andyismilesaway 20 Posted August 23, 2016 Share Posted August 23, 2016 Good evening all, I had the Westfield trailered to the local garage today for a check of brakes, headlight alignment and emissions - the good news is all 4 corners were braking as expected and headlight are now pointing in the right direction - however no matter what we did we couldn't get the emissions to pass... The car is a 1.8 1997 mx5 engine with k&n filter, hoses to accommodate, WF 4-1 manifold with normal mx5 lambda sensor and a WF cat exhaust, standard ECU and stock engine. I've followed the coolant reroute with ECU temp sensor (where the thermostat once was) in the front of the block and temp gauge sender at the rear in the thermostat moulding. Engine was running for a good 20+mins and water was well up to temp of 100deg with fan kicking in and out as I'd hope. Now the numbers: Fast idle run 1: CO 0.544, HC 41, Lambda 1.013 Fast idle run 2: CO 0.477, HC 60, Lambda 1.009 Idle: CO 0.176 So it was the CO that was a FAIL and only at fast idle. The car build has been a steep learning curve, and I've loved every second (even the wiring?...) - but I'm really not sure what the numbers are telling me. The garage suggested using checking all air hoses after the MAF sensor and using brake cleaner sprayed on all the joins to see any changes in revs to highlight any leaks. Other than that, and checking, tightening connections has anyone anything more scientific or systematic I can do? Quote Link to post Share on other sites
KugaWestie 3,339 Posted August 23, 2016 Share Posted August 23, 2016 Good advice from the garage, check for vacuum leaks. All round the manifold, make sure all the dead ends are capped off. Does it run without the MAF plug connected? Quote Link to post Share on other sites
KugaWestie 3,339 Posted August 23, 2016 Share Posted August 23, 2016 Have you run a diagnostics check? Quote Link to post Share on other sites
KugaWestie 3,339 Posted August 23, 2016 Share Posted August 23, 2016 Have you got the EGR sender connected onto the loom to eradicate any errors? Quote Link to post Share on other sites
andyismilesaway 20 Posted August 23, 2016 Author Share Posted August 23, 2016 Not tried without MAF, will give that a go. Il give diag a go and yes, I've got all the egr kit attached to hope to not generate any diag errors. Thanks, all good thoughts Quote Link to post Share on other sites
Mark (smokey mow) 1,417 Posted August 23, 2016 Share Posted August 23, 2016 Andy looking through your build pics, have you connected the Idle control valve (ISC) which is below the throttle body to the inlet ducting? This would normally be a piece of 15mm hose, its hard to tell with the angle of the photos but I can't see one. https://andyswestfieldbuild.wordpress.com Quote Link to post Share on other sites
andyismilesaway 20 Posted August 23, 2016 Author Share Posted August 23, 2016 Evening, yes all connected up with a small piece of L shape hose from the isc to a spur I added into the main big intake pipe. Good call though. Next job is to try and spray some of the fittings and hope to note a change in revs/behavior - realistically reckon seeing any change is likely if there is a small leak? Quote Link to post Share on other sites
Kit Car Electronics 1,954 Posted August 23, 2016 Share Posted August 23, 2016 You wanted science... Look at it this way - the test is supposed to be a cat test. If you didn't have a cat, you'd likely meet 3.5% CO and 1200ppm HC at 1.0 lambda. A functioning cat shouldn't have any problem getting to >85% conversion efficiency, which would be 0.5% CO and 180ppm HC, hence the 0.3/0.5% and 200ppm limit. But you made it to 40-60ppm HC which would be >90% HC efficiency, yet failed the CO. It suggests that your engine-out gas might be richer than 3.5% CO, but the lambda probe (and presumably the engine sensor) read lambda 1. That normally happens when: (a) an exhaust leak lets air in near the sensor so the engine runs richer than the sensor indicates. (b) a poor fuel distribution across cylinders makes some richer than others (dirty injectors or intake leak) © ignition is retarded to cause incomplete combustion I'd be looking for leaks first, particularly on the exhaust joints 1 Quote Link to post Share on other sites
andyismilesaway 20 Posted August 23, 2016 Author Share Posted August 23, 2016 Thanks, appreciate the info! Okay, intake checking and exhaust side leaks - Il give all the above a bash Quote Link to post Share on other sites
andyismilesaway 20 Posted August 23, 2016 Author Share Posted August 23, 2016 Thank you all by the way! Quote Link to post Share on other sites
KugaWestie 3,339 Posted August 23, 2016 Share Posted August 23, 2016 I am looking forward to you reporting back already Quote Link to post Share on other sites
andyismilesaway 20 Posted August 24, 2016 Author Share Posted August 24, 2016 Okay, quick update: a few mins in the garage show one of the inlet manifold takeoffs capped end was a bit loose and i suspect not a great seal. Also the heated oxygen sensor was only a bit beyond finger tight in the manifold - argh! I've just ordered a new washer for the headed oxygen sensor so I can tighten it up properly. I guess either (or both...) of the above could have caused the emissions results I saw:( Annoyed with myself I didn't check everything in advance but you don't know until you know! 1 Quote Link to post Share on other sites
Kit Car Electronics 1,954 Posted August 24, 2016 Share Posted August 24, 2016 sounds promising! Quote Link to post Share on other sites
KugaWestie 3,339 Posted August 25, 2016 Share Posted August 25, 2016 Hopefully it's as easy as that! Quote Link to post Share on other sites
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