Noisy relays

I've noticed that when accelerating, i get a chattering noise coming from the drivers footwell. Having investigated, i understand that the injector and fuel pump relays are located there. Is this noise normal, or does it mean a faulty relay?!

Thanks guys... im learning slowly...

Depends on what kind of disco u have

It's not normal, could be a faulty relay, a loose relay but likely the supply to the relay coil a loose connection etc somewhere.

on a D1 ?

Sorry, its a D1 3.9 v8.

Any way of testing the relays apart from buying a new one and seeing if that fixes it?

Yes, unplug it and connect the coil terminals to a 12v supply if it operates ok, then you can check continuity through the relay contacts with your meter.

Thanks.. um stupid question but not sure how to do this?

According to the trust haynes the pins for the brown wire lead to the +ve terminal and the fuel pump relay, but which do i earth to? The blue/red wire leads to the ecu, one brown and orange goes to the injectors and the other to the ecu.

Also once i've worked out which pin i connect to +ve and which to -ve, how do i know if it's working properly?

Have a look at this site, relay pins 85 & 86 are the relay coil. VWP - relays

Ok, so ive bought myself a multi meter! (about time really) and tested the relay.

When there is no voltage across the coil, pins 87 and 87a are connected. When current is applied across pins 85 and 86, pins 87 and 30 are connected.

The relay clicks loudly when current is applied though. This is the same noise as when driving, so can i assume faulty relay rather than circuit issue?

Thanks again for your help everyone, I appreciate threads like this are boring and i'm taking more than giving as a newbie but I am learning!

its very common for relay to click if what it feeds fails eg light relay if bulb blows

well that's worrying, it's my injector relay that clicking!

As I said though it clicks just by passing current across the coil when it's not connected to anything other than the battery?

clicks once or many times if the latter just replace it

ok I ended up going to a main stealer and replaced the main injector relay. THe new one makes exactly the same noise as the old one!!

To recap fishsponge style (nearly reading his thread, fantastic! Hopefully i dont ask as many stupid questions but you never know)....

It's a 3.9 V8 D1, with LPG conversion. To start with, I found it was missing an air filter completely (empty air box), idleing high around 1200 and smelt like running it was rich. Also noticed a clicking from the driver footwell which sped up when accelerating.

Decided to do a service as lack of filter indicated it's not had the best of care. Put in an air filter, new HT leads, new genuine lucas rotor arm and dizzy cap, new plugs and oil change. Then engine started back firing, hesitating when trying to pull away and idling around 800 but going up and down like the moods of a manic depressive.

Indy mechanic suggested air mass sensor, so brand new one purchased and fitted. Idle is a stead 750 now, back firing gone but when cold really difficult to pull away without engine cutting out and through the rev range sounds quite rough still. Clicking noise from driver footwell is the main injector relay i decided, but i've now replaced that and noise is still present.

I also decided to run it on LPG for the first time yesterday, as the petrol is killing my wallet. The difference was amazing - purring away without the stalling when cold and the hesitation is vastly reduced. It's still not running completely smoothly though, and as I say the relay clicks away loudly when driving.

Any ideas? Is the fuel system clogged, causing the running problems on petrol,potentially injectors clogged as well if the running isn't completely smooth on LPG? Why is the relay still noisey after replacement? Thanks people!

have you checked all injectors ,have you got emultors fitted? i thought you had checked relay out of vehicle

jamesmartin said:

have you checked all injectors ,have you got emultors fitted? i thought you had checked relay out of vehicle

Click to expand...

I did check relay, when putting current across the coil there was an audible click. Thought you said this meant it was knackered! Perhaps this noise is normal then?

Not checked injectors,how do you? Is it just a case of taking them out of the head, leave them connected and turn the engine to measure the flow etc, or do you need a seperate set up?

At the risk of sounding really stupid... what are emultors?

clicks once is good many times means its knackered,i did say that ,emulators are used with lpg system toi switch injectors off when running on lpg but still letting ecu think theres no fault ,yes remove injectors from manifold and put some form of collector and run them by cranking engine with king lead disconnected

That makes sense. So the fact that the injector relay still clicks when running LPG would indicate that I don't have emulators I assume?

Think i'm going to have to find more info about LPG conversions.

Does it sounds like thats the fault, or one of potentially many?

on mine i just cut ecu off when on lpg but many use emulators usually fastened to bulkhead wired into injector loom,the fact you were running rich could be faulty temp sensor or poor injectors ,i have had emulators fail before

How can I find out what type of LPG system i've got? I assume that the LPG and petrol are independent in terms of delivery i.e. if i'm running petrol the fact that it has had a conversion is irrelevant when trying to make it run perfectly on petrol?

they are seperate ,look on bulkhead for emultors usually labelled ,ecu just runs petrol side by altering amount of fuel to suit engine ,gas is just sucked in by amount of vacuum on vapouriser,i have had failed emulators that didnt switch injectors off so running badly on two fuels ,and injectors that leaked on ones without emulators doining similar ,later lpg systems are more complicated ,on any v8 its allways worth checking tightness on inlet manifold bolts they often come loose ,most lpg systems shouldnt effect petrol side unless leaking gas or air after air flow meter