Rotten egg smell on fast acceleration

[areznik]

I smell rotten egg smell whenever I hit the pedal to the metal and push the car to 80-100 mph. There is also a ruttling noise from the buttom on idle. It feels like the cat converter is dying. I had an injector problem before that oversprayed fuel and burned a little bit one of my cats. Local shop checked the emission and said that its withing the standards. I was wondering if I can put a universal one because the cheapest OEM is ~$600 and the universal is about $150. I heard that people put custom exhaust, but I don't have any idea how they do it (what fits for my Q and what not).

Any reply would be greatly appreciated,Andre.

[DAEDALUS]

The OEM one will be better probably. "Within standards" could me a lot of things...a good Q should pass even CA smog with flying colors. The rattling is probably a heat shield. A leaking injector may also have caused more wear on that cylinder.

[areznik]

I drove it when the problem started maybe for about 20-25 minutes to get to the local dealership until they fixed it. This was a really toughie injector problem and I would like to share it if someone is experiencing the same thing. After I replaced all 8 injectors, one month later my Q started vibrating occasionally. Whenever I took it to the shop it was driving fine. They ran power balance and other things which pointed out that the car was fine. Once when the problem occured and I could show them it, they ran the power balance on it while it was vibrating, and the results showed random cylinder misfire. They suggested to replace distributer - didn't help. Then both power transistors - didn't help. Then these guys checked ignition coils - but these were fine. I also had new spark plugs and new fuel pump. They said that if injector fails it will fail all the time, and because misfiring was random they took this assumption out. Eventually, when I took it to another local shop where they were not equipped with the consult tool, they manually disconnected each injector and found that one of them was faulty. What a luck, I put 8 new ones and one of them was defective. These guys also said that power balance isn't always a good test because ECU will automatically adjust the rpms to keep the engine from dying. Anyways, this was a very enoying month and I would recommend to try the same approach if vibration exists and power balance shows random misfire.

As with the cat, I will try to look for a cheaper OEM than $600, but probably replace mine only if it becomes much worse.

[DAEDALUS]

Intermittent failures are indeed rare, unless there's a bad harness connection. The dealership's tool will prevent the ECU from compensating for RPM drop during the PBT. Have you called one of our sponsors for a quote? I know they beat my local dealer silly on prices. I will never buy something locally unless I absolutely can't wait for it.

I had a leaky injector once that I drove for maybe 50 miles at most. That cylinder is lower than the others on a compression test by maybe 10-15 psi.

[Q45tech]

There are many ways to perform a Consult based power balance BESIDES the normal proceedure.

I like to do two or three different ones: Loaded in drive, AC on max, all lights, blowers on [Foot on brake]......obviously with this one the rpms [deviations] are lower.

Never pay attention to the Consult " OK " as this just signifies that the cylinder is adding some rpm no matter how little or that there is no negative rpm [a gain when the cylinder is shut off from not wasting power compressing the gasoline.

[maxnix]

As with the cat, I will try to look for a cheaper OEM than $600, but probably replace mine only if it becomes much worse.

I would suggest you read the previous posts on this topic, expecially by Q45tech. Non OEM catalytic convertors are rather like non OEM alternators; their standards are not sufficient for a long life of service. With all you have done to return your car to OEM original performance, why compromise now?

[AZhitman]

If you DO decide to go with an aftermarket cat, I have them for $100 +shipping (not the ebay junk).