Printable Version | Subscribe | Add to Favourites
<<  1    2  >>
New Topic New Poll New Reply
Author: Subject: Megasquirt rich running problems
shaunod

posted on 13/6/14 at 06:33 PM Reply With Quote
drop me a text and we can try and arrange a stop off. 07891512664.
View User's Profile Visit User's Homepage View All Posts By User U2U Member
clairetoo

posted on 13/6/14 at 06:58 PM Reply With Quote
quote:
Originally posted by BaileyPerformance
quote:
Originally posted by clairetoo
quote:
Originally posted by shaunod
I am mapping in Derby on Sunday .. if you want me to pop in on the way home I would be glad to take a look.

Feel free to pop round - there has to be something that no one has spotted yet................


Are you sure it's not misfiring? You posted a vid ages ago of you driving the car - it was on 5 cylinders at best.
The suggestion of checking header temp is a good one, you may have a miss (one header much cooler that the rest)

Pretty sure thers no miss-fire - 200bhp on five cylinders ? ? ? Plus I would have an exhaust full of petrol , along with assorted pops and bangs , surely ?
I'd love to check exhaust temps , but I have no way of doing that





Its cuz I is blond , innit

Claire xx

Will weld for food......

View User's Profile Visit User's Homepage View All Posts By User U2U Member
BaileyPerformance

posted on 13/6/14 at 07:14 PM Reply With Quote
The point is it could well be missing at light throttle due to badly balanced throttle bodies (miss match between left and right banks) but pick up all cylinders as full throttle.
Spit on your finger and touch each header at idle, if one is much colder it will be obvious.

As suggest before unplugging injector plug at idle to see if rpm changes is a good test.

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
shaunod

posted on 13/6/14 at 09:01 PM Reply With Quote
I will bring a temp gun with me.
View User's Profile Visit User's Homepage View All Posts By User U2U Member
clairetoo

posted on 21/6/14 at 07:51 PM Reply With Quote
quote:
Originally posted by shaunod
I will bring a temp gun with me.

And this showed even temps on all cylinders....... There was a very slight in-balance across the two banks , with the second (linked) bank refusing to close right down at idle - this has now settled out , and resulted in a stable 600rpm tickover .
The injectors are a bit over-sized for this engine - I've dropped the fuel pressure a little to 40psi , this seems to have helped at low throttle openings , and given a more stable leaner tickover .
I also moved the air temp sensor away from the engine , its now in the cold airflow into the engine bay - heat soak cured .

The main thing , however , is Shaun gave me some good pointers on light throttle mapping . I've been creeping up on the figures he suggested , and its just getting better and better
I need to re-fill the tank after this afternoons drive , but going by the fuel gauge its looking to using at least 40% less fuel when cruising..........I'd call that a result , with maybe more to come





Its cuz I is blond , innit

Claire xx

Will weld for food......

View User's Profile Visit User's Homepage View All Posts By User U2U Member
shaunod

posted on 21/6/14 at 08:06 PM Reply With Quote
Glad to hear it .. keep plugging away with the mapping .. you will have it perfect soon enough.
View User's Profile Visit User's Homepage View All Posts By User U2U Member
clairetoo

posted on 30/6/14 at 07:29 PM Reply With Quote
Sad news is......I was being a bit optimistic on what I saw to be better fuel consumption........that first guess was after mostly motorway and slow A road driving..........a week of commuting had the needle plummeting as normal .
I just filled it up , and it had managed a staggering 24.8 mpg................and that was with not going over maybe 15% throttle , and no more than 3000 rpm

I did have a thought tonight - the only part of the entire system that had not been run on my Fury , was the adjustable fuel pressure regulator . I still the ebay cheapy I ran before , but the hose take-offs would need to be modified to work , so I did the next best thing , and plugged the pressure gauge into a spare port on the new (far more expensive) regulator..........and the pressure reading was very different on the extra gauge !
Where I had the fuel pressure set to 40lbs on the new gauge , it read 55 on the old one . So I've dropped it to read 45psi on the added gauge - just about to nip out for a test run.............





Its cuz I is blond , innit

Claire xx

Will weld for food......

View User's Profile Visit User's Homepage View All Posts By User U2U Member
BaileyPerformance

posted on 30/6/14 at 08:21 PM Reply With Quote
Fuel pressure will have a big effect on the injector flow for a given PW.
But, assuming the fuel pressure is stable then you tuned at that pressure, the lowing the fuel pressure will just make the whole map leaner.

Is your FPR connected to a vac source? (Should be open to atmosphere)

How did you balance your throttle bodies?

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
MkIndy7

posted on 30/6/14 at 08:42 PM Reply With Quote
You say a similar setup to your Fury and I'm not sure I've seen it asked..

Is the inlet tract from engine valves to the end of the trumpets shorter on this car?

When we were trying to map one of our engine combinations you couldn't fine tune the difference between it cruising and being on load so it drank fuel regardless!
That had a very short inlet tract (trying to squeeze everything under the bonnet) so we made it longer by extending the trumpets on and it made a massive difference to the mapping and economy.

View User's Profile E-Mail User View All Posts By User U2U Member
clairetoo

posted on 30/6/14 at 09:01 PM Reply With Quote
Thye are quite short - but only a few mm shorter than the Fury , and only in the trumpets (the bodies that are on there now are the first set I made for the Fury , just with Pico type injectors instead of normal Bosch type)

I was running the complete setup lifted straight from the Fury , this is actually the third set of bodies I have tried , and the fourth set of injectors , along with two megasquirts , three Edis units , two coils ............ the FPR is the only part that hadnt been changed !

It is balanced spot on............the AFR's are fine...........it will tick over at 600rpm , and pull away clean at less than 1000 revs in second........but it drinks fuel , and the whole back of the car is covered in black soot

As an extra thing - as well as turning the fuel pressure down about 10psi , I also dropped the req' fuel a couple of points - did a short mapping run , and had to go leaner at low speed / cruise........ go figure......





Its cuz I is blond , innit

Claire xx

Will weld for food......

View User's Profile Visit User's Homepage View All Posts By User U2U Member
BaileyPerformance

posted on 30/6/14 at 09:09 PM Reply With Quote
You said the balance is spot on, how did you do it?

If you balanced just at idle, you need to chk at light throttle. You'll probably find one set of throttles are opening before the other - so, one side if engine is running leaner than the other.

How did you balance them and what did you use to do it?

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
BaileyPerformance

posted on 30/6/14 at 09:10 PM Reply With Quote
Hi you got a wideband in left and right or just a common one?
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
shaunod

posted on 30/6/14 at 09:18 PM Reply With Quote
The bottom line is ... if the AFR is 15 ish on cruise and 13 under load ... and it is drinking fuel ... something is wrong with the burn. The only real suggestion I can make is that the fuel is either not being ignited fully or at the wrong time. This is why I mentioned Dwell previously.
I don't have a definitive answer .. but that is certainly where I would start looking .. if you are absolutely convinced that both sides of the engine are burning equally and the mixture you are seeing in the exhaust is correct .. you would have to start asking if the cam timing is correct .. the ignition timing correct .. the list goes on ... but the answer will be there .. it always is.
Have you had it on an MOT gas tester .. if so .. what were the HC and CO readings at 14.7 AFR?

Shaun

View User's Profile Visit User's Homepage View All Posts By User U2U Member
clairetoo

posted on 30/6/14 at 09:24 PM Reply With Quote
Do you actually bother to read what I post........? Are you seriously trying to tell me that an un-noticable imbalance will half the mpg , but not effect drivabilty at all ?

Yes it has a wideband . Just one . In the exhaust as close to the collector as possible , just after the balance pipe . Oddly enough , pretty much the same as I ran in my Fury .

If you could at least think of something else , that may actually help , I would appreciate it . But going round in circles asking the same question over and over , and getting that same un-helpfull question answered over and over - is just not helping .





Its cuz I is blond , innit

Claire xx

Will weld for food......

View User's Profile Visit User's Homepage View All Posts By User U2U Member
clairetoo

posted on 30/6/14 at 09:30 PM Reply With Quote
quote:
Originally posted by shaunod
The bottom line is ... if the AFR is 15 ish on cruise and 13 under load ... and it is drinking fuel ... something is wrong with the burn. The only real suggestion I can make is that the fuel is either not being ignited fully or at the wrong time. This is why I mentioned Dwell previously.
I don't have a definitive answer .. but that is certainly where I would start looking .. if you are absolutely convinced that both sides of the engine are burning equally and the mixture you are seeing in the exhaust is correct .. you would have to start asking if the cam timing is correct .. the ignition timing correct .. the list goes on ... but the answer will be there .. it always is.
Have you had it on an MOT gas tester .. if so .. what were the HC and CO readings at 14.7 AFR?

Shaun


I have checked cam timing - all good , to the factory marks . The TDC mark on the pulley was done by me , exactly the same way I always do it - and checked a while ago when I first started trying to work out where all my fuel was going........
Yep - there is something wrong with the burn , but whatever it is is way beyond me........

I cant understand why a lighter car with a near identical setup can do double the MPG .





Its cuz I is blond , innit

Claire xx

Will weld for food......

View User's Profile Visit User's Homepage View All Posts By User U2U Member
BaileyPerformance

posted on 30/6/14 at 09:31 PM Reply With Quote
Has the car got twin separated exhaust systems?
If so a trip to local MOT station as suggest would be good, note HC and CO from each tail pipe.

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
MkIndy7

posted on 30/6/14 at 09:38 PM Reply With Quote
Another one I may have missed but a new set of spark plugs?..

We had a few sets in the pinto that would work fine on idle yet break down under load, the cores would become damaged internally so if you twisted the pip on the HT lead end you could feel movement even tho the pip was tight down.
Hence all the usual idle checks, balancing, timing, injectors, temps etc all checked out.

Yet when mapping I presume it was getting a cylinders worth of unburnt fuel shoved through it, (damn can't remember now if that made it show rich or lean) but it was leading me down the wrong track maybe a little like your findings tonight.

View User's Profile E-Mail User View All Posts By User U2U Member
BaileyPerformance

posted on 30/6/14 at 09:45 PM Reply With Quote
quote:
Originally posted by clairetoo
Do you actually bother to read what I post........? Are you seriously trying to tell me that an un-noticable imbalance will half the mpg , but not effect drivabilty at all ?

Yes it has a wideband . Just one . In the exhaust as close to the collector as possible , just after the balance pipe . Oddly enough , pretty much the same as I ran in my Fury .

If you could at least think of something else , that may actually help , I would appreciate it . But going round in circles asking the same question over and over , and getting that same un-helpfull question answered over and over - is just not helping .


Yes that is what I am saying - unbalance of 20% at part throttle and you would not notice because you will have one side at say 11afr, the other 14afr.

Your throttles may well be balanced perfectly at idle.

You still haven't said how you balanced your throttles.

I don't bang on about stuff to annoy you, I have seen these sorts if problems at least a dozen times.
From what you have said (you have changed everything) the only things left are the throttle setup or the actual engine.

When It comes to getting MPG we know what we are doing, customer popped in Friday and said his TVR 4.0 v8 is doing 37mpg since we converted to MS. That normal driving.

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
clairetoo

posted on 30/6/14 at 09:56 PM Reply With Quote
Balanced with a syncrometer - and cruise is at 4 to 5 % throttle , so only just off the stop.........
I've lifted it to about 2% on the tickover screw and checked balance - no change . I've sat in the car , watching tuner studio , and pushed the peddle slightly , 1 or 2 % , and it picks up clean with no stumbling at all .





Its cuz I is blond , innit

Claire xx

Will weld for food......

View User's Profile Visit User's Homepage View All Posts By User U2U Member
clairetoo

posted on 30/6/14 at 09:57 PM Reply With Quote
Just a couple of weeks ago it had new plugs , oil change and new filter ......... Exhaust temps are all the same at tickover , so no miss-fire or imbalance there........and it made over 200bhp on the rollers , so any timing problem would have to be pretty minor , surely ?
It may have four cams , but only two cam pulleys - if anything is out of place , then it probably left the factory that way (I have not had it apart , and judging by the look of the motor when I got it neither has anybody else !)





Its cuz I is blond , innit

Claire xx

Will weld for food......

View User's Profile Visit User's Homepage View All Posts By User U2U Member
mark chandler

posted on 30/6/14 at 10:24 PM Reply With Quote
Are you sure the wideband sensor is reading correctly?

You could try disabling any lambda corrections and just run on a fixed map to see if this improves things if it's got closed loop enabled.

View User's Profile View All Posts By User U2U Member
BaileyPerformance

posted on 1/7/14 at 06:51 AM Reply With Quote
I haven't checked back thru all your posts, but I'm assuming you have swapped the Ecu with your other car?

You would probably see this on laptop while driving but any random acceleration enrichments firing? To make sure set the threshold to something like 900. (If MS2) 10 if MS1.(unwanted enrichments normally caused by noise)

Assuming you have V3.0 hardware, there is an issue with the injector fly back circuit that can hold injectors open slightly, you can end up with a longer PW on one driver.
Cut out the two large black diodes to the right of the processor, near the top of the board. This will defeat the circuit. It cannot be switched off in software.
There are no negative effects in doing this. When in order an Ecu I request they are not fitted, or if I build one myself I omit them.

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
coyoteboy

posted on 1/7/14 at 12:40 PM Reply With Quote
Interestingly, my car started drinking fuel some time back. Made no sense as I had great reported AFRs, nice and rock steady and leaner than the stock setup. No notable misfires except at idle where one would creep in every 20 events or so, but the exhaust stank of fuel. Shifting timing about didn't seem to make much difference though it did change the AFRs, but then eventually my ringland failed. From the level of carbon deposits and marks on the piston I think the ringland had cracked about 18months earlier and finally gave up the ghost when I hoofed it. I always had great compression on the failed piston until the very last when a proper misfire developed.

I'm wondering if this cracked land may have been contributing to ongoing poor performance on that one cyl which lead to a ~15% increase in fuel use.






View User's Profile E-Mail User View All Posts By User U2U Member
<<  1    2  >>
New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content © 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [© 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.