Hello all

I am after a bit of advice, I have been playing around with the tuning of my Duratec for a little while now and decided to change to Alpha-n.

Now I could be wrong, but as soon as I changed to this (admittedly I did not change all the settings) it seems that it is reading lean (around 19ish) even though when just idling I can see fuel coming from the exhaust pipe.

So tonight, I went through the whole mega tune program, changed as much as I could, re-calibrated the sensor (think it needs doing again) and burnt it to the mega squirt.

Now as I could see fuel coming out I made the area leaner and the readings were closer to what they should be (even though they were erratic) and it idled better

So, if the car is fuelling too much can the readings be showing lean??? If not... what may I be doing wrong...?

2.0 Duraburp, zx10 throttle bodies, Standard injectors, MS&S V3 and I have attached a copy of me msq file

In the LC-1 Instructions it says when and how often it should be calibrated, so that may help as to how often it needs doing or under what situations.

You might be unlucky as us, When first setting it up it ran as lean, it didn't seem to matter how much I richend the fuel map it wouldn't compensate and the car was sluggish.

Turned out we were a cylinder down, as the spark plug broke down under load but would idle fine.

So in our case it was running lean basically because there was a whole cylinder full of air and a little bit of petrol going straight through into the exhaust, making it appear it was lean!

I'm afraid I can't help with the Alpha-N settings as i've just moved onto them as well.

Another thing to consider is it also changes the timing map to be TPS controled if the MS does the sparks as well.

If you have fuel coming out of the exhaust with the engine running there is something seriously amiss, are you sure it's not water coming out. Fuel would evaporate under the slightest heat and cause massive backfires in the exhaust system. Water is a by product of combustion of hydrocarbon fuels and is blown out of the exhaust of most petrol engined cars till they are hot.

You need to bare in mind that if you run relly rich it coats the O2 sensor in petrol which means it can't get a decent reading so reads it as really lean. Basically the sensor reads O2 not petrol so if its covered in petrol theres no o2 to meter and it thinks it lean. (so I've read anyway). LC-1 is great but not idiot proof. You've got to ge the mixture in the right ballparik to start with...HTH Oli.

Hi Cheers for the replies, I think that i may be a cylinder down thinking about it, i will check later on.

and also it may be water coming from the exhaust (cant find red faced smiley)

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Originally posted by ibakes
So, if the car is fuelling too much can the readings be showing lean???

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Hello All

Right, it looks like its not firing on number 3 or 4 cylinder (pull the plugs and no change in revs etc), spark is all ok new plugs 700 miles ago, bit sooty but still playing with fuel tables, 240psi (throttle open) on all cylinders, and all injectors are squirting fine.

New coil pack, old lead all measuring around) 1500 ohms (roughly depending on length).

Don’t think it’s the wiring from the edis system other wise it would be ok between 1&3 or 2&4 etc

Any ideas?????


[Edited on 22/9/07 by ibakes]

Not sure on this one, but we've had a go with Alpha_n today.

Our TPS needed re-calibrating for some reason and all our VE bins were out as the MAP only went as low as 30KPA and of cause the TPS starts from 0 all the way to 100! DoH!.

Then the exhaust can bracket snapped! so it was time for home... was just getting the hang of it as well.

P.S The +12V for injectors 3 and 4 are likely to be commoned.. are the butterflys as well, are they opening?

[Edited on 22/9/07 by MkIndy7]

Sorry to hear about the exhaust bracket

Right the exhaust manifold for 1 and 2 get very hot very quick but 3 and 4 take quite a bit longer.

Fuel being suirted in to the cylinders as i took the fuel rail off earlier and all 4 operated fine

Will get the exhaust bracket welded up soon enough.. just need to prey for some more dry days!

As you've said most of the spark problems are related to cylinders 1 and 4 or 2 and 3... although swapping the leads and plugs about if there the only 'old' components can't do any harm.

Are they pairs of TB's or singles?
Are they Joint butterflys so 1 and 2 could be opening more than 3 and 4 and thus not balanced correctly.

Is it set to batch injector fireing?
I remember a setting about you needing atleast 2 squirts per event or certain cylinders get no fuel.

Is there some kind of fast idle, 'choke' or air bypass that could be working only on cylinders 1 and 2?

Try and think about what is Unique about cylinders 1and2 and what they have in common.
When we checked our plugs 1 and 2 were pretty sandy but 3 and 4 were quite wet.

Nah the problems have been mostly between 3 and 4, if they had been between 1 and 4/3 and 2 I would have swapped the leads over on the coil pack

When I take the plug leads off either 3 or 4 spark plug the engine doesn’t change, but f you do the same with 1 or 2 the engine almost stalls out

I have taken all plugs out swapped them around but that doesn’t really make much of a difference.

The car is on ZX10 throttle bodies, which are in 2 pairs, 1&2/3&4 I have not balanced them but by eye using the throttle stop adjuster they open at exactly the same time, but it is something to double check

And not using a fast idle valve

Here is a picture of one spark plug and all look the same as this



The only thing that is not new are the leads, because they are of a fixed length I cannot swap them around. But they all read the same resistance at 1500 ohms (which I thought was a bit high)

Probably a silly question, but did it run ok before changing to Alpha_N.. or was there maybe a bit of a problem then and thats why you've changed?.

Another possibility i've just picked up on from another thread is an air-leak on the connecting rubbers if they've been moved around a bit or had a few bacfires.

Nah all ok before hand.. but....

i had just removed my throttle bodies to fix my new starter, so i will double check tomorrow to make sure they are nice and tight

have silicone pipe connecting throttle bodies to manifold

Right, (sorry for the delay) made sure the throttle bodies were done up tight and all exhaust pipes get hot within the same time and temp etc.

took out all plugs gave them a bit of a clean up and with the revs up to 1500ish the engine drops in revs whith each lead pulled

but the lc1 sensor still reads above 19????

not taken it around the block yet to see if it runs ok

Does it read and AFR of 19 in Megatune or the in LC1 software - or both? If you've not done it then you need to check you've got the same calibration in Megatune as in the LC1 itself.

Hi, Not checked that yet, was on the list of things to do.

I thinking that it is just over fueling, the spark plugs are sooty, no other reason for the misfires and it stinks of fuel, on idle you can take 2 of the plugs off without a change but when up the revs to 1500ish they are all effected.

also found this within the manual

Beware that if you go so rich that you start to see misfires, the lambda sensor will read the unburned mixture as dead lean (since unburned oxygen is present) and the closed loop algorithm will attempt to add fuel, which the Auto-Tune algorithm will detect and adjust the VE bin richer, thus making a bad situation worse

So currently the map on idle sits around 47, revs are around 900, Is it ok to alter the throttle stop to open the butterflys more then reduce the fuel as the revs increase?

You really have to go through everything with a fine toothed comb and make sure its right in your own mind before asking (please don't take that the wrong way)

All the calibrations settings for the TPS, Lambda, temperature etc must be correct for it to ever have a hope of running correctly.

Have you re-done your REQ fuel since changing the code.. that will give you a blank canvas to start with and it could have changed.

Have you changed all your VE map bins to got from 0-100 since swapping the code... also the timing bins as well if it controlls timing (as MAP will have only gone from approx 30-100 KPA).
This could be another reason for the backfires if the ignition timing is now advancing and retarding according to the TPS

900 Rpm sounds a good strong idle so if it needs raising much more its likely to be something else thats wrong.

I had a similar problem and had forgotten to balance the throttle bodies, I did it by eye when I respaced them but didnt check once it was running. Listen at each buterfly with a piece of thin tubing to your ear with the engine idling and adjust the balance screw or get a carb balancing tool. The other thing I found when changing to alpha n is that the tps bins use raw figures ( 0 to 255 ) so you have to scale your bins from your tps calibration, mine goes from 52 to 220.

Having sorted that out I was tuning using megalogviewer but it was only adjusting the lower half of the ve table. This was because MLV assumes tps range of 0 to 100 as opposed to the raw tps values of 52 to 220. I did a search on the forum and found the solution on a thread somewhere. Hope this helps.

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Originally posted by zetec mike
I had a similar problem and had forgotten to balance the throttle bodies, I did it by eye when I respaced them but didnt check once it was running. Listen at each buterfly with a piece of thin tubing to your ear with the engine idling and adjust the balance screw or get a carb balancing tool.

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quote:

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Originally posted by zetec mike
The other thing I found when changing to alpha n is that the tps bins use raw figures ( 0 to 255 ) so you have to scale your bins from your tps calibration, mine goes from 52 to 220.

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quote:

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Originally posted by zetec mike
Having sorted that out I was tuning using megalogviewer but it was only adjusting the lower half of the ve table. This was because MLV assumes tps range of 0 to 100 as opposed to the raw tps values of 52 to 220. I did a search on the forum and found the solution on a thread somewhere. Hope this helps.

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