DaveFJ
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 posted on 7/5/11 at 09:26 PM |
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Engine running rough
YES thats right... me asking for help yet again!
so....
I SORNd the car in november and have been replacing the dash
tried to take it round for MOT last week (its first one!) and didnt make it out of our road
seems to be running really badly, feels like it is on 3 cylinders but is MUCH worse when actually moving, on the drive it seems ok - ish.
have checked the following:
compression: 9,9.5,9.7,10 (not hugely out but not perfect)
plug lead resistances 14kO, 6kO, 6kO, 4kO (lead 1 seems a bit high but well within the 30kO i have seen quoted...)
resistance on all 4 injectors is 14 Ohms
fuel pressure is steady 3.5 bar
cranking fine
checked MS and tried loading an old 'known good' config
checked and cleaned plugs, all sooty black due to rich running but none wet
all 4 headers are nice and hot but dont have a decent temp tester to check exactly how hot each one is
fresh fuel in
checked crank sensor and looks fine, MS shows a good signal
tried unplugging each injector in trun whilst idling, heard a cinsistent dip in engine note/speed for each one..
thing is i think it is much worse when driving, on the drive it seems ok ish but as soon as you try to drive it becomes awful!
so any suggestions of other things to check/try welcome!
cheers
Dave
Dave
"In Support of Help the Heroes" - Always
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MakeEverything
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| posted on 7/5/11 at 10:04 PM |
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The high impedance on lead 1 could be because of its longer length.
Have you put new fuel in it?
Checked the fuel pressure?
Had the injectors cleaned?
I had a set of injectors that i had cleaned professionally, and one was 40% down on power. I would never have found that until last.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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coyoteboy
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| posted on 7/5/11 at 10:37 PM |
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Are you running resistor plugs? I've recently had them (champion plugs) cause me all sorts of issues in a tin top, one 3Kohm (about normal), two
at 6kohm and one at 20kohm - it started misfiring only under load and ended up misfiring almost always except idle and cruise. They were almost new
too.
[Edited on 7/5/11 by coyoteboy]
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jollygreengiant
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| posted on 7/5/11 at 11:46 PM |
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Whats the ignition, distributor or megajolt?
If distributor, have you checked the points if fitted, or if electronic have you checked the distributor cap and rotor, I have know the resistor in
the rotor arm fail, also it could be burnt/corroded contacts in the distributor cap or the carbon brush in the cap has failed/gone missing/spring
failed. It could also be damp in the cap.
It could also be a faulty earth some where near the engine.
It could also be that the fuel has 'gone off'
[Edited on 7/5/11 by jollygreengiant]
Beware of the Goldfish in the tulip mines. The ONLY defence against them is smoking peanut butter sandwiches.
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coyoteboy
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| posted on 8/5/11 at 12:03 AM |
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quote:
It could also be that the fuel has 'gone off'
This seems to be a common suggestion but from two angles I'm fairly sure fuel doesnt "go off" to that extent. One is a boat we have
that wasn't used for 5 years, we ran the remaining fuel on its next outing and it was fine (carb'd BMW straight 6) and the other is my GT4
which has sat on the drive, in a shed or in a field for the last 3.5 years and still runs as sweet as a nut on the same tank as when it was
SORN'd.
Fuel does lose its octane rating, but I don't think it's as bad as it used to be when you'd get varnishing and all sorts from the
manky contents. Just my experience though.
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MakeEverything
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| posted on 8/5/11 at 08:43 AM |
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quote:
Originally posted by coyoteboy
quote:
It could also be that the fuel has 'gone off'
This seems to be a common suggestion but from two angles I'm fairly sure fuel doesnt "go off" to that extent. One is a boat we have
that wasn't used for 5 years, we ran the remaining fuel on its next outing and it was fine (carb'd BMW straight 6) and the other is my GT4
which has sat on the drive, in a shed or in a field for the last 3.5 years and still runs as sweet as a nut on the same tank as when it was
SORN'd.
Fuel does lose its octane rating, but I don't think it's as bad as it used to be when you'd get varnishing and all sorts from the
manky contents. Just my experience though.
My experience of old fuel is that if its not contaminated from rust in the tank, it degrades as you say and seems to lose its potency. My kit car was
stood for over a year outside (before i bought it) and the fuel was totally 'off' through contamination of water, rust and god knows what
else. Ive experienced the same with old bangers as well.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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DaveFJ
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| posted on 21/5/11 at 04:30 PM |
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OK.....
I have totally refilled with fresh fuel
replaced the plugs - old ones where apr6fs resistive and looked fine but i replaced with ap7fs non resistive as that was the spec for 'fast
road' as per burtons......
new 8mm silicone Bosch leads
used carb cleaner and a home made test rig to clean the injectors and ensure that they are flowing ok
used those spark plug test light jobbies to prove i am getting a regular spark to all cylinders
checked compression
checked fuel rail pressure is steady at about 3.7 bar (a smidge high??)
still running like cr*p
any more ideas?
Dave
"In Support of Help the Heroes" - Always
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rusty nuts
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| posted on 21/5/11 at 06:45 PM |
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I see no mention of valve clearances, have you checked them?
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BaileyPerformance
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| posted on 21/5/11 at 10:11 PM |
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quote:
Originally posted by DaveFJ
OK.....
I have totally refilled with fresh fuel
replaced the plugs - old ones where apr6fs resistive and looked fine but i replaced with ap7fs non resistive as that was the spec for 'fast
road' as per burtons......
new 8mm silicone Bosch leads
used carb cleaner and a home made test rig to clean the injectors and ensure that they are flowing ok
used those spark plug test light jobbies to prove i am getting a regular spark to all cylinders
checked compression
checked fuel rail pressure is steady at about 3.7 bar (a smidge high??)
still running like cr*p
any more ideas?
Hi, please provide details of your megasquirt install, what version do you have? basic engine details, trigger system, coil(s)
If the engine mapped on vacuum (manifold to megasquirt) "speed density" of is it mapped on throttle angle "Alpha N"
Cheers Dale.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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coyoteboy
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| posted on 21/5/11 at 11:34 PM |
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Can you post some MS datalogging and tooth logging data?
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DaveFJ
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| posted on 22/5/11 at 10:06 AM |
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OK...
i'm runing MSnS extra on 29y code
i have the MSns driving a Mondeo 2.0 coil pack (the early sort with the clips on the ignition leads)
Wideband o2 sensor from innovate (lc1)
trigger wheel from an online site 36:1? triggerwheels.com???
pickup from the same site and mounted fairly well.
engine has been running ok (not perfect but well enough) for about 3 years
TBs are GSXR750/1000 with the standard injectors
using TPS from the throttle bodies and have checked in MS that the TPS reading is coming through properly. MAP is connected but not used.....
have just tried backing the fuel pressure down to 3bar and it seems to have made a little difference, still running like a bucket of bolts though.
I have a short log file, problem is the car is SORN at the monment so the most i can risk is once round the block....
car probably wasnt up to full temperature when log was taken, note the coolant sender needs recalibrating as it reads about 20 degrees high in
MS....
will post the log file as soon as i can work out how!
how do i get 'tooth logging' data?
[Edited on 22-5-11 by DaveFJ]
ok look HERE for files.....
[Edited on 22-5-11 by DaveFJ]
Dave
"In Support of Help the Heroes" - Always
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coyoteboy
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| posted on 22/5/11 at 11:39 PM |
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How do you have the LC1 configured? The only thing "obvious" to me is you look to be running really rich but I can't tell exactly
how rich without knowing your LC1 output setting.
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DaveFJ
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| posted on 23/5/11 at 12:08 PM |
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LC1 is IIRC setup in the 'standard' way .. ie 0v - 5v
I have been thinking that it does seem rich and the new plugs were wet after the first run (only a couple of minutes run time)
The fuel map I am using is now very different from the one i started with 4 years ago and has just been tweaked through the use of the megalog viewer
and its autotuning tweaks. over time it got better and better.
So a bit baffled why it would suddenly start playing up now... the fuel pressure did seem a touch high (3.8 bar approx) so i backed it off to 3bar and
that seemed to make for a more stable idle but I now have it 'popping' back through the throttle bodies which was a problem early on when
i first set her up....
the weird thing with the current issues is that it will idle ok but when i try to put some load on it by driving up the road it starts to really
playup... sounds like it is only running on 3 or possibly even 2 cylinders! and then dies.
having pretty much replaced the ignition side of things and successfully cleaned the injectors I am now thinking about repolacing the coil pack... not
a huge expense but the missus is beggining to question the fact that i keep throwing money at this problem and havent fixed it yet.... if i throw £50
away on a new coil and it makes no difference she wont be happy!
Dave
"In Support of Help the Heroes" - Always
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coyoteboy
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| posted on 23/5/11 at 12:23 PM |
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In MLV the logs show you're idling at ~ 12:1 and at higher revs you're at 16.5:1? Massively rich at idle (might be needed for your engine
but mine struggles <13:1) and at revs and light load you're up in a range that mine misfires like mad even unloaded? We have different
engines but I can't see yours being that tolerant?
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DaveFJ
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| posted on 23/5/11 at 12:32 PM |
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Are you saying i need to lean off the idle ?? but higher up is ok?
one of the things i struggled with (and had a hard time getting advice on) was the target AFR table... I pretty much worked on a finger in the air
type solution.... will try and grab my target table to post and also my current fuel table...
here you go......
[Edited on 23-5-11 by DaveFJ]
Dave
"In Support of Help the Heroes" - Always
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coyoteboy
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| posted on 23/5/11 at 12:45 PM |
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I'm wondering if you've a variable air leak if you've tuned it as you really could do with leaning off at idle and richening up at
higher revs/load. I'll happily post my AFR targets but it's for a turbocharged 4 pot so will not be overly instructive. Was it your thread
I posted a generic one to a while ago? Are you relying heavily on wideband feedback...hang on, I'll check in your msq 
You say you're not using MAP for tuning, did you try? What's your reasoning? Basing fueling off TP is a bit of a nightmare - 10% throttle
under load is totally different fuel requirements to 10% unloaded, both of which you'd see in a day to day scenario.
[Edited on 23/5/11 by coyoteboy]
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DaveFJ
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| posted on 23/5/11 at 01:02 PM |
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quote:
Originally posted by coyoteboy
I'm wondering if you've a variable air leak if you've tuned it as you really could do with leaning off at idle and richening up at
higher revs/load. I'll happily post my AFR targets but it's for a turbocharged 4 pot so will not be overly instructive. Was it your thread
I posted a generic one to a while ago? Are you relying heavily on wideband feedback...hang on, I'll check in your msq
You say you're not using MAP for tuning, did you try? What's your reasoning? Basing fueling off TP is a bit of a nightmare - 10% throttle
under load is totally different fuel requirements to 10% unloaded, both of which you'd see in a day to day scenario.
[Edited on 23/5/11 by coyoteboy]
variable air leak? are you talking about induction leak - ie extra air going in? or somehwere else?
I do have a small leak at my 4-1 collector on the exhaust which i know can cause some weird issues with idle revs going up and down
Reason for MAP is, when i set this up the best advice on here was that TP was the way to go for large-ish TBs. looking at my map signal its a bit of
a mess so i guess i would need to try to stabilise that before using it?
Dave
"In Support of Help the Heroes" - Always
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coyoteboy
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| posted on 23/5/11 at 01:02 PM |
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Cant get your MSQ to open in TS yet, something to do with your TP based tuning I suspect. Couple of things I've noted:
1) Your VE table values, on my PC at least, look reasonable (though very rich in the high load, low revs area, lean those out even if you rarely see
them.
2) You timing looks OKish, accept that for now while we work on the main problems.
3) Your VE table is very low throughout - you're using only about 30% of the resolution you could use (i.e. max values are 255, ideally your VE
table should cover 0-255, not 0-80. You need to scale your req_fuel and table to suit - on my engine I'd struggle to tune it to a stable AFR
with so few values.
I'm not a fan of Alpha-N, it's such a compromise it's not worth it IMO.
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coyoteboy
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| posted on 23/5/11 at 01:09 PM |
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Your map signals look pretty usable to me, would be nice with a small restrictor in to just smooth out some of the tiny lumps, but it's about
the same as mine on the stock MAP sensor/restrictor. What are you classing as a large TB? I've a 60mm TB on a 2 litre engine and it's
perfectly tuneable?
As I say, alpha-N is only really needed where MAP is massively variable (ITBs where you can't take a feed off all 4 ports, or single cyl
engines) - the rest of the time a pneumatic solution and speed-density is preferable IMO, for the simple reason that alpha-N assumes your engine only
sees one set of load conditions at any given throttle and RPM - this clearly isn't the case. I personally would switch to SD, but I know how
much time and effort will have gone into getting it to the stage it's at now so you may wish to continue down this line.
Secondly, when you're in positive pressure, how does your target AFR map know? I mean how does your throttle position relate to boost? I can get
15psi at 3000rpm, 10% throttle or 15psi at 3000rpm 100% throttle, I'd be happy with 13:1 at 10% throttle, but at 100% throttle I'd be
seriously worries about the engine health.
Re variable air leak - I'm thinking on the intake side - with alpha-n you're saying "at this throttle I'll have this air, so
give me this much fuel" - to have a change in tuning you must have had a change in airflow (if it worked fine once before). That said, with a
tuned exhaust system, a leak could effect scavenging and so cylinder fill, so you could be looking at changing the tuning that way yes.
[Edited on 23/5/11 by coyoteboy]
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coyoteboy
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| posted on 23/5/11 at 01:25 PM |
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Are you turbocharged? I'm seeing 165 in the MAP field, but your posts indicate only ITBs on a pinto? Back in a bit, just off to work on a
CBR600RR that's squirted too and causing me headaches also!
[Edited on 23/5/11 by coyoteboy]
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DaveFJ
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| posted on 23/5/11 at 06:36 PM |
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nope no turbo here... considering a supercharger install though
having a looksy at mt tables now to see what can be attempted.
a bit wary of jumping ship and letting map do the work... will have to investigate whats involved
cheers for all your input so far!
Dave
"In Support of Help the Heroes" - Always
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omega 24 v6
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| posted on 23/5/11 at 07:42 PM |
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This sounds EXTREMELY similar to my initial ms problems. Can you change/try a new crank sensor for starters? then are the ITBS all balanced. Mines
would idle all day in the garage but as soon as you touched the accel it'd fart and po and bang big time.
As for your afrs
My c20xe WILL NOT idle above 14afr and it never likes to be more than 14.5 at any time in the table. I;d have thought that 16.5 was WAY to lean and
would cause spitting back through the bodies.
ETA in megalog viewer you can see spikes on the clt whenever you touch the accel so looks like interference somewhere.
[Edited on 23/5/11 by omega 24 v6]
If it looks wrong it probably is wrong.
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DaveFJ
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| posted on 23/5/11 at 09:06 PM |
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quote:
Originally posted by omega 24 v6
This sounds EXTREMELY similar to my initial ms problems. Can you change/try a new crank sensor for starters? then are the ITBS all balanced. Mines
would idle all day in the garage but as soon as you touched the accel it'd fart and po and bang big time.
As for your afrs
My c20xe WILL NOT idle above 14afr and it never likes to be more than 14.5 at any time in the table. I;d have thought that 16.5 was WAY to lean and
would cause spitting back through the bodies.
ETA in megalog viewer you can see spikes on the clt whenever you touch the accel so looks like interference somewhere.
[Edited on 23/5/11 by omega 24 v6]
could try a new sensor, just worried about throwing more money at it.....
have a simple carb balancer and all tbs are balanced nicely.
obviously something has changed which is directly effecting the tune, just wish i could see what!
Dave
"In Support of Help the Heroes" - Always
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omega 24 v6
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| posted on 23/5/11 at 09:08 PM |
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Have you ntried tuner studios tooth logger?? i think you need a registered ( paid version) though.
What type of crank sensor have you?? get one from a scrap car or borrow one perhaps to try.
If it looks wrong it probably is wrong.
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coyoteboy
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| posted on 23/5/11 at 11:15 PM |
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Tooth/trigger logger is free and will indeed tell you if you have any missing teeth or problems but from the fairly consistent RPM I'd say
that's fine and dandy unless I missed some? If that were a problem I'd expect RPM spikes and dips. Here's a couple from mine - my
hall effect sensor is starting to get flakey as I'm over-currenting it....
spike2 by j.buckle, on
Flickr
spike by j.buckle, on Flickr
I'd be looking for air leaks. I'll keep looking over the logs and seeing if I can see anything else but my primary concern would be the
AFRs being WAYYYYY out for some reason. I'd also like to know how you ended up with positive manifold pressure (I'd expect a tad at times,
but not 160kpa!) unless alpha-N adjusts the readings from it. If that's out for some reason, who knows what other readings are out of whack?
I just wish you were closer, I'd love to come down and have a prod about with my scope.
[Edited on 23/5/11 by coyoteboy]
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