Oxygen sensor

[markssupra]

Just checked the voltage on the O2 sensor and its going between 0 and about 0.6 - 0.7v.

 

I printed Mayby's thread and it says that it should hunt between 0.5 and 0.7v.

 

Is mine OK or is it knackered. I'm gradually working through checking different parts to see what the problem is.

[Ian C]

If it's hunting then that shows correct behaviour. What's your problem then

 

-Ian

 

PS yes, Mawby has done some great FAQs

[markssupra]

Problem starting when cold, once it fires it feels lumpy for a few seconds then smooths out.

Also a b**tard to start when hot as well, lumpy as hell for some time, even had to turn it off and start it again to try and clear it.

 

sometimes it hesitates quite badly from pull away until it revs to about 2200, then no.1 kicks in.

Other times its not so bad. It just doesnt feel like its pulling like it should. My previous supe felt much quicker from pull away and that was pretty much standard.

[merckx]

Have you tried doing a diagnostic check?

[markssupra]

I checked for error codes tonight but none were stored. I reset the ecu about a week ago and driven it everyday since then, but nothing has shown up.

[merckx]

When Oxygen sensors become faulty they richen the mixture up to prevent damage to the engine.

 

The car should still run okay, mine did. Infact it ran great with a faulty oxgen sensor, didn't pass the mot though.

 

Think I would be looking at the ignition side, plugs and coil packs etc.

[andrew7]

Is your idle low on cold tickover?.. If so, try cleaning the connections to your temp sensors (they aren't always the tightest of connections)...

Also, if you use plat plugs they can deteriorate incredibly quickly, over about 100 miles or so.....

[markssupra]

Might have found the problem. Removed the fuel pump assembly to check the pump filter and noticed a huge split in the rubber pipe that connects the pump outlet to the fuel pipe.

 

Looks like whoever fitted the walbro pump cut the steel pipe back a bit but left a burr on it and over time has cut through the rubber pipe.

 

I'll get a new piece of fuel pipe tomorrow and hopefully this will cure the holding back and poor starting.

 

Thought I was doing quite on fuel consumption, most of its leaking back in to the petrol tank.

[markssupra]

Changed the piece of split hose from the fuel pump to the fuel outlet inside the fuel tank, problem has now gone.

 

Starts up straight away, even when hot and no holding back from standing start. Now it goes like it should.

[b_have]

Wow , you were lucky to catch it in time. That could have been a 'Jake'.

[Jspec Germany]

Wow, this has me worried. I have a problem somewhere in the system, but don't know where yet. Sometimes, when the car is cold, and I first take off, if I give it a little, the car boosts, but then when I lift off mid rev range, it hesitates a little, like it isn't getting fuel or spark. I put new plugs and a new fuel filter in about 6 months ago but it was doing this before then. Also, When I installed the second decat, my jspec was boosting to .9-1.0 bar (summer) for about a month, then it suddenly dropped, and now only boosts to .7 -.8 bar, even on really cool days. Power is noticebly lower than it was before at .9-1.0 bar. I have a Walbro ready to go in, just haven't had time to get over to the auto hobby shop and put it in. Look like I'll be busy week after next.