The crankshaft position sensor and the distributor phase sensor; if the gap is set incorrectly it can make the engine to get overfuelled and I assume they can also make the mixture go too lean??

What's the explanation for these sensors that they have influence on the mixture of the engine?

Is there someone who knows the technical know-how about this and can explain it??

 

i think that you're mistaken

if either one is gapped incorrectly or broken, the engine will not start.

if the phase sensor has a fault during driving, nothing happens on L8, but on lesser ecu's it will cause a misfire

if the crank position sensor fails, the engine will not run.

as far as i know, that is the situation. i look forward to being corrected, as that would mean that i would learn something

 

It is just what I have read in the Fast Ford december issue, that the crank position sensor has a great influence on the fuel injection. Or I didn't understand it completly..

And I was also told that when the phase sensor on the distributor is not in time it has got influence on the fuel injection..

As my cosworth is running very very lean I try to find all the possibilities that can cause it..

Thanks for your answer hope someone else will support it.

 

Hi

Look around fuel pressure regulator, first.

Regards

Claude

 

haven't read the article

 

Thanks Claude,

But with this post I hope to get some usefull information about that crankshaft and phase sensor!

 

Your reading about Fast Ford article was not correct.
I have this article on my desk.
Article say (MD say) regarding crank sensor :
"Problem with these sensors normally result in poor throttle response, hesitations, sudden engine stops, and non-start situations."
Article say regarding phase sensor :
"Problems here normally relate misfires."

It is simple and very clear.
Never say : poor or rich mixture !!!!

Regards.

Claude

 

Well Claude than I have to correct you because about the crankshaft sensor it also says:

"The ECU uses this engine speed information to deliver not only fuel but also spark advance."

And in a personal email from Stu (MSD) he wrote me about the phase sensor that "It can have an effect on fuelling as it dictates when the injector should open."

So...

 

you are kind of correct, they can affect the fuelling mixture

of course it does. but only because it needs to know how fast the engine is turning to look up the values in the maps. if you had an unlikely situation where the engine was doing 5000 rpm, but the ecu was getting a signal from the crankshaft sensor that looked like it was only doing 2500rpm, then of course it would give the wrong fuel amount and spark timing. that would be where the hesitation, misfiring etc comes from

true. the fuel injection on yb's is sequential. that means that the ecu uses the phase sensor to know which cylinder is next to fire and injects the fuel at the right time to be sucked in past the inlet valve. if the timing of the fuel injection is wrong, it will not be correctly sucked in and mixed as it would likely be squirted at the back of a closed valve and might just 'pool' rather than properly atomise. all of that is in theory though, and i don't know if it makes a big difference in real life

bottom line is, if you feel something is wrong with hesitation, boost or misfiring or something, don't drive hard until you know the fault. use the diagnostic tools that are available these days to find the problem quickly and easily rather than wasting time and money randomly swapping sensors

 

Thanks Nick, so in that way you are explaning that if these 2 sensors are wrong gapped or not in time can effect the fuelling and therefor the engine can get too rich or too lean. Am I correct?

And for that software, that will be RP Lab I assume.

Well I am into electronics but I have to admit that seeing those screenshots of this program it's not so easy to understand for someone who is not a engine tuner. Of course afer hard study I will hopefully know what it all means, but I think it's a big risk for someone if he intisapates (?)the values wrong and takes the wrong action..

So therefor I collect as many as possible info what can cause my engine to go lean. Hope you will understand.

 

YBJ i guess that i am. i am not an expert though, i could be wrong.

i was talking just about diagnostics. the are many ways of diagnosing simple problems with yb engine sensors.

even the std diagnostic port can give you a fault code through an led for broken sensors or wires

http://www.homepages.hetnet.nl/~pete...ecu_error.html

then there are standalone monitors like SECS or pectel/collins that can definitely show you faults with Crank & Phase

and then there is the daddy, the RP Labs IAW Monitor software

available through Motorsnort Developments, http://www.motorsport-developments.c...iawmonitor.htm , or as you are outside of UK where UK distributor rules do not apply, you can go direct to RP Labs

 

There is a screw on all cosworths to adjust the idle mixture. Mine is on the ECU, had to adjust this to pass MOT. Earlier models is under the bonnet. Don't know how this relates to mixture further up the revs though


Rgds,
Pete.

 

that screw is known as the CO pot as you can use it to adjust the mixture at idle to set it correctly (usually done at MOT time using an exhaust gas anlyser that measures carbon monoxide content of the exhaust gases).

however, the ecu reads the voltage across that potentiometer and uses it as a multiplier for the main fuel map, so it affects every fuelling point, not just idle. so be very careful when changing that, as you could cause massive problems by changing the on boost mixture

 

Thanks Nick for that link. I know the owner of that site William Peters (also a dutchman but now doesn't own a cos anymore due to an accident), but haven't seen this page yet.

And Pete I do know this adjustment screw and have had the car on a CO machine to adjust it to the required 2.7%.

At idle it seems ok, but as soon as I tried to move the car it feels sluggish and only after setting the CO at about 4.5% or higher it wants to drive away.

With that higher CO setting I went to a rolling road session and I found a good power figure: 322bhp/485NM. (the usual greens, 3 bar, MSD chip etc).

But the operator showed me how lean it was from start till end. AFR started at 15,5(!) and the lowest figure at peak power showed an AFR of 13,9 (!!) (20 PSI boost).

Well, shocked from these AFR results but happy nothing went wrong I put the car in the garage and now checking everything to find out what this can cause before I will drive it again..

 

if it's throughout the whole speed range, i would suspect something like fuel pressure rather than the speed or phase sensor. as if they are having problems due to gap or old wiring etc, they tend to work ok at lower rpm but break down completely at higher rpm

that is if it was ever correct. if not, could be wrong chip

 

I have had a fuel pressure gauge connected and had it set at 3 Bar at idle.

Than when revving it I saw the fuel pressure going up with the same amount as the boost gauge showed. Of course when revving in neutral the boost didn't came above 0 psi so till that point I could see that it looked ok. Didn't have a chance to drive the car with this fuel pressure gauge as it was connected under the bonnet.

Did you see the pink AFR line in the dynosheet I put up here?

https://passionford.com/forum/viewto...light=#3230578

 

with the pressure signal pipe disconnected?

just looked. shape looks good, but looks to be offset from where you would ideally want it to be which indicates a multiplication factor of the fuelling to be out somewhere. something like the CO pot set too lean, too little fuel pressure, or possibly just an air leak in the exhaust before where the rolling road lambda sensor was placed.

get it to a proper tuner who can check your fuel pressure and fuelling on the road

 

No Nick, not with the pipe disconnected cause than it should be 3.5 Bar shouldn't it?

And yes your saying about the offset also came to mind when I studied the dynosheet.

Like I told you, CO was set at about 4.5% otherwise it wouldn't drive (but set at the required 2.7% CO all seems nice at tickover), fuel pressure like explained above and for the air leak, well could be. But the car hesitates when driving and accellerating. So only when set the CO higer and turning up the fuel pressure from 3 bar to 3.6 bar the car feels better to drive. But I did the rolling road session only with raised CO, not with the higher fuel pressure.