matto_89
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| posted on 26/7/11 at 04:21 PM |
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X-Flow not starting
Hi All,
the time has finally come to fire up the X-Flow in the 7 that my Dad and I have built over the last few years.
The engine has caught a few times and has run well, before stopping due to fuel starvation after about 30 seconds. We've since cleaned out the
jets and adjusted the float in the single carb that its running.
However, the engine now doesn't want to fire up. We've got a spark at all the plugs, and the distributor timing is right. We think the
engine is simply turning over too slowly to catch and the power taken by the starter motor means that the spark is weak. (We've had a look at
the spark when the engine turns over on it, it seems weak). We reckon the problem lies with the ballast resistor, does that sound right?
We've used and adapted the wiring loom from the Escort Mk2 donor. Its seems likely that we've discarded the ballast wire along the way,
but we wanted to see if that sounded like the problem before we cut away at the wrapped up loom!
The engine has been rebuilt and tuned, but was running in the Escort beforehand.
Any help would be much appreciated!
Matt
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bmseven
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| posted on 26/7/11 at 04:34 PM |
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Quite a few posts already about ballanst/non ballast coils
Starting with http://www.locostbuilders.co.uk/viewthread.php?tid=152683
[Edited on 26/7/11 by bmseven]
BMW 7 Resource
Bures Pit anyone?
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Kev36
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| posted on 26/7/11 at 04:45 PM |
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'engine starting for 30 secs'
happened in mine , ended up i forgot to turn the fuel pump on ... just a thought.....
' A rich man is just a poor man ...with an awful lot of money..'
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steve m
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| posted on 26/7/11 at 05:26 PM |
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Removing the ballast wire would not do a thing to the starting, as it is there to give 12v on starting but once starting the coil would run on about
9volts
I would stick a wire from the + on the coil to the + on the battery, and try again, if it runs then you will have the feed and the ballast the wrong
way round
also the cranking very slowley, this will only be a bad earth, or weak battery
Try and jump the 7 's battery while cranking, does this improve the turning over speed considrably ?
If it does then your battery is duff, if it does not then you have a bad earth
There IS fuel in the carb ??
Is the choke working ?
Have you tried pumping the throttle 2-3 times then starting ?
Xflows are the most basic of engines, i know, my 7 has one!
Steve
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David Jenkins
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| posted on 26/7/11 at 05:38 PM |
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I can say definitely that x-flows like a well-charged battery! The combination of a cold engine, cold and heavy oil, and all the other factors mean
that the battery has to be spot-on to turn the engine fast enough to start.
Your problem does sound like a fuel issue though (IMHO) - it's as if you were filling the float chamber, but not keeping it topped up when
running.
Are you using the mechanical pump? If so, is its filter clean? Is its diaphragm intact? These can be checked by undoing the screw on the top and
taking a look.
If you're using an electrical pump - is there a decent flow at the carb? (try pumping into a jug and see how fast it comes out - take all
necessary safety precautions!).
Did you re-assemble the float valve correctly? (just trying to think of all the angles...)
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matto_89
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| posted on 26/7/11 at 06:57 PM |
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Cheers for the rapid responses!
I've taken a read of some previous threads on ballast resistors, I'll add some detail to answer the questions.
Just checked, we're running a 12v coil rather than a standard 9v one, which would seem to suggest that a ballast resistor wont be necessary, so
barking up the wrong tree with that one!
Fuel pump is working. Battery is fully charged. We've been jump starting it, which hasn't notably increased the speed of the crank, so the
earthing probably requires improvement. However even with the negative lead from the other car battery going straight to the chassis rail or
transmission tunnel, it still doesn't improve (If I'm right in thinking that should temporarily improve the earthing?).
Even if that is part of the problem, it would seem likely that something's up with the fueling somewhere. David - on the occasions when it did
start, i've had plenty of fuel in the float chamber to begin with, but not after its died. That was what led us to take the top off the carb and
check the needle valve/jets/float, which are all clean and appear to be correct. We've got an old carb (not recon'd as per the one on
there at the moment, but it was working on a X-Flow a while back), and all the internals of the one on the car appear to be exactly as per that one!
Matt
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chris_smith
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| posted on 26/7/11 at 07:36 PM |
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Where abouts are u someone may be able to pop round to give you a lift?
The secret of success is to know something nobody else knows."
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britishtrident
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| posted on 26/7/11 at 07:49 PM |
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Fords used a wire connected to an extra terminal on the solenoid to by-pass the ballast resistor when starting --- because of the way the ignition
switch is wire this connection is required even if the ballast is removed.
Also for contact points are trouble some with the cheap nasty Fomoco/Autolite/Ford distributer the points gap is 0.023" to 0.027"
re=check this as the gap closes up with in minutes of first starting on new points.
Also 10w/40 or 5w/40 oil in the sump can make starting much easier.
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David Jenkins
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| posted on 26/7/11 at 08:16 PM |
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quote:
Originally posted by matto_89
David - on the occasions when it did start, i've had plenty of fuel in the float chamber to begin with, but not after its died. That was what
led us to take the top off the carb and check the needle valve/jets/float, which are all clean and appear to be correct. We've got an old carb
(not recon'd as per the one on there at the moment, but it was working on a X-Flow a while back), and all the internals of the one on the car
appear to be exactly as per that one!
Matt,
It does sound like you're not filling the float chambers quick enough. Is this a Weber 32/36 DGV or DGAV? If so, have you checked its inlet
filter (if it's got one!) - when my engine had a DGV it had a mesh filter in the area just under where the fuel pipe connected - part number 11
in this picture.
[Edited on 26/7/11 by David Jenkins]
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David Jenkins
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| posted on 26/7/11 at 08:31 PM |
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Afterthought regarding the reluctance to fire since mucking about, and the slow cranking:
Can you turn the engine over easily by hand, when the plugs are out? In other words, is the engine itself free and easy?
Do you have a big fat earth cable between the engine block and the chassis? With a cross-section at least equal to your battery cables? Have you
checked that all the major cable connections are clean and tight? (bearing in mind that it used to turn over ok!).
Have you tried squirting some of that quick-start stuff into the carb while cranking? (I was thinking of that Aussie "Start-ya-bastard"
spray!) If it fires up with that then you really do have a fuelling problem to sort out - if not then you need to work on the sparks/timing/whatever
else.
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David Jenkins
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| posted on 2/8/11 at 06:52 PM |
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Did you ever get this sorted?
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matto_89
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| posted on 9/8/11 at 01:16 PM |
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quote:
Originally posted by David Jenkins
Did you ever get this sorted?
Hi David, cheers for asking, I was waiting until we'd fixed everything before posting up.
It appears we basically had a whole plethora of small problems.
The crank turned over faster after we improved the earthing. The engine caught regularly, but still wouldn't really start. When it did start, it
still only ran for a limited amount of time before cutting out.
Then we had a look at the fuel filter, and noticed the fuel seemed gungy and cloudy. Turns out that there was some water left over in the tank from
where we'd previously tested the fuel sender - we'd flushed it out, but I'm guessing some must have been caught around the baffles
somewhere. There wasn't actually a great deal of water in it - the ratio of it to water was probably around 1:10. However, fuel float on top of
the water, both in the tank and also in the float chamber. Therefore, as the carb drew in more fuel from the float chamber, after about half a minute
it was just sucking through water... We've now drained all the crap, and brimmed the tank.
Unfortunately it doesn't end there, because as we started to fire it up again, the starter motor blew. Sourcing another has proven frustratingly
time consuming, but I picked one up today and will fit it this evening. Fingers crossed!
Thanks for the suggestions in this thread, even if no one suggested we'd be daft enough to attempt to fuel the car with water, they certainly
helped rule out lots of other potential causes along the way.
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richard
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| posted on 9/8/11 at 06:14 PM |
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just a couple of things that spring to mind, do you have a small wire at least between the battery and the chassis as well as the big one between
engine and chassis , the crossflow i am working on turned over slowly as if the bendix was worn until i realised i did not have this fitted
correctly.
Regarding the resistance wire, never known them fitted on crossflows but when we forgot to fit on pintos and essex engines used to melt the heel on
the points so the gap would close up and lastly have you got the flow and return on the carb the right way round ( it it has a return ) as i managed
that as well although with an elctric pump and it would only run on low revs.
Good luck
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matto_89
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| posted on 10/8/11 at 07:40 AM |
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quote:
Originally posted by richard
just a couple of things that spring to mind, do you have a small wire at least between the battery and the chassis as well as the big one between
engine and chassis , the crossflow i am working on turned over slowly as if the bendix was worn until i realised i did not have this fitted
correctly.
Regarding the resistance wire, never known them fitted on crossflows but when we forgot to fit on pintos and essex engines used to melt the heel on
the points so the gap would close up and lastly have you got the flow and return on the carb the right way round ( it it has a return ) as i managed
that as well although with an elctric pump and it would only run on low revs.
Good luck
Yup, while we were sorting out the engine to chassis earthing, we also did that. Speaking of points, we also found that they were in need of
adjustment. Like I said, lots of small things that were not right (the water in the fuel tank being the big exception!).
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