Welcome Guest! To enable all features please login.

Notification

Icon
Error

bainbridge
#1 Posted : 11 October 2018 21:31:30(UTC)
bainbridge

Rank: Regular poster

Groups: Registered
Joined: 24/04/2017(UTC)
Posts: 94
Man

Thanks: 26 times
Was thanked: 9 time(s) in 9 post(s)

Hi MX5ers 

IL motorsport 4-1 manifold is fitted, phew that was a job and a half!

Snag 1: The precat o2 sensor is fitted to the manifold itself and the postcat o2 sensor is now fitted downstream of the midpipe cat via a no-weld bung and the wiring extension provided with the exhaust. To my dismay I had a CEL on the dash when starting the engine 

On Torque Pro the fault code reads as: 

P0037 – Heated oxygen sensor (HO2S) 2, bank 1, heater control -circuit low

I cleared the fault code and the CEL is now extinguished but I still get the fault when I run the diagnostic.

I was getting very tired on this job (took me literally all day, and into the evening with a lamp) and clumsily dropped the secondary o2 sensor onto the concrete driveway. So it's had a whack. Also when refitting the midpipe with o2 sensor installed I was very wary of the propshaft right next to the excess cable, so spent some time under there manipulating the cable and clipping it out of harms way. Some damage to the sensor wires might have resulted from me being too rough.

Snag 2:

When fitting the no weld bung I decided to orient it with the nuts and bolts below the midpipe in case further tightening was needed, however the X shaped brace which screws to the underside of the car is now touching the new bolts. There's no noticeable rattle but I want the exhaust hanging completely clear. There's an easy solution to this: rotate the band on bung 180 degrees. 

Mpg has reduced from low 30s to high 20s.

 

The plan now is to remove the midpipe, rotate the bung fitting, fit a new o2 sensor and CAREFULLY route the wires clear of the midpipe and propshaft.

Any comments most welcome. 

 

2009 2.0 Sport Tech PRHT
Lukebarog
#2 Posted : 12 October 2018 08:36:00(UTC)
Lukebarog

Rank: Forum newbie

Groups: Registered
Joined: 16/07/2017(UTC)
Posts: 15

Was thanked: 3 time(s) in 3 post(s)

Well done for fitting the manifold. I think I will be doing this myself also at some point.

I'm pretty sure that oxygen sensors are quite fragile and don't take kindly to being dropped. Perhaps your diagnostic device might offer a live sensor readout and you can check if you able to see voltage from this sensor to know if it is working or not. I would imagine/expect that you would see similar values to the original post main cat sensor. They normally cycle between around 150 and 850 mV. You might find with this fault the car is running in open-loop mode which means it will run on a predefined values rather than than take readings from sensors to optimize fuel mixture. These usually err on the rich side which might explain the lower MPG.

I am a bit confused by the sensor situation on these. As far as I can tell the original manifold has a hole nearer the top for an EGT sensor and then a hole after the cat for the oxygen sensor. It seems this is also the case on the aftermarket ones but am I right in saying that if you were to put the sensors in those holes that would then trigger a CEL light unless remapped? But if you relocate it behind the main cat this will not trigger the CEL light with the car running the standard ECU map?

I am intrigued by this weld-free bung, is it a case of just drilling a hole in the exhaust and fitting some kind of band on clamp with the bung in?


Hope you get it sorted.

 1 user thanked Lukebarog for this useful post.
bainbridge on 12/10/2018(UTC)
bainbridge
#3 Posted : 12 October 2018 17:35:55(UTC)
bainbridge

Rank: Regular poster

Groups: Registered
Joined: 24/04/2017(UTC)
Posts: 94
Man

Thanks: 26 times
Was thanked: 9 time(s) in 9 post(s)

Originally Posted by: Lukebarog Go to Quoted Post

Well done for fitting the manifold. I think I will be doing this myself also at some point.

I'm pretty sure that oxygen sensors are quite fragile and don't take kindly to being dropped. Perhaps your diagnostic device might offer a live sensor readout and you can check if you able to see voltage from this sensor to know if it is working or not. I would imagine/expect that you would see similar values to the original post main cat sensor. They normally cycle between around 150 and 850 mV. You might find with this fault the car is running in open-loop mode which means it will run on a predefined values rather than than take readings from sensors to optimize fuel mixture. These usually err on the rich side which might explain the lower MPG.

I am a bit confused by the sensor situation on these. As far as I can tell the original manifold has a hole nearer the top for an EGT sensor and then a hole after the cat for the oxygen sensor. It seems this is also the case on the aftermarket ones but am I right in saying that if you were to put the sensors in those holes that would then trigger a CEL light unless remapped? But if you relocate it behind the main cat this will not trigger the CEL light with the car running the standard ECU map?

I am intrigued by this weld-free bung, is it a case of just drilling a hole in the exhaust and fitting some kind of band on clamp with the bung in?


Hope you get it sorted.

Hi Lukebarog

The faultcode says low voltage but when I try running the monitor for the secondary o2 sensor it's as if the sensor isn't there.

Torque reports the fuel mixture as a closed loop operation and mixture being determined by o2 sensor, rather than the open loop which I think is using predefined values, but I'm not sure if this is just being reported as what the operation should be, rather than was is actually happening. The lambda sensor reads as 1, but I realised it reads 1 with the engine off!

I ran the fault checker today and no fault is being reported at all. I might just change the sensor anyway because I need to rotate the no weld bung:

https://h-tune.co.uk/aem-no-weld-o2-sensor-mount-for-2-25-to-2-5-inch-diameter-pipe/?gclid=CjwKCAjwjIHeBRAnEiwAhYT2h7Iib9BxEYtUjWDPN8K_vMkdoHecjVngabY39tuboBMrpuPVyaNlKRoC3ZgQAvD_BwE

As you suspect you simply bolt it on after drilling a hole in the pipe.

If you're fitting the manifold yourself there's a great guide on miata forum, there's a link to it on this site somewhere. 

Hand tools to have in addition to the usual are a 500mm wobble bar to get onto some of the manifold bolts via the drivers side wheel well and a 10 mm flexible ratchet spanner to remove the manifold heatshield bolts.

Edited by user 12 October 2018 17:40:05(UTC)  | Reason: Not specified

2009 2.0 Sport Tech PRHT
Users browsing this topic
Guest (3)
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Powered by YAF 1.9.6.1 | YAF © 2003-2018, Yet Another Forum.NET
This page was generated in 0.228 seconds.