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Home > Help Needed / General Tech Chat > Fueling at start

JackZwiebel

89 Posts
Member #: 11786
Advanced Member

Hey guys,

I am still tying to get my fueling right, and at the moment i dont really know where to start.
I have a HIF44 with a BCA needle (as far as i can remember). Part throttle lean off is connected.

The engine starts perfectly fine and idles smooth - just a bit rich (AFR 11)
Now the problem: when i put in the first gear and dirve away the engine rattles and leans off - to AFR 15-16.
As soon is the clutch is all in and i am driving it is normal again with AFR 11-12.

It leans off a bit if i quickly accelerate and when boost sets in (AFR approx. 14.) and then runs at AFR 12-13 at load/boost. I am running 10psi boost - is the AFR ok under boost?

What can be the cause of the rattling at the start - is it fueling or maybe the clutch? Never had a problem with the clutch befor.
I thought it may be the dashpot oil, but i am already using a thick gearbox oil. Any suggestions?

best regards


JT

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2726 Posts
Member #: 637
Post Whore

Hertfordshire

Try the standard bdd needle and block the part throttle lean off.

Edited by JT on 13th Mar, 2019.

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

The BDD is a bit leaner at the top - so i would get richer at bottom. Do you think i run lean when starting and thats the rattling? But why does it idle so rich then?


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

The part throttle lean off didnt change anything at start.

Is it possible that im getting so rich when starting that i dont have combustion at one cylinder - and therefore have that rattle and the lean reading on the AFR...since not combusted air comes through?


JT

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2726 Posts
Member #: 637
Post Whore

Hertfordshire

Have you tried adjusting the idle mixture screw on the carb?
Anti clockwise for rich, clockwise for lean.

Edited by JT on 16th Mar, 2019.

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

I have now adjusted the mixture a bit to lean. also changed the damper oil to 20w50. It idles now at 11.5 and idles way smoother. The rattling is (almost) gone. The afr while driving looks good too.
Running quite rich at cruise (11-12). when the boost sets in it gets a bit leaner....running at 12.5-13 at boost but not full throttle (didnt try that yet).
Guess thats ok so far? Dont want to make it more lean on the screw since i would get too lean on boost.

One thing i have noticed and dont really understand:
Since i blocked off the part throttle lean off the pressure of the flow out of the exhaust is waaaay lower. Also it idles smoother.
Befor you could still feel the wind from the exhaust over 2meter away. Now you can only feel it in a distance of maybe 40cm.
Anyone has a explantion for this?

Edited by JackZwiebel on 19th Mar, 2019.


metroturbo

766 Posts
Member #: 989
Post Whore

North Yorkshire

The rattling isn't pre-ignition, is it? Are you using a distributor or mapped ignition?


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

I'm using the standard metro turbo distributor and i set it to the factory settings (approx. 7degree at 1500rpm with disconnected vac.).

How do i know if its pre ignition? Wouldnt pre ignition get worse when i get i leaner mixture?

Edit: Also its worse at cold engine - not sure if this helps recognizing the problem

Edited by JackZwiebel on 19th Mar, 2019.


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

I'v been thinking and pre-ignition doesnt particular mean that the ignition is too advanced right? Or should i try retarding the ignition a bit?


Joe C

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12232 Posts
Member #: 565
Carlos Fandango

Burnham-on-Crouch, Essex

Drop gear rattle?

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



JackZwiebel

89 Posts
Member #: 11786
Advanced Member

no, dont think its the drop gear. its a too low frequency for drop gear - also a too high for the clutch. Also too strong for the drop gear, it was reall hard rattle that shakes the whole car.

Kinda worried now to damage something with pre ignition.
Its almost gone now since i blocked off the part throttle lean off and put it a bit leaner. It now occours sometimes with cold engine...only a little bit, almost not noticeable.

Not sure if it is good to lean it off even more.

Edited by JackZwiebel on 19th Mar, 2019.


metroturbo

766 Posts
Member #: 989
Post Whore

North Yorkshire

With a correctly timed in distributor and tick over CO set correctly there should be no risk of pre-ignition at tick over. If you had had mapped ignition it might have been a rogue number causing a problem. Have you got a wideband air/fuel ratio meter fitted?

A video might help to identify the noise?


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

I will check the ignition again today and see if it still occours. If so i will take a video.
Yes i have a wideband afr meter

Does pre-ignition result from loo lean or too rich mixture?

i cant really tell if making it more lean made it better since i blocked the part throttle lean off and made it leaner in one step. so maybe it was just the part throttle lean of that made it better.


metroturbo

766 Posts
Member #: 989
Post Whore

North Yorkshire

My understanding is that it is caused by running too lean and/or too advanced ignition timing.

I'd try the BDD needle to rule out the needle being the source of it leaning out when driving away. I assume you are confident you have no air leaks on the manifold?


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

I had some, it was running better there *happy*
I now have sealed them and pressure tested the whole system, also checked with brake cleaner - no leaks.

I checked the ignition just now and it was about 2 degree off. I put it at 6-7° at 1500rpm and no vac connected.
Adjusted the mixture a bit (a bit richer again) and it sets off perfectly fine now. Also fueling is more constant over the whole band.
Guess it really was the ignition. I would never have thought of pre ignition thanks mate!


Edit:
It runs fine so far, with 12.5-13 AFR in boost and 12 AFR off boost. Only on transition when the turo sets in it leans off shortly, if i accelerate quick. The higher the gear the more it leans off at this point.
What do you think? thicker damper oil? am using 20w50 now.

Edited by JackZwiebel on 20th Mar, 2019.


Turbo Phil

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4425 Posts
Member #: 20
My sister is so fit I won't show anyone her picture

Lake District

If you’re already using 20/50 oil, try a stronger spring. It’s a bit of a balancing act to get right but worth some effort.

Phil.

WWW.TURBO-MINI.COM


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

what afr am i looking for at transition to boost? Should it stay at 12.5 or is a bit of lean off ok?


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

I'v been driving quite a lot this weekend and been playing around with the settings. When the engine is hot the fueli g is quite good now. 12.5 at boost and 13 when getting in boost. Off boost its quite rich...running around at 10 at cruise and 11 at idle.
Good so far - BUT i think my timing is way retarded now
Not only do i habe waaaay less power then befor adjusting the ignition by 2 degree to late. Also i get a "sensor over temperature error" from the afr gauge after a longer drive. The exhaust tunnle in the middle feeld quite hot and its missing out sometimes when shifting and accelerating.
So that are all signs for me for a retarded ignition.

So heres my problem. Its too retarded now and if i advance it by two degree i get pre ignition when starting. 🤔


metroturbo

766 Posts
Member #: 989
Post Whore

North Yorkshire

Throw the ancient technology away and fit mapped ignition. Also, fit the correct needle and then setup your mixture.


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

haha, yeah that thought crossed my mind several times.
Unfortunly i have a kink for ancient technology *wink*
I give it one more summer, if it doesnt run by winter it will replaced radically (injecrion + mapped ignition)


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

Ok, i have been driving quite a distance now to really heat it through and test a bit.

The lean off isnt really from quick acceleration its more when power sets in.
For example: Driving at constant throttle at the flat and then up a hill, boost starts setting in when going up the hill and it leans off.

It seems it is mostly at low rpm when power is needed. after shifting while acceleration and so on.

Can it still be the damper oil when it occurs on constat throttle?


I still have the feeling the ignition is too retard - is it possible this causes these effects?

Edited by JackZwiebel on 1st Apr, 2019.


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

The engine now runs at 25° max advance under boost and 10psi boost with a CR of 9:1

So after some more driving here is my theory: Whenever it goes from vacuum to bboost there is a quick change in vacuum, but the revs dont go up that far. therefore the vacuum advance is eliminated quite quickly befor the advance from the revs can set in. So it retards too far and runs lean/backfires.

Do you think its save to go to 28° max advance? I had it at 23 and went to 25....it got better and got wayyyy more power - at 23 it had almost no power at all and the turbo was overheating really quick


Joe C

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12232 Posts
Member #: 565
Carlos Fandango

Burnham-on-Crouch, Essex

in a word... no

dont fuck with the timing unles you know exactly what your doing, or odds on you end up shagging the pistons.

you want to get it set up properly on a rolling road, while the mixture is being measured, adding in a little advance at a time, untill power flattens out.

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



JackZwiebel

89 Posts
Member #: 11786
Advanced Member

ok, guess im going to drive about 1k km with the current setting to run it in a bit and then put it on the rolling road.

really dont know if i should keep the engine in the current configuration. Been driving a few hundret km now and the straight cut drop gears are noisy af. After half an hour you need ear protection or loose your mind.
Gearing up to a 7port wouldnt change much on that fact...


JackZwiebel

89 Posts
Member #: 11786
Advanced Member

I finally found the main problem with my engine:

The guy who built that engine used a T3 turbo and optimized the dizzy for that turbo. He sold the engine the guy i bought it from.
This guy fitted a other turbo....a hybrid of T2 and T3 what delivers boost way earlyer than the T3.
So the advance curve of the dizzy doesnt match at all and thats why i get misfire at load and low rpm.

Unfortunly i drove with way too less ignition advance for a while and killed the turbo.

SO! The dizzy has to go to hell and i am going to a mapable ignition and a new turbo inkluding the whole exhaust system.
I am thinking of a GT1752 with the fusion fabs stainless steel exhaust system.

My questions now about the ignition:
I was looking for a megajolt, but didnt really find where to buy / a whole list what i need. At triggerwheels you can buy a kit but as far as i understand you still need to find a EDIS Module.

The far more complete kit would be the SC A-Series Ignition management kit. But i read that the software is a horror to set up.

Is it still that bad? I guess you guys still recommand Megajolt?

Also what do you think about the SC A-Series 5 port management kit. I read a bit into EFI turbo and found very mixed experiences with the SC kit. How hard is it to set this up?

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