Description
The setup is Zetec RS1800 Twin 45DCOEs Nodiz Pro
We have a misfire at approx 3500rpm under load in all gears, when the the car is stationary the engine will rev higher but still starts cutting out
around 4000rpm.
Initially thinking it was a fuelling issue. Things we have triple checked is jet sizes, venturi sizes, pump jets, float levels, and fuel pressure.
Jets etc installed:
34mm Chokes
50 F11 Idle Jets
145 Main Jets
170 Air Correctors
F16 Emulsion Tubes
4.5 Aux Venturi
40 Pump Jtes
200 Needle Valve
Facet Posi Flow 4-7psi Fuel Pump
Filter King Fuel regulator
Nothing has improved the issue so now looking at spark issues.
The Nodiz Pro has decided to be very unstable connecting to the laptop over bluetooth but the map loaded is for a 2.0 Zetec on carbs supplied by
Nodiz.
Planning on double checking the timing this weekend.
Spark plugs are new.
Could be coil pack or HT leads?
Has anyone got any other suggestions?
[Edited on 27/6/19 by mark.silcock]
Check for corrosion or possible short circuits on your ignition circuit. Has the car been mapped at all? It would be good to get an idea of the air/fuel mixture as it stands.
this is the map on the Nodiz
Description
What Crank sensor are you using? I had similar issue with my megajolt setup, using a ford CPS. It would drive fine under light throttle and die
momentarily under load. Idling it would rev high under light throttle up to approx. 4k. Replaced CPS and all returned to normal.
Hope this helps.
Rob
Thanks, using the Zetec CPS
Will look into it.
Am I right in saying the Nodiz only does ignition? You'll need to get the fuelling table to see if theres a problem, just get a run done on a
dyno.
All engines are slightly different, so cause someone else has the same parts and it works fine, yours might need some fine tuning to get it there.
I'd start by checking the electrical side, all your sensors (cps is a good shout) make sure the alternators good, earths, everything. Then move
onto the fuelling side of things.
I hope I'm not telling you how to suck eggs!
Yes the Nodiz only does ignition.
Planning on getting it on the dyno but would rather check everything first, dont want them chasing their tail identifying an issue if I can help
it.
Dont worry any advice is good advice at this stage.
Worth noting we need to get it through the non cat emissions test for the IVA.
Is this when the engine is Hot and Cold?
Is it worse when either of the above applies?
I had a similar problem, are you using a shielded cable for the nodiz to crank sensor with the shield connected to earth at one end? I wasn’t and was picking up interference from somewhere else that was causing a similar fault.
Have you checked for a "Soft Cut"? in the ignition table?
i had a problem like this with megajolt trigger wheel set up. the vr sensor was picking up viberation at higher rpm
one of the cables in the vr sensor was loose. not only that the vr sensor was too far away from the trigger wheel.
i re wired the vr sensor at the trigger wheel side.
i re mounted the vr sensor so it was almost touching the trigger wheel.
the way i realised it was this, was on the laptop at high rpm i noticed the rpm digital gauge would go out of synch at high rpm after3500-4000rpm.
cheers
So I still havent got to the bottom of this issue, have thrown at it new coil pack, leads, plugs, main jets, idle jets, chokes, needle valves, pump
jets, fuel pump and nothing has made a difference. Engine temp doesn't make a difference.
Spoke to Nodiz and they dont believe its an issue with the ECU as it is only running off the crank sensor so the unit cannot detect any engine load,
and seeing as it can rev fine with no load up to the limiter the unit is working as it should. Also the crank sensor seems to be fine. Have checked
the soft cut settings and the launch control setting on the Nodiz and nothing is set to around the 3500rpm.
Other things I have tried are used a colourtune to tune the idle adjustment, sync'd the carbs, checked float levels, set the fuel pressure at the
last carb to 2.5psi..... think that is about it.
So the assumption now is that the carbs need rebuilding, or I might go EFI as I have a Ginetta intake manifold and fuel rail sitting in the garage.
Only issue with that is it would need a new ECU and fuel pump, also getting it under the bonnet will be a challenge.
Well that was more a of a vent than anything else but open to any suggestions....
It will be the crank sensor, either it is faulty, too far from the crank wheel or not screened correctly. Change it for a start.
[Edited on 20/9/19 by jeffw]
I dont see how its possible for a carburettor to cause a missfire like this.
quote:
Originally posted by jeffw
It will be the crank sensor
What has changed since it was last running correctly?
quote:
Originally posted by mark.silcock
quote:
Originally posted by jeffw
It will be the crank sensor
Why would load affect it though?
quote:
Originally posted by RichardB123
What has changed since it was last running correctly?
quote:
Originally posted by RichardB123
I dont see how its possible for a carburettor to cause a missfire like this.
quote:
Originally posted by RichardB123
quote:
Originally posted by mark.silcock
quote:
Originally posted by jeffw
It will be the crank sensor
Why would load affect it though?
An ignition system is working hardest under load.
Just revving it up not in gear, the spark can be very weak or late/early and it would still sound OK
Does it missfire when the engine is hot or cold or does it make no difference?
I'd agree with Jeffw though and say Crank sensor
quote:
Originally posted by mark.silcock
quote:
Originally posted by RichardB123
I dont see how its possible for a carburettor to cause a missfire like this.
It just feels and sounds like fuel starvation.
In an earlier post you said..."it is only running off the crank sensor so the unit cannot detect any engine load, "
So to be clear, it has no TPS or MAP sensor?
Or am I missing something?
It wouldn't be the first time.
If it was forced induction I might suggest reducing the spark plug gap. Worth a try?
I had a similar, but admittedly non load dependant misfire on my Megasquirt install, which was cured by
putting a 10K resistor in line with the VR sensor.
Float bowl fuel levels correct?
Many coil packs have an associated suppressor/capacitor attached? Does yours? Should it have? Is it faulty?
Faulty Battery isolator switch ?
Although they usually cause a high speed/RPM missfire...
quote:
Originally posted by perksy
Does it missfire when the engine is hot or cold or does it make no difference?
I'd agree with Jeffw though and say Crank sensor
quote:
Originally posted by SPYDER
In an earlier post you said..."it is only running off the crank sensor so the unit cannot detect any engine load, "
So to be clear, it has no TPS or MAP sensor?
Or am I missing something?
It wouldn't be the first time.
If it was forced induction I might suggest reducing the spark plug gap. Worth a try?
I had a similar, but admittedly non load dependant misfire on my Megasquirt install, which was cured by
putting a 10K resistor in line with the VR sensor.
Float bowl fuel levels correct?
Many coil packs have an associated suppressor/capacitor attached? Does yours? Should it have? Is it faulty?
If it is no different with the new crank sensor I will video what it is doing.
Without any sort of load sensor the 3D ignition map you posted has no purpose. I assume it simply runs across the 100%, "full throttle" line.
Runs across the top line from memory.
I'd prefer the bottom line.
Ok another update.
So I first off checked the fuel levels in the bowls, one carb was off by about 5mm so adjusted the floats so they are both the same and are approx
26mm +-1mm.
Drove the car and again it's no different.
Crank sensor finally turned up and fitted it to the car.
Drove it and it's no different.
It wasn't running particularly well stationary tonight but still would rev past 3000rpm, probably needs an idle adjustment after the float level
change.
Was suggested to try pulling the choke out while its not reving to see if extra fuel would make any different but that didnt do anything either.
Here is a sketchy video.
Could this "rev limit" be due to the Nodiz expecting a load signal and not getting one?
Did you try putting a 10K resistor across the VR sensor?
[Edited on 27/9/19 by SPYDER]
I am not sure what you mean by VR Sensor? Ah crank sensor? No I haven't and what does that do?
The Nodiz is set to no load so its not expecting any signal.
[Edited on 28/9/19 by mark.silcock]
[Edited on 28/9/19 by mark.silcock]
When you changed engine was the flywheel changed also or is the new engine and flywheel as it came as complete know running unit Ok.
Reason for asking is that when changing the CPS for a new one it might not be the actual CPS at fault but the housing it fits into. There are 2-3
different housings with differing CPS location within the housing for the Zetec and if the housing and flywheel are not in correct positioning to each
other you will get what shows as a CPS issue but its not the actual CPS at fault but its location.
Hope that makes sense.
Matt
Yeah it does make sense and something I had been thinking about. The flywheel was swapped over along with the crank sensor from the original engine
that came with the car. Which from memory was a 1997 silvertop. The crank sensors did look the same but if the blocks are different then that would
cause an issue.
How do I check?
Original engine was a Nov 1997
Current engine is a May 1992
[Edited on 28/9/19 by mark.silcock]
[Edited on 28/9/19 by mark.silcock]
The 10K resistor is a well known fix in the Megasquirt community. The problem is noise related and can cause the ECU to miss-read the missing tooth.
It's more common on 60 tooth wheels but can show up on 36 tooth types.
To correct my earlier post.... the resistor goes INLINE with the crank sensor, not across it.
quote:
Originally posted by procomp
When you changed engine was the flywheel changed also or is the new engine and flywheel as it came as complete know running unit Ok.
Reason for asking is that when changing the CPS for a new one it might not be the actual CPS at fault but the housing it fits into. There are 2-3 different housings with differing CPS location within the housing for the Zetec and if the housing and flywheel are not in correct positioning to each other you will get what shows as a CPS issue but its not the actual CPS at fault but its location.
Hope that makes sense.
Matt
quote:
Originally posted by SPYDER
The 10K resistor is a well known fix in the Megasquirt community. The problem is noise related and can cause the ECU to miss-read the missing tooth. It's more common on 60 tooth wheels but can show up on 36 tooth types.
To correct my earlier post.... the resistor goes INLINE with the crank sensor, not across it.
Re flywheel differences, depends on a few things such as Fiesta, CVH, Zetecs 1.6 1.8 2.0 Etc Etc but we have had issues with swapping some lightweight flywheels from old to new engines when not changing the complete CPS and housing.
If you are having flywheel trigger pattern woes.
Surely this aftermarket ignition system can work from a trigger wheel mounted to the front crankshaft pulley.
Like megasquirt/jolt etc.
quote:
Originally posted by RichardB123
If you are having flywheel trigger pattern woes.
Surely this aftermarket ignition system can work from a trigger wheel mounted to the front crankshaft pulley.
Like megasquirt/jolt etc.
quote:
Originally posted by procomp
Re flywheel differences, depends on a few things such as Fiesta, CVH, Zetecs 1.6 1.8 2.0 Etc Etc but we have had issues with swapping some lightweight flywheels from old to new engines when not changing the complete CPS and housing.
The CPS fits into a housing which fits onto the block and there are different housings/CPS for manual and auto gearboxes.
Heres a pic of two. but have found over years 4 different ones.
Wont let me add pictures here but added photo to my page.
https://www.facebook.com/Procomp-motorsport-376574512390043/
Ah I see, could not remember noticing that but luckily have a photo of the engine code that shows the mount.
Description
Im guessing thats a good result as it should be close to the flywheel?
[Edited on 4/10/19 by mark.silcock]
[Edited on 4/10/19 by mark.silcock]
Update:
New Nodiz ECU installed and guess what its no different.
So I want to get to the bottom of making sure the crank sensor/housing and flywheel is the right combination.
What do I need to know and how do I check to get it right?
Did they ever do an RS1800 Automatic?
Looking through the photos the original engine was a manual.
Can you tell from engine numbers?
would the engine even start with an auto housing?
[Edited on 5/12/19 by mark.silcock]
If you are using the advance curve on the top line of the map then it has probably got to much advance at 3500 and above , what happens if you reduce
it to about 15 degrees across the map.The figures across the top of map are more like wht it should have on overrun.
Paul
It runs exactly the same with the base map on the new Nodiz that is much more conservative.
We have loaded a few different maps and they have made no difference to the missfire.
What about poor shielding from the CPS? What are the symptoms of that?
Go back to basics on the ignition the way you have on the fuel, if you haven't already.
1) Check your static timing at idle. Check it doesn't wander. Use nodiz set up with values of 10 across the whole row to check it doesn't
wander as you increase revs.
2) Check your crank sensor polarity is correct (it makes a difference to how the signal is interpreted).
3) Check your coil dwell time - insufficient dwell will cause misfire under load.
4) Check your spark plug gap - wrong gap will cause misfire under load.
5) Check for tracking at night in total darkness - tracking will be most noticeable under load but if it's visible at idle it needs fixing.
6) Buy/install a load sensor of some sort, using a 2D timing table is un-necessarily archaic, better to fix it now.
7) Running "too lean" with any of the above weaknesses can cause misfire.
Is there a "rising/falling edge" setting in the Nodiz?
So I first want to get the Crank Sensor Housing question sorted as I need to know if I need to take the engine out.
Here is a video showing the timing marks through the CPS hole.
Can someone please compare, should they be in perfect alignment or is this how they are?
[Edited on 8/12/19 by mark.silcock]
quote:
Originally posted by SPYDER
Is there a "rising/falling edge" setting in the Nodiz?
quote:
Originally posted by coyoteboy
Go back to basics on the ignition the way you have on the fuel, if you haven't already.
quote:
Originally posted by mark.silcock
So I first want to get the Crank Sensor Housing question sorted as I need to know if I need to take the engine out.
Here is a video showing the timing marks through the CPS hole.
Can someone please compare, should they be in perfect alignment or is this how they are?
[Edited on 8/12/19 by mark.silcock]
Had an oscilloscope on the crank sensor last night.
Signal looks fine and clean at idle and at high revs.
Image taken at approx 4000rpm which is higher than the miss-fire occurs on the road.
Description
I think it's safe to put that to bed and move on?
Update time.
Took the car to AP Racing Engines in Blidworth today and Andrew managed to sort the car out.
So it was running very rich and the main issue which I wouldn't have believed if I didnt see it for myself was the air filters!
Andrew had the car to a point he was happy with pulling 131bhp at about 5500rpm with the filters off, then put them on and the engine produced 76hp
and wouldn't rev past 3500rpm.
He was staggered and so was I.
The two runs, bright yellow line filter off, dark yellow line filters on!
Description
These are the offending filters, which have had very little use and not dirty.
https://www.ramair-filters.co.uk/shop/automotive/carburetor-itbs-automotive/sock-filters-automotive/twin-inlet-carb-socks-and-velocity-stack-filt
ers/
Would never in a million years had guessed they were the issue, but of course everytime I road tested the car it had the filters on, and when working
on the carbs in the garage the filters were off so would rev ok stationary then wouldnt on the road. I assumed it was fuel starvation not air
starvation!
Still can't believe it myself, but at least the car is pulling nicely now and apart from the rain in the face I had a lot more fun drive home!
IVA time!