1997 VT Commodore won't idle after a new battery

[Enrique]

Hi Guys, love this website but returning means I've got a new problem.

My 97 VT Commodore is on it's last legs but my 16 has just got his license so I will keep it for him to drive. I recently change the battery and they gave me a cheaper one than the normal one and that's when the problems started. The next day it wouldn't idle properly - idling very low and then cutting out. A mechanic told me I had to start it and let it idle for about 10 minutes for it to readjust. I went ok for a few weeks then one Sunday it cut out with car load of people. 10 minutes later it was fine. I took it to a mechanic and he couldn't find anything wrong with it and said it wasn't idling as good as it should but was ok.

I took it for long drive down the South coast and didn't have a problem. The next day it would turn over but not idle and cut out. It would only stay on if I rev'd the engine. Sent a Lube mobile mechanic down there and it started fine, first time. He couldn't find anything wrong with it and because it was idling well said there was nothing he could do. I've driven short distances and again no problems.

I really want to get it fixed so I'm not stranded again, alternatively it will be relegated to short trips only.

I'm planning on driving it back up to Sydney but any clues of what to check would be great.

Many thanks

 

[krusing]

Is the MIL on ?
or, when its not running correctly, does it trigger the MIL ?
How many k's ?
Service correctly ?

Doesn't run correctly when cold, or up to temp, or both ?

It sort of sounds like -

Vac leak, (Smoke test it if you can)
Plugs, (Remove and check the state of them, and their colour)
Leads, )Breaking down, check it idling in a VERY dark location, as there might be a Christmas tree under the bonnet)
Coils, (Have been know to intermittently fault)
DFI, (check for any damage, especially the coil connections)
DFI plu, (Check the connection plug to ant damaged pin, or corrosion in/on the plug/socket)
Get is scanned and see if there is any Historical DTC's, as they may be a lead you to the fault.

Check all the above first before throwing $'s at it,
As it could be an easy/simple fix.

 

[Bay 13]

Get a new fuel pump. First to be sure swap fuel relay see if it's not sticking.

 

[BlackVXGTS]

Make sure all the battery wiring has been correctly replaced and is nice and tight, especially the earth cable. You didn't initially install the battery the wrong way around by mistake, did you?

 

[Enrique]

Great thanks guys.

To answer some of the questions. About 250k kms, so its done its time but I want to get another couple of years out of it. Serviced regularly, went through a bad patch of breaking down and not starting then changed the DFI module in May 21 and that solved the problem. Its had a new starter motor and new fuel pump in the last 3 years.

The outside temp doesn't seem to matter, it's stopped on hot days as well as cool mornings. Just cuts out, no spluttering or choking, definitely seems electrical. No warning signs come on before it stops.

The battery was changed by a professional, but good point I'll check the earthing.

I'll have a tinker and a chat to a mechanic and come back.

Thanks again.

 

[Lex]

changed the DFI module in May 21

Maybe time for another dfi coil packs?

Was the wiring & dfi plug checked?

 

[Fu Manchu]

I’d say the battery was shorted during install.

Look on the terminals for evidence of arching. Any spots/marks on the body where a spanner might have contacted. Do some detective work.