Title: low EGT values on specific cylinders Post by: lakis1982 on October 01, 2018, 08:14:44 am Hello,
I am trying to finally program my ECU parameters (i am using an Ecumaster EMU device) on my 2100cc oxyboxer turbo injection engine.. I have one EGT sensor installed on every cylinder so that i can monitor their values.. No wideband sensor yet... My problem is that i see very low temperatures around 70-100C on cylinders 1 and 3, while on cylinders 2 and 4 the values are more normal around 500C.. These are values after letting it idle for a couple of minutes.. I did a test to make sure that my ignition per cylinder is working consistently and is syncronized and i see that all the ingition angles are correct.. So i assumed that the problem is injection related. I also swapped the injectors between cyl 1 and 2 and the same problem occurs, low EGT values on cyl 1 and 3 and normal values on cyl 2 and 4.. Then I did took off the spark plug from cylinder 2. The weird thing is that in this case, the EGT values on cyl 1 and 3 became normal !!!! around 480C and on cylinder 2 around 80C (as expected) and on cylinder 4 around 180C... DO you know why does this could happen ?? WHy do I have low EGT values on cyl 1 and 3 , and then when i take off spark plug from cyl 2, why the EGT values on cyl 1 and 3 go normal ??? I am not using any EGT based correction yet on the pulse width of every injector I am using SIemends Deka genuine brand new injectors The engine is fresh built brand new i am using batch fire injection Please give me your thoughts , I feel i am stucked... REgards Title: Re: low EGT values on specific cylinders Post by: Basti on October 01, 2018, 09:33:28 am Hi!
Are the EGT sensors in the same Position on all cylinders? ;) I think this is not possible or? The distance to exhaust valve is very important, also the deepth of the Sensor in the exhaust pipe changes the values a lot. Did yiu check this? Cheers, Basti Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 01, 2018, 11:46:29 am yes..all EGT sensors are installed in the same way with the same depth and distance from exhaust port of the cylinder( around 10cm)...
I dont think that the values of EGT are misleading.. I can see it in the way that the engine idles that there is not consistent performance on all cylinders... I just try to figure out the problem based on the EGT readings... Title: Re: low EGT values on specific cylinders Post by: Jesse Wens on October 01, 2018, 12:09:11 pm Wasted spark?
Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 01, 2018, 13:28:07 pm yes it is wasted spark...
Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 01, 2018, 14:32:15 pm Does your engine have individual throttle bodies or a single throttle body? (Pics pls)
How do the plugs look? Im curious. Why dont you use a wide band? And why are you not using sequential injection? Title: Re: low EGT values on specific cylinders Post by: richie on October 01, 2018, 16:09:49 pm So the problem moves with the spark plugs? then most likely the 2 low cylinder have fouled plugs, try a new set of plugs and see if problem goes?
cheers Richie Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 01, 2018, 16:29:19 pm I'm not using wideband yet because it is the first steps of setting up the ECU and I'm afraid i will poison the sensor..I will hook one up when I make things a bit better...
I chose wasted spark for simplicity reasons.. [attachment=1] [attachment=2] I checked that all spark plugs output a strong spark..I will give it a try to change them.. It's frustrating.. Title: Re: low EGT values on specific cylinders Post by: wph on October 01, 2018, 20:34:14 pm Cylinder robbing... single throttebody feeding two cylinder. Even worse with carburetors. My first guess, swap EGT sensors from cold to hot cylinders and see what it does
Title: Re: low EGT values on specific cylinders Post by: Erlend / bug66 on October 01, 2018, 22:04:13 pm Looks like you are feeding a lot more air to 1 and 3...
Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 01, 2018, 22:24:33 pm Cylinder robbing... single throttebody feeding two cylinder. Even worse with carburetors. My first guess, swap EGT sensors from cold to hot cylinders and see what it does Haha, you might be thinking of Kads? The only reason I had the only Kad engine in town idling in all four was that we adapted a larger diameter balance tube compared to the original. My first thought on this problem is how does the engine drive? Im usually happy if my engines idle at all, yet alone idle on all four. (Like, who cares about idle, just crank up the idle speed and be happy) :D Title: Re: low EGT values on specific cylinders Post by: dannyboy on October 01, 2018, 23:03:21 pm i had a bent butterfly that caused big differences in temps on tick over ?
Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 02, 2018, 07:44:44 am Looks like you are feeding a lot more air to 1 and 3... If cyls 1 and 3 get a lot more air than required, should't the EGT values for those be elevated due to a lean situation ?? The engine does not drive at all .. the car sits on a lift and we try to make the ECU parameters acceptable so that the engine can run in an acceptable manner... Now it feels like it is working on 2 or 3 cylinders only.. Do you think there could be more air going to one cylinder that the other that sits beside ??? I am using this throttle system https://vwspeedshop.com/product.php?productid=16759&cat=395&page=1 Yesterday we also hooked up the wideband sensor just to confirm what we expected.. At around 1400rpm the lambda is around 0.73 and AFR around 10.8 .. SO it appears to be excessively rich... The ignition is wasted spark as mentioned...so it has the following firing sequence per engine cycle: igntion event 1: fires on cyls 1 and 3 igntion event 2: fires on cyls 2 and 4 igntion event 3: fires on cyls 1 and 3 igntion event 4: fires on cyls 2 and 4 The injection is batch fire injection and uses the following sequence: injector 1 injects when ignition event 1 occurs injector 1 injects when ignition event 1 occurs injector 1 injects when ignition event 1 occurs injector 1 injects when ignition event 1 occurs you can check it below the settings i am using [attachment=1] I am using ECUMASTER EMU as an ecu for the engine .. Title: Re: low EGT values on specific cylinders Post by: Erlend / bug66 on October 02, 2018, 07:52:30 am The divider in the intake is not in the middle of the air path. You could help the engine with moving the centre tube to above the fan shroud. The distribution would be much better.
Title: Re: low EGT values on specific cylinders Post by: Basti on October 02, 2018, 08:01:18 am I am not an expert in your ecu but for me it Looks like the Injection and ignition are at the same time or? No injection angle??
Looks like you are feeding a lot more air to 1 and 3... If cyls 1 and 3 get a lot more air than required, should't the EGT values for those be elevated due to a lean situation ?? The engine does not drive at all .. the car sits on a lift and we try to make the ECU parameters acceptable so that the engine can run in an acceptable manner... Now it feels like it is working on 2 or 3 cylinders only.. Do you think there could be more air going to one cylinder that the other that sits beside ??? I am using this throttle system https://vwspeedshop.com/product.php?productid=16759&cat=395&page=1 Yesterday we also hooked up the wideband sensor just to confirm what we expected.. At around 1400rpm the lambda is around 0.73 and AFR around 10.8 .. SO it appears to be excessively rich... The ignition is wasted spark as mentioned...so it has the following firing sequence per engine cycle: igntion event 1: fires on cyls 1 and 3 igntion event 2: fires on cyls 2 and 4 igntion event 3: fires on cyls 1 and 3 igntion event 4: fires on cyls 2 and 4 The injection is batch fire injection and uses the following sequence: injector 1 injects when ignition event 1 occurs injector 1 injects when ignition event 1 occurs injector 1 injects when ignition event 1 occurs injector 1 injects when ignition event 1 occurs you can check it below the settings i am using [attachment=1] I am using ECUMASTER EMU as an ecu for the engine .. Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 02, 2018, 09:00:06 am here is the explanation for the injection phase
[attachment=1] im non sure if i should use an injection offset angle.. Erlend, if the problem is the location of the center tube that appears to sit in a non symmetric location, shouldn't the differences for the EGT values appear between the left and right sided cylinders ??? In my case, the problem is that the differences on EGT values appear between the front and the rear cylinders. Title: Re: low EGT values on specific cylinders Post by: Erlend / bug66 on October 02, 2018, 10:33:50 am If you follow the air path on the outside of the bends, you see that 1 / 3 will get most of the air. If you move the centre tube to above the shroud, the air will still travel at the outside wall of each bend, but will meet the divider in the intakes straight on.
Title: Re: low EGT values on specific cylinders Post by: spoolin70 on October 02, 2018, 12:17:19 pm Why not try removing the silicone hoses and just let the throttle bodies take air from directly above (at least to set the idle).
That will prove if the bends are causing the imbalance/unequal air supply Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 02, 2018, 12:31:14 pm Spoolin79,
thats exactly what i was about to ask right now.. I will take off the silicone hoses and let the throttle bodies take air directly from the air.. Besides i am now testing around the 1300rpm region only.. If the EGT values get much closer for all cylinders then we could say that the assumption of the air distribution through the tubes issue is correct. If indeed is correct, could you tell me what i could do about it ?? I mean, if i cant move the center tube because of limited spacing above, is there something else i could do to improve the situation ??? Or you can just live with that and acccept that the idle will rely mostly on 2 cylinders..As far as i understood, this situation with uneven EGT values and air distribution should not exist on higher rpm regions e,g at 4500rpm , I will let you know tonight the results after i take off the silicon hoses... All comments are appreciated.. thanks Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 02, 2018, 14:11:05 pm If cyls 1 and 3 get a lot more air than required, should't the EGT values for those be elevated due to a lean situation ??
Lean doesnt necessarily mean higher temps. As mixtures go leaner they cool down until the flame goes out. 10.8 is super rich! Thats like what you might see with boost enrichment, not at idle. The air intake setup should not make a difference at idle. There is no boost and the turbo is just freewheeling. Dont worry about the spark as you have lots of sparks going on, its the 10.8 mixture thats killing the combustion. Can you reset the ecu back to default and start over with some kind of known baseline that works? Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 02, 2018, 15:27:59 pm Martin,
thats the main problem.. That i dont have a baseline to start from.. Apart from a megasquirt file that someone gave me, that actually has the same engine specs with me...2100cc, turbocharged, same heads, same cam, etc.. SO i used his file as a reference to convert it to an Ecumaster ecu file... Now as far as i get super rich values, should i start playing with the VE tables values so that the actual lambda starts getting close to the Lambda target table ??? Please eee below the target lambda table that i am using and give me your comments .. I guess the lambda target table is one of the most important parameters of all [attachment=1] Regards, Title: Re: low EGT values on specific cylinders Post by: cassa on October 02, 2018, 17:22:06 pm Cylinder robbing... single throttebody feeding two cylinder. Even worse with carburetors. My first guess, swap EGT sensors from cold to hot cylinders and see what it does X2 Try leaning out cyl 1 and 3 Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 02, 2018, 20:51:49 pm So here we are..
As a test, I removed the silicon hoses from the throttle bodies so that they could breath physically ...the same problem.. the cyls 1 and 3 still see egt values below 100c around 1500rpm, while cylinders 2 and 4 still have egt values around 500c..I also cross checked this condition of extremely uneven temperatures using a laser gun pointing to the the exhaust ports of the cylinder.. cyls 1 and 3 have temps of 50c and 60c while cyls 2 and 4 have temps of 150c and 180c..this happened also after I have managed to bring the AFR at 1400rpm around 13.2...so, why still that extreme uneven condition between cylinders? It's not only that I am obsessed with the egt numbers but I hear that the engine is not running smooth at those low Rpms..sounds like some cylinders are not functioning properly Obviously i think the problem is not the center tube that feeds the throttle bodies with air..let me know if I am missing something...should this problem get minimized when rpm are getting higher? I also started playing and modifying the VE table in the region between 1000rpm and 2300rpm for Map 100-110kpa , so that the actual lambda is close to the target lambda... Could someone share their lambda or afr target tables that they use? I need to know that my current lambda target table is consistent.. Thanks and regards Title: Re: low EGT values on specific cylinders Post by: JLaw on October 02, 2018, 22:34:59 pm Have you double checked your valve clearances are correct on all four cylinders, just a thought..
Title: Re: low EGT values on specific cylinders Post by: modnrod on October 03, 2018, 02:18:37 am Cylinder robbing... single throttebody feeding two cylinder. Even worse with carburetors. My first guess, swap EGT sensors from cold to hot cylinders and see what it does X2 Try leaning out cyl 1 and 3 Yep. You could tune it up beautifully by adjusting fuel to reach exhaust temps so all cylinders match, you don't need a wide-band. Title: Re: low EGT values on specific cylinders Post by: Erlend / bug66 on October 03, 2018, 07:52:12 am My list would be:
Check spark plug leads: Meassure ohm on all four. Check for vacuum leaks Check injector wiring Change sparkplugs As a starter Title: Re: low EGT values on specific cylinders Post by: andy198712 on October 03, 2018, 14:15:39 pm If you follow the air path on the outside of the bends, you see that 1 / 3 will get most of the air. If you move the centre tube to above the shroud, the air will still travel at the outside wall of each bend, but will meet the divider in the intakes straight on. my fluid dynamics is a little rusty but i don't believe thats how it works. lets say when a cylinder draws in its air, the air in the intake moves, say 12 inches down the tube, depending on volume, so does the other side as it draws in its air, so long as the volume of one cylinder's worth of air doesn't exceed the volume of the air in the intake tract to the TB opening, it shouldn't effect it. do that seem right? i case that off alot of OEM engine, look at the 6 cylinder BMW diesel engines, they have an inlet manifold shaped like a J, so number 6 is closest to the TB and number 1, a bout 2 feet further from it.... works well for them. your thoughts? good ideas on the general service items too, if its not following the injectors and its spraying and sparking as it should, could well be valves. Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 03, 2018, 15:39:48 pm My screens are different but heres one for you.
I did not tune the engine so I cant help you there unfortunately. I do have all my current tune screens available if you want to see one. ;) Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 03, 2018, 23:26:55 pm i have just checked the valve clearances and all good...no problem there... no vacuum leaks.. tomorrow i will try new spark plugs.. but anyway, today i was trying to play with the fuel trims per cylinder, so that i could lean or rich the cyls 1 and 3 that have low egt tamperatures... In the following two videos you can see all the live data and the EGT values that i had... one video is when i was running the engine around 1200rpm and the other when i was running around 2000rpm.. the egt values in cyls 1 and 3 are in both cases quite different compared to cyls 2 and 4...no matter if i was trying to rich or lean cyls 1 and 3 , no big changes would occur... https://www.youtube.com/watch?v=PMKB0FXEgfo&feature=youtu.be (https://www.youtube.com/watch?v=PMKB0FXEgfo&feature=youtu.be) https://www.youtube.com/watch?v=KfoF01tGzh4&feature=youtu.be (https://www.youtube.com/watch?v=KfoF01tGzh4&feature=youtu.be) The guy where i took the injection system told me that the fact that i have one common throtthle plate per 2 cylinders is mainly the fact that i have uneven conditions between cyls and unstable idle... He told me that i cannot expect much with that setup.. WHen i bought the turbo injection system from him, my initial plans was to install it on a 1776 engine.. he insists that this setup could work with small engines like 1776 ... do you agree ? should i go to individual throttle bodies per cylinder as he proposes (which means more money to spend >:( ) or things will not change much and the problem is hidden somewhere else. ?? Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 04, 2018, 03:21:26 am He does have a point. Most people on here have one throat per cylinder with Webers. (Although my turbo engine only has one in total!) Although I havent measured EGT on Kadron engines, I do know they idle badly and not on all 4 and need a stupid balance pipe like dual carbed stock T4 VW Bus motors to idle. They are one throat per 2 cylinders.
One weakness of adapting EFI to this setup is the need for manifold pressure to give the signal to the ecu that there is a change. Carbs seem to be less sensitive to this and will meter fuel nicely regardless. Where is the MAP sensor mounted on your setup? To make things even worse in this regard can be the cam. Carbs wont care. But if you like the thumpa lumpy idle sound that cam with big overlap will have even less vacuum signal when the lobes keep both valves open. How does the car drive? If the problem is near idle related, does it at least rip when you floor it? Title: Re: low EGT values on specific cylinders Post by: alex d on October 04, 2018, 06:59:10 am The guy where i took the injection system told me that the fact that i have one common throtthle plate per 2 cylinders is mainly the fact that i have uneven conditions between cyls and unstable idle... He told me that i cannot expect much with that setup. there's probably ways to minimize the effect a little depending on the size of things, but yes, sharing the throttle plate for two cylinders with the firing order we have in a VW will always have some kind of these of issues Title: Re: low EGT values on specific cylinders Post by: andy198712 on October 04, 2018, 10:03:49 am So would a single tb fix this issue?
Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 04, 2018, 10:30:18 am Martin,
in my previous posted picture of the engine, you can see a silicon hose (the left one beside the vertical tube) that is attached on the center horizontal tube.. THis is were my ECU's internal Map measures pressure from.. I am using engle FK8 and i dont think this cam could case bad idle.. i dont know how the car drives because i am still trying to setup the ECU... It definetily sounds much better when i reach 2000rpm(havent gone above that yet) but the EGT values even at 2000rpm still have major differences between cyl pair 1-3 and pair 2-4 as my videos shows... I cross check this by measuring the exhaust ports of the cylinders with a laser gun in order to make sure that it is not a matter of the egt sensors .. And as expected the laser gun shows 60c-70c for cylinder pair 1-3 and 170c-180c for cylinder pair 2-4... Title: Re: low EGT values on specific cylinders Post by: alex d on October 04, 2018, 10:31:57 am I am using engle FK8 and i dont think this cam could case bad idle.. that would be true if you had individual runners....but you don't Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 04, 2018, 12:44:46 pm I am using engle FK8 and i dont think this cam could case bad idle.. that would be true if you had individual runners....but you don't <<This is a good cam for larger engines, with a powerband from 3000-6500 RPM max, it will idle a little rougher than stock with dual 2bbl carburetors, but is very rough with dual 1bbls.>> The reason that engines run rough at idle is the overlap. These Engles are all 108 degrees. I have a Web Cam ordered specifically with less overlap for the EFI intake. (My engine guy thought overlap was stupid and people just want the sound :-\ Take it out for a drive and let us know how it runs above 2000 rpm. (This is my cam card) http://cal-look.no/lounge/index.php?action=dlattach;topic=10956.0;attach=80387 Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 05, 2018, 19:31:13 pm Hello,
Today I have replaced the spark plugs with brand new..and I operated the engine at 2000rpm for around 10 minutes.. the cylinders 1 and 3 temps as expected remained at low levels around 160C while on cylinders 2 and 4 at levels around 580C..but anyway I just wanted to posted a picture of the spark plugs exactly as they were after those 10 minutes of operation... Starting from left is the spark plug of the first cylinder and then of the second third and fourth cylinder in sequence.. So what does this picture makes you think as conclusion? [attachment=1] Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 06, 2018, 00:32:53 am Looks like 1 and 3 are not working at all. You said all 4 plugs were firing. Double check that.
Otherwise the injectors are not firing. Since you tried switching the injectors it could be the injector wires. Can you monitor the injectors on the ecu? Try listening to each injector while running with a screwdriver or stethoscope. Can you try a new file from a different person or source? Maybe yours is corrupt. Title: Re: low EGT values on specific cylinders Post by: richie on October 06, 2018, 01:52:19 am Those plugs are wrong heat range for a normal street engine and will foul really easily, a NGK dpr 7ea would be a better choice & it does look to me like number 3 isn't working at all and number 1 hardly at all either
I would be trying for 0.90-0.92[13.23-13.52] lambda for gasoline/petrol once engine is warm and all cold start corrections are off[0.89 lambda would be ok still and shouldn't foul plugs] Title: Re: low EGT values on specific cylinders Post by: richie on October 06, 2018, 01:56:03 am Also you said you haven't fitted a lambda sensor yet? so if that is correct then the lambda tables are worthless until you do, it cant tune if it doesn't know what the number are
cheers Richie Title: Re: low EGT values on specific cylinders Post by: andy198712 on October 06, 2018, 10:29:11 am is it batch fired ignition? guessing if so 1 & 3 are paired.....?
wasted spark from a single coil or again, paired COPS? Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 06, 2018, 20:59:58 pm Here are pics of my last 2 sets of plugs. I?ve run DPR9EA (pictured on the left) and DPR7EA (right) with success.
You need a good ignition for these to not foul of course, but I have never had either heat range foul on my street turbo in thousands of miles. Run whatever you feel is necessary. Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 06, 2018, 21:00:52 pm Richie,
I have already installed the wideband sensor some days ago.. you can see it's functioning in the YouTube links of my previous posts.. Andy, Yes it is batches fired and it fires in pairs .. cylinders 1 and 3 together, and then cylinders 2 and 4 together as well.. Today, I tried the installed again the same spark plugs that I showed in my post yesterday, and let the engine run at 2000rpm.. after the engine was warm so that no extra corrections were applying but only the fuel correction due to wideband sensor, I started unplugging every injector.. When I unplugged injector 1, the engine started dropping rpm and it showed that was affected significantly by the fuel that was absent on cylinder 1.. the same behavior occured when I unplugged injector 3...if the injectors 1 and 3 were not functioning, then normally when I unplugged those injectors , I shouldn't see any major differences in the behavior of the engine, right??? Also, after this test and with the engine still running at 2000rpm, I started unplugging the spark plug leads.. when I unplugged the lead from cylinder 1, the engine's running behaviour was affected significantly.. the same happened when I unplugged the lead from cylinder 3...obviously if the spark was not working at all on cylinders 1 and 3, I should not see any changes in the running behaviour of the engine, right?? At last, I continued running the engine at 2000rpm with everything plugged in , and increased the values of the VE table in order to create a rich condition , quite rich that the wideband could not correct.. my purpose was to see if that rich condition would make the spark plugs 1 and 3 to get some colour... I did run the engine in total for around 20 minutes and below you see a new photo of the spark plugs after these 20 minutes.. no changes at all compared to yesterday's photo... [attachment=1] Your conclusions??? Title: Re: low EGT values on specific cylinders Post by: andy198712 on October 06, 2018, 23:29:09 pm Are the plugs (1&3) wet with fuel? (Can?t see from the picture)
Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 07, 2018, 04:49:24 am No all spark plugs were dry after we took them off..
Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 07, 2018, 15:53:02 pm ?wasted spark from a single coil or again, paired COPS??
I was wondering this too. The ignition is hidden behind the shroud. The 1 and 3 problem is just too obviously related. Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 07, 2018, 19:13:20 pm Hello..
In this image you can see my coil pack.. [attachment=1] What do you mean with" paired COPS" ? Title: Re: low EGT values on specific cylinders Post by: lakis1982 on October 27, 2018, 06:43:16 am I have finally managed to change my single barrel throttle bodies to dual ones.
Quite happy about that (my pocket was not) because: 1. The engine completely transformed to a well idling and responsive engine. Now it behaves like an engine where all 4 cylinders are participating to provide power 2. The EGT values are now quite close together even though I haven't started fine tuning the ECU parameters.. https://youtu.be/HHeC-M0dnho 3. They look much better that the previous ones.. [attachment=1] Thanks for pointing me to the right direction.. Title: Re: low EGT values on specific cylinders Post by: PPRMicke on October 27, 2018, 11:27:35 am Hello
I would think your ignition energy is too small for that mix You can try to reduce the distance of your spark plugs to 0.20 (if it works with it you can change coil) Have had a similar problem with a golf that had wasted spark coils Then the limit was 11.6 AFR Then I injected into an injector tester so and checked such Should you not be able to buy certain types of injectors about those with three holes For them can be very different One thing that you can test is if you have the same pressure in the system. If you do not have to put a pressure damper on it (such have many car manufacturers when using large injectors) (Volvo V60R Awd / V40 / Saab Viggen / Bmw M3 /Bmw m5/porsche ) /// `Micke Title: Re: low EGT values on specific cylinders Post by: Martin S. on October 27, 2018, 23:30:09 pm It?s cool you?re using EGT like your car is a vintage aircraft :D
Congratulations on solving the problem and have fun with your tuning. Take your time. I?ve heard some people spend hundreds of hours tuning :o Title: Re: low EGT values on specific cylinders Post by: lakis1982 on February 04, 2019, 08:56:28 am HEllo,
it looks like i still have another problem... around 4 months ago i changed my throttle bodies and indeed this directly changed the behavior and operation of the engine instantly as the EGT values were quite similar on all cylinders without digging further into my ECU settings.. All that time i fired my engine just a few times (not drivable) on the car lift and it was idling and revving up to 2500rpm OK.. So now its time i start tuning me ECU maps and going to the dyno...But yesterday i tried to fire the engine as it was the first time after installing the air induction kit (air filter and hoses) because so far my turbo was sucking air directly from the air. Last time i fired it was before christmas. And i realised that two of the cylinders EGT values are quite low (around 40C) while the other two are increasing rapidly.. >:( What I did: I made around 15 trials trying several things and on all of them the cylinders 1 and 2 were working (high EGT values) while cyls 3 and 4 were having low EGT values. So under cyls 3 and 4 i could see the unburned fuel on the floor. I continued a few more trials but now it was the cyls 1 and 3 that were working while the other cyls 2 and 4 were not... THen i made a couple of more trials and initially for 10 seconds all of the cyls started showing increasing EGT values but while the engine was running suddenly cyls 2 and 4 continued increasing their EGT value while on cyls 1 and 3 the EGT values started decreasing down again. THen again i made around 5 trials and again cyls 1 and 3 were having high EGT values, cyls 2 and 4 low.. So now this is quite weird.. All of the cyls worked normally during all those trials but never all of them together at the same trial except once that happened only for a few seconds.. The EGT sensors seems to be OK because on the particular cyls that showed low EGT values i could touch the cyls and they were much much colder than the others and also i did see the unburned fuel droping to the floor through the exhaust gaps. All the trials i did were around 15 seconds duration. I also checked the loom that goes from ECU to the ignition coil tower and the cables were fine. I changed spark plugs I switched spark plug wires between trials but it didnt change anything. Between two trials it was still the cyls 1 and 3 that were working and it didnt affect this. My voltage reading while the engine is running is 14V No ECU settings were changed since it was working with those some time ago. Do you have any idea about that ??? What could be the problem ?? Thanks a lot in advance. |