What option to choose to get the engine running
Turbo Mini Forums

tripple post?

Edited by JackZwiebel on 12th Jul, 2019.

triple post

Edited by JackZwiebel on 12th Jul, 2019.

So I have it running now and took the first spin around the block. I am now running the above map but backed off a few degree to be extra save.

i noticed that the idle at 20 degree is quite rough, it seems to get better if i go up...to about 24. Although i also think my vacuum is pretty bad...running at 350-400mbar in idle - but its the only way to keep it at 1000rpm.
The AFR is at 12-13 at idle at the moment. Am i going in the wrong way? should i try to get more vacuum by closing the idle screw? but i think i am already really far advanced with the ignition and retarding it will drop the rpm even more.

Not sure if its fine to let it idle at 24 degree (28 when cold) and 350mbar vacuum or should i try to get more vacuum? where should i go with the advance and the afr then?

Edit: Btw i did check the timing - the ecu sayed 18 degree final advance and when i set the timing light to 0 degree i am at about18degree on the pulley wheel. since the 0 marking is the most accurate and i only checkt this one whe building the engine i set the timing light to 36 degree (wasted spark) and it was spot on zero. so i guess its correct

Edited by JackZwiebel on 12th Jul, 2019.

What ignition advance do you guys run at idle / where does it usually idle the best?

mine liked about 15-18 deg, one thought on tuning is to adjust the timing so it gives the highest vacuum.

Thanks Joe, i will try this tomorrow. Not happy with my idle yet

i put the idle egnition to 16 degree now and it actually changed nothing at all. It still idles at 350-400mbar with 900-1000rpm and 11-12 afr. I checked with the ignition light and it actually did change the to 16 degree.
I than changed the value at the running engine and the ignition doesnt really have a effect on the engine rpm - it just gets a tiny bit smoother if i advance it more.

from the dizzy i know that the ignition had quite a big effect on the idle rpm - how comes that changing the ignition by almost 10 degree doesnt really effect the rpm?

anyway, the engine runy quite good when driving now - on and off boost. Right now its running on 5psi (no bleeding) and 11 afr on boost and feels really good to drive. definatly good enough to get it on the RR.

Hope these guys can sort out the idling issue too - maybe i need a set of smaller injectors, i am running 20% on boost and 3-4% on idle now. Since the resultion of the injection map is 0.3% one step at idle means almost 10% more or less fuel.

Im supprised that theres not much difference too, at the least I'd expect a change in idle speed by 1-200 rpm,

350-400mbar is pretty reasonable for idle, mine was up around 550mbar, but that was a 7 port with big valves & ports, and also a fairly big cam and 1.5 rockers.

in terms of the production idle figure, IIRC the idle advance would have been about 8 deg, then on top of that the vac advance would add a max of 13deg, so call it 22 deg max, but i think you would normally see around 15-16 deg. I thionk youve goit it around where it should be idle advvance wise

I would look at leaning it off at idle and see if that cleans the idle up, you should be able to idle at stoic pretty well, maybe a little richer, also plugs might be having an effect, I'd be looking at 6's tor start with.

apart from that, is there any other odd stuff in the spec/ setup that might cotribute to the idle? light flywheel? low idle rpm ( look for about 800rpm)

Ok, thanks. So i keep worrying about that for now and see if the RR operator can do some magic. Maybe i lean it out a bit.

I run 7's for plugs and have a standard flywheel. The engine idled pretty well already, so it should be possible with this setup too.
I usually try to idle at about 1000rpm. Never got it running smooth at 800.

Aaaand its fucked :/
Did take a little test tour and suddenly it ran on only three of two cylinders. Lucky i was not far from home and made it home.

Guess its a blown head gasket, have to do a comp test tomorrow. Big question: why did it fail :/

Now it gets interesting.

I checked the timing with a timing light befor and it fits with the values the ecu gives for final advance perfectly.

The sparks are dry and dark from running too fat - not wet as i would expect from running on only two cylinders.

I have a spark on all four cylinders

I made a leak down test and i have 5-7%, almost idebtical an all four. you can hear it leaking down in the crankcase. since the engine was honed about 100 miles ago i guess thats a pretty good value und nothing to worry about. So i cross out the head gasket as well.

Maybe the injectors? only one is fireing and due to port robbing only two cylinders are running? but wouldnt it read bloody lean on idle then? it still reads a afr of 12 when in idle while running on only 2 cylinders.

any idea what else i can check?

swapped the plugs out?

there were new about 5miles ago and still look as good as new.

edit: maybe its the fuel pressure - have to check if the filter is shut - it occured one mile after filling at the gas station

Edited by JackZwiebel on 2nd Aug, 2019.

So, i guess i have found the root of the problem.
Joe C you were kinda right, it was the plugs.

The guy who built the engine put 8's in. In my opinion thats too cold, so i changed them to 7's. In particular to NGK BPR7ES
I gapped them to 0.8mm plug gap.

So after it started running on only 3 zylinders (sometimes 2 but mostly on 3) i firstly checked what plug was the problem and it was nr 2. Unplugging it made no different in engine running.

I also checked with the timing light if i get a signal and was kinda confused by what i found:
- Zyl 1: One flash per rev, like i would expect from a wasted spark ignition
- Zyl 2: No flash at all
- Zyl 3: One flash per rev, like i would expect
- Zyl 4: One flash every secon rev....uhm is that normal?


So firstly i took the secon plug out and looked if i can see a spark and i didnt see a spark. I tried a new plug and got a spark.
So my thought was to close the gap a bit (to 0.6mm) and now i get a spark and it runs fine again.

When checking with the timing light i still have a very weak signal on 2 (only get it sometimes when holding right) and still only every second rev on cyl. 4.

Can this be normal? Shouldnt there be a spark every rev at every cylinder? And why the weak signal?

I still have a tiny little hesitation mid boost - what i guess is also the ignition. Do you think its the plugs or the coil pack? Or should i go for 6's? Or close the gap further?

Edited by JackZwiebel on 8th Aug, 2019.

Anyone had this problems? Where would you start looking?

Well, that does sound odd, what exactly is the ignotion setup? Std Coil and Dizzy? wasted spark? Dizzy with ECU driving the coil?

If its wasted spark, then that would account for 2 sparks per rev, but they should all be doing the same,

If its a dizzy, I would look at the alignment of the dizzy cap/ rotor arm, could it be cross firing

other than that check aout all the HT leads and connections and resistances,

It is the specialist components ECU with a wasted spark ignition.
With my (very basic) electrical understanding there should be a spark at either both cylinders or at none - its odd that one fires and one doesnt.
Thats why i think its the coil pack - maybe a short between the two coils.

Since i tried other new plugs already, i will next try my old HT leads and if it doesnt help change the coil pack.

It has to be one of these parts since the ECU obviously gives the right signal, since 1 and 3 are fireing perfectly fine.

Aren't 2 & 4 normally on the same coil?

Usually 1/4 and 2/3.

with the coil packs they can do funny stuff as they are ( ususally) a single double ended coil, so if one end has a problem it "can" affect the spark on the other end of that coil.

oh also SC use a generic ford coil, so nothing odd there.

Edited by Joe C on 9th Aug, 2019.

What kind of timing light are you using ???

If it's an inductive one (that you just fit over the outside of the HT lead) look for an arrow on the jaws of it.

The Ford wasted spark system is quite bizzare because the double ended coils put a positive voltage to one plug and a negative to the other.

This always means the spark energy is different - so you can get a misfire on one plug on one end of the coil and not on the other plug at the other end of the same coil - but if your little arrow on the timing light "clamp" is facing the wrong way it may also not work properly.

Schrödinger's cat - so which one am I ???

Thats interestig, i didnt know that you can put it on two different ways. i am using this timing light:
https://www.conrad.com/p/equus-5568-pro-dig...ight-12v-857336

Anyway, the energy should be easely high enough to get a good spark at both plugs with a plug gap of 0.8mm.

Also i have the typical symptoms of a weak spark - bad idle, rattling at load at low rpm, sometimes loss of power under load.

0.8 isn't that small, I'd try shutting them a bit, say 0.6

i did that tonget it running at all again. have them at 0.6mm now. It runs now but still very rough at idle. you can feel at the exhaust that he keeps missing ignitions every now and then

I changed the plugs again, changed the leads, changed the coil pack.
It didnt change much on the idle, it runs a it etter on low rpm and still misses out sometimes on load.

When checking with the timing light its still the same:
1 is firing every rpm
2 has a very weak signal.....only sometimes a little flash from the timing light
3 is fireing every rpm
4 is fireing every sesond rpm.

I checked the direction from the timing light and put it on the same direction at every cylinder. The question that came to my mind afterwards is: Do i have to put it on the wrong way around on two cylinders? .... since they are on opposite sides of the coil?