sltous

Yes, 0-15 throttle sites Josh asked me to measure the raw TPS voltages so I de-pinned the connector again and took some quick additional measurements. Old TPS has V_Initial_Raw_Old = 4.72v New TPS has V_Initial_Raw_New = 4.66v

Update after the mail arrived: The OLD TPS has No return spring resting voltage V_Initial_Old = 0.32-0.33v resting throttle site Throttle_Site_Initial_Old = 0.0 peak voltage V_Final_Old = 3.8v peak throttle site Throttle_Site_Final_Old = 14.6 The NEW TPS has Return spring requiring ~90 degrees of preload resting voltage V_Initial_New = 0.36v resting throttle site Throttle_Site_Initial_New = 0.0 peak voltage V_Final_New = 3.5v peak throttle site Throttle_Site_Final_New = 14.2 Thoughts? Safe to use the new TPS as is or do I need to make any changes?

The TPS I have removed has part number PBT(GF20+GB20) molded in which Josh at Rocky Mountain Caterham identified as being the same as Ford part number 988F-9B989-BB which is apparently the same as the current 420 Duratec part

Unlocked MBE. I am thinking of slightly changing the starting rotational position of the TPS, not any changes to the ECU. As it it, the rotational position is very close to fully closed at 0.33v (perhaps 0-5 degrees), I would be changing it to perhaps 5-10 degrees such that V_initial is 0.43v rather than 0.33v. Per

An update while waiting for parts: I connected my laptop to the ECU via Easimap and my TPS was at 0.32-0.33v at rest. However occasionally while poking at the system the TPS would jump from 0.33V -> 5V as if (like ashyers thought) it was wrapping around or as if there was an internal short. This makes me feel very hopeful that the new TPS will reduce at least one of my issues. I have seen references to the TPS being at closer to 0.42v at rest, should I adjust my resting TPS position from 0.32V->0.42V to have a little more headroom, or is that likely to confuse my ECU maps?

Hi Croc, I have only collected a few data sets so far and can only confidently identify the problem with the engine running fully hot. However if ashyers' thought about the TPS wrapping around is correct this might be a problem all the time masked by consequence of not using much throttle during engine warmup. I think the problem is new but there has been enough fettling of small issues over the last year I cannot be sure it is a new problem. My thoughts on changing Easimap were to widen the range of the TPS (assuming this is an option) such that 0% throttle is at perhaps 5.0v or 5.05v rather than 4.95v. Again I have not opened this portion of Easimap so I don't know for sure if that's an option. I think I'm leaning to replacing the TPS as a relatively cheap fix that may not necessarily fix the problem but will probably make diagnosis easier. My harness is a bit of a mis-mash as a prior owner did a Zetec -> Duratec swap so I'm hoping that's not the issue but if it is I'll just dive in further.

I have the roller barrel throttle bodies and there isn't any obvious place to push to overshoot the bottom of the TPS back around to 100% but I think it does match the behavior I'm seeing in the datalogs. I'll think about it some more and try to do a more scientific test. I took another deeper look into the datalogs, trying to determine if there was a noticeable change in road roughness around where I was having problems (nothing obvious here) and added in the Throttle Voltage layer. It looks like the throttle voltage is not dropping to very low voltages at the same time as the TPP signal is spiking. Do I possibly simply need to go into Easimap and adjust my throttle voltage min and max?

That's a very interesting thought, you may be on to something there. TPS has part number PBT(GF20+GB20) which might be the same as 97vb - 9f832 - ab.

Thanks again ashyers. I took a trace with the engine off over the course of approximately 1.5-2s. Same AIM data logger / CAN bus setup as before. Without the engine running I don't see any evidence of noise in the data. I also did not see any evidence of noise in the TPS data today for approximately the first 30 minutes. According to my histograms the TPS was at >70% throttle just 0.1% of the time in the first 30 minutes (all up-hill) and at >70% for about 2% of the time (all down-hill) for the last approximately 20 minutes. I don't see a viable explanation for clean TPS -> RPM -> Speed correlation some of the time and terrible noisy TPS -> RPM -> Speed a small portion of the time unless there is a bad electrical connection somewhere. Happy to get alternate thoughts on where the problem may be. Here I have the TPP spiking between 0->100->0->100->0 while the car is decelerating (sharply) and RPMs are dropping on the left side of the trace and on the right side I see the TPP having my expected behavior of increased TPP -> Increased RPM -> Increased Speed (I am assuming a fixed gear for the last but not for the throttle -> RPM)

Thanks ashyers. I tested the wiring by depinning the mating plug, connecting one end of my multimeter to the actual pin where it connects to the TPS and the other end of my multimeter to the actual pin where it connects to the ECU and gave the wire a good healthy wiggle. All three wires passed with flying colors climbing from 0.2 or 0.3 ohms to a peak of 0.4 or 0.5 ohms with the same behavior from all three. Additionally once the 36 pin main plug was connected back to the ECU the ground pin where it mates to the TPS has resistance of ~0.6 ohms to the chassis ground. I think all of this is OK, the crimped connections have good seals and unless I add solder to the crimps I don't see any realistic way to improve this part of the wiring.

The TPS and the plug both appear to have OK terminals (at first look) however the TPS is missing the locking part of the plug. I also noticed that the wiring for the TPS is not grounded/shielded which was a clear requirement when I installed a distributor-less ignition system previously. Do I need (a) a new TPS with the locking bar (b) grounded wiring (c) something else?

Collected some data logs on a drive this morning. All screenshots are taken at the same zoom level and show Speed, RPM, and TPP only. I believe there is one that shows the TPS performing correctly and two with significant evidence of problems in the TPS. I plan to look for corroded electrical terminals at both ends of the TPS wiring but is this an obvious 'you should replace the TPS'?

Thanks Croc. I have been concerned by a wiring choice made somewhere along the line where effectively the 12v line to all of the switches was hot even before the key was inserted (allowing me to turn on lights, even spin the starter with the push button etc. without the key) so I was starting by correcting that and I am beginning to suspect it was made as a consequence of a dodgy ignition switch. I pulled a spare keyed switch, fabricated up a column mount, and wired it up in place of the Caterham part. The Caterham part looks like it is a Lowe and Fletcher 2201 locking cylinder attached to a Lucas 157SA switch, the one I had on hand has some very nice threaded connector lugs instead of the male spade connectors on the Lucas part. Testing to come but initial reactions are that it behaves exactly as a switch ought to, fuel pump primes, the headlights/turn signals/starter motor all run (only when the key is turned) etc.

Followup: I picked up a Solo DL and an OBD2 cable, after remembering I had to actually turn CAN on in Easimap following the instructions on https://www.aim-sportline.com/download/ecu/racing/MBE_9A4CAN_101_eng.pdf I was able to connect wires correctly and get a first data log. I am beginning to wonder if the kangarooing is in fact due to the ignition switch, however, and would like to try temporarily bypassing it with a toggle switch, is there any information on the current rating needed for that switch? I was getting several (2-5) ohms of resistance in the switch and when I took it apart the insides are looking pretty corroded.

If you want to keep your existing cable driven speedometer because you like the look or the size there is at least one GPS cable driven speedometer sender https://speedhut.com/accessories/sensors/speed-sensors/speedbox-cable-included-gps-vss-to-mechanical-drive-speed-converter/ I considered it for a bit and ended up with a Speedhut GPS speedometer since there were problems with the speedometer hardware and it needed to be replaced anyway

I just swapped my 13" wheels/ZZS at 22psi back for 13" wheels/R888 at 25psi now that it's warming up and for me the R888 have a lot more compliance and are a nicer ride. I'm not chasing lap times and get more confidence from the R888 on warm days on the street

I inspected with a multimeter and it looks like there is approximately 1.3-1.6 ohms resistance between OBD2 plug pin 6 and 36 pins J2 Delphi pin 8 (CAN high) and similarly 1.3-1.6 ohms between OBD2 plug pin 14 and 36 pins J2 Delphi pin 19 (CAN low). Although I might usually would like to hardwire for better performance I don't see an obvious improvement over use of the OBD2 plug as I could always cut the cable and hardwire so I have chosen an AIM Solo DL with the OBD2 plug. Hoping to test relatively soon,

Is there any difference between the Pin 6 CAN Bus High and Pin 14 CAN Bus Low at the OBD2 plug and Pin 9 CAN Bus High and Pin 8 CAN Bus Low at the 36 pins J2 Delphi connector?

Thanks Graham. My concern was that I drained 2L from the transmission and can't seem to refill beyond 1.6L but I did find some references to this being normal on Caterham and Lotus 7 Club. https://www.caterhamlotus7.club/forum/techtalk/gearbox-oil-level-question

After checking the levelness on the ground I adjusted the car on a set of jack stands instead of assuming the maxjax was holding it level. For my setup that required the rear jacking points at the gas tank supports to be held one notch higher than the front jacking points at the cruciform. I did check the garage floor is relatively level to ensure I am not simply reproducing an off-level situation and the garage floor looked OK. This did not fix my transmission fluid problem, when I removed the fill screw a small further amount of transmission fluid dribbled out. Any further thoughts welcome.

Hi Anker, Thanks for the note about rake. I haven't checked levelness of the setup on the ground, I was looking to understand if my car is accepting less transmission fluid due to the nose being a bit down or if the variability is normal.

Hi all, I did a full transmission oil change today and was wondering if the car is at the wrong angle to get sufficient new oil in. Per the docs I have found the car should be able to hold approximately 1.9L of oil, I put approx 1.6-1.7L of Redline MTL after draining from both the transmission fill plug and the drain plug at the bottom of the transmission. The nose of the car was slightly low compared to the tail of the car as measured with a level across the body / bonnet mating surface and I was surprised that a relatively large quantity of oil came out from the transmission fill plug when I removed that first. Pics attached, any thoughts appreciated.

Where are you located? Any specifics you're looking for? You might want to start your own thread with some details under Cars Wanted https://usa7s.net/ips/forum/38-cars-wanted/

https://www.racingjunk.com/lotus/184308785/1971-Lotus-Seven.html?category_id=&search=lotus&quickSearch=1&np_offset=0&from=search Previously at Bring a Trailer https://bringatrailer.com/listing/1971-lotus-seven/ I remember being impressed with the car and the spares when it was on Bring a Trailer, not currently registered for the road but was a road car sold through Wirewheel

https://www.hemmings.com/listing/1957-lotus-7-619012?utm_source=autotempest&utm_medium=cpc&utm_campaign=autotempest_auctions