Vovchandr Posted July 28, 2023 Author Share Posted July 28, 2023 On today's episode of "an idiot with a volt meter" As per advice before putting new ECU in I started testing the pinout of the harness plug to see whether wires were compromised. Went for easy ones with volt meter, ground and 12v. As I was testing the 12v or the 5v I don't recall with one lead on input and other lead on engine ground I saw all dash go blank I thought it might be a fluke and I triggered something. So I restarted. All lights back on, crank is fine, 15 seconds or so goes by and a relay or something under the dash by the fuse panel clicks and everything goes dark. Thought it might be because ECU is disconnected. Plugged it back in and now the same result. What relay or something else could be doing this? Is there a main relay on these? I feel like this is head gasket all over again. Try to do the best I can and just make it worse.. Stay tuned to next episode when I get a power prope into my hands Link to comment Share on other sites More sharing options...
MV8 Posted July 28, 2023 Share Posted July 28, 2023 Resistance checks are usually safe to do, versus applying power and checking voltage. The battery should be disconnected because inadvertently checking resistance on a powered circuit can damage the dvm. What you should be checking for are shorts to ground on wires that normally have B+. A good dvm will have a beeper function under resistance checks to where the meter emits a tone when the positive and negative leads are brought together. Alligator/roach clips are good for making four foot long jumper wires for testing greater distances than what the meter leads will reach. Write down each thing you test to keep track. I know you have a 2001, but there should be a 2010 assembly guide for dedion and sigma in the site library with harness layouts in the last few pages that will probably be as close as you can get to an actual schematic. 1 Link to comment Share on other sites More sharing options...
Vovchandr Posted July 30, 2023 Author Share Posted July 30, 2023 Ok new update. The strange cutout 30 seconds in appears to be Lithium battery shutting itself off due to low voltage. Instead of a tradition battery fading and getting weaker, Lithium batteries shut themselves off sharply out of safety. Certainly didn't expect that. I'm in a pause right now while pending on ECU and further wise testing. I heard mixed feedback on whether the harness is safe or not. Some say that it's extremely unlikely for harness to be damaged as wires don't care about voltage direction. Others say don't plug new ECU in until you verify the harness as safe. I feel like between me doing more harm then good with my experience I'm better off going with the odds and just plugging a new ECU in and seeing whether car will start. My meter only does noise on a continuity test, not one for resistance. Link to comment Share on other sites More sharing options...
kayentaskier Posted July 31, 2023 Share Posted July 31, 2023 Regarding the battery shutting down, I think you are running the AntiGravity SC-1, the same battery I just had installed in my 420R. I’m thinking it may be a little too small for cars that don’t start first time, every time. I just put 550 miles on my car last week, driving from So UT to Northern UT (I took the long way around). The battery performed perfectly except for one time. As I was filling the gas tank, I had the key on so I could watch the fuel gauge as I filled it. Once I was finished, I just pushed the car into a shady spot. I then went to get a cold drink; about 15 minutes later the car would not start. I had neglected to turn off the key and/or the Master Switch. So the electrical system was drawing power for the fuel pump and other things. Apparently, this was enough time for the battery to lose enough voltage that it would not start. It’s not like the battery was weak, it’s more like it was switched off. As soon as it was jumped it was fine, lesson learned. However, if I was choosing a battery again, I might go up in capacity. 1 Link to comment Share on other sites More sharing options...
Vovchandr Posted July 31, 2023 Author Share Posted July 31, 2023 1 hour ago, kayentaskier said: Regarding the battery shutting down, I think you are running the AntiGravity SC-1, the same battery I just had installed in my 420R. I’m thinking it may be a little too small for cars that don’t start first time, every time. I just put 550 miles on my car last week, driving from So UT to Northern UT (I took the long way around). The battery performed perfectly except for one time. As I was filling the gas tank, I had the key on so I could watch the fuel gauge as I filled it. Once I was finished, I just pushed the car into a shady spot. I then went to get a cold drink; about 15 minutes later the car would not start. I had neglected to turn off the key and/or the Master Switch. So the electrical system was drawing power for the fuel pump and other things. Apparently, this was enough time for the battery to lose enough voltage that it would not start. It’s not like the battery was weak, it’s more like it was switched off. As soon as it was jumped it was fine, lesson learned. However, if I was choosing a battery again, I might go up in capacity. Sc1 is what I had at first and what resulted in me frying my system. As you know as an owner it's very easy to reverse mount. Yes I agree, it's just enough to keep the car running with little safety cap. Maybe a perfect track battery. I believe it can start the car about 5 to 12 times in a row from full without driving. Makes it very hard to troubleshoot a no start condition. I've upgraded to AT12 as some other members here did and it even has its own internal jumper, which is pretty clever. So far so good. I think it's capacity is about 4x of SC1. Once I fried the battery I had same feeling as you and went up in size. 1 Link to comment Share on other sites More sharing options...
MV8 Posted August 2, 2023 Share Posted August 2, 2023 On 7/30/2023 at 7:51 PM, Vovchandr said: I feel like between me doing more harm then good with my experience I'm better off going with the odds and just plugging a new ECU in and seeing whether car will start. My meter only does noise on a continuity test, not one for resistance. Continuity testing is resistance testing. The noise is optional. All sorts of videos to teach you basic electricity. Link to comment Share on other sites More sharing options...
Vovchandr Posted August 19, 2023 Author Share Posted August 19, 2023 Got the new ECU in. Same symptoms. No start. Still no communication from software to ECU to run. Does connect to it though. Voltage in ECU software still showing as 9.Xv when battery is 13.3v. Checked the pin thats supposed to be 12v input and it's reading 0.2v. Further troubleshooting tba. Was hoping for a miracle, it didn't happen. New ECU is likely good but hasn't been pre tested... Do have a new engine harness sitting now to potentially put in 1 Link to comment Share on other sites More sharing options...
Vovchandr Posted September 16, 2023 Author Share Posted September 16, 2023 A few updates. Took the old Alternator to a local parts store to get tested. One store didn't have plugs for it, others didn't have operators that knew the tester, the 4th store was the charm. Alternator was dead. Ordered a new one and put it in, so that issue is closed. Had a mechanic friend come by to help with some testing. Revelations. All the relays on the fuse box are good ECU fuse is reading 12v, but ECU pin and software still reads 9v All 4 injector pins on ECU also read 12v when key is on for power. Strangely their voltage is a true 12 unlike the ECU 12v pin. At this point not sure if the "12v" pin is input or output in the ECU Both ECUs show same symptoms. After taking to quicksilver they are willing to test both ECUs next week so they are in the mail now. If they both pass as working means I have a likely somewhat simple wiring mixup somewhere. With that said the new harness was questioned by my mechanic friend. The same pin that should be 12v input? On the harness is showing continuity on a fuel pump relay on the new harness so we aren't sure if it's setup correctly to match my current setup So pending hearing back from Quicksilver 1 Link to comment Share on other sites More sharing options...
CarlB Posted September 17, 2023 Share Posted September 17, 2023 These two documents might be helpful Caterham7 T2.001.pdf ECU Pinout Zetec T-2.pdf 1 Link to comment Share on other sites More sharing options...
Vovchandr Posted September 20, 2023 Author Share Posted September 20, 2023 Quicksilver tested both ECUs. Both work just fine. Amusingly enough the new one has a reversed TPS table like some other member here had as an issue. Charged me more than I wanted to spend but beggars can't be choosers. Next weekend diving into the wiring harness and trying to pinpoint the issue in the wiring. Injectors and ECU pins seem to be getting 12v from the fuse link with key on. Pull the fuse and all see 0v. Put it back in and injectors see 12v but ECU sees 9v. That's likely one of the main issues I have. My wiring guru friend will be over next weekend. Pulling seats out to make it easier to get to all the wiring and will do the nut weld mod at that time too Link to comment Share on other sites More sharing options...
Vovchandr Posted October 7, 2023 Author Share Posted October 7, 2023 (edited) *Drum roll* Not a day too soon the car runs!! Got an expert to come down and we did a deep dive into the harness and tests of everything. 6 hours into pulling the harness out to give it a good once over and wipe it from all the oil under the old electrical tape as well as plug up random terminated ends etc we come across this peeking from underneath the tunnel As we out curiosity piqued we found this trouble maker under After fixing all other harness issues and going out to buy a micro 3A fuse we put everything back together and after a few other gremlins the car fired right up Always thought it might be a rather simple fix (10% chance) but didn't think it would be a hidden fuse. The ECU was likely reading 9v after back feeding from the alternator, that's why it would show 0v in a feed wire to ECU and would only show voltage when ECU was plugged in. Edited October 7, 2023 by Vovchandr 3 Link to comment Share on other sites More sharing options...
wemtd Posted October 7, 2023 Share Posted October 7, 2023 Fantastic news!!! Now if the weather will cooperate (or I’ll bring my PFD) next weekend. 1 1 Link to comment Share on other sites More sharing options...
BlakeJ Posted October 7, 2023 Share Posted October 7, 2023 2 hours ago, Vovchandr said: *Drum roll* Not a day too soon the car runs!! Got an expert to come down and we did a deep dive into the harness and tests of everything. 6 hours into pulling the harness out to give it a good once over and wipe it from all the oil under the old electrical tape as well as plug up random terminated ends etc we come across this peeking from underneath the tunnel As we out curiosity piqued we found this trouble maker under After fixing all other harness issues and going out to buy a micro 3A fuse we put everything back together and after a few other gremlins the car fired right up Always thought it might be a rather simple fix (10% chance) but didn't think it would be a hidden fuse. The ECU was likely reading 9v after back feeding from the alternator, that's why it would show 0v in a feed wire to ECU and would only show voltage when ECU was plugged in. So happy for you, Vlad. Look forward to seeing you next weekend. Link to comment Share on other sites More sharing options...
yellowss7 Posted October 8, 2023 Share Posted October 8, 2023 Congrats Vlad. I would have thrown in the towel a long time ago. Glad you finally caught a break. Tom Link to comment Share on other sites More sharing options...
Croc Posted October 8, 2023 Share Posted October 8, 2023 Congratulations! Hard earned win but good to see you get the win in the end. Link to comment Share on other sites More sharing options...
Vovchandr Posted October 8, 2023 Author Share Posted October 8, 2023 Thanks. I'll tighten a few things up on the rebandaged harness and give a quick test drive this week to get it ready for the weekend. It's been almost 3 months since the last drive, I hardly remember what other issues the car might have. With that said, there is a chance that the wiring harness work has fixed the weird off-throttle issue I've been having as there were a few questionable wires here and there. We will see. 1 Link to comment Share on other sites More sharing options...
CarlB Posted October 8, 2023 Share Posted October 8, 2023 Great News!! looking forward to seeing you and your car!! Link to comment Share on other sites More sharing options...
Vovchandr Posted November 9, 2023 Author Share Posted November 9, 2023 (edited) A few updates Last shake down run resulted in DNF. Turns out my brand new alternator, that was bench tested in the store isn't outputting voltage which resulted in me having to go from the fast last on the highway to the shoulder without power or blinkers. Parked the dead stick on the shoulder. Tried to start again and it started! Ran for 15 seconds and back to dead. Popped the bonnet and used the handy volt meter I brought with me along with an array of other tools and saw that the battery read basically 0. While on the side of the road with the better half, I saw that a brodozer pulled over. As the person was walking towards me I realized that I know this particular brodozer and I was rescued by a friend that happen to be driving by. It was only about half a mile from the house. I know better than go too far on shakedown runs now. The Lithium battery I have happens to have a jump feature built into it, and I had a portable jumper pack that might have been enough power to get me home but I didn't want to find out. Edited November 9, 2023 by Vovchandr Link to comment Share on other sites More sharing options...
Vovchandr Posted November 9, 2023 Author Share Posted November 9, 2023 (edited) Not having much time to fix anything or drive anywhere at this point in the season I only had one more mission left and that was a foliage shoot and a Halloween shoot. Keeping in mind that mind driving radius was severely limited by how far my battery would take me I went to a local park a few blocks away and put on full winter mode of windscreen, doors and half hood. Might as well use them once or twice a year Edited November 9, 2023 by Vovchandr Link to comment Share on other sites More sharing options...
Vovchandr Posted November 9, 2023 Author Share Posted November 9, 2023 (edited) A long sought after key fob arrived today Nobody was able to source this for me and Caterham appears to only give them with a small purchase of a whole new car... Which isn't exactly in my budget at the moment Going to have to Dremel down another blank copy to fit into shell Hardest part was explaining to the better half why on earth I ordered a key fob from across the planet when I already had one (or two actually) Compared to "old" and regular retail unit Edited November 9, 2023 by Vovchandr Link to comment Share on other sites More sharing options...
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