HDi Starting Issues (lift pump power circuit)

[mcglynn]

Hi guys.

I commented on another thread, but thought I should open my own thread.

I have been having an intermittent issue lately. My cars lift pump wont run sometimes when the key is turned on. Its hit or miss.

So far ive checked the following;

- Its not the pump, its a brand new APS one & has been bench tested.

- The continuity of the earth wire from the pump checks out. Not sure how to test the power wire?

- I have changed the brown relay to another second hand one with the same results so it says to me its something other than that.

- I tried as suggested by cully to bridge connector 4 & 8 of the relay plug and the pump runs.

- Checked the fuse f35 in the engine bay too, and the other 15 amp ones

- Strangely I was getting 7volts accross the wires when the ignition was off and 3.5v when it was on?

- Checked the plug under the blower motor and seems fine to look at.

- Took the earths all off throughout the car, scraped the paint from beneath them and refitted them back again.

..... The only one that MAY be problematic is the gearbox one?



- Scanned the car and got p0560 which seems to have cleared but may be relevant. The usual egr/glowplug codes too. I ran my battery flat but it cameback even after I had charged my battery and cleared it. Its not there now though.

Im running out of ideas I have nothing else in the tin of ideas. Really losing heart in the car with this problem, as when you think its fixed it creeps up again.

[cully]

inertia switch

[powerandtorque]

What condition is the actual relay socket in? Not unheard of for the pin to be damaged through heat causing poor/intermittent connection.

[mcglynn]

I continuity checked the switch and it works. It does its job when I shunt it it opens and when I click it no resistance. It may have been the oyher way if its a push to break but it works.

It looks fine powerandtorque. Its actually pretty clean I was abld to read all tbe humbers etc ok and no dis colouration

[mcglynn]

Cully, when I turn my interior fan on, the soeedo lighting etc dims, is this related?

When I was driving home earlier and turned on the interior fan the temperature gauge got higher too.

Any light shed in this issue would be greatly appreciated.

[Poodle]

Checked your dash earths?

[cully]

could also be a bad battery clamp on the + terminal

[mcglynn]

I have two new clamps will try them with engine bay earths aswell.

Where do I find the dash earths poodle? I checked one underneath the drivers side by the pedals and it was fine.

[cully]

http://306oc.co.uk/forum/thread-9057-pos...#pid180334

[mcglynn]

#9 I checked this, is the #10 an earth point or is it the same as #9 only on left hand drive?

[mcglynn]

I also rewired the main battery earths today.

New terminal on the negative of the battery, new connector on battery end & gearbox end of that earth. New connector on the earth from the gearbox to chassis. Also installed two of the 'big 3'. These are the alternator output -> battery + terminal & the battery - terminal -> the chassis via top mount.

The issue of dimming clocks when I put on blower motor is happening still.

Will add an engine to chassis earth tomorrow and see if that helps although I very much doubt it.

Starting to get lost for ideas, will try a known good battery on it & see if there is any difference although the car starts fine etc on this one.

[mcglynn]

Also thought I would take the blower motor out and see if the issue still occurred when the control nob was moved.. Nope, no issue when the blower is disconnected so could it be a faulty unit & shorting out somewhere?

Sorry to be a pain wanting to try all avenues and get to the bottom of this.

[Jimbo]

I had a similar problem, where lift pump would intermittently not come on/car cut out

The plug onto the pump itself had been making poor connection and one pin had got hot and.gone black

I cleaned the pin and closed them up a bit, its been fine since

[Poodle]

Sounds like you've found the issue tbh lol.

[mcglynn]

Ok the lift pump issue is back, car wouldn't start. Im getting all sorts of funky voltages accross the P+ & P- pins on the plug for the pump?

Battery seems to run flat after a few cranks too.

Im stumped, is it worth getting any new relays etc as im at my wits end.

Completely understand why people sell/scrap cars.

[Jimbo]

*COMPLETLY UNDERSTAND WHY PEOPLE LIKE XUDS

[Tom]

Can you check continuity between the relay socket and the plug to the lift pump?

[mcglynn]

How do I do this? The only test i know was to wire pin 4 to pin 8 and the pump should run.. it did

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Haha jimbo I feel ya! Take back what I said before :p

[Niall]

In that pic of the earth on the gear box, follow the right hand wire, where does it bolt to? I don't think you have enough earths bolted to the chassis leg in that photo

[mcglynn]

I rewired the gearbox connectors, that one goes from gearbox to chassis and both ends were cleaned with a screwdriver underneath.



Done the wire from the alternator + to the battery +



I added this earth aswell the other day.

The ONLY thing im worried aboyt is corrosion on my fan plug (its disconnected). Should I cut the corroded plug off and insulate each wire?

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Sorry Niall, I think there are three to the chassis leg on the nearside and one on the offside. I also cleaned the rear nearside earth connector too. All seemed fine before I started.

[mcglynn]

Batterys on charge, should I cut up my fan plug, and insulate each wire?

[Poodle]

Is that red amp wire your alternator wire? That might not be big enough, would explain the battery issues.

What did you do to solve the problem before, did you replace the blower motor?

[mcglynn]

Yeah thats the alternator, and its 4 gauge (150 amp) wiring, which is the rating of the alternator on a HDi so I assume its fine.

The battery is still getting 14.5 volts when running I checked before & after installing this wire.

Would the cooling fans plug being corroded cause such issues? If this doesnt sort it im stumped. Really dont know what else to do.

Will try get planet on it and see if it helps.

I didnt do anything bud just randomly started working. The earths were done when it was working to try help the lights dimming issue.

Ive the blower motor unplugged atm

[Poodle]

Is that 4/0 or 4awg? Because if it's 4awg that's too small, she'll be struggling to get enough amps to crank.

[mcglynn]

Seems your right. Its 4awg.

Ill get it removed, although the car was going fine before this I was just adding it to do the 'big 3'

I'll take it off and see if there is any difference.


Will the earths be ok to use 4awg?

[Poodle]

Oh i see, you've got it as an extra to the standard wire? If so, that should be fine, i've never understood all the gubbins that goes with ice and that sort of stuff. Should be more than adequate for earthing bud.

[mcglynn]

Yeah its in addition to the original wire (looks thicker than original too?)

The battery is on charge if the lift pump doesnt fire im going to order a new relay and see if that helps.

If not, I really don't know.

[Poodle]

Ah ok, shouldn't be anything wrong with that then.

I don't know if you've been keeping track in this section, but there's someone else who found a problem with a relay that was causing these issues.

Missed your edit before, but: I can't see how the fan plugs would be causing this issue, mine is half missing and caked in shit from scraping the road all the time and i don't have this issue. Wouldn't hurt to blank i off properly though i guess, at least then you're sure.

As i've said to others recently; electrics aren't my strong point. I know you can usually chase it down to a single component by testing with a multimeter, but i don't know how exactly lol.

[mcglynn]

Haha ive tried, Cully has been on to me with pin outs etc of thr relay in question.

I think its maybe best just to buy a good one, at least its a known quantity then.

The fact theres a constant live to the fans (apparently) may be draining my battery?

[mcglynn]

Ok battery was fully charged, put it in the car and after about 5 attempts to crank it over the battery was flat. So it seems I need to replace a battery.

Wouldnt think this would be the reason the lift pump isnt running as surely with a good charge the lift pump would have worked.

Seems I need a new battery & perhaps a new relay aswell.