4TNV98 hard starting in the morning

[JJones]

Hi

The machine is a Hyundai r80-7 with a 4tnv98 engine with the mp4 fuel pump, The temperature at the machine location is min 24 max 32 , First attempt to start has white smoke coming out of the exhaust and will not start unless they use a flammable spray down the intake, The machine will run fine and stop start the rest of the day. Apparently at one stage it was run out of fuel and this is when it all started.

Could it be the cold start function on the injection pump that works off the coolant temp , but with a low temp of 24 deg I wouldn't think any cold start would be needed, Is there anything else that could go wrong in the injection pump to give these symptoms , Otherwise I'm thinking it could be getting low on compression.

I will be able to look at this machine first hand on Wednesday just hoping to find someone who has come across something similar.

Thanks

 

[thepumpguysc]

Pull the return line banjo bolt on the inj. pump.. it has a filter screen on it..
It'll give you an idea of your fuel quality..
Pull the inlet banjo bolt also.. Look to see if its rusted..
I think your gonna play hell trying to find a compression tester adaptor for that engine??
The injectors are quite small.. Unless you have a spare injector laying around that you can "gut"
you'll be better off trying to borrow one..
Good luck.

 

[JJ960E]

thanks for the reply , the machine it self is in a remote area so will be chance that I have the right fitting. I know of a couple of compression testor kits but I have no injector to match up or anything , What are your thoughts on it being related to the fuel pump ? I have only read a bit on that cold start mechanism that changes the timing with cold coolant temp . but no idea if it makes a difference or even comes into play at 24deg, another problem is the stepper motor is not connected and the throttle is just wired back but it has been like this for a long time, the starting issue is only recent.

I plan on taking a dial gauge to check pump timing, compression test if possible , valve clearances, cranking speed etc

 

[thepumpguysc]

1st thing I would do is remove the shut-off solenoid on the back of the inj. pump BEFORE I started diagnosing it..
THAT WAY, your not fighting the electricals..
The sh-off solenoid is a know problem w/ them..
& you can reach in the hole & move the main control rack back & forth to see if it drags..
Just remember, your not gonna be able to shut it off w/ the key if you remove the solenoid..
SO, become familiar w/ how it operates so you can shut it down if things go sideways on you..

 

[heymccall]

My 9k hour 4tnv98 engine likes a bit of preheating to start flawlessly. In my Takeuchi, I have to choose to preheat. How does your engine preheat?

 

[JJ960E]

After investigating the fault it was low on compression , excessive blowby and got to the stage it would not start at all. Going to head back to rebuild it soon