emmissions update .Help....
Discussion
Hi all.just a quick up date .Well .Good news first.We got the car to idle.After talking problem through with last owner D1MAD.good guy.i went into garage and sprayed carb cleaner down mixture screw and into plemmem .Tryed this last weekend made no difference.This time might of cleared some gum.Mate came around today new plugs and leads fitted.Found a fault with connnecter block from tpsensor earth fixed.plug in gunson co reader .Bummer cant get the emmissions to lower............. .So i think its off to TVR car parts.I am down but not giving up ................ i know it could be ecu realated not sure any help would be most welcome .As allways thanks for your help ......................Mike 1986 350i s2.My mate thinks it might be over fueling .
Sell it and buy a cerb;)Did pop up your way last weekend sir,hope all finds you well.If your around next weekend will pop up if weather turns to sun,can only hope the good old summer will show up soon.Is the car ready for Mot sir last time we spoke she was nearly there,or are the Emissions holding you up.
Mike do the emissions come into the mot for your car,thought there was a cut off point,may be wrong but i know sam looked into the emissions for mine but could not wangle it,but did say there was a point where the test cannot be applied.Am sure that Dulfords will sort it out for you.When the car gets hot do you reach better readings?
Right guys .the co reading goes up to 7.and 9 .The same readings as the mot showed.Mixture allen screw on the air flow meter does not alter any thing on the co,s I was hoping when the idle was fixed it might improve the co readings. i just want it fixed now.lol........... Is there any thing in the mass air fow unit that might affect the readings.The black top to the meter looks as its been off in the past.thanks again .Mike .Spongy you are on the wrong forum.....lol good to hear from you mate .Mike
inside the afm is a potentiometer activated by the air flap - you can just move the toothed wheel around a few noches until you cut the emmissions down enough for mot - i do this every year with mine. suggest you check the fuel pressure first as leaking injectors or knackered regulator play havoc with co levels at idle
Mike Brewer said:
Right guys ........ Is there any thing in the mass air fow unit that might affect the readings.The black top to the meter looks as its been off in the past.thanks again .Mike
Mike the top was taken off to adjust the fuelling when the car was rolling road tuned, there is I seem to remember a small signal needle that moves with the flap and a slight tweak one way or the other richens or weakens the mixture. If you adjust this it will effect the mixture across the entire rev range so be careful if you fiddle with it, best left to the experts this one!Regards. Steve.
Thats cool Steve.The car is booked in for the end of the month .For a mot and for them to sort out emmission problem.i just hope they can fix find problem .It might be ECU related.i am in there hands..They will check fuelling etc .thanks for everybodys help .i just wanted to try and fix it .But hey ho sods law .Cheers Mike
Hi Adam .we replaced the coolant tempature sensor last weekend .i think it was a intermotor one.still have the old one.i did read your thread about the colour of the sensor...Thanks for your help.i know this thread has been running a while .But i do thank every one for thier help...Mike.Maybe its over fueling.i just dont understand why nothing alters the cos at idle. Mike
hey adam - can you explain how the temperature sensor makes a difference to the mixture ? as far as i can tell on mine the 4cu brain doesn't change the injector duration relative to coolant temperature only air temp through the afm - all coolant temp sensor does is fire the cold start injector, so if this is blanked or clamped off the temp sensor isn't doing anything. on my system the afr is unchanged by disconecting the temp sensor - maybe my ecu is busted ?
honourablepickle said:
hey adam - can you explain how the temperature sensor makes a difference to the mixture ? as far as i can tell on mine the 4cu brain doesn't change the injector duration relative to coolant temperature only air temp through the afm - all coolant temp sensor does is fire the cold start injector, so if this is blanked or clamped off the temp sensor isn't doing anything. on my system the afr is unchanged by disconecting the temp sensor - maybe my ecu is busted ?
The cold start injector doesn't respond to the coolant temperature sensor but the thermotime switch (which is mounted next to the coolant sensor in the inlet manifold).in which case i definately have a problem ! the thermotime switch isn't connected, i dont have a cold start injector and the unplugging of the temp sensor makes no difference at all. curiously though i'm getting a afr from the lambda sensor in the headder of 13.8 to 14.2 across the rev range and the car runs and starts perfectly - strange eh
honourablepickle said:
hey adam - can you explain how the temperature sensor makes a difference to the mixture ? as far as i can tell on mine the 4cu brain doesn't change the injector duration relative to coolant temperature only air temp through the afm - all coolant temp sensor does is fire the cold start injector, so if this is blanked or clamped off the temp sensor isn't doing anything. on my system the afr is unchanged by disconecting the temp sensor - maybe my ecu is busted ?
I thought on the flapper cars there was no air temp sensor, just air flow, unless there is a temp sensor in the AFM also.I was also thought the thermotime switch controlled the cold start injector and Extra air Valve. and engine coolant temp. sensor did affect the ECU, else why have it, as there is a separate one for the gauge.
One day I hope to be able to spend some time and work out in detail how everything works, and link up a data logger to the ECU.
TVRleigh_BBWR said:
I thought on the flapper cars there was no air temp sensor, just air flow, unless there is a temp sensor in the AFM also.
There is an air temp. sensor in the AFM.TVRleigh_BBWR said:
I was also thought the thermotime switch controlled the cold start injector and Extra air Valve. and engine coolant temp. sensor did affect the ECU, else why have it, as there is a separate one for the gauge.
Thermotime switch does fire the cold start injector, the aux. air valve has its heating element plus heat soak from the inlet manifold.TVRleigh_BBWR said:
One day I hope to be able to spend some time and work out in detail how everything works, and link up a data logger to the ECU.
Join the club, I've been tinkering for years 
- though mostly from the point of view of repairing faults. I have oscilloscope traces etc. under various conditions. Bench simulation is difficult mainly owing to the difficulties of providing an ignition trigger signal and with no clue as to what airflow is going through the meter at any flap position (so you can't easily equate injector period to cu.ft./min. etc.). I guess some cleverclogs could work it out but aerodynamics isn't my best subject 
The ECU circuitry is interesting as it seems to be largely a number of constant current sources interfering with each other
Lots of summing and differentiating going on as I recall.Gassing Station | Wedges | Top of Page | What's New | My Stuff