Thread: How to improve 4.6 economy

Hi all, been really interested in this thread as I'm due for an injector clean.. just wondering if these injectors are the same as mine in my 99 Thor motor, not sure if I should get mine cleaned or purchase these ones... which ones are better,any advice would be much appreciated. .
Cheers
Sam

Sorry forgot to mention it's a 4.6ltr

Ok,

Follow up on "fault code 18 O2 sensor error", turns out to be a faulty iridium spark plug missing causing O2 sensor not being able to measure oxy on that particular firing point, hense a fault sensed.

Its funny how I couldn't feel the miss on 1 cylinder but when Its fixed Its so much smoother

All plugs replaced with platinium type, they reckon their more reliable.

Thats more wasted money on my part, as I put the iridiums in the car in the first place

No further info on remapping of ECU as the guys were really busy when I picked the car up.

Rob

Originally Posted by DANMAL

Hi all, been really interested in this thread as I'm due for an injector clean.. just wondering if these injectors are the same as mine in my 99 Thor motor, not sure if I should get mine cleaned or purchase these ones... which ones are better,any advice would be much appreciated. .
Cheers
Sam

Unless you have real proof that your injectors are suss, my advice fwiw is to run the tank down to a bit less than quarter full, pour in a bottle of injection cleaner and then fill tank with 98 oct. Take it for a long run...I mean several hundred km then see if it's improved...or not and then plan yr next move...the std "green" Bosch injectors in the Thor 4.6 are (normally) very reliable.
Cheers

Originally Posted by Hoges

Which engine? If it's a Thor, you need to drain a few litres of coolant and remove the top inlet manifold... this entails a fair amount of work but it's straightforward ...RAVE is your friend. Also check PaulP38's website for pics. One tricky bit is disconnecting the fuel rail from the flexible fuel line...
Take a lot of photos and seal bits in clip lock plastic bags with labels inside the bag ...including a rough sketch as to how / where they fit...sometimes photos are not enough

It's going to be a long exercise if you're going to do a DIY comparison between different sets of injectors... but you'll certainly be an expert in dismantle/replace!
One more thing: there's a metal gasket required between the upper manifold and inlets on the Thor engine. Get a replacement and smear it both sides (clingwrap thickness only!) with Locktite 518 to ensure an airtight seal.

Good luck with it!

Mine is a 96 GEMS 4.6, towing a small 6x4 box trailer on the highway over the weekend, i didnt really notice the weight of the trailer behind it because it always feels sluggish, but cruising along about 90-100kph i was using around 19l per 100km, this seems excessively high considering it was such a small trailer and i was driving it as conservatively as possible.

The motor seems healthy enough, doesn't seem to miss at all, doesn't use coolant or burn much oil, but it is definitely sluggish and thirsty. The only other sign i have had of an issue is a very very brief hesitation when it first starts, it turns over then coughs and comes to life straight away occasionally, apparently it has done this and stalled on my wife before too.

CAL415
Those fuel consumption figures look terrible! Without the trailer do you normally experience such bad figures? If your fuel consumption is considerably less without the trailer, check the bearings on the trailer, you may find they are in need of replacement.

Gary

not much better(possibly almost the same) without the trailer... it just guzzles the juice, it smells very rich at idle too i have noticed.

Cal415

Certainly worth checking out the usual list, filters, spark plugs, spark plug leads, MAF etc. Also maybe check to see if the choke is remaining partially on?

Gary