/help, thats all.
 
#3 ·
Worth keeping an eye on :beer:

Not had the car that long and I'm just sorting out all the niggles the previous owner has left me with before doing any real work on the car.
 
#7 ·
I've always been told that an eggy smell from the cat is normally due to the following (in order of occurance)

Over fuelling
Excess sulphur in the fuel
Worn out cat
 
#9 ·
I knew I posted something similar around 6 years ago lmao

Heres a bit of a thread from an auto advice place over in the states :

Q. I have a 1994 Plymouth Sundance/Duster with the 2.5 liter engine and an automatic transmission. It now has 13,000 miles on it but at 8000 miles I noticed a rotten egg odor coming from under the car. I bought the car new from a Plymouth dealer so I took it back to his service department. The mechanics there checked it out and found that the source of the odor was the catalytic converter. They told me that the engine was burning very clean and changing the converter would not help. Is this true? I've tried different brands of gasoline, too.
H.S. Gloversville, NY


A. The problem isn't in the converter - it's doing its job too well. It's being overheated by an over-rich fuel mixture (too much gasoline and not enough air) and is causing the sulfur in the gasoline to break into hydrogen sulfide (H2S). This is the odor you're smelling. The fuel/air mixture in most of today's engines is computer-controlled so the problem may well be an electronic malfunction. On older engines, the problem was very often traced to one of several malfunctions (localized vacuum leak, faulty spark plug wires, etc.) that let unburned fuel pass into the converter. The emission control system on your Plymouth is covered under a federally mandated warranty so have your dealer call in the factory rep if his mechanics can't cure the problem since there may be a recall. A high sulfur content in the gas your using could be a possible cause, also.
 
#10 ·
hmmmmmm, i have also noticed an odd eggy smell coming from my car, i have been thinking that it was the clutch (why im not sure!) its not constant, only after some quite long trips! its been known to waft in through the vents and be gone just as quick............ i have not long changed the leads and plugs and i checked the plugs a while ago and they showed that its running perfectly normal (the normal sandy coloured deposits) WHATS GOING ON WITH IT!?!?
 
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