Been a loooooooong time, but got the itch again- and so bought myself a non running 02 w/ -75k mikes, bone stock...she's pretty! My NA has proven unstreetable, and has barely seen any use. So decided that I'd get myself a nice platform to build a fun but daily driveable car so I can see some time driving not just working on it or watching it sit.

Story from the seller is that he bought a 1 owner car for his son. He learned to drive manual on it, then had the clutch as well as lots of maitenance done by a shop and his son took the car to school.

He got about 10k miles on it, when the TB snapped while driving. Towed to a shop who did the TB, but they couldn't get it started. Was quoted $1500 to put in a new head. Towed it to a buddy who tried his best but was unable to figure it out. At that point it was listed for sale, and I grabbed it.

The car cranks fine, but won't start. Sounds good, engine spins freely, no unusual noises or obvious red flags


Today I spent a few hours redoing the TB, and checking the crank wheel to make sure was properly reinstalled as seems to be a common issue and sounded like similar symptoms.

Found each cam was off a tooth, and the crank wheel was on correctly (raised center facing towards front of car). Redid the belt, but did not start. Crank sensor was also cleaned well, and gap\spacing seems correct.

So I turn to the experts to try and hunt down what could be the cause and for help getting this car started... You guys are amazing and looking forward to any input.

 

02 is VVT, right? Wonder if the timing belt whacked the cam sensor on its way out.

 

Correct VVT.Not sure, no signs of any damage visually

 

Came across this thread w similar symptoms.... I think I already troubleshooted a few more items https://www.miataturbo.net/general-m...ng-belt-86636/

Verified the trigger wheel was correct
Confirmed fuel and spark
Confirmed timing lines up (was off 1 tooth on both cams but now fixed)

My cluster does show a CEL, but I have to go purchase a code reader...would this be next logical step or does anyone have suggestions before going this route?

*how about the crank position sensor? Gap is correct, but perhaps should replace?

 

Not the best of ideas, and certainly not the easiest, but:

If you could borrow a PNP megasquirt from someone, and try to start the car in flood clear (doesn't inject fuel, doesn't try to start the car), you could run a composite log and look at the readout from the cam/crank signals to make sure all is good with them. Your problem certainly sounds like a sensor error to me. The same could be done with an oscilloscope if you have access to one of those.

FWIW though, I do run my crank sensor a little closer than the OEM stated gap, as I was having cranking issues that this seems to have fixed.

 

Picture of the top cam gears at correct position so we can see the cam lobes. It is possible to have the exhaust cam gear off and cause starting problems.

 

Here's what I have so far, I'll have to pop open the valve cover tn to get pics of the cams themselves.

Megasquirt unfortunately not an option, I needs better friends lol

I've never had an NB, so used to CAS vs Crank Sensors...I'll do some reading up later to see what the process is to adjust unless someone has a real simplified explanation.

Also, is there an easy way to test if the sensor is working at all? As mentioned, my next unguided step would be to order a new one to rule it out

Very much appreciate the guidance

 

If you've got spark, it's working.

Can you take a wider shot of the cam, showing the lobes as well?

 

Also wanted to mention...

Plugs seemed fine, gap/overall condition, as did wires and cops (verified spark w a screwdriver while cranking)

And fuel is def getting there bc opening the TB after cranking, and having plugs out after confirmed there's no shortage.

Also no notice of loose grounds/connectors

Agree seemingly sensor related, just need to figure out where..

Someone mentioned there's a ground that's often overlooked when putting the TB covers back on. Any pics of said ground?

**will get pics of lobes tn, car is home and I'm working atm

 

Got pics but receiving an error when trying to post! Security token?

At TDC my first lobes appear to be intake @ 9oclock, exhaust lower than 3, but not quite 6 (about 4-5 oclock position)

From what reading I've done, this doesn't seem correct...wish I could post pics to show

 

what's the distance between the crank sensor and the trigger wheel? It should be adjusted so it's about a credit card's distance from the nubs on the trigger wheel.

 

For the time being I think it's best to use offsite image hosting, like this.

Except, instead of pasting the image URL, just manually type [img] [/img] around it inline with your post.

I don't have VVT, but the lobes should look like this.

 

This is perfect, I can clearly tell my exhaust cam lobe is much lower than the one pictured above when all marks lineup/TDC

Going to fix this and see how it goes...

 

 

 

 

Pictures loaded...thanks deez, never used that option to load pics..Working w only a cell and tablet, but managed

Now that I get a close look at the pic, its unfortunate that the exhaust side was a bit dark, hopefully between the overhead and exhaust shot you can see the orientation.... Safe to say its def not 3oclock, and yes this was at TDC when all the markings lined up and confirmed w dipstick in #1.

Obviously needs to be fixed, question is...do you guys think its off enough to cause no start??

 

Told you.

 

98%sure...with MY 50/50 skills = 100% fail lol

Now that we're 100% sure, with my 50/50 skills = 98% fail...so there's HOPE!!

 

HE'S ALIVE!!!

Your exhaust cam sprocket is most likely bolted on 120* out of wack. Take it off, position the cam at ~3 o'clock, position the exhaust cam with the E pointing straight up, and you should see a semi obvious slot on the sprocket that the pin on the cam is supposed to line up with.