Engine wont rev between idle and 2000rpm

[Pluginz]

Hello all,

I own a 1990 UK 8valve GTi. 135,000 miles

After using the search function to try and find a fix for my problem I've had no luck.

The problem I have is that my 8valve motor will just not rev between idle and 2000rpm.  It starts first time, everytime, ticks over lovely, and runs great.  But if I try and hold the revs between tickover and 2k it just wont do it.  This is also making the car lurch on acceleration and deceleration whilst driving in any gear in that rev range. I dont have any idle problems or hunting, fuel economy is good, so I cant work out what the problem is. I hope somebody can help 

Thanks in advance.

[rubjonny]

check me digifant tuning guide, and also make sure the lifter pump is working.  pull the plug from the main pump under the car and turn key 1 click, should hear the in-tank pump prime.

[Pluginz]

Thanks RubJonny for your advice. I will try the lift pump without the connector on. 
I was wondering if you could explain the symptoms of a faulty lift pump if you dont mind as the manual does not explain anything about it apart from changing it if you think its faulty.  I've owned the car since 1999 at 61,000 miles and its always done it.  All i have to do is just touch the throttle or linkage in engine bay and bam...2100 rpm.  I think a full re-tune is in order. Thanks alot bud.

[monzablue16v]

I would also check your distributor cap and rotor arm, Might be that over 2k it is a stronger spark which will make better contact, under 2k it will be a weaker spark so if the cap or rotor arm are old/damp there is not enough spark to carry the current to the plugs

[rubjonny]

no lift pump will make the main pump work harder and cause fuel delivery problems, it doesnt sound like it is the cause of your problem but its a free check

[Pluginz]

Ah thanks you two, thats a great help, i will try out the things i can do myself. Really appreciate the help guys. )

[Pluginz]

Update on my low revving problem.

I took my car for the tune up to try and cure why i cant rev the car in the 1000-2000rpm range.

The bloke said the airflow sensor is fine. The distributor is ok too. He replaced a few pipes that were perished but could not figure out why i have this problem.

He did find out though if you clamp the ISV pipe on the left of the valve it will then rev the car inbetween idle and 2000 rpm just like i want but it then obviously wont idle.  I can even squeeze the pipe with my finger and thumb with the same effect. 

What would that suggest is at fault.  Its quite confusing.

Thanks again.

[rubjonny]

my next test would be another ISV (MK3 2.0 8v one will also work and usually a bit 'newer' then try another AFM. there isnt much else it can be!
with the engine off, check the throttle switch. it should be heard to click just as you lift the throttle from the stop, then when you get to about 3/4 open the WOT switch on top should click.

[Pluginz]

Thankyou there RubJ.

I will certainly try and newer ISV.

Yep, i get the two clicks from the throttle switch.

Hopefully it will be this straight forward.

Thanks for this advice.

[DubJoey]

I have the same problem with my car too its a 1989 8v gti what is the ISV valve i'm bit new to the golf world let me know if you cure it and what the problem was Cheers