Fuel, where does it go?

[axe]

Hi all,

Having a dodgy fuel gauge, it is hard to tell when the car is going to grind to a halt just before a roundabout (been there, done that) and when that happened the needle was oscillating around the middle marker. OK I know the fuel sender unit might be out and I will check it this coming weekend.
However I have read that most S would do from 180 to 300 miles on a full tank (I drive to and from work only, no motorway). I have filled her up about 80 miles ago and the needle is dangerously pointing towards the middle marker... So where does the fuel go?
The engine tends to idle between 1700 and 2000 rpm when cold but when it reaches the full temp, it can go down to 1500... Under that it will choke and stall if left alone.
Does that sound like "normal" on a S?

aXe

PS: Got me 5L can in the boot ready this time

[Le TVR]

axe said:

The engine tends to idle between 1700 and 2000 rpm when cold but when it reaches the full temp, it can go down to 1500... Under that it will choke and stall if left alone.
Does that sound like "normal" on a S?

Doesnt sound normal.
Mine will warm-up idle around 1200-1500 max and gradually drop to around 850 when warm. Will idle quite reliably at 500 but thats a bit too low.

Fuel is something like 10L/100km (28mpg??)

[GreenV8S]

Ignore the gauge, you can tell the consumption by how much it takes to fill it up again. It sounds as if it may be running very rich, perhaps from a failed coolant temp sender or fuel pressure regulator/vac line. You could confirm that easily by pulling a plug.

[spivvy]

Throttle Pot ???

[russ35]

My S3 is cold idle - 1200
normal idle - 900

Normal driving around is 200 miles takes 41 litres to re-fill. I always re-fill so that the fuel is about 3 inches below top of filler pipe.

[petclub]

My S2 is very similar to Russ35's comments. She ticks over less than 1,000 when warm. My fuel gauge needle does vary a lot when less than a quarter full. Dave

[axe]

Interesting...
Anybody around Gosport/Portsmouth knowing this stuff and willing to help me tune it properly?

aXe

PS: I may have a beer or two in the fridge

[Le TVR]

With the revs that high on an S1 you could try squeezing the inlet or outlet tubes of the additional air device. If the revs drop then its more than likely that the AAD is sticking. A good indicator can be that the idle set screw has virtually no effect.

Background read for the K-Jetronic FI system : www.auto-solve.com/mech_inj.htm

[axe]

Thanks, I'll have a look this weekend.
Very interesting page

aXe

[james280779]

Hey

My S1 idles cold about 850 rpm and 550 rpm when warmed, was tuned last year by Rallytec and performs as it should perfectly.

Hope that helps

[ceejay73]

Just thought I would add that like the other guages in these cars, the rev counter reading is not always true. According to my rev counter my S3 idles at about 1050 when warm but measured with a scope its actually around 875.

Carl.

[flinny]

Echo the sentiments above. Mine ticks over at 1200 when cold and 900 when warm. The Petrol pump gets noisey when it needs filling up. I take very little notice gauge. I would say I return 200 on a tank. Mind mines also running a bit rough at the mo, feels like I'm driving with the chokes out.

[spivvy]

flinny said:

Echo the sentiments above. Mine ticks over at 1200 when cold and 900 when warm. The Petrol pump gets noisey when it needs filling up. I take very little notice gauge. I would say I return 200 on a tank. Mind mines also running a bit rough at the mo, feels like I'm driving with the chokes out.

you buying the same kangaroo petrol that i am then

[axe]

update...
I have found the auxiliary valve (hurray) and when I clamp the pipe, the engine goes down to a quiet dumdumdum (if that makes sense)
Took the valve out, sprayed WD40 inside and reassembled the lot. now it is constant 2000 rpm *g* so not good, I probably need to change it I saw it was a Bosch part so should be easy to find.

Now does anybody have bonnet hinges somewhere they could let me get my hands on?
Had to take the bonnet out to try and realign it. In fact the hinges were seized on both axis. I have succeeded giving lateral movement again using brute force, a lot of swearing and some flesh... But the other screw, held by 2 nuts is stuck hard... what I am speaking about is shown here (pic taken before unseizing the horizontal axis). You can see that both of them are not the same position originally HELP
I tried brute force, swearing and felsh on that nut as well but by holding it down using 2 screws, the metal bends too much and I dont want to break them...

aXe

[ianm67]

Axe,
I'd soak both the hinge assemblies in petrol for 24hrs or so. This will dissolve most crud that usually seizes up threads. If that fails (and once you've dried them off) try applying a little heat....
IanM

[axe]

Since I have killed one of the big bolts hammering it out of the hinge, I need to find a replacement.
Can anybody tell me if that one is the one I need?

Will order a few nuts and bolts (had to cut one out to free the radiator as the head was corroded) from screwfix unless someone knows a better place to go around portsmouth.

IanM: Thanks, the hinges are now swimming in unleaded

aXe