NB8A won't start
Moderators: timk, Stu, -alex, miata, StanTheMan, greenMachine, ManiacLachy, Daffy, zombie, Andrew, The American, Lokiel
-
- Learner Driver
- Posts: 17
- Joined: Sun Aug 31, 2014 7:25 pm
- Vehicle: NB SE
NB8A won't start
OK, this me has me stumped and I would really like some suggestions.
I have a 2000 model NB8A. Last week it wouldn't start, although it cranked over as normal, just no starting.
I have followed a number of guides to diagnosing the problem and, so far, everything passes the tests.
One thing that I noticed was that the tacho didn't move when cranking and that lead me to think of the cam sensor and the crank sensor.
I pulled them and tested both. Both appeared to work, although the crank one only gave about 0.75V when metal passed near it. I swapped this (the crank sensor) out.
There is still no starting. Just cranking, with no tacho movement. I should probably add, no spark.
So, any advice?
Nick
I have a 2000 model NB8A. Last week it wouldn't start, although it cranked over as normal, just no starting.
I have followed a number of guides to diagnosing the problem and, so far, everything passes the tests.
One thing that I noticed was that the tacho didn't move when cranking and that lead me to think of the cam sensor and the crank sensor.
I pulled them and tested both. Both appeared to work, although the crank one only gave about 0.75V when metal passed near it. I swapped this (the crank sensor) out.
There is still no starting. Just cranking, with no tacho movement. I should probably add, no spark.
So, any advice?
Nick
Last edited by wyrdeman on Tue Sep 23, 2014 6:54 pm, edited 1 time in total.
- shuey
- Racing Driver
- Posts: 1014
- Joined: Tue Jan 22, 2013 3:23 pm
- Vehicle: NB8B
- Location: Melbourne, Victoria
Re: NB8A won't start
Is that after you have dríven it for awhile or starting up when cold?
2001 Sunlight Silver NB8B - SOLD - 23/6/16 

-
- Learner Driver
- Posts: 17
- Joined: Sun Aug 31, 2014 7:25 pm
- Vehicle: NB SE
Re: NB8A won't start
Well, it was after the car had been left for about 4 hours. So it was cold.
I can still not start it after another 4 days of the diagnostics and getting parts.
Nick
I can still not start it after another 4 days of the diagnostics and getting parts.
Nick
- bruce
- Speed Racer
- Posts: 7770
- Joined: Fri Apr 25, 2003 11:00 am
- Vehicle: NA8 - Turbo
- Location: Victoria
- Contact:
-
- Learner Driver
- Posts: 17
- Joined: Sun Aug 31, 2014 7:25 pm
- Vehicle: NB SE
Re: NB8A won't start
Yes, lots of fuel.
OK, the diagnostics.
Immobiliser isn't the problem (light flashes and goes out)
Checked the timing belt isn't broken.
Check engine light doesn't light up when the ignition is turned on.
Checked the main EIF relay (green one in the engine bay)
Checked the relays under the dash and checked that I get 12V to the ECU (pin a1)
Fuel pump relay is fine.
Fuel pump runs.
Changed the fuel filter.
Fuel tank has lots of fuel (>40l)
Fuel comes though the lines.
No spark from any plug.
Checked all the fuses under the dash and in the engine bay.
Nick
OK, the diagnostics.
Immobiliser isn't the problem (light flashes and goes out)
Checked the timing belt isn't broken.
Check engine light doesn't light up when the ignition is turned on.
Checked the main EIF relay (green one in the engine bay)
Checked the relays under the dash and checked that I get 12V to the ECU (pin a1)
Fuel pump relay is fine.
Fuel pump runs.
Changed the fuel filter.
Fuel tank has lots of fuel (>40l)
Fuel comes though the lines.
No spark from any plug.
Checked all the fuses under the dash and in the engine bay.
Nick
- JBT
- Speed Racer
- Posts: 7946
- Joined: Tue Jun 03, 2003 11:00 am
- Vehicle: NC
- Location: Brisbane
Re: NB8A won't start
Lack of ignition (spark) assuming plugs are OK and ignition power is getting to fuel pump etc.: fuses, coils, leads, CAS, wiring detached.

-
- Speed Racer
- Posts: 6444
- Joined: Mon Feb 04, 2008 11:40 am
- Vehicle: NB8B
- Location: Melbourne
Re: NB8A won't start
In the good old days and even with things like lawn mowers probably the first thing to check is spark. It will not be plugs.
- Okibi
- Speed Racer
- Posts: 10906
- Joined: Thu Aug 21, 2003 11:00 am
- Vehicle: NB SE
- Location: Perth, Western Australia
- Contact:
Re: NB8A won't start
My NB8A also has some fuses right up under the dash near the steering column, I think they're used by the alarm. Might also help to check those.
If you had access to a car like this, would you take it back right away? Neither would I.
- greenMachine
- Forum Guru
- Posts: 4128
- Joined: Thu Apr 24, 2003 11:00 am
- Vehicle: NB SE
- Location: Sports car paradise - Canberra
- Contact:
Re: NB8A won't start
Cam sensor?
Crank sensor?
Easiest way is to borrow someone else's sensor and swap for yours, starting with cam sensor, then crank.

Crank sensor?
Easiest way is to borrow someone else's sensor and swap for yours, starting with cam sensor, then crank.

I never met a horsepower I didn't like (thanks bwob)
Build thread
NB SE - gone to the dark side (and loving it
)
Build thread
NB SE - gone to the dark side (and loving it

-
- Speed Racer
- Posts: 7468
- Joined: Fri Feb 11, 2011 12:49 pm
- Vehicle: NA6
- Location: Purga, QLD
Re: NB8A won't start
Buy a noid light and plug it into an injector. No light no injector signal, possible failed can angle sensor! Are the plugs wet with fuel when you crank?
Noid lights are cheap and a quick way to diagnose or eliminate a problem.
http://www.tridon.com.au/Products/Product.aspx?SG=5&S=21&G=622&P=68586
Noid lights are cheap and a quick way to diagnose or eliminate a problem.
http://www.tridon.com.au/Products/Product.aspx?SG=5&S=21&G=622&P=68586
-
- Speed Racer
- Posts: 6444
- Joined: Mon Feb 04, 2008 11:40 am
- Vehicle: NB8B
- Location: Melbourne
Re: NB8A won't start
Reread Nicks list- the problem is no spark- he listed it.
-
- Fast Driver
- Posts: 287
- Joined: Sat Oct 12, 2013 8:27 am
- Vehicle: NB8A
Re: NB8A won't start
EGI/Main relay? It's the green one in the engine bay fuse box.
-
- Fast Driver
- Posts: 133
- Joined: Wed Dec 25, 2013 11:48 pm
- Vehicle: NB8A
- Location: Ipswich
Re: NB8A won't start
I had same problem in mine a few months ago. I changed the crank angle sensor and seemed to fix it but it started doing similar things only a little while later. Replaced cam sensor and its been fine ever since. I did also buy a new EGI relay but it made no difference to my car.
It's the wife's car.
-
- Speed Racer
- Posts: 6444
- Joined: Mon Feb 04, 2008 11:40 am
- Vehicle: NB8B
- Location: Melbourne
Re: NB8A won't start
How can an engine run without spark?
- gslender
- Speed Racer
- Posts: 2330
- Joined: Sat Feb 19, 2011 10:49 pm
- Vehicle: NA6
- Location: Brisbane, QLD
Re: NB8A won't start
Mr Morlock wrote:How can an engine run without spark?
A diesel engine can.
MX5 91 NA6 LE completely stock and loving it!
MX5 92 NA8/ITBs Silver "aka Track Beeotch"
MX5 92 NA8/ITBs Silver "aka Track Beeotch"
Return to “MX5 Engines, Transmission & Final Drive”
Who is online
Users browsing this forum: No registered users and 6 guests