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obedb

3126 Hard Smoky Starting

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7 days into our planned 2 1/2 month trip Cat 330 starts hard and really smokes for a minute after about three days in a park. The smoke seems almost brown. My series 60 would smoke a very short time on the coldest of mornings, but otherwise never. Cat runs fine after a warmup. Power seems normal.

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Smoke on start up with the 3126 could be an intake manifold heater that is not working. Pretty easy to check the heater for power when ignition is turned on and check it for resistance to make sure it is not an open circuit.

It could also be improper fuel pressure causing it to run on less than all cylinders. If you have a manual primer pump, pump it. If immediately hard to pump, this is not your problem. If it pumps up and then starts easier, fuel pressure may be bleeding off while parked. The "usual suspect" is the check valve at the back of the head (front of coach) that connects to the fuel return line. Not expensive or difficult to replace.

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3126 330hp in a Phaeton 40 ft. No primer pump and only 1 fuel filter. Changed just before the start of our trip that now has not quite 1900 miles on it. The symptoms started last Monday morning after three days in a park. If I exercise it daily everything seems normal. You are right about the engine model as usual.

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I guess the manifold heater is not working. Found the plugin for the block heater under the bed. What a great place!! This AM there was no wait to start light and the engine fired within a few seconds. Still runs a little rough at low idle but there are a lot of sensors in the system. Perhaps one is at fault. Will get that checked soon.

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Brett,

Could ObedB have bad valve stem seal that might allow oil to slip past and accumalate in the cylinders? I will cause smoke intil the oil is burnt off. This was a problem in gas engines in the past.

Herman

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Herman,

I guess it could be, but never heard of valve guide problem on either a Caterpillar or Cummins engine with the kind of miles/usage we put them to. And, were this the issue, the smoke would be blue.

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I had to trash a large piece of carpet to get to the access panel. I now have a 40" x 24" opening with a generous view of the top of the engine. The carpet was even glued to the doghouse and the cover. What a mess, but that will be a cosmetic project for the future. With block heater use the engine starts very easily and no smoke. The manifold electric heater is clearly not working. Couldn't trouble shoot the relay because the engine is warm enough to keep the ECM from sending a wait to start signal to the dash and (my guess) not closing the relay. I removed the short cable from the heater positive terminal and very carefully wrapped with moisture sealing electrical tape and zip tied the end. Now I can use starting fluid if shore power is not available.

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Sorry your coach maker made it so hard to access the engine. But, the access will allow you to clean the CAC and perform other "top of engine" jobs. Because it doesn't sound like the top of the engine has ever been accessed, it is not likely that the initial valve adjustment has been done. Recommended for around 30,000 miles.

I have to ask-- why not fix it instead of having to hope ether will start it without damaging the engine???

Even if the engine temperature is too hot to call for the intake manifold heater to be on, you can verify that you do have 12 VDC to the large wire/lug from the battery to the relay. There is likely a breaker or fuse on that line that you may want to check. Then when the engine is cold, you can check the rest.

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DW already questioning our decision to buy this coach. We don't boondock with this thing so the block heater will always have the engine ready to go. I will repair the manifold heater when we get home. Doesn't look too challenging and I can use the repair shop that I used for the heavy work on my Star Car to give me a fair price on parts.

As far as ether goes/ used a lot of it in my early years of trucking (1965 was my start ). Back then ether and bitter mornings went together. Two people are best. One on the key and the other experienced person spraying ether into the air cleaner. Thanks for your advice!!

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Engine still starts quickly with no smoke using the block heater, and "knock on wood" the rough idle has stopped. I have been using Power Service since starting the long trip we are on, but two fuel stops ago I started using Lucas Injector Cleaner at 150% the minimum level. Sure hopes this keeps up. I am gonna buy it by the gallon and use the leftover quart bottles to measure Power Service and Lucas dosage. Anyone else have any experience wit the Lucas product?

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ObedB.

I have used a number of Lucas products over the years. Use there injector cleaner in every second fill up of the Coach and every 6 months in the cars and truck.

Use there gear oil in all the differentials and the wet bearings on the coach when a change out is needed.

The last trip to the west coast this summer I used Stanadyne Diesel fuel additive(Lubricity Formula). Just to see if I there was any difference in overall performance. There was nothing that stud out !

I think that using additives for the diesel fuel is not needed on every fill up when using a brand name fuel, refineries and there blends do need to meet a specific blending standard as far as I know to meet EPA requirements.

That still leaves you with different blends, Ultra Low Sulfur, B5 to B20 and the door open regarding lubricity and jelling points.

Rich.

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Our Cat idled rough enough to be almost embarrassing. I waited a short while and then set it at a grand to make it sound better. When I started it in Durango on Thursday morning I noticed immediately that the tach was not doing a dance. I will keep adding Lucas for a while and always add Power Service because research tells me it is worth it. Huffy Puf got me interested in it. The product has been around since the 50's I think. Where additives are displayed Power Service is always prominent. It adds 7 cents a gallon to cost.

Heading over Wolf Creek on Monday. Looking forward to a better running engine. Knock on Wood. Went over and back from Pagosa Springs today in our toad. What a beautiful ride. Stress free in a Subaru Forester. Talked to a fellow trucker up top from my home state of PA. Had 100 pound bags of potatoes on. Just shy of 80,000 lbs. gross. 7% most of the way down to that sweeping right hand curve. Oh well! Yes, I miss it! As always, thanks for your interest and knowledge.

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Engine (3126 Cat) was running like a dream yesterday. Gross is a little over 32,000 and the ten mile pull with a lot of it at 7% yielded a top speed of 45 with engine temp in low normal range. I eased off of the accelerator a bit to settle in between 35 to 40. Richard/ I am reluctant to stop the additives as a test, to see if the previously mentioned problems start again. Wolf Creek pass is fun when engines are running well.

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ObedB,

LoLo Pass is interesting, but I do not think I could say a lot of fun!

You mentioned a load of potatoes in your post and it brought back a memory. We where fallowing a rig, just outside of Salt lake City on a state Rt. that connects to I-80. Just before the point you get on there was a red light, the driver started braking; as he applied the brakes the trailer tandem slid back to the stop plates. The noise was really hard to describe, but the wheels stayed under the trailer.

The shotgun dove out of the cab faster then a person his size should be able to and the driver was not far behind.

Talking to then at the pull off just beyond the entrance ramp to access the issue, they had just pull out of the terminal and someone forgot to set the locking pins and no jacks that could raise the trailer. They had to return to the yard. Not the way to start a run to the windy city.

Rich.

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We just had to replace the check valve/ pressure regulator located at the rear of our 3126 (rear of the engine equals toward the front of the coach). Our coach had been increasingly hard to start even on warm mornings - with the grey smoke mentioned by others. Replacing this check valve/pressure regulator not only fixed the fuel leaking problem (at the filter) but also seems to have fixed the hard starting problem. Wish I had known some time ago.

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