Tomiam

With mine, it was the lambda sensor. Id replaced it once already, but the one I replaced it with was faulty. http://www.lotus7.club/forum/techtalk/r400-d-electrical-problem-i-think ​Dont know if that thread will help at all. Symptoms:- Running rough on part throttle. WOT was fine. Starting it up it would run "lumpy" for a bit before eventually stalling at about 70 deg C on the coolant.

Smiffy, Had a day off from work so got the 2nd set of logs done. 1: http://www.filedropper.com/smiffylog2 2: http://www.filedropper.com/smiffylog2lsn_1 Experiment was run as follows:- Start up car and leave until coolant at 80degC or higher. Turn off engine and leave it until coolant was done in the mid 60's. Start engine on button only and leave to run for 2mins. Observations: Car started fine on the button both times. Didn't stall after being started the 2nd time. I don't know if this helps at all, but at the very least you have a couple of sets of logs for comparison. :)

Video of easimap on my R400 D which shows the lambda sensor fluctuating and the "waiting" timer after start up.

I have not... but I feel that I shall now be googling away! edit: Nifty! :) Any recommendations?

Thanks folks! I was told that I had a leaking caliper, by the garage who attempted to fix the above fault... After taking the wheel off, removing the caliper and looking for any sign of a leak... I cant find any. My dad even popped around to help and whilst one of us sat in the car, the other pressed hard on the brakes and held them down for 2 mins or so. Nothing... nothing at all. Apparently the garage had done this and it leaked for them. I did however see that the pads on the car are in a terrible state. Probably the original ones from the previous owner. So those need replacing. Flexible hoses will be considered for the future for sure, but at the moment Id just like to get her in a decent shape. Yet there is a lot of oil on the drop link (I think thats the right term) and when left over night I found a small pool of fluid / oil on the floor. It turns out its coming from the (and please excuse me if I get the names wrong.. this is all a massive learning experience) CV joint boot. Its a big rubber seal / sleeve. Thats a photo taken of it. Looking towards the front of the car on the left hand side. ie: Its the back left hub in that photo. Essentially oil is coming off the bottom of the boot from where the clip goes on. There is evidence of a small dent on the clip (about 5mm long). I believe I need one of these: http://caterhamparts.co.uk/product.php?id_product=2360 So I now know how to take a caliper off, remove hand brake cable, change brake pads etc. So thats good.. Just need to learn how to do this next bit. :) ps: Thanks for the link to alcester racing website. Very good! Bought myself a caliper windback tool this morning from halfrauds (£33..) who price matched screw fix for the same item (£19.99) :)

Experiement to be re-done with an adjustment. (bits copy n pasted from PM) (Keeping it in this thread in case it helps someone in future.) Previous Experiment:- Engine was started up and left to get to 72 degC It was then left to cool for 15 mins. Engine coolant cooled beyond the 60 deg C point. So when I started up after 15 mins the cold start map (a coolant less than 60C ) ran and when that expired the Lambda is up to temp so the warm up timer is redundant (as Smiffy69 understands it). New experiment:- Have the engine up to temp. Then let it cool down to the point where the coolant temp reads between 65C & 70C. This way the engine will run its warm start map and then start to read the Lambda once the Warm up timer expires. Smiffy69's then leans out the mix as the Lambda is low reading .6 / .7 (not yet in the right temp range) and will stall - if mine does the same then we have the same feature !! (and CC now recommend that the arm up timer is 60secs) or mine is fine and Smiffy69 has another problem to try and fix. Car is currently on stands whilst I learn how to replace the left rear brake caliper (have slight leak), I will update this thread within a couple of days.

Got logs n stuff :) Logging from a cold engine to 72degC. Link1: http://www.filedropper.com/warmupto70degc Link2: http://www.filedropper.com/warmupto70degclsn ***I then turned off the engine and left it to cool for 15 mins. Logging from after the 15 mins cooldown where I left the enginne runnning for 2 and a bit mins, Link1: http://www.filedropper.com/after15minscooldown Link2: http://www.filedropper.com/after15minscooldownlsn I thought about writing down my impressions of the lambda sensor's reading as time went on, but then figured its all in the logging and perhaps a video might be of more use to you. Video of easimap showing the screen for the 2 and a bit mins of running after cooldown. Link: There are some videos on my youtube channel of me driving my r400 on my first few track days.. please dont critique the driving too much lol! :DIn all cases, the car was started with no throttle input and was left to idle in a stationary position. I hope this gives enough information to help compare to yours? If you need anything else, dont be afraid to ask :)

Not a problem at all. I will get it done tomorrow night (Friday) and upload logs for you. Im working tonight. Only issue I have is that mine rarely starts without any throttle input. I have to push button, blip it a couple of times and then it'll start. The main indicator for me on easimap, looking at the live data panels, was that the lambda reading started off at <1.0 but then climbed past 1.0 and never once came back down. The new lambda flutuates every 1 - 1.5 seconds over / below 1.0 ie: 0.86, then 1.1 etc. Also, taking the exhaust apart to check it for leaks and seal everything, the inside of the exhaust stunk of fuel and the spark plugs were sooty black. Running a multi-meter across the signal wires on the lambda gave no different reading between the duff lambda and the good one. I think it was 3.9ohms in both cases.

Couldnt wait... just went for a test drive / slide (its a bit wet out) and all went well. :) Performed perfectly. No hesitation, no odd feelings, just a precise throttle response. Whizz pops bangs coming from the exhaust, but these are the good ones :) I feel a need to book a track day! I'd definately like to add my vote to Aerobod & Johns comments :) Coming soon... learning about brake calipers & (maybe) playing with the TPS / throttle stop.

Ok... cue drum roll... I have the new Lambda sensor. Went into the garage. Tried to plug it in but the connection was bloody tight. Checked pins & after a few mins of wiggling back n forth it went in. Looking good! Turned on laptop. Fired up easimap. Connected to car. All systems looking good! Lambda is at 0.86 Fired her up. Started ok and I then sat in the car watching the coolant temp rise on easimap. "Bad AFR Reading" was showing for the lambda but thats ok because coolant isnt up past 60 deg yet. Lambda still shows 0.86.. in fact its not moved at all since I started her up. Coolant 58.... 59..... 60.... (still Bad AFR Reading)... 61.... 62.... (still Bad AFR Reading). Oh for... (insert word)!!!! So I stopped the engine. Sat there looking at the steering wheel, thinking.. really? Got out, checked the connector and one of the pins looked a little loose on the back. A small push and it went in. It must have been pushed out by my wiggling the connector about to get it in! Started up again and YES!!!!! Lambda sensor is fluctuating between 0.7 and 1.2 back n forth every second or so!!! Engine sounds much better and didn't stall in the 5 mins I left her running. I also held my foot down on the accelerator, keeping the throttle angle constant and the RPM didn't continuously drop until the engine stalls. It did fluctuate by about 100rpm but... well that could be the amount of sooty crap in there and tbh... Im not convinced 100rpm is that much flutuation. Is it? I have the original lambda sensor I purchased from Caterham, which was meant to fix this fault, about 2 months ago. They are happy to receive it back and test it, by putting it in a car apparently, and if its duff I'll get a full refund. Which is good... because whilst I was under the car looking for duff wiring & connections I noticed a smalll amount of leak from my near side rear brake caliper area. So that'll go towards that. I'd like to say "Thank you!" to everyone who has helped me in this journey but "Thank you!" doesn't quite seem enough and I don't know how else to say it. Soo... err.. "Thank you loads?!" especially to Aerobod whose explanations were so simple and comprehensive even I understood them and also to John Vine for his offer of ecu's / lambda's etc. You wont regret getting the cable John. I was a bit overwhelmed by the amount of info to begin with but it soon starts to make sense. I have learnt more about my car in the past couple of weeks than expected, which is good, I spent more too....which isnt so good.. On pay day Nuke the Luke will get a £50 donation as promised. VERY much appreciate your assistance chaps! **disclaimer.. not wishing to tempt fate but this is assuming that the fault doesn't come back on the test drive tomorrow.. ;) EDIT: Mods / Admins.. I dont know if you want to change the title of this thread in case it helps someone else in the future.

Cancelled order with cheap online company. Phoned a friend of a friends garage. Lambda sensor on its way and here within an hour. :) Sooooooo... its looking like tonight is the night when its fixed / head scratching time. :D

Ordered Lambda. Shouldve been here yesterday / today. Chased company. Told me the batch of lambda sensors they were given were defective and that it should leave them today. Will be with me in 3 - 4 days and they dont have express delivery to get it to me quicker. I will update once Ive got my hands on one.

Yep it certainly seems that way. We replaced the lambda sensor right at the start when this problem occured but it didnt fix it. The logical thinking, now that pretty much every other option has been explored.. is that the new lambda sensor I put in is a duff one or failed near instantly. Current thread linked in case someone else has the same: http://www.lotus7.club/forum/techtalk/r400-d-electrical-problem-i-think ​

I can but the timethis problem started initially was about 2 months ago. Guess it won't hurt.

Thank you all :) Today:- Examined exhaust. Small amount of soot around the 4 into 1 pipes at the 4 pipes end. Purchased copper silicone sealant. Dismantled exhaust. Cleaned up where the pipes connect. Applied sealant around pipes and the bits they go in. Reassembled exhaust. Applied sealant as much as I could around the joins of the pipes. Lambda sensor checked to ensure all pins go into the correct pins on the connector on the loom. All fine. Have previously checked from the loom back to the ecu. Heater element resistance measured at 3.9ohm Started engine. 0.6 was initial lambda reading. Very quickly got to 1.01 and then climbed to 1.2 before engine stalled after enough time for coolant to get to 77 deg C Have ordered a new lambda sensor based on the reference code given above: Bosch 0258 003 229 Should be here in 2 or 3 days. Thank you for the offer of yours on loan John, but its about £37 quid all in for a new one. Buying a new one saves arseing about with P&P etc. Btw... if you wanted to borrow my cable from SBD, I know you were considering one, then once my car is up n running you are more than welcome. Thank you Aerobod, John Vine, Smiffy, Jonathan and Sim. :)

Hi Jonathan, Yea I did a search of the interwebs this afternoon to see if I could find a reliable way to test the lambda. Couldnt find anything reliable which didnt involve an oscilloscope. Which I sadly dont own. From my notes I believe the lambda sensor number is: ​MHK10006 LSH 24, 0 258 003 229, 9923032, 12v Which I think is.. HERE This is of course assuming that Aerobod, or someone else, doesnt look at the logs and tell me Im talking rubbish :)

Spent the day under the car. Bruised fingers, aching head and a minor case of "seriously??...." later... I can confirm that Ive been over every connector plug that I can see and can not find anything amiss. I've scanned everywhere I can see and can not find any damage / frayed wires etc. I've taken the lambda sensor out. It was covered in black soot. Inside the exhaust looks the same. I can not see any damage to the exhaust or manifold. All connections look secure and as far as I can see everything is bolted in place properly. Going by the data logs, is it possible that Ive replaced a duff lambda sensor with another duff one?

Hi Aerobod, Thank you once again. I know I keep saying this but the help is appreciated! Testing of the wires. Battery disconnected. Paper clip + multi meter on ECU connector end, multi meter on lambda connector plug at end of loom (lambda unplugged) Power ground, Black / Yellow. Pins 6 & 7 tested fine. No resistance. 12V Supply. Green / Orange. Pin 13 tested fine. No resistance. Sensor Output. Blue / Brown. Pin 29 tested fine. No resistance. Signal Ground to ECU. Brown / Black. Pin 5 tested ok. No resistance. Pin 23 couldn't get any reading from this at all. Pin 24 is missing from my ecu plug (guessing its not used), ------------------------------------------------------------------------- Lambda sensor testing. Loom side connector plug for Lambda sensor. Green / Orange is receving 12v without engine running & ignition on. Is receiving 13v with the engine running. -------------------------- Lambda sensor connector plug, on lambda sensor. Lambda sensor unplugged on its own, and a continuity test is done across pins. I have continuity between the power ground (black/yellow) and 12v supply (green/orange) pins. I no continuity between the sensor output (blue / brown) and signal ground to ecu (brown / black). This normal? ------------------------------ Lambda sensor connected. 12v power (green / orange) tested by putting safety pin into the back of the connector on the lambda sensor side. 12v being received, New logs attached. As before, I started the engine. Let it warm up. It then stalled after a while. I then restarted and kept my foot on the accelerator at a fixed position. Whilst it was during 'waiting time' for the lambda, the engine revs remained quite constant. Once the waiting time passed, the revs increased before continuing to drop. Is it possible that the lambda , even though its been replaced, is broken? Dat file: http://www.filedropper.com/sunamlsn Lsn: http://www.filedropper.com/sunam Another thought... fuel pressure regulator? But i guess that wouldnt explain the Lambda saying "lean!" when we believe its actually running rich.

No need to apologise mate. More than grateful for anyone trying to help ;) I see what you mean by that photo :D

0.8mm Since Ive had the issue, Ive changed the spark plugs to a brand new set to try and rule them out.

Today has been a good learning experience. Summary of situation & findings:- Problem gets worse the warmer the engine is. Perhaps linked to the reduction of fuel adjustment as it warms up? Spark plugs were black & sooty. A powdery soot on them. Have cleaned and re-inserted. With the engine up to temp (60+ deg C) holding the accelerator down to get 2000 rpm results in the rpm continuously slowly dropping. Starting the engine from cold. The engine runs smoothly and is audiably smooth. Rpm is about 1000. As it warms up, it becomes less and less smooth with the rpm dropping suddenly and then back up as if it was about to stall. Rpm drops to around the 800-900 mark. After the engine has fully warmed up, it eventually stalls. Whaat I did on log file: (below) Car is started from cold. Left to idle on the spot. Eventually stalls. I then restart it and hold the rpm at about 2000 twice. First time no issues (lambda on start up timer?) and second time the aforementioned rpm drop happens. (on log file) TPS is showing a value of Throttle Site 1.1 on easimap at idle. (on log file) Engine Speed starts off very consistant. As time goes on it fluctuates a lot more including a number of big up/downs. (on logfile) I dont know what it means but when I graph the data, the data for Oxygen A (Raw) drops just before the engine stalls. It also disappears from the graph for a time period. Lambda data also (which normally fluctuates) stops fluctuating during this time and returns a flat line which I assume is because the number its sending back has reached a maximum? Log file: http://www.filedropper.com/sateveninglsn If someone is able to have a look at it and advise I would be VERY grateful.

EDIT: double post.

Update regarding MAP sensor. I believe it's working and the fact that easimap shows a barometric pressure panel in red is a red herring. If I disconnect the sensor then the panels for air temp and manifold pressure and manifold comp are blank. If I put a pipe over the sensor and suck/blow on it then the readings change. The air temp reading goes up as the engine warms up too. Conclusion. Sensor is working. Steep learning curve this lol. I will get a clean log of starting up from cold and upload later this evening.

Ive just done a logging session. Engine runnning. Car sat still. Allowed car to warm up at idle. Once warmed up and lambda saying "all ok" I pressed the accelerator and held it still at 2000 rpm. I kept the accelerator still. Didnt move my foot. Checking both the throttle angle and throttle site readings which remained constant. Engine rpm (at 2000rpm) starts to go lower and lower.. down to 1300 rpm ish. At this point there is occassional THUNK! noise coming from somewhere up front. After a couple of THUNK!'s I've taken my foot off and the rpm drops to idle. Ive linked the log file in the hope someone can have a look and say "it looks like this". Its from about 4mins into the log (is obvious when looking at the data). Prior to that i was unplugging MAP / Lambda to check connections etc. EDIT: MUCH BETTER LOG FILE - FURTHER IN THE THREAD. Dat file: http://www.filedropper.com/miker4009am28hnovlsn ​Lsn file: http://www.filedropper.com/miker4009am28hnov ​re: MAP sensor (reconfigured as Air Temp / Barometric sensor according to John). I did try to source a new one locally but no one had one. Im unsure whether its outputting everything normally , and the panel which is showing red on easimap (barometric pressure) is fine because the data that sensor is sending is showing up ok on 'another panel'.

Forgot to add... barometric reading is red. I'm going to check the part number on mine to confirm if it is meant to be a map or air temp/ barometric as suggested earlier in this thread. Edit. Part no. Confirming it as a manifold absolute pressure sensor but when I disconnected it.. the air temp figure on easimap disappears. No. 1S7A--9F479-AC