A friend of mine has a Sylva Mojo with a 1600 CVH engine that cranks very slowly when cold. We've fitted a brand new fully charged battery
(260CCA) which didn't make much difference. During cranking, the voltage at the battery terminals drops to around 11V so this should mean that
the earthing etc is ok as reading at the battery will ignore any wiring losses. The resistance between the battery negative and the engine block is
<0.1 ohm.
The engine itself is fairly modified with Kent cams, Pumaspeed head, larger valves, Webber 45's etc.
At tickover, the battery voltage is 14.1V (measured with a DMM at the battery terminals) so the alternator seems fine although the battery light will
come on if you leave it to idle for 5 minutes or so. A quick blip on the throttle makes it go out immediately. The idle speed is steady with no
hunting.
When the engine is warmed up, the cranking seems somewhat faster and the engine catches much more quickly (1-2 revolutions). When cold it can take a
few goes of 10+ revolutions for it to start.
So - has anyone got any ideas what we could try next? It seems that something is loading the starter heavily so my next guess is the starter motor
itself or something as simple as really thick sludgy oil although it did look ok from a quick wipe of the dipstick. Maybe it's just the way
modified CVH engines are? I must admit, I'm more used to the quick starting Zetec SE engines so this is unknown territory for me!
Your help would be appreciated as always!
Ed.
cranking advance? what ignition is he using?
This will have a more noticeable effect when cold
I would guess thick oil, as it's cold.. Is it the correct grade? Also CCA of 260 is probably a small car battery, so in combination this maybe
why.
Dan
[Edited on 19/2/10 by Bluemoon]
Get some jump leads and ground the battery (gound) then try it - This will tell you for sure if you have any grounding issues.....
If your feeling brave you could also try a jump lead to the starter...again, it it acts differently, it's the battery / starting wiring...
Ditto comments on the advancec - If he has a distributor, then try coming off the advance to see if it helps......
Also, check the sparks are good at initial cold cranking....
I've a 'more' modified CVH, and it starts on the button every time (although I have electronics ignition and fuel injection).
i had similar problems on my car
<<<<
And thought it was more engine related with cams and modifying the engine timing etc
Turned out to be the earthing stap from engine to battery and chassis
so replaced with a new cable
Engine spins over fine now !!!
you have ruled out battery,leads and earthing problems............
only leaves the starter
thats what i would look at next
what you describe can be a symptom of a failing starter
cheers les g
[Edited on 19/2/10 by les g]
Starter or earth lead i would say. A jump lead as an extra earth whould show this up.
We'v had loads of starters at work which turn slow when theyr cold. Its actually quite a problem with fords.
Remember 0.1Ohms is a high resistance at 100A.. That would be 10V drop! So high it would not crank over at all (the resistances are so low a DVM is
useless to check this on the resistance range).. so I don't think you can eliminate that in the way you have tried.. You could measure the
voltage across the starter when cranking, but doing this safely may prove difficult..
Dan
[Edited on 19/2/10 by Bluemoon]
Battery is way undersized for cold cranking but my gut feeling is too much static ignition advance
Also check the volts drop between the engine and battery negative when cranking and the voltage drop between the main starter terminal and the
battery positive when cranking.
Might find this handy:
linky
Dan
Bad earth, or starting starting to give trouble, i fitted a geared starter to my mates anglia rally car it was expensive (£185) but unreal at cranking the engine over, the used to have 24v starting to crank it over due to high compression ratio.
In the dim & distant past I had a highly modified Pinto that was a very lazy starter due to compression. That ended up on 24V starting.
quote:
Originally posted by Richard Quinn
In the dim & distant past I had a highly modified Pinto that was a very lazy starter due to compression. That ended up on 24V starting.