David_17
|
| posted on 25/3/11 at 08:54 PM |
|
|
Megasquirt beginners tips
I've been playing with my megasquirt for a while now and not making any progress.
It turns out there was something wrong inside the ecu, causing misfires and eventually stopped sparking, which has now been fixed so its running on 4
cylinders.
I'm having problems with very rich running, which if i reduce the req fuel causes pops and bangs if i touch the throttle. I've tried
reducing the ve table at low revs which didn't seem to work either 
I don't know what to try next, any tips?
It's a 2.0 zetec with standard injectors and gsxr throttle bodies.
All sensors are calibrated and working, fueling is set to alpha-n, and lambda is a tech edge wideband.
Any tips I can try? Or anyone near middlesbrough who knows what they're doing able to pop over and have a look/listen?
I'm stumped.
[Edited on 25/3/11 by David_17]
|
|
|
|
|
austin man
|
| posted on 25/3/11 at 08:58 PM |
|
|
Have you tried one of the maps that are available on the net for your setup ? and are you sure you havent got any air leaks on the inlet side
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
|
|
|
coozer
|
| posted on 25/3/11 at 08:59 PM |
|
|
David, it sounds very like the problems I had.
Want me to pop down with my lappy and see if we can get it running?
I was stumped for a while but after 3 full tanks of petrol I got there
Steve
1972 V8 Jago
1980 Z750
|
|
|
David_17
|
| posted on 25/3/11 at 09:01 PM |
|
|
Hi. Thanks for the rapid resopnse 
Im using a base fuel map and spark table designed for a zetec, yes. I haven't looked for an air leak, as i thought that would cause it to run
lean, not rich???
|
|
|
David_17
|
| posted on 25/3/11 at 09:02 PM |
|
|
quote:
Originally posted by coozer
David, it sounds very like the problems I had.
Want me to pop down with my lappy and see if we can get it running?
I was stumped for a while but after 3 full tanks of petrol I got there
Steve
That would be great! When are you free? I'm usually available sundays.
|
|
|
ashg
|
| posted on 25/3/11 at 09:18 PM |
|
|
when you try to rev it press the accelerator very gently . if you push it down too fast it will engage the acceleration enrichment which may be your
problem.
if you can get it to build up revs by slowly pressing down on the accelerator but not if you press the pedal down reasonably fast look at the
acceleration enrichment settings.
do another log of it running on idle try to increase the revs slowly first then quickly and post it up.
have you installed megalog viewer? it makes it much easier to see what is happening by loading up the log files in it and scrolling through.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
|
|
|
paulf
|
| posted on 25/3/11 at 09:19 PM |
|
|
You need to calculate the required fuel accurately using the correct flow rate of the injectors which means running them at the original correct fuel
pressure at least to start with.Then adjust the idle fuel bins until it runs at about the correct mixture and idles smoothly.With alpha_n the map bins
rise steeply with throttle opening and so if the required fuel is not correct then it is difficult to adjust the next bins from idle. Then try for
light throttle openings with the car stationary until it revs cleanly then try driving on light throttle with some data logs to get an idea of the
bins for higher load and revs.
I found it much easier to work out a working map for speed density but could not get a clean throttle response at light loads and so eventually
changed to alpha n and found it worth the extra complication involved in the mapping.
Paul
|
|
|
David_17
|
| posted on 25/3/11 at 09:21 PM |
|
|
Thanks for the tips ash. Yep i've been moving the throttle as slow as possible and having the same issues. Also already using log viewer. 
If there wasn't enough vaccum on the fuel pressure regulator would that do it? As i've used the orignal feeds on the throttle bodies which
only have very small holes in.
|
|
|
David_17
|
| posted on 25/3/11 at 09:23 PM |
|
|
Cheers Paul.
I've been told 2 different flow rates for the injectrs, one gives a req fuel or 13.4, the other 20. I've tried both these settings and
both run very rich.
|
|
|
paulf
|
| posted on 25/3/11 at 09:31 PM |
|
|
Are you using the original fuel pressure reg? if not then the flow rate will be different depending on the pressure.Im using gsxr injectors and the
flow 230cc and my required fuel is 13.5 .If there Bosch ones they will have a number on them that denotes flow rate which you should be able to find
on Google.I would turn off the accel enrichment at first as ive found it confuses things when first making adjustments and is not needed until you
have a basically drivable map on light throttle.
Paul
|
|
|
David_17
|
| posted on 25/3/11 at 09:34 PM |
|
|
Yes, i'm using the fuel pressure regulator that came with the zetec and the zetec injectors. The vaccum is off the throttle body take off pipes.
The acceleration enrichenments is off already too.
Will check for an inlet leak tomorow evening, although i can't see that being the problem.
|
|
|
coozer
|
| posted on 25/3/11 at 09:54 PM |
|
|
u2u sent.....
1972 V8 Jago
1980 Z750
|
|
|
ashg
|
| posted on 25/3/11 at 09:58 PM |
|
|
Ah there could be your problem. i would bin the vacuum fuel pressure regulator if i was running itb's and fit an after market one that you can
manually set. the vacuum on itbs doesn't behave in the same way as it does on a single throttle body so i doubt the standard ford regulator
will be able to cope.
i have got a couple of good books on the subject. will have a read up tomorrow for you but im pretty sure it could be related to running the vacuum
fpr
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
|
|
|
David_17
|
| posted on 25/3/11 at 10:05 PM |
|
|
Hmmm... Anything i can do to the regulator to see if its that?
u2u replied to.
Cheers
|
|
|
paulf
|
| posted on 25/3/11 at 10:30 PM |
|
|
You dont have to have the vacuum connected to the reg, it does help with the fueling on light throttle however as it compensates when the vacuum is
high.I have a Mondeo pressure regulator capsule in a housing that i made to fit it and it copes perfectly well.The cheap E bay adjustable ones may be
less reliable in my opinion.
Paul
quote:
Originally posted by David_17
Hmmm... Anything i can do to the regulator to see if its that?
u2u replied to.
Cheers
|
|
|
coyoteboy
|
| posted on 26/3/11 at 12:34 AM |
|
|
It's very very hard to tune properly without a wideband, I spent more in fuel than the price of the LC1 trying, then still had to buy it to get
it right.
|
|
|
RazMan
|
| posted on 26/3/11 at 09:13 AM |
|
|
quote:
Originally posted by coyoteboy
It's very very hard to tune properly without a wideband, I spent more in fuel than the price of the LC1 trying, then still had to buy it to get
it right.
Absolutely right IMO - My Wideband sensor & gauge are an essential part of my mapping procedure. I can instantly see what's happening with
every tweak. You still need to put a lot of miles on the clock, adjusting the map as you go - I'm on my 3rd tank full now but I am getting close
to finishing it ...... if it ever gets finished 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
David_17
|
| posted on 26/3/11 at 05:25 PM |
|
|
As per my first post, i have a tech edge wideband.
It's running very rich all the time and won't rev past 2000, if i slowley increase the throttle from idle, it gets to 1900 ish revs then
the exhaust pops the mixture goes lean and it's back to square one.
Hard to explain, i don't have a clue what's going on. I'm assuming the timing can't be out or it wouldn't start at all??
|
|
|
David_17
|
| posted on 26/3/11 at 05:36 PM |
|
|
Forgot to mention, had a play with it this afternoon and I've also noticed the Target AFR Gauge in tuner studio says something like 10.76
(can't remember the exact number off the top of my head) - i cant find any way to change this to 14.7
What's going on there?
Also had a look at the log file. Looks as though it's loosing the rpm signal just before 2000 revs. What would cause that?
[Edited on 26/3/11 by David_17]
[Edited on 26/3/11 by David_17]
|
|
|
scudderfish
|
| posted on 26/3/11 at 06:48 PM |
|
|
How is your crank sensor mounted? I would suspect flex/resonance if it is predictably cutting out at specific revs.
|
|
|
scudderfish
|
| posted on 26/3/11 at 06:50 PM |
|
|
Are you running EDIS or controlling the spark directly?
|
|
|
David_17
|
| posted on 26/3/11 at 06:53 PM |
|
|
Thanks for the reply.
It's the standard ford zetec sensor bolted to the block, the wiring has a few inches of slack to allow for engine movement then is clipped to
the chassis. (it does pass close to an alternator wire).
|
|
|
scudderfish
|
| posted on 26/3/11 at 07:01 PM |
|
|
I had a problem going the other way with big spikes in RPM (I wish I really could get > 9000rpm out of a Rover V8 ) which was down to the crank
sensor mount flexing. However it was a homemade thing, not part of the block. I would concentrate all your effort on getting a good RPM signal with
no noise as if you don't have that, all bets are off for everything. You can play with fuelling forever, but if the ECU thinks the engine is
running at a wildly different speed to what it really is then it will never put the right amount of fuel in.
|
|
|
paulf
|
| posted on 26/3/11 at 09:52 PM |
|
|
Have you got the rev limit set at 2000rpm? also the fuel and ignition load bins should match, yours looks like the fuel is up to 100 as would be used
for a speed density map and ignition bins are going up to 235 ADC value which would be about correct for Alpha -n, Double check the fueling is set to
alpha -n then calibrate the throttle sensor and put the correct values into the maps.
You should have a couple of rows near the closed throttle position for idle and a few near together for cruise around half throttle and a couple of
rows near full throttle.Set then in the ignition and fuel maps the same.
Paul
quote:
Originally posted by David_17
Forgot to mention, had a play with it this afternoon and I've also noticed the Target AFR Gauge in tuner studio says something like 10.76
(can't remember the exact number off the top of my head) - i cant find any way to change this to 14.7
What's going on there?
Also had a look at the log file. Looks as though it's loosing the rpm signal just before 2000 revs. What would cause that?
[Edited on 26/3/11 by David_17]
[Edited on 26/3/11 by David_17]
|
|
|
scudderfish
|
| posted on 27/3/11 at 09:49 AM |
|
|
That's not the rev limiter, it's a signal problem. If you look at the second cut, there is no way the engine revs drop and accelerate
that quickly without the engine exploding. You can however nicely smooth the curve without the spike. Either the crank sensor is lying to the
megasquirt or if there is EDIS, the CS is lying to the EDIS module or the EDIS module is lying to the MS.
Do you have a spare crank sensor? Is the lead from the sensor shielded? Is the shield earthed only at one end?
Regards,
Dave
|
|
|
.jpg)
.jpg)
