ARC 4.0

Can anyone reccomend a cheap replacement? probably a K&N style? just i dont know any of the american 4x4 places ( im from england ) and will buy one when im there in a few weeks time ( PA )

many thanks

inkslinger

You can go to most any auto parts store and pick up universal cone filters with universal pipe. Some pipe is just flex pipe and some you can buy in precut lengths and get the 45 or 90 degree elbows to make it fit how you want. Looks like a k&n setup without all the cost. Did it in mine and it works great!

DFlintstone

Sounds like a good part to get from a wrecking yard.

tiwvr1

Find out why it back fired first, not normal for a FI engine to do that.

cpttuna

Get a piece of 3 inch pipe from a junkyard. A little extra in length and a muffler shop can bend it the way you want. The K&N 89010 3" universal cone filter is a good choice. My last one was $32.00. the cvc line can be run into the pipe by drilling a hole.

Slick761

I got a 30* bend Chrome intake.piece at oreilly, drilled two.holes, one for evap one for ccv, and a cone filter. Put it all together and BAM! 30$ intake.

ARC 4.0

Sounds like a great idea, to the autoparts store! The backfire was a result of a buggered sparkplug and backfire by my LPG system.

The LPG system delivers the propane through what can only be described as a inverted gas ring that sits above the air intake/throttle body.

The misfire (surprisingly on cylinder 3..) must have caused a backfire which then traveled up my air intake system and blew the side out of my OEM airfilter box --- i must admit it was very loud!!

freegdr

Best response posted ....

ARC 4.0

t'was the sparkplug !

ARC 4.0

and when its running on LPG its not fuel injected - the propane travels though the air intake

ARC 4.0

and therefore works more like a carb - search for single point lpg and it will explain. You americans are lucky your petrol is 1/3rd of the price it is in the UK! hence why i run mine on propane because it is taxed much less

ARC 4.0

Single point (or mixer) closed loop type systems



Suitable for most fuel injected vehicles produced up to around year 2000 and a smaller proportion of more recent vehicles. These systems can also be fitted to carburettor vehicles if a further inexpensive part (Lambda probe) is fitted in the exhaust. These systems use most of the same parts as the single point open loop systems described above, but have a few additional and different parts. The manual control valve is replaced with an electronically controlled LPG control valve which is controlled by an electronic unit that has a computer. The advantages over the single point open loop system are that the computer continually monitors the exhaust emissions and adjusts the electronic control valve to keep the air/fuel mixture correct with all the associated advantages such as optimised fuel economy, emissions and preventing catalytic converters being burned out. In addition, when you put your foot down on the accelerator they can be set up to give a richer mixture for more power - this is what carburettors try to do and fuel injection does. They can cut off all fuel when you are on the ‘overrun’ (foot off accelerator, maybe coasting downhill), so further save fuel, and again this is what fuel injection does. They are completely independent of the petrol fuel system, so as long as the ignition system on the car works the engine will run even if the petrol fuel injection system is completely broken. They have some of the same disadvantages as the single point open loop system above, in that a backfire is possible because the whole inlet manifold will contain a combustible mixture (again as with carburettors). This system is suitable for many fuel injected vehicles, usually those produced up to around the year 2000 but in some cases later vehicles too. When compared to fully sequential LPG systems described below, they cannot control the mixture as quickly or accurately but on suitable vehicles this makes very little difference in real terms. On most petrol injected vehicles (most petrol injection systems are closed loop), the advantage described above about these systems being independent of the petrol fuel system can also be a disadvantage. This is because the petrol system will always be running in the background, thinking it is controlling the engine fuelling when actually of course the LPG system is. Because the petrol injection also has it’s own closed loop system, the petrol system itself continuously tries to correct the mixture, but of course since the petrol system is not actually in control of the mixture - it only thinks it is still controlling the mixture - the fuel trims of the petrol injection system can drift to the extreme range of adjustment. What this means is that when you then switch back to petrol the vehicle can be hesitant until the petrol system retunes itself. On some petrol injection vehicles (up to around year 2000) the petrol system won’t illuminate the engine warning light on the dashboard (or go into an error mode) because it can tell that the mixture is around the correct level even though it reaches the limits of it’s adjustment capabilities. Most later vehicles will see that the petrol adjustments have gone to the limits, will illuminate the engine warning light and may go into an error mode. This reason, and the potential for backfiring, is why these systems are only suitable for certain models of fuel injected vehicle, usually older vehicles and those without plastic inlet manifolds.

cruiser54

I drive a propane delivery truck with that system on the 496 CI engine. They don't take kindly to ANY intake vacuum leaks or faulty plugs or wires. Kaboom. Scares the daylights outta ya. Especially in a propane truck!!!!

OP, what is the recommended interval for replacing plugs and wires on your LPG Jeep?

ARC 4.0

Yeah certainly catches you off guard! It overfuels on rundown too, which gives me a rally car style "pop" when the unburnt fuel goes bang in the cat, usually when im coming off the motorway...

I usually see 15-20k from a set of Bosch spark plugs, although cylinder 3 seems to eat them occasionally and the insulation cracks. The wires i replaced when i got it, and they havent been any hassle for the last 30,000miles.

Well worth the hassle though, 70p per litre compared to £1.35!

cruiser54

Interesting. We use NGK spark plugs and replace them every 10K along with wires. Keep in mind weidle alot pumping propane though. The wires don't survive being removed to install new plugs, so that's why they get replaced. The intake explosions can be expensive!!

The backfire on decel is an overrich condition.

I wuld switch to NGKs and ditch those bosch plugs.