2.5 PI Electric woes
Posted By : Jason Chinn, 27-Mar-2007, 08:13am
If you've been through a few alternators then I would start to suspect the connections rather than the alternator itself. Earth straps first. Remember
also that the PI pump can draw some serious amps if in poor condition. When dealing with PI, this sit eis your friend http://www.lucasinjection.com/index.html
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2.5 PI Electric woes
Posted By : Pete Davies, 27-Mar-2007, 09:40am
Hi Jason
Thanks for the link - I'll have to trawl through it later at home. I've tried earthing the alternator directly from it's casing to the battery using a jump lead, and it made no difference at all.
Rimmer Bros' website shows that the Spitfire & 2500 have different alternators, although everyone I've spoken to said that they didn't think it should matter. The one I have fitted is definately one for a Spitfire - but I still don't know why it would get hot.
I'll keep investigating and I'll have a look at the Lucas website
Thanks again
Pete-
2.5 PI Electric woes
Posted By : Jason Chinn, 27-Mar-2007, 10:13am
Electrickery isn't really my forte but just a thought - pulley size?-
2.5 PI Electric woes
Posted By : Pete Davies, 27-Mar-2007, 10:26am
It's the same pully that was on my original one, when you exchange an alternator at Halfords, you retain the pully and the fan - so try not to bend the blades when you undo it!
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2.5 PI Electric woes
Posted By : Chris Povey, 27-Mar-2007, 10:55am
All the lucas alternators are pretty much the same but with varying outputs (15,16,17 ACR etc)
I would suspect that you have a fault somewhere in the wiring of the car - the alternator is probably OK - but if its getting hot very quickly it won't be OK for long!
I would fit an ammeter in the main electrical feed (large brown wire attached to the starter solenoid) and see how much current is flowing - I suspect a lot. Then you need to find what is drawing the current. I am not familiar with PI pumps but as they have a motor attached it could well be the culprit. It could be a wiring fault but I would have expected to see smoke or blown fuses (assuming there is a fuse in the circuit) if high currents are being drawn.-
2.5 PI Electric woes
Posted By : Pete Davies, 27-Mar-2007, 11:16am
Thanks Chris,
I'll have a poke around with my electric testing kit. The car is fitted with a Kenlowe fan, and when I switched the manual override inside the car, it blew the fuse. I concluded that there was a short in the override circuit and that I would investigate it when I had some (what we laughingly call) "spare time", in the mean-time I disconnected the switch to prevent accidentally turning it on.
Your post now points me towards moving the fan diagnosis up on my list of priorities, I'll disconnect it all together and see if this helps.
Cheers
Pete-
2.5 PI Electric woes
Posted By : Colin Wake, 27-Mar-2007, 12:21pm
Pete
You don't say what version of PI car you have.
A Mk1 has a 15AC, An Early Mk2 has a Delco (?) one, and it is only later ones that have a 15ACR (or 16/17/18).
The first 2 require re-wiring to make an ACR type fit.
What year is your car???
Cheers
Colin-
2.5 PI Electric woes
Posted By : Pete Davies, 27-Mar-2007, 01:34pm
Hi Colin,
It's a 1977 2500 TC that was converted by someone else in it's history to PI. I'm afraid that leaves me with no idea of which wiring harness it uses or any other details. It was also off the road for 5 years before we bought it, so any number of gremlins could've moved in during that time.
The attached photo is of it in the barn - photo off the eBay advert
If you're interested, I've started a website for it - http://www.micad.co.uk/davies/2500.asp
Cheers
Pete
2.5 PI Electric woes-
2.5 PI Electric woes
Posted By : Pete Davies, 28-Mar-2007, 07:46am
Another day another note...
Hi "everyone"
I couldn't spend too much time on the PI last night as it was my brother's birthday (Bloody family!). I did however get to undo the kenlowe fan connection from the battery terminal and also "another" wire that led into the bulkhead - investigation proved it to be the permanent live for the radio.
Once all was removed, I started it up - and sure enough, within a minute, the alternater got hot again.
Tonight I'm going to swap the battery from my Spitfire and try that. If that doesn't fix it, I'm going to remove the fuel pump power feeds from the main loom and power it from another battery and see if that is what is making the alternator hot - I'll keep you posted.
Any more ideas for me to try?
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2.5 PI Electric woes
Posted By : Clive Speaks, 28-Mar-2007, 09:45am
Check that the earthing strap from the back of the gearbox to the chassis still exists. These often disappear and can make quite a difference-
2.5 PI Electric woes
Posted By : Pete Davies, 02-Apr-2007, 10:19am
Latest info - still no answer.
Hi everyone (Anyone!!)
I have now tried three different alternators on the car, and all three get very hot and stop performing as well as they should, all three are Halfords reconditioned units, one is a year old, the other two are brand new.
I disconnected the Fuel pump and powered it from a separate battery - the alternator still go hot.
I removed all the fuses and the alternator stayed cold - whoohoo!!!
I replaced the fuses one at a time and diagnosed which fuse caused the issue.
After some investigation I found out that it was the Kenlowe fan that causes the alternator to overheat. I checked all the wiring and replaced some of the connections that I thought were a bit "dodgy". Still the alternator got hot.
I have another second-hand Kenlowe fan in my garage that (one day) I'll fit to my Spitfire. I took this to the PI and connected it directly across the batttery - bypassing the relay and the thermostat, and disconnected the one fitted to the car. Started up, and the Alternator got hot. ARGHHHHHH!!!!!
I called Rimmers this morning (Who were very helpful) and asked some info, and they said that a Kenlowe fan should NOT put too much draw on an alternator to make it hot, I've had my - long suffering - wife check for any partnumbers on the alternators, and she can only find "607167".
Does anyone have any other ideas?
Cheers
Pete
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2.5 PI Electric woes
Posted By : Pete Davies, 02-Apr-2007, 02:41pm
Some more for you all.
I'm worried it may be the "Halfords" reconditioned alternators. You never know their supplier could have a batch of faulty diodes.
So I've taken the plunge and bought another (Yes you read that right - "Another") alternator from another source. It'll be delivered tomorrow and I'll fit it in the evening. I'll let you know whether it cures the problem or not. If not, I know there is nothing wrong with my plethora of Halford's alternators and you can look out for them on eBay!!!!
If anyone has any other ideas, let me know.
Cheers
Pete -
2.5 PI Electric woes
Posted By : Chris Taylor, 03-Apr-2007, 00:10am
ANY 12 volt alternator feeding a system with a 12 volt battery should not overheat. Only 2 faults can cause overheating; one is in the alternator itself, either mechanical friction (unlikely) or a faulty regulator allowing excessive current to flow, usually because the voltage is able to climb well above 14v.
The other is in the load on the whole electrical system, again allowing excessive current to be drawn through the alternator. HOWEVER, any alternator should be able to run its maximum output current without overheating.
Silly question time: you do have a fan on the alternator, behind the pulley? The alternator is properly earthed through clean bolting surfaces, and engine to body earth strap is clean and tight? There is no separate alternator control box in the circuit? (early Lucas alternators had a separate external control box, whereas newer ones, and the most common ones, all have internal regulators). ISTR the early 2.5PIs had such an external regulator, but probably only Mk1s.
How hot is hot? I DO expect an alternator to be warm when working, but not too hot to touch.-
2.5 PI Electric woes
Posted By : Pete Davies, 03-Apr-2007, 10:05am
Hi Chris, thanks for the comments.
First (And don't worry about asking the obvious) there is a fan on the alternator, and it is fitted the correct way round.
As to Friction, the alternator stays cool - until the Kenlowe fan kicks in (Or I put my spare across the battery).
I have earthed the alternator using a jump lead both to a good earth on the body and to the negative terminal on the battery - and it still gets hot.
More Info...
I came to work in the PI this morning (Keeping a watchful eye on the volt meter) and for the ten mile motorway journey I was getting a really good 14 volts with no fluctuations. Fantastic!
However, once off the motorway and in the traffic queue, I noticed the temperature gauge creep up.... and up....
I pulled over and popped the bonnet, checked the alternator and it was warm, but not hot, I checked the wiring to the Kenlowe fan and noticed that one of my replacement bullet connectors had come undone. I refitted it and the fan kicked in.
I continued to work (Only one more mile) and when I got there I re-checked the alternator, and it was hot.
Never mind - as soon as the new alternator comes I'll fit that and let you know.
Cheers
Pete-
2.5 PI Electric woes
Posted By : George Ralph, 03-Apr-2007, 12:52pm
Sorry I haven't been following this thread, but just a quick thought as I idle away a couple of minutes in my lunch time. Check out your Kenlowe fan. Fans like this should not draw more than about 20amps max. It is conceivable that your fan or the thermostat switch are faulty and drawing considerably more than this causing the alternator to run flat out to keep up?-
2.5 PI Electric woes
Posted By : Pete Davies, 23-Apr-2007, 04:16pm
A final (I hope) Instalment
Well, after much anguish, swapping of parts and lots of &163;&194;&163;&194;&163;s, I gave up and took the PI to an auto-electrician.
He checked everything over and said that the standard alternator I had fitted could not cope with the amps being requested under load. He replaced my standard alternator with a 70amp one.
Over the weekend we attended a weekend run out with the Manchester Area to Coventry and Warwick and the PI behaved impeccably. Finally!
So thank you to you all for your advice and assistance - and I hope to see you at the International weekend at Stafford.
Cheers
Pete
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2.5 PI Electric woes
Posted By : Hugh Glossop, 24-Apr-2007, 08:14am
Pete, just a small point, a kenlow pulls approximatly 25 amps and a pi pump up to 10 amps without the other electrics running, a lucas 17acr has an output of 33-35 amps, you are straight away into an overload on the alternator (gets very hot), for info the ign cct is 4 amps, heater motor 4-5 amps, headlamps 4-5 amps each. side lamps 0.5 amps each, indiators 2 amps per lamp.Any triumph with a kenlow needs an uprated (65 amp alternator) and the kenlow must be wired seperatly through a 30A relay or it will melt the ignition switch as well.
P.S i towed the car to the barn location for the previous owner, give me a ring on 01591 610433
hugh-
2.5 PI woes ... cont'd
Posted By : Jonathan Binnington, 28-Apr-2007, 04:43pm
to continue the tread, took the green car out for a thrash on thurs night and it developed a misfire
seemed to be ign and it was popping on the overrun, running on 5 and sometimes intermittent
swapped the spark plugs
swapped the ign leads
swapped the condensor
scrubbed up the rotor arm
then looked at the injectors, nothing coming out of number 5 injector...
I have some spares, replaced it and watched the petrol spray
back up to full power now
jonath
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