Contour Enthusiasts Group Archives Forums General Troubleshooting Anybody Ever Replace a Cat Converter?

I've got a '99 Mystique, Duratec engine with 106,000 miles. The CEL has been on for a few weeks, although car has been running just fine. I had the dealer pull the codes yesterday, and he got a PO430, catalytic converter inefficiency. He quoted $1100 plus installation for a new converter.

Has anybody replaced a converter? I'd really hate to spend the money and have the CEL come back on a few weeks later. Yeah, I know other things could trip the CEL, too. Dealer said if I just ignored the CEL, I might see lower gas mileage plus the CEL light would be unable to warn me of new problems.

Any thoughts or advice about shelling out $1100 to replace the cat compared to just ignoring the CEL? I plan to keep the car as long as I can. Dealer tried calling NAPA to see if they carried converters, but they didn't.

I got thoughts...tell him for $1100 he better wine and dine you before he bends you over! Go to www.ctamotorsports.com and get a high flow cat for $100...local shop will install for maybe $50.

Or...check out the BAT Y with high-flow cat...$255

Make sure which cat he is talking about, since the O2's are after the precats and before the main cat he should be giving you an estimate for the manifold cat job.

With that many miles on the car, you could start cheap and try replacing just the downstream O2 sensors - if they are slow or reading low it may show up as a cat efficency problem, and if you can change your own oil you can get under the car to replace them in about 20-30 minutes. It's not even really shotgunning, it's just catching up on maintenance (modern heated O2 are good for around 100k miles or so) before shelling out big money for a repair.

If they've never been done, you may want to do the upstreams too. If you've been running richer than you should be due to old/tired sensors it could quickly overpower the cats. That being done, it's still entirely possible that your cats are toast, but if you do replace them it'll be less likely to kill them again with good O2's all around.

Originally posted by GeoPappas:

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Check here for your codes: http://www.contour.org/FAQ/FAQ.php?s=probs&display=checkengine

The following is from the Ford TSP (Technical Service Publication):

Diagnostic Trouble Codes (DTC) P0420 and P0421 indicate that bank 1 catalyst system efficiency is below the acceptable threshold.

Diagnostic Trouble Codes (DTC) P0430 and P0431 indicate that bank 2 catalyst system efficiency is below the acceptable threshold.

NOTE 1: Complete the spark timing check in «Quick Test» before proceeding with this test step. Spark timing retarded below specification may increase exhaust gas temperature and decrease catalyst efficiency over time.

NOTE 2: Be sure customer has not:

(1) Refueled vehicle with leaded gasoline.
(2) Experienced high vehicle oil consumption.

NOTE 3: If entering this Pinpoint Test for symptoms only, go immediately to «HF5».

NOTE 4: Internal deterioration of a catalytic converter is usually caused by abnormal engine operation upstream of the catalyst. Events that may produce higher than normal temperatures in the catalyst are particularly suspect. For example, misfiring can cause higher than normal catalyst operating temperatures.

Possible causes:

-- Use of leaded fuel.
-- Oil contamination.
-- Cylinder misfiring.
-- Damaged HO2S.
-- Damaged ECT sensor.
-- Downstream HO2S wires improperly connected.
-- Fuel pressure too high.
-- Damaged exhaust system pipe.
-- Damaged exhaust manifold.
-- Damaged muffler/tail-pipe assembly.
-- Damaged catalytic converter.

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Originally posted by Beachboy:

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Dealer said if I just ignored the CEL, ... the CEL light would be unable to warn me of new problems.

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Not completely true. Although you won't be able to tell how many codes you have (since the CEL comes on for 1 or more occurances), the computer in your car can hold multiple CEL codes. They stack up one behind the other. And anyone with a good CEL scanner can read them one at a time or all at once.

I'm not saying that you should skip fixing the problem. You should get it fixed at your earliest convenience, but just want you to understand that any other codes that are thrown WILL be stored.

I had a cat problem which I took to the dealer. Since I had 50,000 miles on the car, he told me it was covered under warranty. Good thing. They had to replace both pre-cats and the main cat. while doing this, the studs on the Y pipe broke, so they had to replace this as well-at their cost. Moral of story-with an exhaust system as old as yours, expect a lot more than just replacing the cat, and go to a good reputable shop.

I just replaced the Downstream O2 sensor and its been OK for 1 WEEK