Streetka revving issue

[Buzz26]

Hi there, wonder if anyone can help?  I have a 03 1.6 Streetka that normally runs ok but yesterday started this issue of revs not dropping off when you take your foot off the pedal.  This morning I try it and it runs fine again.  No doubt it will return again when it feels like it!  Likely causes? What to do?

Although she normally runs real sweet, she has had the engine light on for a while. The local indy took a look some time ago and suggested it might be one of 2 sensors on the exhaust, but that one is likely to break off when changed and if that happened it might mean replacing the exhaust.  Is it possible to check a sensor?  This morning I have pulled Obd code P0420, which is clearly to do with the exhaust but not sure of the best plan of action?  Could this be something to do with the revving issue or have I now got 2 separate problems to sort.

Any thoughts or advice would be greatly appreciated.

Jeff

[Omendata]

A code P0420 may mean that one or more of the following has happened: Leaded fuel was used where unleaded was called for A damaged or failed oxygen sensor (HO2S) Downstream oxygen sensor (HO2S) wiring damaged or connected improperly The engine coolant temperature sensor is not working properly Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe Retarded spark timing The oxygen sensors in front and behind the converter are reporting too similar of readings Leaking fuel injector or high fuel pressure Cylinder misfire oil contamination

In my experience code po420 will probably be the lambda sensor on the exhaust manifold on top of the engine. Symptoms are random engine stutters and if really bad engine sounds like its going to stall but then perks up and is ok for a while. If you connect an obd tool and your mobile you can monitor both 02 sensors usually o2s1 and o2s2 and see if the values are correct - if you monitor shrtft2 (short term fuel trim sensor 2) and if its way out in terms of % trim , its a sure sign its o2 sensor number 2 on top of the engine not on the exhaust outlet which is the number 1 sensor.

Using an obd tool will save you a fortune in garage bills if you use it properly - if you have a hard wired version and a laptop there is no end to the naughties you can perform - the hamilton accies use it to clock the motors they sell to take tens of thousands off the digital speedo and to decode the radio security , break into the engine management system and reprogram the ecu and lots more bad boy stuff!

I doubt its has anything to do with the revving however , it sounds like you have two or more problems which is not uncommon with these buckets of pish water they call a car and thats probably due to the ICV - If you take the ICV out and clean it , it may fix the problem otherwise its a tenner for a new one off eBay! Its reasonably easy to remove (two screws) give it good clean with wd40 (it will probalby be coated in black carbon gunge all around the black rubber sensor end and up the silver shaft - ooh er missus) and just refit! Worth giving it a go , its made my engine as smooth as silk on idle now and cost nowt.

This question comes up a lot:-

Did  you not check the forum posts before you posted? Just look three lines below your post!

 

[Omendata]

If po420 is not o2 sensor 2 (this is the pre exhaust sensor) then it is likely a faulty catalytic converter - is there any rattling noise from the cat when you lie under it with the engine on?

Code PO420 is the most common fault code found on most cars so i am lead to believe and not always easy to debug without the right knowledge and correct procedure to isolate and find the problem by stepwise refinement! Using an obd tool makes it much easier especially in live data mode.

Means a piece of the honeycomb platinum filter has broken off and is rattling about inside the cat body - easy to hear!

If you have a catalytic converter that has overheated (outer Shell having a bluish color) look for the problems, like too much alcohol in the fuel, too lean a mixture from stopped up injectors, overheating engine, vacuum leaks, misfiring cylinders, etc

http://troubleshootmyvehicle.com/gm/3.1L-3.4L/how-to-test-trouble-code-P0420-page-1

 

[Buzz26]

Wow! Now that's what I'd call one hell of an answer, or two even!  Should be fun working my way through that lot. Cheers bud. Not sure that my reader can cope with live data though?, but I can have a go at the rest. Will be back with my findings. Thanks again, for now.

[Omendata]

Get yourself a cheapie like the D950 one above £17 on eBay (IT WILL PAY FOR ITSELF IN LESS THAN A WEEK GUARANTEED) although i have a few expensive ones and a few of the bluetooth ones for using with a mobile the handheld ones are mid price , bluetooth ones can be had for less than a fiver and the expensive one i have was £120 second hand from Usa and i hardly ever use it and got all the software from 'ahem.... alternative streams , rivers , tsunamis and ........
?;o)

Good luck and dont be a f@nny! and not post your results back...
Not nice to take and run like most of the single posters on here...does my nut right in....

The picture above is my cleaned ICV - Nice and shiny should have taken a photo of it dirty but you will see when ye get it off!

Dont forget to clean the head the shaft and the hole!!!!

>;o)

[Buzz26]

Update - your suggestion about the ICV seems to have sorted the revving issue and I have done a manual check on the cat and all appears ok - no rattling and no blueing. Next I'd like to check out the sensors but my reader don't do live data... bummer. I took a look at the D950 reader that you suggested was on eBay for £17ish, but it is not actually a D950 and according to the seller it don't do live data either!  Can't find a D950 anywhere else, but do you know anything about the D900... would that do the job?

[Omendata]

Thanks for letting us know Buzz, always good to know if something fixes an issue , lets others in future get a quick fix.

The D950 is a special model i couldnt find it anywhere after a few months either.

You can have mine for £170 if you want (collectors item now and all that p1sh) lol

Here is the one you want - its a d900 - does live data - nice little pouch with it as well and cheaper than that which i paid!

http://www.ebay.co.uk/itm/D900-Vehicle-Car-OBD2-EOBD-CAN-BUS-Fault-Code-Reader-Scanner-diagnostic-tool-/331052859667?hash=item4d1449c113:g:UG8AAOSwEeFVNRiK

Try a bluetooth one (just google search for mini elm 327) alternatively and use your smartphone - it gives way more live data than the handheld one even though its under a fiver.

http://www.ebay.co.uk/itm/Mini-ELM327-OBD2-V2-1-Car-Bluetooth-Scanner-Android-Auto-Scan-Diagnostic-Tool-DE-/281927807099?hash=item41a434f07b:g:husAAOSwKtlWtJVe

You will need the Torque Pro app from the google playstore!

And an Android smartphone!!! - posh nobs and showoffs iphone or a nokia (microsoft os) are no use for Obd stuff!

Hackers and IT Pros and proper engineers dont use iphones! lol rant over....