NB NO START, has spark fuel and air

ED_MX5 · Postby **ED_MX5** » Wed Aug 10, 2016 10:06 pm

Here's one for the experts.

2000 NB8B VVT

Car stopped about a month ago.
Coughed twice and cut out. That was the last time it ran.
It cranks fine, and has air fuel and spark.
Crank sensor new
Cam sensor new
Tried new afm
Tried new main relay
Installed PS1000 pnp haltech after it seeming ecu had died.
Had 3 mobile mechanics try, 3 of us at my workplace are mechanics, and had a guy from haltech out to help as well. The ecu is recieving all signals well, we tested wiring, it has injector pulse. Brand new plugs installed for a test wreak of fuel and then aerostart after we tried that too.
Timing belt intact (can see exhaust cam move)
Still not start.
Mr haltech played with ignition advance to a bizzare amount, and it started to splutter.
Possible VVT actuator fault? As in stuck?
Any other ideas?

Cheers, Ed

Postby **NitroDann** » Thu Aug 11, 2016 12:51 am

It isnt just fuel air and spark you need, you need compression too.

Cam timing.

Dann

ED_MX5 · Postby **ED_MX5** » Thu Aug 11, 2016 8:24 am

Thanks Dann.
Yeah compression is the next box to tick in the list.
What do you think has happened if the belt is still intact?

hks_kansei · Postby **hks_kansei** » Thu Aug 11, 2016 1:23 pm

If moving the ignition advance a heap allowed the car to almost start, have you confirmed that he crank trigger wheel is in the correct position?
Ie: it hasn't spun, or lost a tooth. (Or been installed backwards)

If it's got the air/fuel/comp/spark then next would be to confirm they're all happening at the correct times.

93_Clubman · Postby **93_Clubman** » Thu Aug 11, 2016 2:29 pm

ED_MX5 wrote:What do you think has happened if the belt is still intact?

Jumped teeth - happened to STM's Patchy last year (jumped 6 teeth) - result was Patchy wouldn't start.

StanTheMan · Postby **StanTheMan** » Thu Aug 11, 2016 2:37 pm

x2

I had to officially shoot the mechanic :shock:

although referring to myself as a Mechanic is a serious long shot

To be fair though, I got the timing right initially & it ran for a few weeks....until the pulley tension-er came loose & the cam-belt jumped a few teeth. (errr....6 in total thank you 93_Clubman :mrgreen:

)

The result was Patchy just died while hooning along.....

StanTheMan · Postby **StanTheMan** » Thu Aug 11, 2016 2:47 pm

By the way Ed
Where abouts are yoyu at the Northern Beaches ? I'm at Seaforth.

StanTheMan · Postby **StanTheMan** » Thu Aug 11, 2016 2:53 pm

I think the general consensus is that THe MX5 can handle 1 tooth. Although it will run like shite. 1 tooth is equal to 14 deg I think? so you would have some serious overlap. or Underlap :lol:

It is worth pulling off the Cam Cover & check the timing. Especially if your timing belt was done recently. That's not to say that it cant happen at a later stage but much more unlikely. It will only cost you some time to check. You can the either fix it if it does prove to be the issue or deduct it as a possibility. I know with the VVT its a bit more work than the NA's but that's how it goes

ED_MX5 · Postby **ED_MX5** » Thu Aug 11, 2016 6:32 pm

Checking the teeth sounds good.
What do I look for alignment wise?
Car has had no major work done to engine in last 2 years. Not even minor work in last few months.
Been running fine everyday...then stopped.
And I'm in Chatswood Stan.
I'll also be checking timing mark on tdc after I've checked compression. But it does sound good compression wise when cranked.

ED_MX5 · Postby **ED_MX5** » Fri Aug 19, 2016 9:41 pm

Update.
Checked compression today.
Dry test showed 150 psi across the board.
Removed valve cover to find this...

Cus · Postby **Cus** » Fri Aug 19, 2016 10:27 pm

Only a few more bolts and you'll have that right off and into the bin

If you need some visual guidance I found "The Miata King" on youtube had some good videos on replacing the timing belt for various models.
He's irritating and I'd like to karate chop his face, but he has all of the information and hints you need to get the job done correctly the first time.

There are also they wordy articles on the m.net garage section.

ED_MX5 · Postby **ED_MX5** » Fri Aug 19, 2016 10:35 pm

Thankyou for the hints.
Yeah, need to check timing but didn't have the right socket on me to turn the crank over to get tdc.
But making the assumption of skipped teeth looking at some of the mashed bits of belt.
Hoping that's the final stage and it'll finally start again.