Tomiam

Ok... connected everything up. Pretty simple to install the software and everything worked first time without any effort. First thing Ive spotted. At both idle and when the engine is off, its reading "Throttle Site 1" as 1.1 not 0 - 0.5 as suggested above. The TPS was replaced during the investigation into this problem. Ive read on a few websites that you can reset its position by turning on the ignition and pressing the throttle pedal to the floor 5 times. Havent googled beyond this yet. Video: https://www.youtube.com/watch?v=0X5ObENv16E ​In the first bit you'll see me pressing the accelerator to get the rpm to 2000 with the throttle site shown as 3.4 However, after a few seconds the engine rpm starts to drop (by 300rpm) even though Ive kept my foot still and the throttle site is still showing 3.4 This would explain the stalling at idle, if this is happening then too. In the second part of the video. after the engine stalls, I keep the ignition on and press the accelerator to the floor a few times.

Thank you so much! Last night I decided to just rig it all up and go for it. Hopefully something will be obvious. Your post will save me a massive amount of time searching the Web for what values I should be seeing. Again. Thank you! I'm off to the garage right now!

You know... I didnt think of that. I'm sure he would appreciate a bunch of folks in Sevens turning up with various differing medical opinions... :) Tension.. Ive long gone past the point where Im surprised with these things happening. Lol. Its almost comical (in a basil fawlty way) as Ive only posted the main crux of whats happened thus far to get in the way, as I didnt want to waste peoples time with irrelevant info. Im hoping for a phone call later today and will see if I can arrange for him to pop out this weekend. I have a busy work week next week. A busy work week at the start of Dec is unheard of in the last 13 years Ive worked here, but ya know.. it makes it awkward to get time off to fix my car.. so perhaps I should've expected it! I have a lap top so could do a logging session on my own but its only got about 10 mins battery life in it... I'll see what happens after the phone call. Tune in same time, same place, next week/month/year for more exciting adventure!!! ;)

Auto electrician just texted me. Due to emergency he can't make it today. What did I say about things continually happening to stop this fault getting fixed...

Thats absolutely 'flippin' brilliant information! I was thinking of using an inverter Id used to power a PS3 in the family car, so thats a mistake avoided there! Good idea about planning a route too, hadn't even thought about that. I've asked the auto electrican to bring his own laptop whilst I'll be providing the cable & software (installation notes duly acknowledged). I shall be making a donation to Nuke the Luke after this. You've all been very helpful and , with nothing in it for yourselves, have gone out of your way to assist. Very much appreciated. :)

Cheers John. I've been out to double check and it looks like you are correct. I believed it to be called a MAP sensor as thats what CC had told me it was and described its location as being there. Unless Ive misunderstood... entirely possible... There are four wires coming out of it. Cable from SBD Motorsports has arrived. Tbh.. its not much more than a printer cable and an adapter but hey.. if it works. I've booked Friday off work as auto-chap is coming over then. The adapter connects to a black diagnostic connector underneath the dash, where the steering wheel is. Cable supplied looks to be long enought that it'll connect to a lap top on the passenger seat. When I first started trying to find the cause of this problem, I disconnected the lambda sensor. Which appeared to solve it. However, after replacing the lambda (with a new one) and cleaning up the connector pins the problem still remains. I will try unplugging it, but Im not 100% convinced that it will be an indicator of something given my experience with the lambda sensor. Doesnt the ECU drop into a 'safe mode' when it detects a sensor is offline or am I talking out of my rear?... ie: If the fault is sensor A and I disconnect sensor B, the ECU will drop into a safe mode because its not getting info from sensor B, which makes it look like sensor B is the fault one. Here's to Friday and hopefully a productive day...

John, I shall ensure I keep this thread updated :) Latest update: Ordered the MBE MAP KIT 3 from SBD. £128 inc Vat and delivery. Should be here tomorrow. Found a manual for software. http://www.sbdev.co.uk/Engine_Management_Systems/ECU/easimap_software/Easimap%205%20manual.pdf

Thank you once again. :) I've taken a photo of the ecu and the diagnostic port and sent them off to sbd in an email so that when I call they can make sure that the right connection is on the lead. :) When I spoke to the auto electrician he asked what ecu I had on the Caterham and when I said MBE he said it would be fine and would DL the software over the weekend. You're probably right though.. and even if he does have the right kit, I think it's still worth me getting a lead myself.

Sounds like a very good idea. The auto electrican I've spoken to give me the impression he has the necessary cables / software (I did explain its a Caterham R400) but even so... for the money it will definately help either now (if he doesnt have them) or in the future. Will give them a call tomorrow. Thank you! :)

Thank you! I will certainly keep you in mind :)

Cheers for posting John. I've had to resort to booking an auto electrician to come out as I my back has decided it's time to play up. I will defiantly get him to check those points you listed. Unfortunately it's not possible for me to drive it down to you. It really is rough as anything below 4k rpm. Thank you for the offer though.

LOL thanks but its an intermittent long term fault which is not getting any better with age... ;) Hope to get to the car on the weekend. :) Thanks again!

Cheers for the info Ian. I shall get a look at them tomorrow. :) Jonathan. Photo of the sensor (in positiion) Im talking about re: checking the wiring for it. Just tweaked my back at work taking a plastic bag down off a shelf... hopefully will be ok to work on the car tomorrow. What was it saying about stuff happening to stop this fault being fixed...

Hi Jonathan, Thank you very much for your speedy reply! Thats the sensor. It's fitted on the top of the carbon fibre bit for the air filter cover over the throttle bodies, so that the sensor is inside. I can get some photos done later for sure. at the moment im at work. The fault has gone from intermittent to being very evident everytime I've driven it in the last 3 weeks. I would suggest that if the fault doesnt appear for 2 hours of driving, then thats going to give me a lot of confidence that its fixed. Its a piece of cake to replace the MAP sensor. Would take about 3 or 4 minutes max. In terms of replacing the wiring, Im not sure. The wiring disappears into the loom which is wrapped in what appears to be black insulation tape. I can put a paper clip in and then croc clip to that, or I could get someone else to help hold them in place whilst I wiggle the wire. Does the MAP talk to the ECU from cold or is it only working once up to temperature? I will try and get some video of the fault in action too.

I would be VERY appreciative of some advice please. Scenario: Had car since June. Bought 2nd hand. Was fine when I bought it. Sent it away to get it the geo / flat floor set up done. On the way back, it rained incredably hard. Car started running VERY rough. Since then its been an issue and its been away at a garage for the last month trying to fix it. I dont think this garage has a lot of Caterham experience though. My mechanical knowledge is very low, but increasing quickly. Description of my Seven & problem: Caterham R400 Duratec with roller barrel throttle bodies (minister) and dry sump. Problem: Engine runs very rough at less than 4k rpm when it's being driven. Spluttering and losing power. Almost like its flooding itself. This is the main problem & its near undriveable when its like this. If starting from cold, (most of the time) driving it'll be fine for a few to 10 minutes but will splutter for 0.5 seconds and then a minute later, it will do it again. Then 30 seconds or so later it'll splutter like mad, losing power. As soon as the revs go over 4k rpm, it clears up and away we go! Its not running perfectly at this point though and you can hear it in the engine noise but its much much better. At idle its a little rough. Once the engine is up to temp, the engine will die when you pull up to a set of traffic lights after 3 or 4 seconds. Starting it after this is a bit tricky and will require 2 or 3 attempts with some throttle pumping. Spluttering and losing power appears to happen only when the engine is up to temp. Rain may be a contributing factor. It appears to run rougher in the rain. Engine is a bit 'iffy' to start. Always requires a little bit of throttle to start it. Never starts just on the button. Whats been done thus far: All electrical connections checked. Two corroded ones found , pins replaced and electrical contact cleaner used to ensure all is clean. Garage found alternator was on way out. This has been replaced but didnt fix it the spluttering. Lambda sensor has been replaced. Throttle position sensor has been replaced. Throttle bodies have been checked and rebalanced. Spark plugs replaced with gaps of 0.8mm on all.I went to pick it up from the garage yesterday believing it should be fixed. Got about 10 mins away from them and it started playing up again. After someone pulling out on me on the way home and me missing them by about 20mm... Im starting to think things are not destined to go right.. ;) Id rather not take it back to the garage straight away. About time I wrapped me head about doing this myself (with assistance). I spoke to Caterham yesterday who were very helpful and pointed me towards checking the Manifold Air Pressure Sensor and its wiring. Which seemed easy enough when they explained it over the phone. I have also acquired a wiring diagram for the R400. http://www.lotus7.club/sites/default/files/images/Docs/Guides/guide.pdf Couple of questions, and please excuse if these are a bit obvious but:- 1) How do I check the MAF wiring for breaks? I understand that I can put the + terminal of a multimeter on a wire at the MAF connector plug end and put the - terminal of the multimeter on the other end but... would I be right in saying that I need disconnect the ecu plug and put a paper clip down the corresponding pin and test off that? i.e The wiring diagram for the MAP shows a code of UN45 for one wire, which corresponds to pin 21. Is it that simple? 2) Anyone had experience of something like this happening before? ANY assistance / advice / information very greatly appreciated at this point. ​

If it helps.. I recently had to replace the windscreen glass in my R400D SV. Taking the frame apart was very easy and I made a plywood template of the existing glass. Took it to a glass maker and they made 2 windscreens for me at £35 + vat each. Its not the heated type but a bottle of isopropanyl alcolohol (to stop it misting) is only a few quid or so and I just clean the inside of the screen with it from time to time. A little bit cheaper than the £570 or so on CC site for the whole assembly.

I also have this problem and would be very interested to know if you fixed it. My r400d has been at Williams automobiles for a number of weeks trying to track down this issue. Exact same symptoms and have so far replaced the tps, lambda sensor and alternator. Low rpm =incredibly bad running. It just about idles and is all but undriveable at less than 4 or 5k rpm but if you put your foot flat to the floor then engine opens up and it clears. R400d dry sump. Roller barrel throttle bodies. Kept in garage. Have also ruled out bad earth. Problem started about a month ago. Is it possible to be the ecu?

Update.... /sigh. Alternator replaced - car is now charging the battery at any rpm whereas the old one wasnt. However... its still running like a bag of crap at anything below 5k rpm. Its with a garage at the moment who are waiting on a call back from Caterham to help diagnose it. Summary: Car bought six months ago. R400D with Roller barrel throttle bodies. A month or so ago it would intermitently run very rough at low rpm and then seemed to fix itself. Started with 2 - 3 seconds of spluttering as if the engine was dying and over time this has gotten much worse to the point that its now undrivable. At <5k rpm the exhaust is making a bangbangbangbangbang! noise, as if its detonating fuel in the exhaust. Feels like over fueling. No power at all at this point. If I floor it, then once it gets to about >5krpm then the car accelerates like mad. It also runs very rough at idle now. To remedy this I / the garage its at have so far:- Replaced the lamda sensor (genuine caterham one) Replaced all spark plugs. Checked all connections and replaced pins on a corroded connection block to the lamda sensor. Replaced throttle position sensor Replaced alternator Rebalanced the throttle bodies Any thoughts welcome. Im sure the garage its at will get there but in the mean time if anyone else has had an issue like this Id very much like to cut down my labour bill with them... @Bazza. I believe this has been checked. Thank you though! I will double check with them.

They are going to test it once the alternator is replaced. At the moment its not giving hardly any charge unless its above 4000rpm. Easy to test once its been replaced.

Update: 3 weeks ago I replaced the lambda sensor and the corroded pins within the connector block. Initially it appeared to have fixed the issue and she ran fine for 30 min test drive. I already had her booked into Williams Automobiles for a flat floor & geometry session. Whilst up there she again repeated the same symptoms so it isnt the lambda sensor..... They are investigating the issue and looks like it the alternator. If I understand what they said correctly, anything below 4k rpm and the battery is going down in power as its not supplying anything to the battery. Once above 4k rpm the alternator then springs into life and the car is running on that instead of just the battery. Once its comfirmed I'll post it back with information in the hope it helps someone else.

Advice duly noted. Sadly the garage close to me didnt have a tap that big so Im waiting on a lambda sensor thread repair kit to arrive in the post. :)

Update: Have removed Lambda Sensor. Unfortunately it was so tight that no amount of plusgas / tighten * untighten or levers would remove it. Ended up welding a lambda socket to it and even then it wouldnt budge. So I've drilled it out and am waiting on a new sensor to arrive from CC. Unfortunately there is so much crap in the thread, in the pipe, that I need to realign the thread. Either a tap or a high tensile bolt (I think its 18mm diam & 1.5mm pitch) is needed. Going to gently use the HT bolt first as I dont want the tap to get catch and mess up the existing thread. Why do I think its the lambda sensor? Car runs fine when its unplugged. Repeated this test several times. The spluttering / dying / minor hesitation only happen at 4000 rpm or below when its connected. Above that it instantly clears. Only happpens when the engine is warmed up. The existing lambda sensor has zero markings on it. Possible that previous owner used a cheap one but either way Im getting one from CC to ensure its the right one and rule out any possible problems. Will update once Ive got the sensor in and have done a few miles.

Slap-ed here is a link to the thread I've got on the symptoms. http://www.lotus7.club/forum/techtalk/r400-duratec-spluttering-engine-low-revs-then-fixes-itself Tried heating it up. Plus gas. Tighten and untighten. And all manner of things even welding a lambda socket to it... Did not want to come out and we ended up drilling it out and collapsing its core to get it out without damaging the thread. No markings on the sensor at all so I'm wondering if at some point in the Sevens life its been replaced by a cheap one and hence the reason its failed now.

Thank you! I've yet to get it off the exhaust to be honest.. Ive dismantled the exhaust and am bringing a blow torch home to heat it up. Thus far even a socket set and lambda socket havent been able to remove it. There are no numbers on the outside of it at all. Having shone a torch down the pipes to have a look, I couldnt see anything on it. I've left it with a ton of WD40 soaking into it so hopefully blow torch will heat.

Having issues with my lambda sensor and need to replace it. Can't see the part number on it anywhere. have done a search but can't find it on the Web. Anyone happen to know it please?