My MK1 Service or Tuning?

I've got a MK2 GTI 1.8 in my MK1 and i've had it now since the summer, it drives brilliantly and goes like stink, - i don't know if this is just me getting used to the car but i swear its not accelerating as well as it used to, in lower gears its fine, but if i'm motorway driving and in 5th, i'm usually doing about 3500rpm @ 75/80ish.

Had some problems last month and had to get the mixture sorted out, i've done about 400 miles in the last week or so seeing family (all prety much motorway driving)..

and i've probably used about ?65/?70 worth of fuel, on that basis i've done either 32mpg or 36mpg on average - i aint been raggin it, but i aint been driving it slowly neither.. is this reasonable?

I've also found that my acceleration & mixture problems seem to have comme on since i've been sticking Super Unleaded in my car (90% of the time Shell Ferrari V3 SuperUnleaded) as i was recommmended to.

Should i stick it back on standard unleaded? - I swear it feels like it's dropping off on acceleration perhaps being flooded?

What would you recommend? Doing a basic service? (i think i may do this anyway) & how much would it cost to get the car tuned? - also is this possible being that i have a MK2 1.8 GTI lump in a MK1, my engine as alot of stuff that isnt connected (but not required) because the Mk2 engine had alot more electronics than the mk1 engine wise.. (apparently)

any help is greatly appreciated, especially answers to my questions..

3500rpm at 75/80mph seems high geared - higher than my 1.8GTI.

You need to do an accurate brim-brim evaluation, to properly find out the mpg. But 32-36mpg sounds about right.

Can't see any explanation for onset of issues with change of petrol from 95 to 98RON - the only thing I can think of is, its coincidental, or a bad batch/contaminated fuel.

When you say servicing and tuning - what do you mean? The things to do on a service (on the engine) would be oil + filter change, air filter, fuel filter, plugs. Tuning would mean CO and idle speed adjustment.

Unless your Mk2 engine is a Digifant, then no electrical connections would affect the running of the engine (with the exception of the TCI, which is unlikely to have been interfered with, since its just 1 plug and module). The K-Jet is a purely mechanical injection system.

Can you take a pic of the engine bay? This would confirm if its Digi or K-Jet.

The only thing I can see disconnected is the vacuum switch. This thread will help a little. It only operates when the engine is cold, not fully warmed up, in any case.

I presume since the lump is a MK2 that i should get MK2 basic service parts not mk1.. or could they be a mix?

If so how do i tell  -  part numbers off the bits on the engine?

Wildchild said

I presume since the lump is a MK2 that i should get MK2 basic service parts not mk1.. or could they be a mix?

If so how do i tell  -  part numbers off the bits on the engine?

Oil, coolant, plugs, oil filter will be the same. You have a Mk1 airbox and Mk1 chassis, so you have a Mk1 fuel filter and air filter.

Have you adjusted the timing to run on Super???

mine does this too when i run it on super….



and just for the books, cars the same colour (unique blue) as procal x who was banned, point proven for those who said i was accusing

"tupac" you seem to gain some sort of satisfaction from accusing me of being "procalx", either way I hope that you feel forfilled in your conquest.

and it's hardly proof is it, - please as I have said, the moderators/admins of the site can see when browsing the forums similiar IP addresses. - I think you'll find that they will be substantially different. - To any admins that read this i'd appreciate it if you would post the different IP addresses to show Tupac..

As i believe you owe me an apology. - As having the same "looking" or colour paint on a car hardly warrants a justified accusation or actual proof  that I am this other member.

Eitherway, thanks for the suggestion of adjusting the timing, will do