This Komatsu FG18HT-17, serial number 670347A with a 3.0 Mazda engine in it will crank all day long with multiple spits and sputters like it is going to start, only to go back to cranking. Had a bad cam and crank sensor when I first looked at it along with the codes to confirm that. I have since replaced the crank sensor two more times, the last time with a special metallic sensor that was supposed to fix this issue. I have also replaced the main injector and the fuel pressure sensor. When it is cranking, it will not start with any type of starting aid so I think fuel is not the issue. I am getting good spark and the engine will start at times, and it runs really good when it does start. Any help would be greatly appreciated. Thanks.
Showing items 1 - 9 of 9 results.
The OEM can and crank sensors did the trick. Thanks for all your help. We followed the bulletin and used those part numbers.
well i stand corrected then
i just checked a cat bulletin about spark plugs and they are NGK.. DOH!
not sure where i saw that about the denso plugs
maybe i was confusing it with the mitsu engines in the older cat trucks.
my mistake
Swoop,
The Nissan K21 and K25 engines all come with NGK FR2B-D plugs.
There is a tech bulletin put out by Nissan not to use anything but NGK FR2B-D plugs as they have the last few threads removed so that they do not pull the threads out of the head due to build up of carbon.
Denso does not produce a plug with the threads removed and in the heat range that the NGK is.
I'll have to agree with jeff on the fact that these trucks did come with a nissan engine and on the plugs, all nissan engies come with Denso (nippondenso) plugs in them. NGK plugs may work but they are not OEM plugs.
As for the sensors for the crank and cam i also agree they should be replaced as a set, and if at all possible try to use OEM replacement parts. And to add to any errors that throw the POS cam phase or crank codes you might want to check the EGI and main C relays, they can also interrupt the signal for those sensors and cause a misleading error that will run you in circles and replacing parts that don't need replacement.
just some facts to consider while troubleshooting :o)
First this truck has a Nissan (now GCT) K21 Engine (not a Mazda 3.0) from the factory. Yes there was a problem with crank/cam sensors. A Parts & Service News was published in May 2013 (FT13004). The New Crank Sensor is 23731-6N21A & New Cam Sensor is 23731-6J90C. Its important to replace them as a set with the new ones.
NGK?
is that what comes in these from the factory? if so then i guess we can say it probably isnt the plugs as long as they are gapped correctly.
So when it does run it runs good but when it acts up nothing will get it to run. Replacing the crank sensor fixed it in the past, now it has a metallic sensor. Have you gone back and rechecked this sensor to see if it is failing? or checked the cam sensor? (i'm sure you have)
Have you checked the timing to make sure it is staying in time? It might be a key or something could have sheered and is slipping causing the engine to get out of time occasionally causing this failure. It seems unlikely but i'm thinking outside of the normal box now.
As long as you know you are getting spark, air, and fuel then it would seem likely to look at other possibilities that could cause this.
i know this sounds crazy but what spark plugs are in it?
OEM or some knockoff brand like champion or autolite?
I've ran across problems like this that wound up being the spark plugs not being OEM plugs and the truck would give problems like this.
Forkliftaction accepts no responsibility for forum content and requires forum participants to adhere to our rules of conduct. Click here for more information.
If you are having trouble using the Discussion Forums, please contact us for help.