This may Interest People Using Electric PAS

[Penelope Stopit]

The below circuit can easily be altered so that it connects to the fuel pump relay rather than the alternator, thanks to phazed for pointing out that if the circuit is wired to the fuel pump relay, when the fuel pump primes it also acts as a PAS circuit test by running the PAS Pump during the fuel priming and you should be able to hear it run

When using electric PAS there is the advantage of being able to keep the PAS working even if the engine cuts out as long as the battery is good
The operation is simple
1) Turning the ignition on switches a negative through a relay to the main pump relay coil
2) The alternator switches a positive through a relay to the main pump and its relay coil which activates it
3) The main relay once activated holds itself in by switching its own switched positive to its own relay coil
4) The hold-in circuit is broken by turning the ignition off and the cycle is ready to go again

[Penelope Stopit]

It was staring us all in the face and none of us saw it, one day it just clicked

[Penelope Stopit]

PAS is fitted to most modern cars and is of great benefit to many people, due to numerous reasons there are many people that struggle to drive a vehicle that doesn't have PAS
Motor manufacturers don't fit PAS to their cars for the sake of it
Any TVR owner that benefits from having an electric PAS system fitted will benefit from a small modification to the PAS pumps electrical circuit so as to still have the use of PAS if the engine should cut out while driving
It is common knowledge that people are prepaired to make fools of themselves when posting to internet forums or attempt to take the piss out of those that are prepaired to post useful information for some to benefit from
Evolution has never ceased to amaze many of us, unfortunately none of us can stop devolution such as what has been posted by some above

What I have posted above is a very simple useful circuit for an electric PAS system and it contains no new methods, there is nothing amazing or clever about what I have drawn, many of us draw similar circuits day in day out and they do come in useful to some

[Penelope Stopit]

You're trying real hard now Dave but failing miserably

[Penelope Stopit]

dvs_dave said:

I’m not following you as to what problem this solves?

If you don't own a TVR that has electric PAS or not going to be installing electric PAS to a TVR this topic was never meant for you
If you need to ask "what problem this solves" this topic is not for you, anyone that can read a simple wiring diagram with an explanation of operation will appreciate that this topic is about a modification to an electric PAS circuit that may be of benefit to some rather than read it as a problem solver

dvs_dave said:

So having the power steering available whilst the engine isn’t running is what this does? The steering weight is already perfectly manageable without power assistance, especially whilst in motion. So under what circumstances do you envisage this system being useful?

Although having said that, rather ironically, you’d be much more likely to have an unexpected engine shut down due to a fuel pump shutoff as a result of this system being installed. So I suppose there’s that.

Now, if you simply interfaced this with an 18V starter booster circuit, you could be on to something. However it would only make sense if it was able to auto-restart the engine after an unexpected shut down

Now you having visited back here and posted The steering weight is already perfectly manageable without power assistance, especially whilst in motion this topic is definitely not for you as you don't need power steering
You having then posted Although having said that, rather ironically, you’d be much more likely to have an unexpected engine shut down due to a fuel pump shutoff as a result of this system being installed. So I suppose there’s that. Shows me that you struggle to understand wiring diagrams and automotive electrical circuits, as the diagram I have posted shows that the main PAS relay is activated from the alternator. In my explanation I have mentioned how poster phazed had pointed out that the main PAS relay can be operated from the fuel pump circuit. Moving on a little - If you think that my circuit or phazed's method could create an "unexpected engine shutdown" this topic is definitely not for you

You finished off with Now, if you simply interfaced this with an 18V starter booster circuit, you could be on to something. However it would only make sense if it was able to auto-restart the engine after an unexpected shut down I have no idea of how 18 Volts could be applied anywhere in my above circuit so as to benefit its functionality.
Bearing in mind that this topic is of no interest to you as you don't use power steering - Will you kindly explain to all of us what an 18V (I think you mean 18 Volts) starter booster circuit has to do with a 12 Volt electric PAS circuit

You return to this topic and post

dvs_dave said:

How deliciously ironic.

What seems to be escaping you is the fact that the feature has barely any real world benefit. It just serves to add real world complications and additional failure modes. Just because you can do it, doesn’t mean you should.

But keep sharing these troll worthy Heath Robinson inventions as they are certainly entertaining.

Ok - It's clear that you don't use electric PAS on a TVR and that you don't understand simple diagrams with explanations, there is nothing wrong with not understanding simple diagrams, none of us understood simple diagrams until we did, yet you have then mentioned interfacing 18V (I think you mean 18 Volts) with an electric PAS, this has confused me no end and I am hoping that you enlighten us all soon

You continue with - What seems to be escaping you is the fact that the feature has barely any real world benefit. It just serves to add real world complications and additional failure modes. Just because you can do it, doesn’t mean you should. If you class the above circuit as of no benefit and an added complication, you need to find someone that can understand wiring diagrams and request that they explain to you some of the circuits wired in your car, you wouldn't be classing the above diagram as complicated if you understood how the electrics of your car operate

You finish with But keep sharing these troll worthy Heath Robinson inventions as they are certainly entertaining
Only on rare occasions do I communicate by internet with people that post as you have above, I can't relate with people that use the word "troll" as I have noticed that many inmature people seem to have been embraced by it. Out of interest how old are you? At a guess with you using the word "troll" in a topic that explains an electric PAS circuit modification I reckon you to be around 25 to 30 years old although it has been known for people older than 30 to use the word "troll" they only tend to use it out of malice
I doubt for one moment that any of your contributions to this topic are posted as a personal attack on me as you do certainly use good English in a well educated manner apart from the odd moment and your vast knowledge base would surely notify you that I Penelope Stopit would sense a personal attack
I wish you a good day and will certainly assist you with any electrical problems you have in the future, I regret that you have misunderstood my diagram and feel there is no point in me going into great detail explaining what electrics are running your car as they are far more complicated than my above simple modification that you have found to be complicated

[Penelope Stopit]

Byker28i said:

I can understand some feel the need to have the power steering pump running when the engine is off. Not sure many have issues where the engine randomly cuts out?

However, why the additional relay into the alternator circuit? That seems over complication, as the alternator will feed the battery and keep that topped up. Just power the pump via the ignition switch relay from the battery. If the ignition is on, the pump runs as long as the battery has power.

I have only now read your post and thought your question why the additional relay into the alternator circuit? had given me a good idea for modifying the circuit to make it even more simple than what it is, I am now not sure if I can simplify it yet still achieve the same functionality, I will take a look later as I'm pushed for time right now, I'm thinking as I type and you may well have put me onto something better - Thank you

In answer to your question. All I have done is used a different method to the one that phazed is using to operate his electric PAS and then added a hold in circuit to keep the pump running even if the engine stops rotating
phazed is using the fuel pump relay to trigger the PAS relay and this method momentarily triggers the PAS relay when the fuel pump carries out its few seconds system priming

I thought it better that the PAS pump does not run until the car has started and the alternator has cut-in, by using the alternator warning light output I was able to give the starter motor full battery power for cranking - The PAS doesn't drain anything from the battery until after starting

phazed's method is very good and will never fail unless used in a car that has a neglected or low voltage battery, the 40/50 Amps or whatever that the PAS pump draws will make a difference to the initial cranking voltage because it has drawn that current for those few seconds of fuel system priming yet those few seconds will barely touch a good battery
It can be argued that anyone with the same knowledge as phazed will not be running a TVR with a poor battery and they don't need the alternator trigger function

Anyone wishing to have the PAS pump running even when the engine is not rotating will not be able to use phazed's fuel pump trigger function

I have run out of time and will take a look at something later unless you beat me to it

[Penelope Stopit]

200Plus Club said:

I think the guy was alluding to one of your previous madcap electrical drawings where (assuming it was you) you'd managed to provide 18v to a starter to crank a v8 over, simply by using 27 relays, 2 miles of copper, 15 push buttons, a phase failure module and some space dust. It was way too overly complicated and solved a problem that didn't exist.

Apologies if that wasn't you.
Ps I've looked at your drawing, it's very simple this time and basic, anyone could understand it however whether it's needed or not is another matter.

Yes it was me that drew the 18 Volt cranking circuit and in hindsight I should have posted it elsewhere or perhaps thrown it on the fire as it soon became obvious to me that anyone viewing it would have thought I was on drugs - I wasn't on drugs I was coming off them
Yes I understand what you thought of that 18 Volt circuit and can only apologise for my moments of madness
Yes i think you have hit the nail on the head, "the guy" is getting stuck into my history

Thanks for pointing out the simplicity of the PAS circuit, I will try and simplify it more later, have a good day

[Penelope Stopit]

200Plus Club said:

A friend of mine is very good tinkering with projects and has recently fitted speed sensitive electric steering to his mk1 cortina, along with DTA management/fuel injection, and is running an arduino device to regulate the steering resistance via an app on his phone!

Never break the friendship, clever friends are the best friends

[Penelope Stopit]

Byker28i said:

Penelope Stopit said:

I thought it better that the PAS pump does not run until the car has started and the alternator has cut-in, by using the alternator warning light output I was able to give the starter motor full battery power for cranking - The PAS doesn't drain anything from the battery until after starting

Now I'm confused, because lookign at your circuit you said:
1) Turning the ignition on switches a negative through a relay to the main pump relay coil

Turn on the ignition and you power the PAS relay from the battery. The PAS will be running as you crank the engine.

Then you said:
In answer to your question. All I have done is used a different method to the one that phazed is using to operate his electric PAS and then added a hold in circuit to keep the pump running even if the engine stops rotating
phazed is using the fuel pump relay to trigger the PAS relay and this method momentarily triggers the PAS relay when the fuel pump carries out its few seconds system priming
I thought it better that the PAS pump does not run until the car has started and the alternator has cut-in, by using the alternator warning light output I was able to give the starter motor full battery power for cranking - The PAS doesn't drain anything from the battery until after starting


But no matter what you do with the alternator powered relay, there's always power through to the pump provided the ignition is on. Which is why the alternator relay is unnecessary and doesn't do anything

Your only power source with the engine not running is the battery. With the engine running is still the battery (topped up by the alternator). Provided you have the pump powered by the battery, which you have with the ignition on, there's no problem if the engine stops, in fact probably the most problem would be brakes and having to press harder

Edited by Byker28i on Monday 5th March 15:02

I think the following explains where you are confused

You mention But no matter what you do with the alternator powered relay, there's always power through to the pump provided the ignition is on. Which is why the alternator relay is unnecessary and doesn't do anything. There is no power to the pump until there is a positive output from the alternator warning light terminal which triggers the relay which in turn supplies power to the pump and the main pump relay which is then activated, takes over and holds itself in

Are you able to point out where you can see power to the pump when switching the ignition on?

Until the relay I show below clicks in the pump has no power to it

[Penelope Stopit]

Ultra Sound Guy said:

Got it!

That's good, my apologies for not replying to your post, I was hoping you would find my explanation to Byker28i sorted anything that had confused you

[Penelope Stopit]

Byker28i said:

Penelope Stopit said:

Are you able to point out where you can see power to the pump when switching the ignition on?

What's the power from the fuse, through the black relay, thats energised when the ignition is turned

The Power from the fuse to the black relay doesn't go through it until it is energised, the black relay isn't energised until the other side of its coil gets a supply from the relay operated by the alternator warning light circuit

The black relay can't energise until it gets a negative from the ignition controlled relay and a positive from the alternator controlled relay

Please do keep asking if you don't yet understand it, I have noticed that many people that don't understand something are for some reason not able to ask
I admire you for asking