rough idling on sat engine

[idoari 10]

Hi,

 

i'm restoring a 1.6 gti for the last six years now. when i got the car the engine ran terribly but i checked  compression it was good.

i replaced everything around the engine (sensors,filter etc...) and made the engine run good. since then the car sat for at least 2 year without starting and now i'm getting a hard time to make the engine ran good. 

 

things i've done (before the engine sat) to the engine.

 

new genuine ECU temp sensor

new AFM

new ignition module (blue one) 

new spark plug and wires

rebuild alternator

new engine loom

rebuild dizzy with genuine parts

cleaned fuel injectors

new filters (air,oil and fuel)

new water hoses + genuine antifreeze + rigid water hose

new expension tank and cap

new radiator

new seals (intake, throttle body o-rings)

new battery

new oil.

clean throttle body

 

after the engine sat i :

 

cleaned the spark plugs and gap them

checked all sensors connection

set the dizzy with a timing light to 3500rpm with the timing plate.

tried to setup mixture and throttle initial position

fresh fuel

 

the engine shaking on idle - when i blip the throttle it goes up than down and almost cut out.

 

what am i missing?

 

here is a video of the engine running

https://www.youtube.com/watch?v=lgOKTzqtalM

 

 

thanks

Ido

 

 

 

 

 

 

 

[SootySport 23]

That sounds like a mechanical problem, valve sticking, piston or ring problem.  Sure it has oil in it?

Edited January 6, 2021 by SootySport

[DamirGTI 342]

Something wrong with the ignition i'd say ... sounds retarded , the vaccum is a bit on a low side @ idle  .

 

Try to play a bit with the dizzy manually without the strobe , mark position and with the engine running/idling try to swing the dizzy on the advance side in small increments .. and see what happens , the revs will rise up when advancing so just re-correct the idle via TB air screw afterwards (if it turns up good of course) .

 

Also i would check if the engine is timed up properly - check timing belt .

 

And check the fuel pressure , as if it was standing for too long and especially with (stale) fuel still in the tank the pump might be going bad .

 

D

 

[idoari 10]

Thanks Damir!

 

checked the fuel pressure - it's 3 bar.

tried to play with the dizzy but no much luck -  i did move it a little clockwise from where it was.

also tried to check for vaccum leaks but nothing was found.

 

 

 

here is where i'm now  

https://www.youtube.com/video/7PxLY0qUksc/

 

there is a little knocking sound it the background of the video - i think it coming from the gearbox - what can it  be?

 

 

 

also, my rev counter is not steady at idle - what can it be?

 

https://www.youtube.com/watch?v=7m80iRX_sAI

 

 

 

 Ido

[DamirGTI 342]

Can't open first video , the link takes me to google sign in ?!

 

rebuild dizzy with genuine parts - what's been done to the dizzy ? new cap and arm or rebuilt internal centrifugal mechanism ?

 

tried to setup mixture - by opening the AFM and playing with the spring tension or ? is the potentiometer carbon track good ?

 

Are the plugs ok. ? or you might've dropped and bent electrode on one while fitting back into the cylinder (happened to me a few times) .

 

Checked the timing belt to see if the engine timing is off ?

 

D

[idoari 10]

Fixed the video link 

 

https://www.youtube.com/watch?v=7PxLY0qUksc

 

7 hours ago, DamirGTI said:

Can't open first video , the link takes me to google sign in ?!

 

rebuild dizzy with genuine parts - what's been done to the dizzy ? new cap and arm or rebuilt internal centrifugal mechanism ?

 

tried to setup mixture - by opening the AFM and playing with the spring tension or ? is the potentiometer carbon track good ?

 

Are the plugs ok. ? or you might've dropped and bent electrode on one while fitting back into the cylinder (happened to me a few times) .

 

Checked the timing belt to see if the engine timing is off ?

 

D

 

Replace cap and rotor, replaced vaccum advance unit. Didn't took apart the dizzy any further.

 

Didn't opened the AFM. Ive got it from ebay . The seller State it's new. Mixture i tried to set with the afm screw. Right now it is fully in (fully rich mixture)

 

I have brand new ngk spark plug i can put.. mine right now is a little dark from the rich mixture and i remove them every few day and clean them with brass brush and some brake clean. I think the electrodes are fine but i will regap them.

 

Didn't tried to reset timing . Do i do it like the haynes workshop manual says - with the 10mm pins? The timing could be off because i replace the plate behind the cam gear and the 10mm pin sliped out getting it  off timing.i return the cam to its location and recheck with the timing pins.

The cam belt and tensioner are fairly from before the engine sat.

 

 

 

[DamirGTI 342]

No still the same , i can't open that link .

 

Do you have picture of that new AFM ? i wonder if it's one of the new Chinese knock off AFM's .

 

Mixture screw on the AFM should be set counting 7-to-8 turns out from fully in .

 

Yes , definitely check the timing belt if you've been working on it and remember it being off .. as it'll make the engine run retarded or advanced , which kinda fits the problems you're having (seems to me it's running retarded) .

Haynes is good for doing timing belt , follow the instructions from there and check/redo the timing belt making sure 10mm pins fit the corresponding timing holes .

 

D

[idoari 10]

copy and paste the link it should work (for some reason it goes to a different link address)

 

it's the genuine bosch one 0280202056

 

 

will check the timing and play with the AFM screw.

 

 

[idoari 10]

checked timing and all OK.

the 10mm pins went in nicely on 7'ish at the camshaft and 12' at the crankshaft  - it could be 180 deg off?

 i set the screw as 7.5 turns out

 

no change so far

Edited February 3, 2021 by idoari

[idoari 10]

look new to me

 

 

[DamirGTI 342]

Yes , that AFM looks like brand new !

 

Not sure what to try next , kinda running out of ideas now ..

 

 

D

Edited February 3, 2021 by DamirGTI