Hi

I was wanting to change my plugs on my impreza, cause i had them changed a couple of months back in a mini service and the car has been idling lumpy, running rich and back firing. I changed the maf sensor on it and it wasnt that, and some of you said it could be the plugs or leads. Is it hard to do, as it looks pretty cramp in the engine bay. I'm not sure whether to just change the plugs and leads to be done with it

Any advice would be helpful

Thanks

 

Yeah tight but not bad i take airfilter box and washer bottle out and also have a uj on the extension bar i use and takes about 30min all in

 

if your in essex i no a garage that can change your plugs cheap

 

check output voltage on the lambda?

 

i had the same problem the other day, changed the lambda sensor and now its fine.

 

could be that the plugs were not gapped correctly/at all?

 

i changed the water temp sensor on mine and that stopped the lumpy running on start up .

 

As its a MY99 car you should be able to find the fault using a simple obd code reader via the obd2 diagnostic port, most garages have these and shouldn't charge alot for a simple diagnostic, you could save yourself alot of money rather than guessing and changing a load of sensors...

 

No you won't. MY99-00 cars have the 16 pin socket but aren't fully OBD2 compatible. Only way to diagnose them electronically, beyond the read memory connectors and the CEL light flash sequence, is via something that speaks the Subaru specific SSM protocol. Generic code readers don't work.

Certainly worth having it checked via this method - should implicate/eliminate the O2 sensor at very least.

 

The symptoms sound like a Lambda sensor. Fuel economy would also be pretty poor.




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lambda sensor,had exactly the same problem with mine couple months back!!

 

If you want to do your own diagnostics you want something like Rom Raider (works in logger mode only) and a £13 VAG COM (usb to obd2) type cable. 99-00 cars talk "SSM" over the obd2 K line and the VAG COM cable I have works a treat. Can log everything you'd need including lambda voltage and the AFR adjustment percentage as a result of a dead lambda.

 

Tell me more. Can I do this on a UK MY97 with a Prodrive ECU?

 

No, you can't do it quite the way Matt has, as the 97-98 cars have a different electrical interface and use an earlier version of the SSM communication language. However you should have a word with L3YMS, as he's doing it - with EvoScan from what I recall.

 

Is it hard to fit the sensor and where abouts is it located in the 99 uk turbo? Thanks

 

Top of the downpipe. Quite straightforward.