Idle issues after Liquid Moly Diesel Purge

[NickJL]

Hi Guys,

Long time lurker here.

I have noticed over last couple of weeks that my idle has gotten a bit rough. It is kind of like it drops the revs a little low then rebounds. The injector noise is really only heard around 1800-2300 RPM when under slight load. This was all only a very slight problem so I thought I would try a diesel purge to give it a clean. I have also tried Fuel Doctor as per the directions and found it didn't do anything at all.

Purge went well, connected a small filter in line just to make sure any crap didn't get sucked up. The first can didn't seem to really affect anything, however the second can seemed to do the trick and it was idling & revving beautifully.

Took it for a test drive once I reconnected the fuel lines and it drove beautifully. Idle was constant & injector noise appeared to be a tiny bit better (may have just been that it was warm).

The next day the idle is doing the exact same thing just as bad if not a little worse. It is now even surging (for the want of a better word) under very small accelerator load (parking etc.) at low RPM (under 1300).

Has anyone had this issue? Seems strange to be running fine after the purge then the next day running worse than before.

I'm thinking maybe the SCV? Would the purge have cleaned this and now the faults are more apparent?

A run down of the vehicle:
2010 D40 YD25
Auto 156000k
As a side note I'm running Activ 2 T 2 Stroke as it seems to quieten the injectors some. I'm not going to add this to the next tank to see if anything changes.

All help is much appreciated.

Nick.

 

[longy509]

Did you check all your fuel lines are connected back up tight it could be sucking a little bit of air in,if thats not the problem there is a good chance it is the SCV.

 

[Old.Tony]

It's also possible that injectors/SCV/pump has some scarring that the dirt was masking, and by removing the dirt you actually make the problem worse - that's a side of the coin we don't want to see.

I've had mine surge in the past - two tanks with a can of diesel injector cleaner in each saw it go away.

 

[NickJL]

Thanks for the responses guys, I'll double check all fuel lines in the morning. I might also throw a can of fuel system cleaner in the next tank for good measure. Will report back with the outcome either way.

On a side note, is there any point in me taking the SCV off and giving it a clean? Or will the 2 cans of purge have cleaned it already?

Cheers,
Nick.

 

[Old.Tony]

It depends on how dirty the SCV is and you won't know until you remove it.

 

[mike1303]

I did this on my nav. Worked for a week then symptoms returned so I replaced the scv. Never looked back

 

[NickJL]

So I've gone over the fuel lines and its all tight & not showing any signs of leaking etc.

Now this morning the bloody thing dropped the revs so low the engine cut out.

Looks like I'll have to give the SCV a clean. I know the normal method is with petrol then rinse in diesel, however I have metho in the shed and it would save a trip to the servo just to get a liter of petrol. Does anyone see any issues with using this for a cleaner with a good diesel rinse after?

Appreciating all the help guys.

Nick.

 

[Old.Tony]

Metho should be fine. You just need a solvent, really, that isn't going to do anything to the metal surface. Xylene is good if you've got a mate in a manufacturing industry.

 

[NickJL]

So I put some Liquid Moly Clean and Boost (funny it smells just like Diesel Purge) in the fuel tank and took it for a 200km run @110km/h yesterday. Then this morning I took the SCV off and gave it a clean in metho and rinse in diesel. Seems to be idling better than it was before. When put in drive without any accelerator it just crawls down the street smoothly, which is much improved of the surging, spluttering & cutting out it was doing last week.

Maybe it was the combination of the above that has gotten rid of any crap that was causing the issue.

I suppose time will tell if I need to replace the SCV. However, I'm hoping not because it is a prick of a job taking it off with all the fuel lines in the way.

I have also stopped using the 2 stroke for a while to see what the injector noise & economy (currently getting 11.5-12 l/100kms) is like without it.

Again, thanks for all the help & ideas guys.