Recent owner of a 2000 C70 - First hiccup

graysonboycie · Post by **graysonboycie** » 21 Oct 2016, 05:01

Recently purchased a 2000 C70, had only 78k on it, and had a new top and liner installed! While it does take awhile to learn and listen, a few quirks and noises are expected, and have been identified for the most part, but our first engine hiccup.

Yesterday, started to get rough idle when accelerating, not so much when in park. We were in traffic when we first noticed it. Would drive OK but still sluggish. Tried it again this morning. Same thing. Yesterday we had the dreaded smell from the catalytic converter once we got home. Today it just seemed rich but only let it run for a minute or so. Hoping maybe just an O2 sensor? One thing to note is that there was not a check engine light, or anything else, on at the time.

Any thoughts? Going to take it to a mechanic that used to work on our v40 to see if he is willing to take on a new patient. Their main business is healing sick Range and Land Rovers.

harryhendo · Post by **harryhendo** » 21 Oct 2016, 06:16

A bad O2 sensor will throw a check engine light code, so that should be ruled out for now.
I would check the cleanliness of the throttle body, and clean it out thoroughly.
Also, at that age, the grounds become corroded, so I would check the two grounds on the front lower part of the engine, to each side of the oil dipstick, as well as the ground behind the left headlight.

Post by **precopster** » 21 Oct 2016, 06:55

Does the check engine light have a globe in it? Does it light up when ignition is in position II?

beigg · Post by **beigg** » 21 Oct 2016, 07:11

It may take a few drive cycles to awake the codes that might trigger related faults or indirectly related fault(s) to troubleshoot.

A sluggish o2 sensor or clogging catalyst could be at the beginning stages of degradation. Monitoring the mV output data and if capable EGT and exhaust back pressure readouts could help track down where to suspect the fault inlays.

Post by **abscate** » 21 Oct 2016, 08:43

You are way, way away from checking O2 sensors and cat.

Spark plugs
coils - possible misfire
compression test
Vacuum leaks

are all much more likely.

Pulling plugs and looking for a problem cylinder and ruling out top end engine work is the next logical step.

graysonboycie · Post by **graysonboycie** » 21 Oct 2016, 09:52

Thanks for all of the suggestions and direction! I will look into the ones that I can narrow down, and pass along the info to my mechanic. As I mentioned in my original post, we certainly smelled a strong sulfur smell yesterday when we got the car home, oddly it seemed stronger on the passenger side of the car. Would bad plugs cause this, too?

beigg · Post by **beigg** » 21 Oct 2016, 15:02

A lazy injector or limp fpr (vacuum line or diaphragm itself) could cause the fueling issue. Does it stumble upon start up and or during a wot?

graysonboycie · Post by **graysonboycie** » 26 Oct 2016, 12:44

Thanks again for all the suggestions! Dropped her at the mechanic and it pulled a bunch of codes, long story short replaced plugs, coils and throttle body thoroughly cleaned. Found a code for the fan that indicated it doesn't run at low speed but I know it runs at high speed. 6110 was the code I believe so will look into that. Back to normal plus some obvious improvements in performance! The roof is down!