A Little Help Please

[Guest Grez]

Well ive gave it a service, changed oils, filters, cambelt and water pump. That didnt do much. So i took it to my mechanic and he says the engines in good condition for its age. So i noticed when i drive it in any gear it doesnt really seem to wanna pull past 4000-5000rpm. Well it takes a while. The car dont smoke at all. What else could i do without modifing bits? Im really stumped, ive ordered some spark plugs. I wanted some leads but i couldnt figure if my distributer was male or female? What could be my performance problem?

 

Also off topic my oil pressure gauge i dont understand. It sits two marks away from the red line while movin, then when i stop it moves to the red. The gauge in the right top corner takes ages to move and i dont understand what it is? Is this normal or something to do with my performance trouble?

 

All help welcome and much appreciated.

 

Im just tryin to do my GTI justice for its age. Its only 4 years younger than me

 

Cheers

 

Grez

[jim21070 2]

Hi Grez,

 

This thread would be better off in the XU Engine area of the forum

 

The easy one first: Oil pressure

 

It appears a bit low on the gauge but the gauge sender is notoriously unreliable. Don't put any faith in it at all As long as the engine seems health and your pressure warning lamp goes off quickly and does not come on when idling. No worries basically.

 

The other gauge is the Oil Temperature and will not move much for the first 10 miles or so and the maxium it will normally reach is about two bars up. Normall winter running is the first bar for me.

 

Slightly harder: The engine

 

It needs a good service first-off. I'd start with new plugs and leads. The leads you require depend on if you have a Bosch or Ducellier distributor. They are totally the opposite sex. IIRC, the Bosch needs females (Don't we all ).

 

Then, you need to check carefully all aspects of the fuelling system. Change your fuel filter and then completely dismantle and clean your whole inlet tract, paying particular attention to the Throttle Body and AFM and checking very carefully for air leaks anywhere south of the AFM. Air leaks really do have an impact on performance.

 

The AFM may well need recalibrating. This is a job that can be done at home but needs some experience and is really best done on a rolling road session. By now the injectors would benefit from a clean and recalibrate. This is a skilled job which must be farmed out.

 

If you have a misfire causing performance problems at high revs, this'll either be caused by the coil or ignition amplifier, the latter the most likely.

 

Another killer of performance is failed vacuum advance on the dizzy, either because the capsule has failed or the pipe between it and the Throttle Body is either hanging off or is perished and leaking.

 

Timing is critical on these engines and is best set on a Rolling Road or set up carefully by ear. Adjust it until the engine just does not "Pink" (detonate) under heavy load. A fair way also is to adjust the timing for maximum idle speed after checking the vacuum advance is fully functional.

 

I hate to say this but please do a spot of searching around here, all of this has been covered in huge depth in the past and a search will be very rewarding. I've given you a few pointers and a search will really flesh it out.

 

Hope that helps a little...

[Guest Grez]

Thanks Ive changed all oils and filters, even the petrol. Im doing the plugs as soon as i get them. I dont think im really that good to take the engine apart You've helped me alot now i can get the leads. How do i sort the timing out?

[steve@cornwall 100]

Thanks Ive changed all oils and filters, even the petrol. Im doing the plugs as soon as i get them. I dont think im really that good to take the engine apart You've helped me alot now i can get the leads. How do i sort the timing out?

 

Is your throttle cable tight? I'm wondering if the throttle is not opening the throttle position sensor to "wide open" position

[number2301 1 1 Cars]

Is it a 1.9? And are you running SUL? I know my 1.9s have always really not liked 95 RON

[Guest Grez]

Well the car is usually at about full throttle when the pedal is only half down. Yeah the car is using 95ron but ive been tryin to get 98. Im not to sure which its set up for. Would it be ok on 99 or 101 ron?

[Exile 0]

Are you joking? Higher ron is to prevent knockick (it explodes slower) Higher CR and faster gnition ->higher ron.

Stock 1.9 should run on 95 (best economic, more power, more noise)

 

For me it looks like your camshaft is ending, or there is lack of fuel (pump?) If you have jetronic it might be AFM or engine temp sensor.

There is still an option with wrongly fitted timing belt.

[jackherer 543]

Are you joking? Higher ron is to prevent knockick (it explodes slower) Higher CR and faster gnition ->higher ron.

Stock 1.9 should run on 95 (best economic, more power, more noise)

 

Are YOU joking? 1.9s need at least 97/98 unless the ignition timing has been heavily retarded and in that case performance AND economy will suffer unacceptably.

[Exile 0]

1.9s? Only 128HP version is designed to run on 97, but it still runs better on 95.

[jackherer 543]

1.9s? Only 128HP version is designed to run on 97, but it still runs better on 95.

 

How can ANY car run better on lower octane fuel? You are making no sense.

[Exile 0]

Don't connect octane number with caloryfic value. Its the same. Higher octane means higher ignition resistance, and it burns slower. Faster explosion means more power, but when engine starts knocking, we should use fuel with higher RON -only then. Normaly we should use as lower RON as we can.

[number2301 1 1 Cars]

Read Haynes, or even just take out a standard 1.9 back to back on regular and super unleaded. They don't like regular AT ALL. Maybe they're set up differently in Poland but in the UK the 1.9 should only ever be run on super unleaded unless you set it up for regular, and then as before you won't have the performance.

 

And as far as I understand higher RON is better fuel? Hence the 101 RON race fuel and stuff like that, I could be wrong there but I'm definitely right on the previous point.

 

99RON will be fine, that's what Tesco sell isn't it? I used to run mine on that anyway.

Edited August 12, 2007 by number2301

[Exile 0]

Haynes(4C -1):

Recommended fuel

Minimum octane rating (see text Section 8) . . . . . . . . . . . . . . . . . . . . . . 95 RON unleaded or 97/98 RON unleaded*

* Note: The XU9JA engine should not be operated on 95 RON unleaded petrol

 

As I said -as lowest RON as the engine can handle.

 

 

Race fuel ? It doesn't mean You have more power from the race fuel just because it is called 'race'.

 

My 1.9 122hp on 95RON

Edited August 12, 2007 by Exile

[jackherer 543]

* Note: The XU9JA engine should not be operated on 95 RON unleaded petrol

 

Your XU9JAZ may have a knock sensor in which case it can retard its timing automatically in response to the knocking caused by 95 ron compared to 97/98. This will lose you both power and economy. With XU9JA engines performance and economy is simply unnacceptable with the timing retarded sufficiently to prevent knock with 95 ron fuel.

[Exile 0]

It's JAZ no J4 There is no knock sensor. On 98/99 It's soooo lazy...

[welshpug 1,657]

my 205 goes like a rocket on high octane

[jackherer 543]

It's JAZ no J4 There is no knock sensor. On 98/99 It's soooo lazy...

 

Its all in your head

[Exile 0]

If You say so... I'll stick to my experience and little knowledge

[welshpug 1,657]

have to agreee with Jack, it would be smoother, thus feeling lazier, just like the 406 V6, smoother thus FEELING lazier, despite being quicker than a gti6 in a straight lone

Edited August 12, 2007 by welshpug

[number2301 1 1 Cars]

Haynes(4C -1):

As I said -as lowest RON as the engine can handle.

Race fuel ? It doesn't mean You have more power from the race fuel just because it is called 'race'.

 

My 1.9 122hp on 95RON

 

The very quote you've picked out of Haynes is the one I'm talking about, where it specifically says the XU9JA should NOT be run on 95.

[Exile 0]

1st page -I said that 128hp wersion was designed to run on 98. Didn't I?

 

OK -explain me please, why do You think higher RON will improve performance?

[sutol 0]

I used to run my race Mini on leaded 4 star petrol (98 ron) plus octain booster and it went like fffffff*ck

[jackherer 543]

OK -explain me please, why do You think higher RON will improve performance?

 

If it doesn't have a knock sensor and it runs fine on 95 then it will be EXACTLY the same on 97/98 or even 101.

[welshpug 1,657]

BUT, if you advance the timing to suit it will perform better

[Exile 0]

If it doesn't have a knock sensor and it runs fine on 95 then it will be EXACTLY the same on 97/98 or even 101.

Maybe I'm wrong, but theoreticaly octane number tells us only self detonation resistance, but self detonation starts with temperature, and if there is a temperature resistance, there must be a spark-ignition and burning resistance, and the blast is slower. I think there is no other way.

 

I've only checked my car and it is slightly weaker on 98/99, but runs more quietly. I've also cheked consuption and looks like there is about 10% more apetite on 98/99.

 

 

PS With knock sensor we should use higher octane numeber (closed loop)

 

BUT, if you advance the timing to suit it will perform better

No, it will run like on lower RON with stock timing or there will be a little difference depending on the rest of the engine spec.

Edited August 12, 2007 by Exile