200 hpdi cold starts rough idling

I have a pair of 01's 200 hpdi's. Last fall one motor began idling rough at idle just on the cold starts. Once warm she fires right up. Now this spring they both are fluctuating between 400-600 rpm, and occasionally stalling. I drop them in gear when cold and they are fine (still tied up to the dock). I have had fuel issues two years ago, and changed all three of my filters, thermostats,water pumps,plugs,ect... this year before dropping her in. once warm she runs great, and restarts great (even after sitting for 2-3 hrs while fishing). My thoughts are the o2 sensors may have something to due with this problem as they have never been touched. I hear about surging issues with o2 sensors. I have no other issues other then rough idle upon start up after a few days of sitting. I currently have 640 hours on the motors. Any help would be greatly appreciated. Thanks <br /><br />P.S Rodbolt you should get paid for all the great advice you put out.

Re: 200 hpdi cold starts rough idling

ya outta be stoned for lack of maint , odds are the O2 sensors are trash. my experience is once they get that dirty they are done, <br /> the three fuel filters on the motor should be changed yearly anyway.<br /> a fouled plug will do this too, the motor at idle in neutral sparks on 4 cylinders and six in gear. could also be a bad intake air temp or cooling temp sensor.<br /> a quick check with the diagnostic lamp or laptop will show it.

Re: 200 hpdi cold starts rough idling

Thanks, I do love rocks, Thanks for the reply.<br />I think i should probbably get these motors hooked up to the computer. I have a feeling it is the o2 sensors but who knows. I found out the hardway about maintenance to these motors, I still think they are the best motors for the dollar except ethanol screwed that up. Great hp/fuel consumption, I get 2.4/2.7 miles to gallon<br />at cruise. Pretty Awesome Thanks Agaien RodBolt

Re: 200 hpdi cold starts rough idling

you will find the laptop rarely diagnoses the problem, however it quickly eliminates a lot of potential issues.<br /> if it tells you nothing is broke you know what not to chase.

Re: 200 hpdi cold starts rough idling

Do you think cleaning the o2 sensors should be done first. That might clear up my problem with-out having to get a tech guy and a appointment. I did purchase the extended warranty, but im a little unclear about what it will cover. Are the 02 sensors like plugs, once they get fouled they are easily re-fouled?? Then maybe new would be the answer. When you purchase o2 sensors do the come with new tubes, or is that extra. Thanks again!!!

Re: 200 hpdi cold starts rough idling

the o2 sensors should have been serviced at every 100 hour/yearly service since 2001. if they are hooped they would be covered by warranty. the draw tube is a separate part. they get fouled as a normal cicumstance with running the engine thats why they must be serviced at least yearly.