4.5 base idle settings and how to...

[Tony66_au]

Yesterday I ran the car (Dual fuel) on Petrol for the first time.

The issue is that it wont start on fuel and wont idle or run under 3000 RPM.

When it does run it runs smoothly but the moment she gets below 3k she roughs and dies almost instantly.

HEEELP!


Tony

 

[SEL_69L]

I can remember reading an article in the MB Club of Victoria Magazine some years ago about another dual fuel 450 that had almost the same sort of problems. EVERYTHING was investigated over about 6 months, and the owner was considering trashing his car, because he became so frustrated with it.

Eventually, the problem was found, and as you can imagine, the cause was not obvious.

In the end, the gas system was checked for air leaks, and that proved to be where the problem was. After that, the vehicle ran with all of the reliability that was originally hoped for.

 

[Tony66_au]

I can remember reading an article in the MB Club of Victoria Magazine some years ago about another dual fuel 450 that had almost the same sort of problems. EVERYTHING was investigated over about 6 months, and the owner was considering trashing his car, because he became so frustrated with it.

Eventually, the problem was found, and as you can imagine, the cause was not obvious.

In the end, the gas system was checked for air leaks, and that proved to be where the problem was. After that, the vehicle ran with all of the reliability that was originally hoped for.

Funny you should mention leaks, that was where I started with a squirt bottle and some soapy liquid.

Nada zilch was the result but I did tighten some hoses and attachments anyway.

I checked the mix screws on the LPG Converter (commonly but wrongly called a "Mixer") and they were tight so it wasn't a walking mix screw.

Next I checked the fast idle screw on the hose from the converter to the mixer ring that sits over the throttle body and that too was snug although I did give it a tweak to see if it made a change but no luck there so it was returned to exactly where it was.

Finally I checked the accelerator linkage again and found that when I shortened a threaded rod on the drivers side that ran firewall to front of the block the idle came down to 750-850 rpm (Off the dash tach) and it all settled down nicely even loaded up with A/C, In drive and turning the steering.......

So I nipped up the lock nuts and went for a drive, Nice, solid and smooth.

But............ and there's usually a but when you work ignorant lol

Now she doesn't rev and to get her to 100kph and hold her at 3000 RPM you have to hold your foot to the floor so im off to see what on earth I've adjusted (That Rod) and then im unearthing my timing light to check that the timing isn't obscenely advanced for the LPG but I seem to recall lending it out and now I cant remember to whom.

As always any hints, smacks up the back of the head or name calling in the pursuit of a fix gratefully accepted.

Tony

 

[John S]

Tony66_au, try spraying around all the inlet manifold, the hoses and the joints with WD40. If there is an air leak the WD40 will get sucked in and either the revs will vary or smoke will come out the exhaust, or even both actions may happen, depending on how much is drawn in.

 

[Tony66_au]

Tony66_au, try spraying around all the inlet manifold, the hoses and the joints with WD40. If there is an air leak the WD40 will get sucked in and either the revs will vary or smoke will come out the exhaust, or even both actions may happen, depending on how much is drawn in.

I've actually just come in from doing just that with WD40 and the straw fitted with no change :-(

Im still wondering what the long bar is that runs down the drivers side of the intake and im going to play with adjustments on that tomorrow but on the bright side apart from the lack of normal throttle she purrs.

 

[Styria]

Obviously your car is fitted with LPG - I know absolutely nothing of those installations, or how they work. I'd probably throw my hands up in the air, and seek the expertise of an installer. bb has an Aurion fitted with gas and he may be able to assist - if that's what is still needed. Regards Styria

 

[Tony66_au]

Ive tweaked and run the car over a few days and she is now fairly stable although still not 100% so im off to Box hill to see a mate about tuning and to see if he knows anything about K jet.

Im pretty much a tweak n drive, Tweak n drive bloke so it can be a tad time consuming so now im at the limit of my experience I give up and shell out some cash lol

Tony

 

[Tony66_au]

Back to fettling this SE the last few days starting from scratch on the fuel system as im going to toss the LPG once the car moves under its own steam running on petrol.

Miles apart from the D jet systems this K jet has me working hard lol so im ordering the W116 manual from MB Spares tomorrow.

I am pinching parts from this for the SEL but as its cosmetic thievery im not writing this car off just yet even though it also has some nasty rust issues.

Pics and blow by blow as i get to it!

Tony