How can Fuel mixture affect your coolant level?
Discussion
How can Fuel mixture affect your coolant level?
OK.. It’s a long story but late last year I had my car set up on the rollers by Mark Adams and noticed at the time, the coolant had gone down from it’s normal 50mm (from the bottom of the expansion tank position) to about 35mm.. When on the rollers Mark holds the car at some high RPM’s whilst mapping sites so put it down to this for whatever reason… He fitted a Bosch MAF and set it up… The Bosch MAF has a variable resistor you set to 1.8volts for cat cars…. I ran the car for the rest of the year (minimal miles) but the level did wanted to be below 50mm.. heading towards the 30mm level.
Then early this year I had a new cam fitted, topped up the coolant and noticed on return that the pressure in the coolant system was lower than before and it was heading towards 50mm again in the header tank with a 1 bar cap. It’s more or less stayed here all year for 2000 miles until last week!
The car started missing a beat when pulling away so I checked all the settings.. The Bosch MAF adjuster was set to 1.12 Volts and not 1.8 volts as it should be. So when the cam was fitted and they were playing about with tune resistors etc I assume this got twiddled! Talking to MA this set’s it weak at tickover but is also carried thru with the map into acceleration etc.. The reason I’ve seen it now and not before is that the 14 CUX adjusts up to a certain % to keep the car running right… But at 9 deg (air temp) there is a step change in the map so it’s obviously thrown a wobbler and started running a bit too lean… So I re-set it to 1.8 volts and it’s great again in theory running richer.
Yesterday I checked my coolant level from about 30 miles I did last week following the adjustments. And it’s now sat close to 40mm!... WHY!!... Has it stopped at this level.. is it still working it’s way down again?.. Why does making it richer have this effect (if it was heat it should be running hotter when lean)…. Is there a fix for this… I’ve seen before changing head gaskets can improve header tank levels? (I didn’t notice if the pressure was back and I’ll check that this week but the temp gauge was showing the as it has all year so no change according to this)
May be the fix is to throw away my coolant level measuring stick…. But just out of interest, why is this happening?? Theories on a postcard please to…….
OK.. It’s a long story but late last year I had my car set up on the rollers by Mark Adams and noticed at the time, the coolant had gone down from it’s normal 50mm (from the bottom of the expansion tank position) to about 35mm.. When on the rollers Mark holds the car at some high RPM’s whilst mapping sites so put it down to this for whatever reason… He fitted a Bosch MAF and set it up… The Bosch MAF has a variable resistor you set to 1.8volts for cat cars…. I ran the car for the rest of the year (minimal miles) but the level did wanted to be below 50mm.. heading towards the 30mm level.
Then early this year I had a new cam fitted, topped up the coolant and noticed on return that the pressure in the coolant system was lower than before and it was heading towards 50mm again in the header tank with a 1 bar cap. It’s more or less stayed here all year for 2000 miles until last week!
The car started missing a beat when pulling away so I checked all the settings.. The Bosch MAF adjuster was set to 1.12 Volts and not 1.8 volts as it should be. So when the cam was fitted and they were playing about with tune resistors etc I assume this got twiddled! Talking to MA this set’s it weak at tickover but is also carried thru with the map into acceleration etc.. The reason I’ve seen it now and not before is that the 14 CUX adjusts up to a certain % to keep the car running right… But at 9 deg (air temp) there is a step change in the map so it’s obviously thrown a wobbler and started running a bit too lean… So I re-set it to 1.8 volts and it’s great again in theory running richer.
Yesterday I checked my coolant level from about 30 miles I did last week following the adjustments. And it’s now sat close to 40mm!... WHY!!... Has it stopped at this level.. is it still working it’s way down again?.. Why does making it richer have this effect (if it was heat it should be running hotter when lean)…. Is there a fix for this… I’ve seen before changing head gaskets can improve header tank levels? (I didn’t notice if the pressure was back and I’ll check that this week but the temp gauge was showing the as it has all year so no change according to this)
May be the fix is to throw away my coolant level measuring stick…. But just out of interest, why is this happening?? Theories on a postcard please to…….
Edited by TVR Beaver on Wednesday 27th October 10:50
Sorry but I don't have any idea what you are measuring John?
Swirl tank or expansion tank, level from bottom when hot or cold...??
I suspect the expansion tank, and that yes its is running hotter when lean, throwing out coolant as the heat expands the volume and then drawing back in air as the coolant cools and contracts.
Swirl tank or expansion tank, level from bottom when hot or cold...??
I suspect the expansion tank, and that yes its is running hotter when lean, throwing out coolant as the heat expands the volume and then drawing back in air as the coolant cools and contracts.
TVR Beaver said:
How can Fuel mixture affect your coolant level?
The car started missing a beat when pulling away so I checked all the settings.. The Bosch MAF adjuster was set to 1.12 Volts and not 1.8 volts as it should be. So when the cam was fitted and they were playing about with tune resistors etc I assume this got twiddled! Talking to MA this set’s it weak at tickover but is also carried thru with the map into acceleration etc.. The reason I’ve seen it now and not before is that the 14 CUX adjusts up to a certain % to keep the car running right… But at 9 deg (air temp) there is a step change in the map so it’s obviously thrown a wobbler and started running a bit too lean… So I re-set it to 1.8 volts and it’s great again in theory running richer.
Ive never managed to get the CO trim to alter the mixture in anyway when running the catalysts map, and one guru on the 14CUX (not MA in this case) stated that this manual adjustment is turned off completely as the ECU can trim the mixture with the lambda probes feedback, so it does not need the manual adjustment. If you are running in non catalyst mode the CO trim will radically alter the mixture up to around 2500 rpm, but beyond that its purely down to mapping and sensor inputs. I did query MA on the reason why he sets this control on the catalyst map, and he said it controls the start point for the mixture setting and although this may be visable as a parameter inside one of the memory locations in the ECU (not the map, but a trim value) that I cant access, but in the real world I cant measure the effect at all.The car started missing a beat when pulling away so I checked all the settings.. The Bosch MAF adjuster was set to 1.12 Volts and not 1.8 volts as it should be. So when the cam was fitted and they were playing about with tune resistors etc I assume this got twiddled! Talking to MA this set’s it weak at tickover but is also carried thru with the map into acceleration etc.. The reason I’ve seen it now and not before is that the 14 CUX adjusts up to a certain % to keep the car running right… But at 9 deg (air temp) there is a step change in the map so it’s obviously thrown a wobbler and started running a bit too lean… So I re-set it to 1.8 volts and it’s great again in theory running richer.
spend said:
Sorry but I don't have any idea what you are measuring John?
Swirl tank or expansion tank, level from bottom when hot or cold...??
I suspect the expansion tank, and that yes its is running hotter when lean, throwing out coolant as the heat expands the volume and then drawing back in air as the coolant cools and contracts.
I'm measuring the expansion tank.. when cold (at least 24 hours)... and that's the point.. you would think lean equates to hotter so more fluid out... But coming from lean to richer has resulted in the level droping???.. All very strange?Swirl tank or expansion tank, level from bottom when hot or cold...??
I suspect the expansion tank, and that yes its is running hotter when lean, throwing out coolant as the heat expands the volume and then drawing back in air as the coolant cools and contracts.
blitzracing said:
TVR Beaver said:
How can Fuel mixture affect your coolant level?
The car started missing a beat when pulling away so I checked all the settings.. The Bosch MAF adjuster was set to 1.12 Volts and not 1.8 volts as it should be. So when the cam was fitted and they were playing about with tune resistors etc I assume this got twiddled! Talking to MA this set’s it weak at tickover but is also carried thru with the map into acceleration etc.. The reason I’ve seen it now and not before is that the 14 CUX adjusts up to a certain % to keep the car running right… But at 9 deg (air temp) there is a step change in the map so it’s obviously thrown a wobbler and started running a bit too lean… So I re-set it to 1.8 volts and it’s great again in theory running richer.
Ive never managed to get the CO trim to alter the mixture in anyway when running the catalysts map, and one guru on the 14CUX (not MA in this case) stated that this manual adjustment is turned off completely as the ECU can trim the mixture with the lambda probes feedback, so it does not need the manual adjustment. If you are running in non catalyst mode the CO trim will radically alter the mixture up to around 2500 rpm, but beyond that its purely down to mapping and sensor inputs. I did query MA on the reason why he sets this control on the catalyst map, and he said it controls the start point for the mixture setting and although this may be visable as a parameter inside one of the memory locations in the ECU (not the map, but a trim value) that I cant access, but in the real world I cant measure the effect at all.The car started missing a beat when pulling away so I checked all the settings.. The Bosch MAF adjuster was set to 1.12 Volts and not 1.8 volts as it should be. So when the cam was fitted and they were playing about with tune resistors etc I assume this got twiddled! Talking to MA this set’s it weak at tickover but is also carried thru with the map into acceleration etc.. The reason I’ve seen it now and not before is that the 14 CUX adjusts up to a certain % to keep the car running right… But at 9 deg (air temp) there is a step change in the map so it’s obviously thrown a wobbler and started running a bit too lean… So I re-set it to 1.8 volts and it’s great again in theory running richer.
Edited by TVR Beaver on Wednesday 27th October 11:19
If it has that much effect, you must be running a non catalyst fuel map methinks (thats a green wired tune resistor under the passanger dash) unless MA does something specific to his chips to bring the CO trim into play on catalyst maps. Ive only ever tried this on TVR chips. As for the coolant level, the expansion tank does what it says, so the level of the water will go up and down in direct relation to the average temp of the water in the system, but dont forget this will be affected by engine bay temp, block / head temp, heater matrix temp, atmospheric pressure (in so much as it may alter the amount the hoses expand- it may not be significant) and ambient temp so you have lots of varables apart from basic mixture. More to the point engine load and throttle opening will alter the heat produced, so You really cant compare water levels unless the tests you are running are 100% controlled and repeatable, the words red and herring spring to mind...
I'll check the resistor but when you fit the Bosch.. you cut a wire and by the ECU put in a small variable resistor (this is not in the MAF)...
On leves and temps... I've watched this for 2 years now (it's a bit of an obsession
) so I know where it should be.. where it was and what alters it... I agree abmient and atmospheric pressures can chamge it.. but this is a loss over a very short distance coz I re-set the thing back to where it was when MA did it.
I have a theory here but not sure if it holds water (escuse the pun..
)
If it's now running cooler localy, (but the engine is still geting to the same temp).. could it be a local expension and sealing issue?.. ie.. when it was hot before and very hot due to lean running... was there more pressure on the head gaskets say due to thinge expanding more (I still have torque bolts).. Now it's running cooler localy.. could this pressure be less allowing a bit (but only a bit) of pressure into the system?... That said, I have no bubbles or traces of gas in the bottle (I've had a Co meter in there).. so not sure... It's a mystery....
I know if I put my 1.2 bar cap back on the level will probably stay where it is now...
May just pull the heads this winter and fit new gasketts and may be a head stud kit with nut's.. just for safe measure..
On leves and temps... I've watched this for 2 years now (it's a bit of an obsession
) so I know where it should be.. where it was and what alters it... I agree abmient and atmospheric pressures can chamge it.. but this is a loss over a very short distance coz I re-set the thing back to where it was when MA did it.I have a theory here but not sure if it holds water (escuse the pun..
)If it's now running cooler localy, (but the engine is still geting to the same temp).. could it be a local expension and sealing issue?.. ie.. when it was hot before and very hot due to lean running... was there more pressure on the head gaskets say due to thinge expanding more (I still have torque bolts).. Now it's running cooler localy.. could this pressure be less allowing a bit (but only a bit) of pressure into the system?... That said, I have no bubbles or traces of gas in the bottle (I've had a Co meter in there).. so not sure... It's a mystery....
I know if I put my 1.2 bar cap back on the level will probably stay where it is now...
May just pull the heads this winter and fit new gasketts and may be a head stud kit with nut's.. just for safe measure..
John I think your reading to much into this. I don't think you have an issue that needs sorting, your car runs strong with no overheating issues, I know my water level in the expansion tank can vary quite a bit, but aslong as there is water in there I just leave it alone.Pulling the engine to bits just for this seems a little exesive unless your bored and want somthing to do this winter;).
Chris
Chris
Hi Chris.. No, not bored... lot's to do... its more from a 'why' point of view?.. it's strange how they run at differant levels... what's your at?.. do you ever top it up in say 2000 miles??
Anyway.. we've got your body to lift off
.
the resistor is white leads colours Orange / White / Black / Brown / Brown..
Is this correct?
Anyway.. we've got your body to lift off
.
the resistor is white leads colours Orange / White / Black / Brown / Brown..
Is this correct?
Edited by TVR Beaver on Wednesday 27th October 20:07
Id agree on this one. If you are worried about the mixture check the lamda probes are switching 0 -1 volt at about 1/2 second intervals at tickover- black to white wires at the lambda connector. Changes in mixture outside its design will will make it stick at 1 or 0 volts. The CO trim resistor that MA puts in just replaces exactly the same thing on a Lucas 5AM, its just a 1k resistor to ground, and has no influence on the AFM out put at all, its just a reference feed into the ECU. The Bosch AFM itself just has a couple of supplys (5 and 12 volts) a ground, and its voltage output, its really not that different to the 5AM in its response curve. Any temperature changes are automatically compensated for so you get a true value for the air mass entering the engine, however hot or cold the intake air. The temp sensor on the Bosch is for ignition timimg control that the Lucas ECU cant use.
TVR Beaver said:
do you ever top it up in say 2000 miles??
Yes I have done aprox 4k this year and have topped up twice each time about 1/2ltr to a ltr or so. I run it so it is two or three inch from the bottom but this can vary from looking 1/2 full to nearly empty but as long as there is somthing in I never top up.Chris
blitzracing said:
Id agree on this one. If you are worried about the mixture check the lamda probes are switching 0 -1 volt at about 1/2 second intervals at tickover- black to white wires at the lambda connector. Changes in mixture outside its design will will make it stick at 1 or 0 volts. The CO trim resistor that MA puts in just replaces exactly the same thing on a Lucas 5AM, its just a 1k resistor to ground, and has no influence on the AFM out put at all, its just a reference feed into the ECU. The Bosch AFM itself just has a couple of supplys (5 and 12 volts) a ground, and its voltage output, its really not that different to the 5AM in its response curve. Any temperature changes are automatically compensated for so you get a true value for the air mass entering the engine, however hot or cold the intake air. The temp sensor on the Bosch is for ignition timimg control that the Lucas ECU cant use.
Well I'll give it a run or two before I cash my tax in (may go out now).. and see if it's been corrected by the ECU back to where it was (that is a point.. I also un-pluged the ECU.. does this go back to base settings then start to 'correct' again when running... It ran great at first then went off a tad when I re-fitter the magnacores... but could this have been the ECU correcting?.. I assume when you plug it in it runs exactly to what's on the chip and mapping... why would it then start to correct?)... but at least I have the right resistor...If the trim does nothing... why is it there even on the Lucas one?...
Edited by TVR Beaver on Wednesday 27th October 21:24
TVR Beaver said:
So you top it up when it becomes empty (or beyond)?.. and top it up to 2 to 3 inches from the bottom... and that goes down again in time back to the bottom?... am I reading this correctly?
Mmmm.. does make my 6mm look quite irelivant then?
Yep thats about how it is uses about 1/2 litre or so in a couple of thousand miles. Didn't think that was a problem TBH. Also uses about a ltr of oil aswell.Mmmm.. does make my 6mm look quite irelivant then?
The car never see's temps over 90 no visible leaks.
Chris
TVR Beaver said:
blitzracing said:
Id agree on this one. If you are worried about the mixture check the lamda probes are switching 0 -1 volt at about 1/2 second intervals at tickover- black to white wires at the lambda connector. Changes in mixture outside its design will will make it stick at 1 or 0 volts. The CO trim resistor that MA puts in just replaces exactly the same thing on a Lucas 5AM, its just a 1k resistor to ground, and has no influence on the AFM out put at all, its just a reference feed into the ECU. The Bosch AFM itself just has a couple of supplys (5 and 12 volts) a ground, and its voltage output, its really not that different to the 5AM in its response curve. Any temperature changes are automatically compensated for so you get a true value for the air mass entering the engine, however hot or cold the intake air. The temp sensor on the Bosch is for ignition timimg control that the Lucas ECU cant use.
Well I'll give it a run or two before I cash my tax in (may go out now).. and see if it's been corrected by the ECU back to where it was (that is a point.. I also un-pluged the ECU.. does this go back to base settings then start to 'correct' again when running... It ran great at first then went off a tad when I re-fitter the magnacores... but could this have been the ECU correcting?.. I assume when you plug it in it runs exactly to what's on the chip and mapping... why would it then start to correct?)... but at least I have the right resistor...If the trim does nothing... why is it there even on the Lucas one?...
Edited by TVR Beaver on Wednesday 27th October 21:24
[/quotEWhen you first plug the ECU in it does rely on just the map and sensor data but quickly corrects the overall mixture at idle once the lambda probes are hot, and will continue to do so as conditions change, typically withing a few seconds, but no more than about 30 seconds even with a cold engine, so there is no long term learning as such. The trim resistor is there as the ECU can be set to run in non catalysts mode easily, after all you did not need catalysts until 1992 in the UK, whilst American spec range rovers needed to run cat's well before this date, so the 14CUX was made easily switchable between the two modes. As for the Magnecores, if you have any HT type issues it completely screws the fueling, as the ECU sees unburnt mixture as a lean mixture, so adds extra fuel to compensate, and so soots up the working plugs and makes the engine run rich. Personally I would not give Magnecors the time of day, you are better of with good quality standard leads.
If your coolant isn't pressurized properly all sorts of weird things happen, new cap and pressure test often show small problems.
Can't say I really worry too much about levels in tanks, but air pockets in heads / blind alleys in engine does bother me (particularly those waterways in the rear of the heads that the efi inlet manifold shuts off)
I do rather miss old style pressure cap systems with an overflow pipe where you could at least trap the excess and see what was going on. This blow off past the cap does seem a backward step in some ways?
Can't say I really worry too much about levels in tanks, but air pockets in heads / blind alleys in engine does bother me (particularly those waterways in the rear of the heads that the efi inlet manifold shuts off)
I do rather miss old style pressure cap systems with an overflow pipe where you could at least trap the excess and see what was going on. This blow off past the cap does seem a backward step in some ways?
It is a new cap... 1 bar unit (had a 1.2 before and this changes the level by about 1.5" believe it or not!).. and I have a pressure tester thing that I made from and old cap, a pressure gauge and tap... I holds up well.. even overnight although I do know I has a VERY small weep on the expansion tank neck (i fill this with aroldite if I'm testing it but once warmed up a few times it does not last.. but it's micro bubbles at 2 bar so this is not the issue)
I've given it a GOOD 30 miles thrash tonight so will see where we are tomoro...
As you say, so long as there is fluid in there don't bother... the swirl pot is always brim full so no issues there.... and squishing any of the pipes never gives bubbles or anything..
The old system in my mind was better... I've even tried a blotting paper washer around the bottle next to see if it shows water coming out... trouble is it must be a fine mist when it vents and its that hot under there anyways.. its always dry when you check it...
I'm sat in the garage office looking out at it... It's like a naught child just sat there!! bloody thing!!
I've given it a GOOD 30 miles thrash tonight so will see where we are tomoro...
As you say, so long as there is fluid in there don't bother... the swirl pot is always brim full so no issues there.... and squishing any of the pipes never gives bubbles or anything..
The old system in my mind was better... I've even tried a blotting paper washer around the bottle next to see if it shows water coming out... trouble is it must be a fine mist when it vents and its that hot under there anyways.. its always dry when you check it...
I'm sat in the garage office looking out at it... It's like a naught child just sat there!! bloody thing!!
Edited by TVR Beaver on Thursday 28th October 21:52
One word comes to mind John.... paranoia
In my humble (non-technical) opinion the water level movement is completely insignificant and co-incidental and probably effected by a number of things like different engine operating temps, atmospheric condistions, driving profile etc etc.
Unless you end up with a puddle of coolant undr teh car like my car did the last time it was on your drive I'd suggest you're worrying unnecessarily.
In my humble (non-technical) opinion the water level movement is completely insignificant and co-incidental and probably effected by a number of things like different engine operating temps, atmospheric condistions, driving profile etc etc.
Unless you end up with a puddle of coolant undr teh car like my car did the last time it was on your drive I'd suggest you're worrying unnecessarily.
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