NB8B starting and running issues

speed freak · Postby **speed freak** » Fri Jan 03, 2014 5:27 pm

Thanks, Ill have a look through those links and decide. Replacing the battery is the last thing I will try though as the starting issue doesn't happen all the time so Im guessing its something else.

The new 'sealant' on the TB butterfly has helped a bit, starts a lot smoother and easier now, seems to run smoother too. Thought it may have fixed the issues driving to work happily and enjoying the car then I pull into work and it plays up in that rough spot again, same on the way home, Happily driving along enjoying some roundabouts got pretty much home without an issue then it plays up again jerking back and forth. I so wish I had another car to drive, Im not liking driving the mx5 at the moment

Unless the base idle has always been set with no sealant on the butterfly, maybe now that's fixed the base idle needs to be set again and hopefully its all resolved and stays that way.

speed freak · Postby **speed freak** » Fri Jan 03, 2014 7:35 pm

So tried a few of those experiments this arvo. The car was still at operating temps so I unplugged the o2 sensor and went for a drive, couldn't get it to play up, then I plugged the o2 sensor back in, couldn't get it to play up lol then I unplugged the IAC valve connection, idle fluctuated between 400 rpm and 600 rpm almost ready to stall basically. Kept revs up and went for a drive and couldn't get it to play up, so plugged IAC back in and went home and it played up in the usual rpm. Although I cant remember if it played up once or twice with the o2 unplugged (bad memory) but if it did no where near as bad as usual.

So I have no idea, hopefully Ill get that relay soon and get the base idle set yet again and see how it goes. Ill be ringing Automotive Plus Monday since they will be open again.

93_Clubman · Postby **93_Clubman** » Sat Jan 04, 2014 9:50 am

speed freak wrote:The new 'sealant' on the TB butterfly has helped a bit...
Unless the base idle has always been set with no sealant on the butterfly, maybe now that's fixed the base idle needs to be set again...

As you say much depends on when the TB bore sealant was removed in terms of when base idle has been set, but base idle should now be reset, particularly as it's a simple process. Keep in mind also that your reapplication of TB bore sealant (ie nail polish) may not be equivalent to the factory application of it, so depending on how it's been done, results could be variable. It would be well worth mentioning to Automotive Plus that you found that the TB bore sealant was missing after TB cleaning, & that you've reapplied some nail polish, & ask them to check your reapplication of TB bore sealant to ensure that it's adequate.

TIP · Postby **TIP** » Sat Jan 04, 2014 10:16 am

I had this issue with my nb8b nobody knew how to fix it because it was interment, but it would start if you crack it for 30 seconds but that would make me look like a tard starting my car for that long .

93_Clubman · Postby **93_Clubman** » Sat Jan 04, 2014 10:23 am

TIP wrote:I had this issue with my nb8b nobody knew how to fix it because it was interment, but it would start if you crack it for 30 seconds but that would make me look like a tard starting my car for that long .

Yeah, your old NB8B's water damaged ECU issue was one of the two in QLD, one in NSW, & one in WA that came to mind:
viewtopic.php?f=29&t=61411

TIP · Postby **TIP** » Sat Jan 04, 2014 10:26 am

You think so, i showed mx-5 plus they reckon it was fine, but they can be wrong.

speed freak · Postby **speed freak** » Sat Jan 04, 2014 6:06 pm

93_Clubman wrote:
speed freak wrote:The new 'sealant' on the TB butterfly has helped a bit...
Unless the base idle has always been set with no sealant on the butterfly, maybe now that's fixed the base idle needs to be set again...

As you say much depends on when the TB bore sealant was removed in terms of when base idle has been set, but base idle should now be reset, particularly as it's a simple process. Keep in mind also that your reapplication of TB bore sealant (ie nail polish) may not be equivalent to the factory application of it, so depending on how it's been done, results could be variable. It would be well worth mentioning to Automotive Plus that you found that the TB bore sealant was missing after TB cleaning, & that you've reapplied some nail polish, & ask them to check your reapplication of TB bore sealant to ensure that it's adequate.

That's true, I think the sealant has been gone for quit a while probably before I bought the mx, so Im guessing each time the base idle has been re set its been with no sealant on the butterfly valve so probably been a very minute gap left open, (TB not closed 100%) so now its got some form of sealant Id say it needs to be re set again which I will get done then all will be good hopefully. Today there were no problems at all, ran fine and not rough. That's what makes these little issues hard to diagnose because they are intermittent and so many different issues its hard to find whats causing it. But something so small like missing sealant on the butterfly valve could very well be the culprit.

Ill get the base idle set again by Automotive Plus and also let them know about the missing sealant and get them to check if Iv applied enough.

So make sure Iv applied enough new 'sealant' on butterfly valve, get base idle re set again, then get new EGI relay (hopefully my mate has ordered it for me on ebay) if the problems still persist get the ecu checked for water damage. Other then that I cant think of anything else.

93_Clubman · Postby **93_Clubman** » Sat Jan 04, 2014 6:28 pm

93_Clubman wrote:
TIP wrote:I had this issue with my nb8b nobody knew how to fix it because it was interment, but it would start if you crack it for 30 seconds but that would make me look like a tard starting my car for that long .

Yeah, your old NB8B's water damaged ECU issue was one of the two in QLD, one in NSW, & one in WA that came to mind:
viewtopic.php?f=29&t=61411