87 drinking vast quantites of fuel!

[Knightmayre]

Hi guys

I have an issue with my RRC...

I know they're thirsty on fuel but I have done 1000km on her now and I know I have spent more than $300 on fuel since I got her!!!

I went to visit Homestar yesterday, it's a 30 minute straight run to his place from mine and I used 1/4 of a tank. :mad:

87 EFI flapper, new fuel pump & filter, air filter, plugs/leads, alternator to name a few. I have just manually advanced the ignition timing by ear as I have no light (but I prefer dialing it in by ear, I advance it and listen for the revs to increase then decrease so I back it off a bit, lock her down and go for a drive to see if she pings under load).

Also, the fuel mixture on the AFM was set to 1 1/2 turns out when I picked her up so I moved it to 2 1/2 turns which cut down on the fuel smell a fair bit but not completely so I have just turned it out by another full turn just to see (and now I am huddled in front of the heater - I'm at work and it's belting down with rain so I got soaked lol) and will take her for a drive later to see.

She takes off OK but I rarely put the foot down because I just don't do that on 29 year old vehicles until I get to know them :D

So, I am in dire need of some troubleshooting- I know I could take her to get dyno'd but that's too expensive for me right now.

Thanks in advance for any info

Cheers
Dave

[bee utey]

Hi guys

I have just manually advanced the ignition timing by ear as I have no light (but I prefer dialing it in by ear, I advance it and listen for the revs to increase then decrease so I back it off a bit, lock her down and go for a drive to see if she pings under load).



:Rolling::Rolling::Rolling:

For 10% of your huge fuel bill you could have bought a cheap timing light and saved 10% of your huge fuel bill, making it essentially free...

NEW Timing Light Inductive Pickup Ignition With Bright Xenon Strobe Auto Tool | eBay (http://www.ebay.com.au/itm/New-Timing-Light-Inductive-Pickup-Ignition-with-Bright-Xenon-Strobe-Auto-Tool-/262332495900?hash=item3d143c381c:g:AycAAOSwR5dXTLD w)

Do remember to check that base timing, mechanical advance AND vacuum advance are all adjusted and working correctly. :)

[PhilipA]

I don't know a hell of a lot about these but maybe disconnect the cold start injector which is located on the RH side of the plenum chamber.
Sometimes the time temperature sensor/motor or whatever it is called buggers up and the cold start injector keeps on injecting.

It could be a simple as the temperature sensor has failed or has a bad connection and the injection thinks it is cold the whole time. It should read 300 ohms or thereabouts when hot.
Regards Philip A
If you use the google box at the bottom of the page and enter 3.5 V8 running rich or similar there should be some threads come up.

[bsperka]

Around town mine used to use 20l/100km. Advice others have provided are good starting point ; remove cold start injector (one on plenum), check temperature sender readings, check flapper is working ok, check throttle position is correct (voltage equal to or a bit lower than required), you can add a resistor to temperature sender to change ecu fuel injection length, use a good quality fuel injection cleaner. Engine does bank injection (all 4 on one side then the other) not sequential (the injector for that cyclinder) so fuel economy will never be flash.

[Rextheute]

Not really helping here .....but if I drive to work return it's 110km in a p38 that's approx 13l of fuel .
So to drive an hr to home star would be approx 80 to 100 kms for you ( I'm guessing ) at a minimum of 15l/100 ish .

Or a qtr of a tank . A rangie is a fat girl shaped like a block of home units - economy is a foreign concept , but very comfy , like a couch .

Now I'll do my fathers impression " slow down a little bit " even 10k will make a difference - oh and try it on 98 over a few longer runs . It seems to make a difference .

Keep in mind my other cars are either a 5l Holden (old n carby ) , a 1960's Valiant . So economy is relative .

Just think , you could buy a really economical new car - it would cost approx $400 a month , it would make you unhappy when you drove it !

At least the RR gives back some involvement - can you see yourself outside in the rain swearing at your "new economical car ? "

[Knightmayre]

Just for reference, the trip was only 54km in total so assuming I have the 79 litre tank (as per the owners manual) that would give me a range of 216Km from full to empty and at $1.35/l that's just over $290!

Most of it was a 100km/h limit and I was puttering along at 70, barely touching the throttle.

Oh yeah, and that's using 98 octane too.

Bah. LOL

I used to have a timing light (well, several) but they either got broken or never came back to me.

[superquag]

Never trust or rely on your fuel gauge... It's only a"gauge":eek: Remember, it's English, NOT 'Japanese'.:angel:

That timing light looks similar to the one I've got, worth their weight in Unobtanium. Buy it.

Ears are OK, but a vacuum gauge is much better, and when both used with a timing light...:D

Amen to getting every detail about the 'timing' to 101% accurate and correct. Remember, they will take a lot more advance than the book sez...
- Also, when you want to waste/spend more money, check IGN leads, spark-plug heat range, Distributor Cap and Rotor. And IGN module/coil, if your wallet is too heavy.

My 3.9 used to guzzle 16 to 21 litres per 100km. That's around $30 per 100km, which is the best way to decide/calculate just what BRAND and 'octane' number gives you the best value.


"Brand" of fuel ??? - Yep, depending on where they all source theirs from, different brands can respond differently in different cars... Keep OCD-standard records and you'll soon see...
#1 son's Statesman-International is fussy, and goes well on Shell... Father-In-Law is convinced that a country run in his Merc. costs less on BP 'Ultimate/98' - despite the higher price per litre.

Tyre pressures ? Tyre size? - Road-Rollers use more fuel than normal width wheels. Checked the alignment recently ? Handbrake dragging? Transmission slippppping a bit ?

Remember the Swiss Cheese model also applies here... a little bit 'out' on several details has a synergistic effect on your bank/mental 'balance' :twisted:

Lastly, get used to it. I don't keep fuel records anymore... too depressing:o

If all else fails, only drive it when the moon is in the 7th House and Jupiter aligns with Mars... :wasntme:

EDIT:- Do your fuel mileage checks by filling the tank to the same (click-off) "FULL" from the same bowser, they can and DO vary, which makes it difficult to be accurate especially when dealing with shrt distances like your 54km.
My money's on the Cold Start system...

[bsperka]

Why 98 octane? Even the high compression model has low compression ratio IIRC. Run 91 octane as no advantage on 98. Won't help your fuel economy though. Engine is too primitive. (Eg no O2 sensor in the exhaust). What's a compression reading of the cylinders give you?
I recall that I also adjusted the flapper to see if I could get better economy.

As suggested by others I'd check the fuel guage. Fill up and run about 100 to 150km and fill up again.

Btw: there's a reason l drove a cheap economy car to work when I had my 87 RR and now have a TD5 Disco.....

[superquag]

IMHO, the only reason to use '98' in a bog-standard 3.5 or 3.9 V8 is IF you've put in lots and lots of advance...

The 3.9 is supposed to run on '92' octane according to my handbook, and alternating between 91 and 95 will do that nicely.

There's lots of info here about advancing the 'standard' timing.

[bsperka]

Fair enough. How much advance are we talking about? Sounds like a truck load. I had mine with a couple of degrees from recollection and ran it on 91.

But mine was the low compression model with a 3.9l cam profile.

[superquag]

From faded memory, mine is 'supposed' to be 6 BTDC, but I think I've got it on around 10 to 12 degrees.

To quote the Great Man when referring to LPG timing...
"10 to 12 degrees BTDC at idle works well but make sure your advances are working properly, lack of vacuum advance will reduce economy, lack of mechanical advance will make the engine sluggish at revs."

Once again, Timing Light to get you within range, Ears to hear pinging for Final Adjustment, mix some 95/8 with your 91... then at least 100 km run to confirm fuel use.

[Knightmayre]

I'm considering taking her somewhere to get everything checked out, would probably work out a little cheaper (and quicker) to get it all sorted by someone who knows what they're doing :)


Any recommendations in the Melbourne area? I'm in Tullamarine and most of the mechanics around here either know nothing about them or are too scared to work on them lol


TIA


Dave

[Mercguy]

To me it seems to be a simple case of / requirement to remove, check, replace or clean & refit a number of key system components - if only to ensure they are in good working order (even if it doesn't solve your problem, checking them helps you to know what is OK before you find yourself in a position of needing to take it somewhere, then being charged for replacing things that are OK)

fuel pressure regulator, injectors (not leaking= good, crappy spray pattern / leaks = replace / reco) the temp sender units, tps, MAF / flapper and ignition (particularly distributor, HT components and module).

Since I recently rebuilt my distributor and did the module relocation / new coil, my fuel economy has picked up by about 3L/100km. the engine has 333,000km on it and has a little blowby, a couple of noisy rockers and it still has good power and acceleration for it's displacement and vehicle mass.

There are loads of things you can do yourself for very little cost. but for a grossly rich fuelling issue, I would look at leaky injectors and temp senders first of all. even replacing the sender won't hurt. replacing injectors - well that is up to you. If you're keeping the engine, then yes worth it. if not.... grab some from a later model with less KM. or a replacement long engine from someone parting out a D1 or something.

I understand you may want to let someone else root around with it, whether that's because you're short on time, or reached your limits - but theyre not likely to be doing anything different to the factory manual diagnostic processes anyway.... fuel, air, spark, and send you on your merry way, then charge you 500 bucks for the pleasure. Without wanting to sound facetious, You can pretty much do the checking without too much effort. Sometimes though, it's better to let someone else get the grease all over them ;)

If you must take it to someone, then yes, absolutely take it to a reputable specialist LR mechanic. It might be a 2 hour drive, but that's at least 2 hours of labour you probably wouldn't need to be paying for. It might be time you don't have - but I'd argue that the time you 'don't have' is time that costs you money and you want to be wise about spending that money.

in the end, it all adds up and evens out. But if you're going to let someone else near your car, make sure they are widely recommended specialist LR workshop.

I know quite a few Mercedes ones down in Melbourne, but no Land Rover ones. Perhaps there are a few mexicans who can vouch for or recommend a professional?

oh, and get a quote for labour rates...... just in case.

[PLR]

G`day ,

none of your post mention the mechanical condition of your engine .

If you have just overlooked mentioning it do the same with this .

The first step of a tune up is an assessment of mechanical condition , it won`t matter how much you do with all the other things if there is a mechanical flaw .

I`d suggest you start with a compression gauge it can tell you some like rings , valves. gasket ETC and a vacuum gauge it can tell of valve timing , camshaft ETC . All these things affect economy .

Cheers

[Knightmayre]

I have a compression tester, will try that later today if the rain holds off.
Don't have a vacuum gauge though.

Thanks to everyone for their replies.

[peter51]

See my reply to Konradical in his post about his 89 model using a lot of fuel.
Being in Melbourne you should be able to find a high end diagnostic workshop to sort you out.
Good luck - you can get very good fuel economy out of the later 3.9 models and reasonable out of you flapper type.

[aussearcher]

Dave,
What is easier for you - Romsey or Thomastown?


Romsey British Automotive, 2 Mitchell Court Romsey 5429 5021
Les Richmond Automotive, 41 Wood St Thomastown 9464 4094


Have not used Romsey, have used LRA, and was happy.