Golf MK3 1.8 fuel consumption

[charbel89]

Hi,

I have a Golf MK3 1.8 petrol automatic transmission L reg (1994).

Over the last couple of months the fuel consumption has doubled. The car is doing 3 Miles to a litre.

Thats about 14 mpg.

I had the car recently serviced (Major service including fuel filter and plugs ) but this did not help.

I had the Injection unit sprayed with a cleaner but still no change.

I notice that sometimes the RPM plays up and down, especially at morning starts.

If I press the gas peddale down and up, the RPM stays quiet high for about 20-30 seconds before it goes back down again.

Currently I am spending close to £250 a month on petrol. A full tank is doing 160 miles.

Any ideas or thoughts on how I can resolve this issue?.

I am considering a new Injection Unit but the cheapest brand new ones I found were close to £300.. so I wanted to exhaust all other options before I spend that kind of a cash on a 1994 car.


Thanks a lot

Regards


Charbel.

[towcestervag]

check the base gasket of the monojet unit and the servo hose coming from the manifold for leaks

[charbel89]

Thanks for the response.

The injection unit itself wobbles a bit, I am not certain if this is normal, or not.

I am not certain about the servo hose? I tried check around all pipework I could see connected to the Injection unit. Nothing seemed obviously leaking, unless I am missing something!!!

Regards

Charbel

[towcestervag]

the base gasket splits through if it wobbles squirt some water at it whilst you wobble and see if it sucks it into the engine and causes a missfire (not too much at a time)

[charbel89]

I sprayed water all over the injection unit gasket and all the air pipes connecting to the air filter.

It did not make a difference.

One thing worth mentioning: the exhaust sprays some liquid that after just few revs the ground below the exahust is covered with watery like black liquid. (Could be not fully burnt petrol.??)

Also I could hear the Injection unit flapping rapidly.. is this normal?

Thanks

[towcestervag]

the flapping noise is probably the single point injector
can you get a diagnostic test done to see if there are any faults?

[charbel89]

Might be able to do it tomorrow.

[charbel89]

I had the diagnostics done.

Two faults showed up for engine and transmission.

Error code : 00515 Hall Sensor Camshaft position no signal.
Error code : 00518 Throttle position sensor (G69) outside tolerance.


Thanks.

[towcestervag]

hall sender fault is always apparent if car not running so dont worry about this one
check throttle valve
with a diag machine go to measuring blocks 08 enter 00 and zone 2 should increase in value until 1/4 throttle then remain constant
zone 3 should increase in value uniformly until full throttle
if not then pull 5 pin connector off of side of monojet unit and check voltages pins 1+5 =5volts
if car is a auto it has a 7 pin connector and its 1+7
if ok then base unit reqd
if not ok then full wiring test between that connector and engine ecu required

[charbel89]

Thanks for this.

I do not own a diagnostic kit. I will have to take it to the garage again.

Can I check the voltage without the diagnostic machine connected?

My car is auto so presumably I have the 7 pin connector.

The connector you refer to , is the blue or red arrow?