Idle screw out of adjustment? and Timing mod questions NA8

booki89 · Postby **booki89** » Sun Mar 09, 2014 6:25 pm

Started looking into the timing mod today,
Jumpered the two connecitons in the diagnostic box using a paper clip, the car makes a clicking noise on ignition, then i fired it up. The idle was the same as normal, everywhere I read says adjust it to 850. I tried to do this, but it seems I have run out of adjustment?

I altered the timing to 14 degree's and the car seems to run better, bit more peppy. It was originally on 12, I even put it back on 12 to see if there really was a difference and the old but dyno recken sthere is. Feels like it revs a little quicker, and overall just has a bit more pull right through the rev range.

I plan on only running 98 fuel here, but most of the other countries have 89-91RON? (states), is it sitll 100% safe and reliable to run my engine with 14 degree's advanced timing? I have never heard a engine physically ping before, So I am a little worried it might ping and I won't notice it.

Any ideas on the idle screw adjustment? It feels stiff when I want to turn it more clockwise, so i just assume its out of thread.

project.r.racing · Postby **project.r.racing** » Sun Mar 09, 2014 8:43 pm

i haven't done one in ages. but from memory you are supposed to have the engine running, put it in diagnostic mode, then you adjustments. then turn of diagnostic mode.

manga_blue · Postby **manga_blue** » Sun Mar 09, 2014 9:24 pm

The butterfly valve in the throttle body has a latex-like coating around its edge. This can fail a bit as the car gets older, so that more air leaks around it and you run out of adjustment with the idle screw alone. Try resetting the adjusting screw to 2 1/2 turns open, unlock the throttle stop screw and adjust the idle using the throttle stop screw instead. Re-lock the stop screw when you're done and go back to adjusting with the idle adjustment screw in future.

Some NA8s will run OK on 91 RON with 14 degree advance but many won't. If you hear pinging then you'll either have to change fuel or change timing advance.

booki89 · Postby **booki89** » Sun Mar 09, 2014 9:25 pm

Bridging ten and ground puts the car in diagnostics mode if i am not mistaken. As i said, the screw won't screw in anymore

So my idle is about 1,000rpm.

I put the timing back to 12 degree's. Although, didn't try putting it to the factory standard of 10.

booki89 · Postby **booki89** » Sun Mar 09, 2014 9:28 pm

manga_blue wrote:The butterfly valve in the throttle body has a latex-like coating around its edge. This can fail a bit as the car gets older, so that more air leaks around it and you run out of adjustment with the idle screw alone. Try resetting the adjusting screw to 2 1/2 turns open, unlock the throttle stop screw and adjust the idle using the throttle stop screw instead. Re-lock the stop screw when you're done and go back to adjusting with the idle adjustment screw in future.

Some NA8s will run OK on 91 RON with 14 degree advance but many won't. If you hear pinging then you'll either have to change fuel or change timing advance.

Currently have 98 octane fuel in it, and plan to keep using it. Just want to make sure its 100% ok, and not going to cause any long term issues. Would rather have a working car then not long term!

Re the butterfly valve, I took off my intake pipe and had a look at it. It seems to be sealed pretty well, although there is no latex like coating, just some carbon build up around the edges. I left it as it was, as i presume thats whats sealing it.

The throttle is full closed, the throttle stop has nill effect basically. Is this normal? or should the throttle be partially open and the seal that you mention sealing it, with the throttle stop actually stopping the throttle?

manga_blue · Postby **manga_blue** » Sun Mar 09, 2014 9:35 pm

When it's set right the throttle plate is usually very slightly open the the air adjusting screw is 2 or 3 turns out.

I assume you're saying there is too much air going through with both the throttle plate and the air scew closed. In that case you need to work out why. It's either leaking around the plate or there's gunk stopping you from closing the adjusting screw effectively.

booki89 · Postby **booki89** » Sun Mar 09, 2014 10:27 pm

Is there a sealant you can buy for the throttle body?

doesn't make sense that its almost basically closed, but my idle screw is closed and I get 1000~rpm.

Any common area's to look for leaks?

Gladiator · Postby **Gladiator** » Mon Mar 10, 2014 7:02 am

Vacuum leak?

manga_blue · Postby **manga_blue** » Mon Mar 10, 2014 9:14 am

Also try blocking each of the hoses into the inlet manifold for a sec and see what that does: brake booster, PCV valve, FPR valve, etc. Check that a blanking rubber plug at the rear of the manifold is OK too.

project.r.racing · Postby **project.r.racing** » Mon Mar 10, 2014 11:16 am

or a coolent sensor is fubarred and it is running in cold loop.

booki89 · Postby **booki89** » Mon Mar 10, 2014 11:18 am

manga_blue wrote:Also try blocking each of the hoses into the inlet manifold for a sec and see what that does: brake booster, PCV valve, FPR valve, etc. Check that a blanking rubber plug at the rear of the manifold is OK too.

I don't think I have one of these blanking rubber plugs, can you give me some more info on where it is?

and re temp sensor, the car has a slightly higher idle on cold start, then goes down quite quickly to my "normal" 1000rpm idle. So i think thats ok?

93_Clubman · Postby **93_Clubman** » Mon Mar 10, 2014 11:27 am

Might be worth cleaning the idle screw & where it screws into the throttle body, but be careful not to damage the sealant around the inside of the throttle body where the butterfly valve makes contact.

booki89 wrote:I don't think I have one of these blanking rubber plugs, can you give me some more info on where it is?

It's at the very rear end of the intake manifold.

manga_blue · Postby **manga_blue** » Mon Mar 10, 2014 12:24 pm

Parts of this apply to your problem.
viewtopic.php?f=76&t=60434

booki89 · Postby **booki89** » Mon Mar 10, 2014 12:40 pm

Hmmm quite a few things on that list. I found the little rubber dildo type object and it appears to be intact and sealing so that shouldn't be the problem.

I have not cleaned the AFM or adjusted the tps. Little hesitant on moving the tps as I don't want to never get it back in the right spot if there is nothing wrong with it.