DaveFJ
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| posted on 26/6/08 at 06:35 PM |
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I did wonder if it was to much pressure in the fuel rail but it doesn't explain why it ran perfectly in the rain?
Also using a zetec coil pack which could possibly be suspect?
all HP hose and proper clips, no leaks evident.
Dave
"In Support of Help the Heroes" - Always
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Jenko
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 posted on 27/6/08 at 08:05 AM |
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Another thought on the single feed rail...I'm assuming that the fuel rail is the highest point in the fuel system.....Could this mean that any
air sucked though the system (say on a hard corner, or even through bubbles), could potentially build up in the rail, and eventyally work down to the
first injector?.....
Now then, are you going to answer the datalog question or not ;-)
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DaveFJ
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| posted on 27/6/08 at 08:08 AM |
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Unfortunately my lsptop was dead by the time it broke down on the way back from newark so didn't have the opportunity to do another
datalog...
Currently the HP fuel system is stripped down in my garage and i am awaitng delivery of my new regulator..
I may possibly have a datalog from last friday when it first broke down. will have a look and see what I can find...
cheers
[Edited on 27-6-08 by DaveFJ]
Dave
"In Support of Help the Heroes" - Always
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Schrodinger
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| posted on 27/6/08 at 12:03 PM |
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First Jenko any chance of reducing the size of your avitar?
If you are using a Sierra HP fuel pump it is hardly likely to give too much pressure, more like too low.
Keith
Aviemore
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Jenko
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| posted on 27/6/08 at 12:47 PM |
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Opps...didn't realise everyone viewed it that big!!!....
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rusty nuts
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| posted on 27/6/08 at 05:48 PM |
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Had similar symptoms when I first got my car running on injection although not intermittant . TPS was faulty. Might be worth changing? Best of luck
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DaveFJ
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| posted on 3/7/08 at 11:30 AM |
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OK have some logs if anyone is interested...
this one is from one of my numerous short runs ending in a breakdown on the friday....
Dave
"In Support of Help the Heroes" - Always
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DaveFJ
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| posted on 3/7/08 at 11:42 AM |
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and from the saturday when it was running well - no changes to system - just running in the rain.....
(I have had to crop the first half of this file so i could upload it)
[Edited on 3-7-08 by DaveFJ]
Dave
"In Support of Help the Heroes" - Always
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DaveFJ
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| posted on 3/7/08 at 11:44 AM |
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and - in case you want it - my current msq file
Dave
"In Support of Help the Heroes" - Always
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Jenko
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| posted on 3/7/08 at 12:30 PM |
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Hi Dave,
Thanks for the files....
OK, on the problematic log can you explain what is happening as you are driving....So, at what point does the engine start misbehaving?.......I notice
a sudden dip in rpm at time mark 733.93...is this where the engine looses power?.....
Anyway, A quick look shows something strange......On the attached file, Ive plotted rpm and tps towards the end of the run. I'm guessing this
was just before breakdown. Anyway, you can see that around about point 735, the throttle poition is 0 and the engine dips, then recovers....
I would question how an engines revs could rise back up with 0 throttle?????........
Now then, if this really is a point where you were seeing trouble then either one of two things is happening....
Either the Crankposition sensor is mis reading your RPM, or your TPS is faulty....At the moment my vote goes for the TPS. But will need to do some
more analysis.
Of course if the TPS is not reading correctly, then with no load, the engine will be trying to use the wrong line in the VE and ignition table
(although ignition should not make that much difference)....
Paul.
[Edited on 3/7/08 by Jenko]
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DaveFJ
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| posted on 3/7/08 at 12:51 PM |
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not sure exactly what was happening at that moment unfortunately...
When it starts to go wrong it does sometimes appear to be running on 3 cylinders.. although that could just be my misinterpretation of the
noises...
What I found interesting is the way the AFR closely follows the TP and RPM until it starts to go wrong at which point the AFR goes mental...
I have checked and cleaned connections on both TP and crank sensor. also tried 'wiggling' both whilst the engine was playing up to see if
i could detect a difference in the engine running - found nothing....
typically the symptoms start with a complete lack of acceleration and then start to slow. engine sounds rough as hell and has very occasionally
backfired. you can see from the logs me 'blipping' the throttle trying to get some response out of it.
At one stage on the sunday i drove for about 10 miles on the hard shoulder at 40mph in 5th gear with WOT! it kept going just long enough but got me to
safety off the A1M....
If I tryu and restart straight away the problem is still there. if I 'fiddle' for a few minutes and then try again the car will run for a
few more miles.... which implies to me either cooling or a build up of pressure/vacuum ?
The engine does run a little hot but I think the readings in the log are a little off... need to recalibrate the sensor again as it read 100 degrees
whilst the seperate (matched) gauge/sensor reads about 87!
Dave
"In Support of Help the Heroes" - Always
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DaveFJ
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| posted on 3/7/08 at 01:05 PM |
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just had another look at that log
you can see that at about 706 s the rpm starts to drop off and I start to react about half a second later starting to increase throttle to compensate
which fails to help....
At that poing the AFR goes through the roof...
looking at the ve table the difference in the bins is small (going from 128 to 130).
when the afr drops back down the revs start to pick up again (between 712 and 726) but as you can see the tps stays pretty stable.
I then blip the throttle and seem to kill it! there is a corresponding crash in the map at the same time as the throttle goes to zero @ 732 s which i
find odd as the rpm only drops off 2 seconds later?
I'm probably talking twaddle but all that made me think it was fule supply issues.. hence I have now re-worked my HP system so the fule rail
flows through and I have an adjustable regulator with a gauge which is set to 3 bar....
I now need to get it out and adjust the tuning for the new fuel pressure and then do a >20mile run to see what happens!
cheers
Dave
"In Support of Help the Heroes" - Always
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Doofus
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| posted on 3/7/08 at 02:14 PM |
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quote:
Originally posted by Jenko
I would question how an engines revs could rise back up with 0 throttle?????........
[Edited on 3/7/08 by Jenko]
Dave took his foot off the clutch?
just a thought.
I agree Dave. It looks like a lack of fuel pressure since you are in a steady state and AFR jumps.
Paul.
[Edited on 3/7/08 by Doofus]
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DaveFJ
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| posted on 3/7/08 at 02:18 PM |
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quote:
Originally posted by Doofus
quote:
Originally posted by Jenko
I would question how an engines revs could rise back up with 0 throttle?????........
[Edited on 3/7/08 by Jenko]
Dave took his foot off the clutch?
just a thought.
Paul.
quite possible - I might have dropped it a cog to try and get some power back - that would explain the throttle dropping to zero....
Dave
"In Support of Help the Heroes" - Always
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Schrodinger
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| posted on 5/7/08 at 06:58 PM |
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Dave I'm not too hot with the data log which is the AFR (O2?) if so what values do you expect to see. Also what are ports a,b,c&d as there
are some odd (read inconsistant) values coming up in there
Keith
Aviemore
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Schrodinger
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| posted on 5/7/08 at 07:46 PM |
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Dave
I've just loaded your map into Megatune 2.25 and your spark and fuel tables do not appear to have any load values against them.
Keith
Aviemore
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DaveFJ
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| posted on 5/7/08 at 09:52 PM |
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quote:
Originally posted by Schrodinger
Dave
I've just loaded your map into Megatune 2.25 and your spark and fuel tables do not appear to have any load values against them.
when i load it up i see the tps values i have setup...
Dave
"In Support of Help the Heroes" - Always
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DaveFJ
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| posted on 7/7/08 at 08:53 AM |
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well, I took the car out today on it's first decent lebgth run since the problems. I didn't even get off the drive to start with because
an injector was spraying fuel everywhere..... O ring had split so a quick trip to Halfrauds was required.
that sorted and I was away. The engine ran well for the entire 58 miles  Still not convinced that the problem is solved but I have a little more
faith now.
I did find a bit of an oil lake under the bonnet but that was due to the breather tank overflowing
I took a datalog of the journey so will try to make that available later on.. I have found I needed to adjust the VE map by -3 across the board to
cope with the now stable 3 bar fuel pressure.
Dave
"In Support of Help the Heroes" - Always
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DaveFJ
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| posted on 7/7/08 at 11:53 AM |
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Here is the log from sunday and the msq it was running...
Dave
"In Support of Help the Heroes" - Always
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Jenko
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| posted on 9/7/08 at 04:41 PM |
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All seems well :-)
Obviously time will tell, but I wonder if that O ring could have been allowing air into the system or allow fuel out?....
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DaveFJ
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| posted on 9/7/08 at 05:05 PM |
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I think i probably dmaged it re-asembling the fuel rail after the rebuild..
cheers for your help
Dave
"In Support of Help the Heroes" - Always
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