990 Help

[ejb17]

This is my plea for help with my 990 MFWD with 116 hours. Yesterday I went to start it and the initial liitle puff of start up smoke lasted much longer than normal. After it was warmed up I went to set it to pto speed and it smoked but much lighter. Usually after warmup it does not smoke. When I was finished I parked it outside on the drive and did not come back to it for two hours. The weather was clear and cool about 55-60 degrees. I went to start it and it fired right up like normal but smoked very bad. I let it warm up for a couple minutes and when I used the foot throttle to move it smoked like a freight train and was missing. I got it into the shop and checked the water seperator/screen and changed the spin on fuel filter. No luck. I use only on road ultra low sulfer fuel and this is the 4TNV-84 engine with the temperature advance/****** system on the injection pump. Any help is appreciated.

 

[RollingsFarms]

This is my plea for help with my 990 MFWD with 116 hours. Yesterday I went to start it and the initial liitle puff of start up smoke lasted much longer than normal. After it was warmed up I went to set it to pto speed and it smoked but much lighter. Usually after warmup it does not smoke. When I was finished I parked it outside on the drive and did not come back to it for two hours. The weather was clear and cool about 55-60 degrees. I went to start it and it fired right up like normal but smoked very bad. I let it warm up for a couple minutes and when I used the foot throttle to move it smoked like a freight train and was missing. I got it into the shop and checked the water seperator/screen and changed the spin on fuel filter. No luck. I use only on road ultra low sulfer fuel and this is the 4TNV-84 engine with the temperature advance/****** system on the injection pump. Any help is appreciated.

sounds like you MIGHT have a bad injector(s). i would call your dealer and explain your situation and he might tell you what the cause is and if you should bring it in or not. you should still be under warranty depending on the year of your 990.

 

[adamls78]

I sounds like you may have an injector problem. I have seen alot of the older model diesels in trucks have problems with the low sulfur fuel. It can cause the injectors to stick close or open. If it turns out to be one of the injectors you may need to use the high sulfur (500ppm) off road fuel.

 

[ejb17]

OK everyone here is what happened. I talked to my contact at the dealer and he said to bring it up he would like to try something. When I got there he hoked up a portable fuel tank with off road diesel. We ran the tractor out of my fuel and got the off road going through it. It pretty much stopped smoking immediately. Hooked it back up normally and it started smoking. Now I know that everyone thinks I got bad fuel but I have 15 Caterpillar powered Peterbilts running the same fuel that I oversee dailey and they have had zero problems. I must add that up until 2 tankfuls ago I was adding cetane boost that said I would gain 4-7 points. I have treated our fuel at work without fail for years all year long and have no trouble even when it is well below zero and I do not mean adding extra kero. Does off road have a better cetane number? 7-8 months ago we had the fuel tested and it showed good with 47 cetane. I stopped the extra cetane booster and look what happens. My op manual does suggest 50 cetane but in my neck of the woods that would be asking a lot. Just looking for some justification about the off road diesel. Thanks for ant insight.

 

[AKfish]

That's pretty dramatic 'cause and effect - I'd say! Sounds like you narrowed down the likely culprit..

I just got my 150 gallon tank on a stand and filled with off-road this past week. I've been using PowerService (read about it on TBN) for 3 years, now.

Hearing too many stories about pump failures and injector problems on older, diesel engines with the new ULSD fuel.

Winter's comin' real fast and I just don't want those kinds of problems. And the fuel cost is nearly $1.10/gallon less than at the pump.

Had one episode of fuel gelling - so, I still add PowerService but with the tank I won't be guessing on how much to add and I won't have to mess with pouring that stuff into 5 gallon jugs, either.

AKfish