First cold start - Chim not happy :(

[V6Alfisti]

First time I have started the Chim when there has been ice on the screen (indication of the temperature!) and it wasn't happy idling so I held it at around 1000 rpm to get some warmth into the engine.

Then I let it go and the revs dip but recover and idles nicely at 1k revs, after around 3-4 mins of idling it then starts to bang (sounded like a backfire) then it did it again...so I turned it off.

Had to get to work so took the MX5 , is this usual for a Chimaera? going back at lunch time (when its warmed up) to make sure it's ok !

[ph1l5]

Have you check to make sure that your HT leads are on and dry.

[V6Alfisti]

ph1l5 said:

Have you check to make sure that your HT leads are on and dry.

That's something I can add to my check list when I pop back home at lunch , unfortunately I didn't have the time when I left this morning

Thank you

[V6Alfisti]

Popped back at lunchtime and it started and ran as usual

The HT leads look older than 12 months, so will replace them for the sake of £25.

Cheers for help

[V6Alfisti]

typical leave work today it starts fine , drive 2 min away and the idle drops and it stalls. go to start it again and the fuel pump doesn't prime, still having no luck, switched the relays and it clicks on, but no joy....waiting for the aa...any ideas?

Sorry for formatting, writing on my phone

[corrine]

corroded wire on the pump?

[V6Alfisti]

Finally back after waiting two hours for the AA !!

Despite me swapping over the relays, it appears that one of them was broken and so not priming the pump.

The AA blokey jammed a bit of foil between the contacts on the relay and off I went!

Easy... (still a little confused why the swapping trick didn't work, as one of the relays definitely works!)

Edited by V6Alfisti on Monday 1st December 19:54

[hoach]

there are two types of standard relay, four and five pin, five will work in four but four will not work in five....

suggest you check temp. sensor for fuel injection ecu. if you need resistances for temp I have.

[V6Alfisti]

hoach said:

there are two types of standard relay, four and five pin, five will work in four but four will not work in five....

suggest you check temp. sensor for fuel injection ecu. if you need resistances for temp I have.

Thanks, yep it was the two silver 5 pin ones - swapped over and still had the same issue. So buying a new one tomorrow.

Do I still need to check the temp sensor? if so, could I have the details please

Thanks

[GreenV8S]

V6Alfisti said:

Easy... (still a little confused why the swapping trick didn't work, as one of the relays definitely works!)

Better to be confused why the swapping relays tricks is ever expected to work. You need both relays to work in order to run the pump. The only way swapping will help is if one relay has got one output burned out and it happens to be the right one, which is unused on the other relay. You might just get lucky, but it's not something you would ever want to rely on.

[V6Alfisti]

GreenV8S said:

V6Alfisti said:

Easy... (still a little confused why the swapping trick didn't work, as one of the relays definitely works!)

Better to be confused why the swapping relays tricks is ever expected to work. You need both relays to work in order to run the pump. The only way swapping will help is if one relay has got one output burned out and it happens to be the right one, which is unused on the other relay. You might just get lucky, but it's not something you would ever want to rely on.

Now that makes sense, I suggested the same to the AA man but he mentioned that most cars run off the one relay...I guess TVR are different

[GreenV8S]

One relay is the main power relay, the other is the fuel pump relay. Since the ECU controls the fuel pump relay, obviously you need both relays for it to work.

[slideways]

GreenV8S said:

V6Alfisti said:

Easy... (still a little confused why the swapping trick didn't work, as one of the relays definitely works!)

Better to be confused why the swapping relays tricks is ever expected to work. You need both relays to work in order to run the pump. The only way swapping will help is if one relay has got one output burned out and it happens to be the right one, which is unused on the other relay. You might just get lucky, but it's not something you would ever want to rely on.

fell into that trap myself but my pump conections were corroded as well as one of the relays,
2 new relays and £50 rounded shoulders and a sore forehead later i worked it out

[hoach]

too much information to type and send, if you are still stuck give us a call I have access to all the information you need but cannot send everything now!

I aint the expert but I have been involved in depth with an LPG conversion recently and have had to find out all sorts!!

I have wiring diags, fault finding charts etc,

07833398695

[Cider Andy]

hoach said:

there are two types of standard relay, four and five pin, five will work in four but four will not work in five....

suggest you check temp. sensor for fuel injection ecu. if you need resistances for temp I have.

A 'standard' relay is a great get-you-home fix but is no good as a permanent fix. A standard relay leaves the lamdba sensor heaters energised when the ignition's off: flat battery in no time. Permanent replacement needs to be a Bosch original.

[spend]

Cider Andy said:

A standard relay leaves the lamdba sensor heaters energised when the ignition's off

I don't follow the logic of that.

You should be using a twin/dual make&break relay, your statement sounds like you tried a changeover relay?

Many come with diodes across the coil as standard, which seems to me to be about all that the 'special' bosch ones have.

[Cider Andy]

spend said:

Cider Andy said:

A standard relay leaves the lamdba sensor heaters energised when the ignition's off

You should be using a twin/dual make&break relay, your statement sounds like you tried a changeover relay?

Yes, exactly, the changeover relay is what I meant by 'standard'.

In fact I replaced my faulty one with an original Bosch item, I didn't try an off the shelf relay because I already knew it wouldn't work.

There's a lot of problems reported with the Bosch relays on here; is there a better alternative easily available?

[spend]

I have some Siemens ones like this:

but they seem to have a diode across the coil.

I purloined them to use in my lighting and fan (a wire to each connector behind the fusebox rather than 2 wires to 1 connector) circuits. I have used them in place of the Bosch relays as a test and found no adverse effects? Think I robbed them from Audi/VW/Vauxhall?

..but I do have rather elaborate strategic disaster planning which was conceived as I re-designed the wiring diagrams for my fusebox ie commonality of relays (more spares / swap outs), jumpers for relayed circuits (manual switching in case control is foobarred - can't be getting wet shorting otter switch when I could just jump the relay inside dry cabin)

[V6Alfisti]

The problem continues....

Got the new relay today (special order - original bosch part), plug it in, then I go to start the car.

Turn off the immobiliser, the fuel pump whirrs and then I turn the key and the dash lights flick on and off wildly (and I assume I could hear a relay going along with it....click click click click click in quick succession).

Would I be correct in assuming that by the AA man creating a permanent connection on the relay, it has slowly drained the battery and now there isn't enough power to start, causing the dash lights to go bonkers?

Thanks

Edited by V6Alfisti on Wednesday 3rd December 16:44

[spend]

yes