running like a dog..lpg misfires..exhaust blown off..amateur tweeker.

So i might have been a bit impatient, bought some ngk lpg1 spark plugs , had my pants pulled down and my arse firmly spank on the cost ..and it running rougher than before.

Just wanted to check in that imnot missing anything . while this one has a long history .

New ignition amp , dizzy cap , leads,coil. 3.9 efi running lpg single point. new dizzy vaccum regulator thingy! after replacing this lot the exhaust stopped smelling like a pertrol tanker .

After a long weekend trying to adjust the timing and find the pinking point i couldn't understand why after v small adjustments of the dizzy the timing strobe was telling me the timing had shifted by easily 10 degrees. turns out i should read instructions on the strobe light before using as it turns out that dialon the back is there for a reason. instruction pfft.

So finally got it setup, and has been running ok on petrol and lpg but the power seems to be tailing of a bit so i decided to buy some better plugs to close the gap between lpg and petrol performance. ive also bought the lpg software so i can calibrate the system.

After work i made a start laid out all the essentail tools , a large glass of red wine and the bottle in reserve.

New plugs gapped at .07. when i started it it was rough so i started to adjust the timing , the logic being give the spark more time to ignite the fuel as lpg is slower burning , which i think means advancing the engine.

Couple of question really , if its missing at 6btdc does adjusting the timing help ?

I have standard leads on , one fell apart when i pulled of the plug , shall i but decent magnacor or similair. any recommendations.

Is it worth cleaning the o2 sensors !

and lastly why does my head hurt so much this morning !

oh and the back section of the exhaust is in the boot as it blew off at traffic lights after a misfire

Is it single or multipoint LPG injection?

Magnecor or STI leads are better in general than anything, other than Champion or Bosch leads.

Mine is a Thor multipoint so different to yours, but we run Champion Double Platinum plugs with a wider gap than standard, plus we find that the plug gaps increase on LPG as the outer contact distorts with the heat, so check regularly.

Misfiring sounds like single point injection, although ours burps on the overrun with a bit of gas in the exhaust and lost spark ignition.

Timing on petrol should be OK on LPG, some advocate increasing timing on LPG, the Bosch Motronic does it all for me and not adjustable on mine.

Peter

its a aeb175 single point system, i have got it running much better this morning by widening the amount the inlet valve is allowed to open. thsi makes a hugh difference n performance and increases the idle speed . just doing some research now to see what settings work on this type of system.

replaced a damaged HT lead which helps, will pick up some magnacores next week , eliminates another problem .

did find the dizzy cap had white ish deposits on the contact point ,only cleaned them 1500 miles ago made quite a difference.

hi

first replace dem leads //use gen lr or magnaore..(bosch ok , but never halfords etc)

if not using gen lr dizzy cap and rotor then fit one!

RE PLUGS..dont waste your money on dem again!!!use copper ngk..
feck platinium right off!!NOT NEEDED..
i run copper ngk on a boosted water/meth injected lpg/petrol 400hp motor..i just replaced mine at 20k..they were still perfect..

yes advance timing for lpg.

At $3.99 per plug, I much prefer Champion Double Platinum, got 60k out of the first set with no problems.

http://www.oreillyauto.com/site/c/detail/CHP2/7013.oap?ck=Search_HP-7013_-1_-1&keyword=HP-7013

Always pick a set or two up when we are in the USA, stupidly cheap out there and have a 5-year unlimited mileage warranty:

http://aftermarket.federalmogul.com...x?CategoryId=2&SubCategoryId=19&ProductId=234

Peter

My 3.5 runs lpg lovely on standard plugs lucas cap and arm silicone leads. Plug gap at 1mm and timing on o of before on the crank.
Make sure everything is good and clean and the coil is tip top.

If you are pumping fuel into the exhaust could be the timing is too far advanced. Usually backfire is on the induction side.
Did you set timing with the vac advance tube off and sealed.

listerdiesel said:

At $3.99 per plug, I much prefer Champion Double Platinum, got 60k out of the first set with no problems.

Champion Double Platinum 7013 - Spark Plug | O'Reilly Auto Parts

Always pick a set or two up when we are in the USA, stupidly cheap out there and have a 5-year unlimited mileage warranty:

Product Information - Double Platinum Power? Spark Plugs

Peter

Click to expand...

yes peter..but the problem here is if plugs are good for 60k them MOST people wont check them...and after that amount of time they are likely to be stuck well and proper in your ali head..and that can work out very expensive..helicoils and all..

NOT saying you dont check them regually and use copper slip etc, but MOST wont

(not that it matters to op, but platium are a no no for boosted engines...)

i still say ngk copper, standard are the best preformance and value for money

zen said:

(not that it matters to op, but platinum are a no no for boosted engines...)

Click to expand...

Why?

Just interested.

Peter

fall to bits and burn out..dont know why they do, but they defo do..cant take the combustion chamber pressure i guess, tiny tips on them..

zen said:

fall to bits and burn out..dont know why they do, but they defo do..cant take the combustion chamber pressure i guess, tiny tips on them..

Click to expand...

I've heard similar. The small electrodes wear away quicker and then small bits fall in to the combustion chamber and can cause damage. That said, I've been running Bosch Super 4's in my RRC for the last couple of years with no issues which reminds me I really should pop the plugs out and check them over.