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Post by mikeeyboy on Jan 2, 2018 22:44:19 GMT
Here's where I looped the pipe, originally the pipe from the inlet connected onto one side.  Then the pipe that now comes out of the manifold has a bolt into seal it off. If you look at the wiring diagram that solenoid is cabled straight to the ECU,  Awesome thanks mate, I dont actually have that part anymore as it was removed when i removed the canister  My car is 1998 mk2 1.8. myself and Paul who is building an Exocet as well looked into this and couldn't find a definite answer. Basically on mine if I have the solenoid disconnected the car runs like crap, strong smell of fuel etc. Connect it back up with the looped pipe and blanked hose, issue goes away. I presume the ECU is looking for a reading from it, otherwise why would Mazda wire it to the ECU? I think the system on the mk1 is slightly different so doesn't have the additional wiring. If you can I would get one of the solenoids from autolink or somewhere and try it, I bet they are cheap enough but at least it will clear it off the list either way. |
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Post by Shane on Jan 2, 2018 22:46:09 GMT
Awesome thanks mate, I dont actually have that part anymore as it was removed when i removed the canister My car is 1998 mk2 1.8. myself and Paul who is building an Exocet as well looked into this and couldn't find a definite answer. Basically on mine if I have the solenoid disconnected the car runs like crap, strong smell of fuel etc. Connect it back up with the looped pipe and blanked hose, issue goes away. I presume the ECU is looking for a reading from it, otherwise why would Mazda wire it to the ECU? I think the system on the mk1 is slightly different so doesn't have the additional wiring. If you can I would get one of the solenoids from autolink or somewhere and try it, I bet they are cheap enough but at least it will clear it off the list either way. Completely agree, found some on ebay cheap but they are for a MK2 1.6 think it will be ok for the 1.8? |
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Post by mikeeyboy on Jan 2, 2018 22:47:02 GMT
Also with regards the dash temperature sensor I do not believe you need the dash to be connected. I have fitted a digital dash which doesn't read the mx5 temp sensor properly. So I left the mx5 sensor in place for the ECU and fitted a separate sensor inline with the radiator. The car runs between 80-90 degrees which I know is accurate as the Digi dash is calibrated for it.
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Post by Shane on Jan 2, 2018 22:51:58 GMT
Also with regards the dash temperature sensor I do not believe you need the dash to be connected. I have fitted a digital dash which doesn't read the mx5 temp sensor properly. So I left the mx5 sensor in place for the ECU and fitted a separate sensor inline with the radiator. The car runs between 80-90 degrees which I know is accurate as the Digi dash is calibrated for it. Thanks alot Mikey, very helpful! Its very annoying as the engine idles and runs perfectly so there is nothing obvious that would throw of emissions nor cause it to over heat. I think the plan for tomorrow is to jump the wires from the temp sensor to the ecu and o2 sensor to rule out any breaks or shorts there and then try a purge solenoid as suggested by you. Ill be back  |
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Post by kiwicanfly on Jan 3, 2018 0:15:32 GMT
Is there not a temperature sensor that gives an actual temp reading to the ecu in order to turn the fan on and off (along with other ecu related temperature tasks)?
Also, if there is such a sensor, is it calibrated the same as the ecu expects?
The gauge you describe sounds like a simple analogue gauge purely for visual indication.
I believe the sensor types can only drive one or the other types of gauge.
Also, according to Omex, you shouldn't piggy back a display guage onto a sensor used to feed the ecu.
Was the fan running when it coughed up?
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Post by mikeeyboy on Jan 3, 2018 13:21:48 GMT
My car is 1998 mk2 1.8. myself and Paul who is building an Exocet as well looked into this and couldn't find a definite answer. Basically on mine if I have the solenoid disconnected the car runs like crap, strong smell of fuel etc. Connect it back up with the looped pipe and blanked hose, issue goes away. I presume the ECU is looking for a reading from it, otherwise why would Mazda wire it to the ECU? I think the system on the mk1 is slightly different so doesn't have the additional wiring. If you can I would get one of the solenoids from autolink or somewhere and try it, I bet they are cheap enough but at least it will clear it off the list either way. Completely agree, found some on ebay cheap but they are for a MK2 1.6 think it will be ok for the 1.8? Email autolink about it, they have loads of spares, I would have thought they could do a direct match. I did some reading and generally on most cars a faulty charcoal solenoid causes them to run rich, so if yours doesn't have it I would definitely rectifty it. I have just booked my IVA for next month so hopefully I do not have similar problems! |
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Post by casesensitive on Jan 3, 2018 14:12:25 GMT
Also with regards the dash temperature sensor I do not believe you need the dash to be connected. I have fitted a digital dash which doesn't read the mx5 temp sensor properly. So I left the mx5 sensor in place for the ECU and fitted a separate sensor inline with the radiator. The car runs between 80-90 degrees which I know is accurate as the Digi dash is calibrated for it. This. My Rocket has two completely independent coolant temperature sensors (well, 3 but never mind that); one that sits inline with the hot feed to the radiator and the engine end (our engine is at the back); this goes to the dash. Then the one that the focus came with that goes to the ECU. The dash one matters not a jot, the vital one is that one that tells the ECU to tell the fans to come on, and how much fuel to put in. Something like this, note that if your CLT think it's -40*, you get 62% more fuel.  It's massive overkill for your issue; but if you put in an ME221 or other independent management, you could control fuel trim, after start enrichment etc. You could measure and log temperature as speed and rpm increases, see where the bottleneck is. There's even a map switching button, you could have a VW-mode for the IVA :-) A lower-tech approach would be to buy a £10 OBDII dongle and connect it to your phone, record true 'ECU temp' from that. Won't necessarily help with fueling though. |
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Post by Stiggy on Jan 3, 2018 17:21:59 GMT
You should start at the beginning. 1. Did it over heat when it was a Mazda? If not then you have changed something during the build. 2. Did it run rich and fail emissions for an MOT when it was a Mazda? If not then you have changed something during the build. 3. Did the fan cut in? 4. Is the stat stuck shut? 5. Is the pump rotating? 6. Any water flow? 7. Fan belt off/loose? 8. Does the running of the engine change when you unplug various items such as air flow meter (next to air filter) or Lambda sensor plug? 9. I remember you had a wiring issue due to your loom being cut, this caused gauges to fluctuate which suggests the wiring may be at fault causing all sorts of issues. mevowners.proboards.com/thread/9100/electrical-nightmare-help10. We always advise builders to get the car through the IVA before carrying out any mods to anything. Doubling back to the build process maybe the answer, good luck, please report back to let us know how you get on. |
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ybot19
Junior
1990 eunos roadster
Posts: 32 
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Post by ybot19 on Jan 4, 2018 18:39:15 GMT
hi Shane, I also had very high emissions, very close to yours I found my o2 sensor was not reading correctly and also replaced the ecu temp sensor underneath the coil pack. going to a garage for an MOT tomorrow I'll let you know the results
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Post by Shane on Jan 5, 2018 15:15:59 GMT
hi Shane, I also had very high emissions, very close to yours I found my o2 sensor was not reading correctly and also replaced the ecu temp sensor underneath the coil pack. going to a garage for an MOT tomorrow I'll let you know the results How did you get on mate?!? |
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ybot19
Junior
1990 eunos roadster
Posts: 32
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Post by ybot19 on Jan 5, 2018 17:14:28 GMT
9% CO and 600 HC so still running crazy rich, tester suspected engine management issue. I’m going to try adjusting the AFM manually as I’ve heard others have had to do before fingers crossed!
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Post by NJ. on Jan 5, 2018 17:21:08 GMT
I found mine had an air lock in the water thermostat/sensor housing. worth unscrewing the temp sensor to let the air out. I found it helped with running temps and may explain your overheating issue as my guess is the airlock stops the thermostat heating fully and so it doesn't open properly....
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Post by snowbird1 on Jan 6, 2018 15:07:15 GMT
The rich fueling can be caused by high fuel pressure, the ECU does not monitor fuel pressure - just 'assumes' it is correct! On earlier cars check vacuum to the pressure regulator or restrictions in the return line.
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Post by Stiggy on Jan 6, 2018 15:31:11 GMT
The loom could be damaged allowing the cable to one of the injectors to catch on the bulkhead. The ECU normally switches the injectors via earth so you could have one open all the time.
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Post by Shane on Jan 6, 2018 17:36:56 GMT
Thanks for all the info guys, im gonna have a few hours with the car tomorrow and do a little sole searching i think |
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