1997 Motor rebuilt now NO START! (Have used search)
 

Before I get any comments about the search button : I have used the search button to try and help me figure out what is going on with my car. I have read thread upon thread on the no start topic (on multiple forums as well) and have yet to come up with a solution to my issue.

Here's the story:
So I recently had my stock 97 miata motor rebuilt by a machine shop and now the thing wont start. I was there when they had everything buttoned up and started the car for the first time since finishing the work. The car started up and began to idle a bit rough. It stayed on and ran for a good few minutes when, all of the sudden, the car died. There was a CEL for crank position sensor that came up on the code reader. Turns out the sensor had been on loose and moved out of position. The mechanic tightened it up the sensor and the head of the bolt snapped off. They removed the radiator and a few other obstructing parts and removed the bolt and retapped the hole and put the sensor back on. Well that's where the headaches begin.

After having repaired and readjusted the crank position sensor the car would turn over but not fire. They got a new CPS and put it in to spec (proper air gap) but the car still would not fire. After having held on to the car for months and not being able to solve the issue I decided to take the car home and try to solve the issue myself because they were planning on throwing more parts at it or sending it to their "recommended shop" for inspection and repair (on my dime).

So far I have gone through these checks and have still not fixed the car:
-Verified all parts of the harness are plugged in and not loose
-Checked voltages and resistance according to The Enthusiasts Manual on: coil packs, plug wires, injectors, CPS, cam position sensor, MAF sensor, relays (both underhood and inside the car), temp sensor, main engine harness
-Removed the valve cover and verified cam position at TDC
-Charged the battery to full
-Cranked the engine to verify oil pressure
-Jumped the fuel pump in the diagnostic box to verify that the FP works (it does)
-The oil on the dipstick smells somewhat like fuel so I assume the injectors are spraying

I have yet to see if the spark plugs will spark if I have them out and ground them while turning the car over. I have not checked to see if the timing is set nor have I checked compression so those are on my list next.

The shop mentioned that maybe the ECU was fried by an aftermarket alarm that malfunctioned (although the car had no working alarm there looks to be wiring for and alarm). I am not sure how likely of a scenario that is, though.

Any insight in to the matte would be greatly appreciated. I will try to update this thread as I go off trying new solutions.

I am in south Orange County so if any of you know of someone that can help that's local I would be grateful for the reference. I am not opposed to having someone come over to help or taking the car (on a trailer) to have someone help me with this issue.

Thank you, MT!

Pull the front covers off and verify the timing belt install

When I had the valve cover off I turned the crank with a socket to align the position of the gears so I could count the teeth between them. I can verify that the cams are properly set and that the timing belt functions.

Picture of the VC off, with timing belt properly aligned. I want to be able to see the front cam loves on either side.

Check to make sure that the CPS didn't take out a tooth on the timing wheel when it was loose. (Ask me how I know that can happen)

So the first picture is from when I first took the cover off and snapped a pic. The following are from today. I had tried to crank start the car a few more times from the first pic to the most recent so the position of the marks moved but I threw the original in for reference.

https://www.miataturbo.net/attachmen...ine=1449083260


https://www.miataturbo.net/attachmen...ine=1449083260


https://www.miataturbo.net/attachmen...ine=1449083260


https://www.miataturbo.net/attachmen...ine=1449083260


https://www.miataturbo.net/attachmen...ine=1449083260

All of the teeth look to be there. I have not spun the crank to check clearance on all of the teeth but they look to be of similar length.

Your exhaust cam is off I believe. There are only 18 nubs on the timing belt between the 2 makes on the cam gears. It should be 19 nubs on the belt.

Could that cause a spontaneous no start issue?

Not necessarily, but if you skipped a tooth on your cam gears, maybe you skipped a tooth on your crank gear too.

Well I attempted to see if there was any spark by pulling a plug and holding over metal to see if it would arc and no dice. I had someone cranking the motor over several times and tried different spots to arc the plug (IE: block, heat shield, body, valve cover) as well as trying different plugs and wires from the 2 coil packs.

I am almost 100 percent sure that the injectors are operating but is there any easy way I can test this?

Holding the plug over metal will show you nothing. Hold the threads of the plug on a known ground and watch for spark at the electrode in a darkened room.

Pull off the rest of the timing belt covers and check the entire timing belt install and take pictures.

When you re-do the bottom, make sure the timing wheel is not on backwards.

This is your problem.

I will try the sparkplug arc using your method. I did not know I was doing it wrong.

I will be removing the front cover stuff as soon as I can. I'll take pics and post here as I upload them.


Would this be the cause for a loss of start after the car was running before the crank position sensor failed? Maybe it might be the CPS?

I hooked up a timing light to see if the plugs were receiving spark and sure enough the timing light did not trigger while I cranked the car. I performed that on all of the wires to no avail. I used both the alternator as a power source and another battery but the light did not once pulse.

I also checked the compression and the numbers were 185~.

Not sure where to start. I may just pony up and get the CPS which originally failed but was replaced.

Ignore the damn CPS for now.What happened was your car started and somoe how most likely skipped a tooth or two. Now it won't run. Until you fix the timing belt, nothing else you are doing is useful.

Fix your timing belt correctly. That is what you should be doing.

^^ This. You're off a tooth.

I'll get to removing the front bits and verifying the proper timing. I will take pics when I get around to it. Busy busy time of the year

If it was the cam being off a tooth it would still run and idle [ask me how I know this]. The car at the worst case scenario it would be back firing and farting. It sounds like it is a electrical issue as there is no spark. I would recheck the or replace the cps. Another possibility is the wires that go into the plug, the wire can be broke in two on the inside of the insulation from pulling on them and not show on the outside, I had that happen on the IAC plug once. But I would say that since it started once and then quit it has to be something to do with that CPS, as the car would atleast misfire if it was getting spark and the cam teeth were off several teeth.

Okay so things are finally winding down after the xmas and new year family and festivities time. I will begin to pull the front bits off of the motor and take pictures to be sure that the timing is set properly.

I will also get a new crank position sensor and see if by any stroke of luck that is the only issue preventing the car from starting.

Expect pics and updates here as I find the time to wrench.

Do the sensor first. Like I said before if it ain't even farting it's electrical not mechanical, either that or no gas, because if it had gas and spark there would be something trying to fire.

A 97 will happily run (but with a CEL) without a crank sensor, so remove that from being an issue.

That doesn't seem logical but if you say it well then I guess it is so, I know a 99 won't. It still is an electrical or no gas problem.

In the '95.5-'97 cars, primary fuel and ignition timing is based on the dual-output CAS plugged into the back of the head, just as in the earlier cars. The crank sensor in these cars is used only to provide a high-accuracy reference for misfire detection as required by OBD-II, by precisely measuring crank position over time during individual engine cycles and looking for crank accel vs. decel after an expected ignition event. The CAS is unsuitable for this purpose owing to an insufficient number of pulses (only one per cycle) and the jitter introduced by cambelt flex.

The crank sensor didn't become the primary timing reference until the CAS was removed in the '99 model year.

As a point of curiosity, the '95.5-'97 engines use a different crank sensor, and a different crankwheel, than the NBs. On the earlier engines, a raw VR sensor is used which outputs a differential AC sinewave signal, and the crankwheel teeth have sharp leading edges but ramped trailing edges. (Or the other way around, can't remember.)

The NB crankwheel has square teeth, and the sensor, while internally VR, contains signal-conditioning electronics which produce a square wave via an open-collector output.

No spark means no sync, or something else, like ignition interlock, is interfering. Check the CAM sensor!
Don't know about NAs, but US NBs won't start without the clutch depressed. And yes, I know somebody who had his (new to him) Miata towed because he didn't know that. No, that person is not a friend, merely an acquaintance.

Are you running stock ECU?

This applied to NAs as well. On any Miata, however, the clutch interlock interrupts only the starter itself, and has no effect on any other circuits (ECU, injectors, ignition, etc.)

A clear reading of the first post in this thread indicates that the starter is operating normally. This problem is not related to the clutch interlock switch.

Indeed. I should have known. So my new posting rules are: Don't post before the third cup of coffee. Don't post drunk. The window is getting smaller.

So if I am understanding correctly you are saying that the car would run even with the crank sensor out but the car will NOT run with the CAS sensor out?

I have tried to unplug the crank sensor and turn over the motor to see if there is any CEL thrown but there is nothing. I have cranked it with the crank sensor connected and disconnected and it never gives me a CEL.

The CAS looks to be clocked well in the pics I posted of TDC but I could be wrong.

if you have no spark , have you checked that the coil packs are getting 12v and ground to them? That should be where you start and not straight to sensors. It could be something as simple as a loose ground or blown fuse. if you do have good voltage and ground, then move on to sensors.

Sorry for the late response.

Yes, that is correct. A '95.5 - '97 car will run normally (but throw a CEL) with the crankshaft sensor disconnected, and it will not run at all with the CAS (back of the intake cam) disconnected.


I think perhaps we should back up a bit here and ask a simpler question, given the nature of what you're describing. Does the CEL illuminate and stay on when you turn the key to "Run" without attempting to start the engine?

I finally got around to doing the timing on the car! I have some pics of the front timing cover parts off to shot the timing marks on the cams and the crank.

Before any work began on the car I checked the CEL when the key was turned to the ON position, as Joe Perez recommended I do. There is a picture with the results. Once that was confirmed I removed the front timing cover parts and harmonic balancer to be sure that the cams and crank were properly timed.

After setting the timing I went through and made sure that all sensors and plugs were connected before attempting to start the car. Once I turned the motor over I still got no sputter nor misfire, only a cranking of the motor.

Here are some pics to show the timing being properly set:


https://www.miataturbo.net/attachmen...ine=1454039588




https://www.miataturbo.net/attachmen...ine=1454039588


https://www.miataturbo.net/attachmen...ine=1454039588


https://www.miataturbo.net/attachmen...ine=1454039588


https://www.miataturbo.net/attachmen...ine=1454039588

Anyone have any ideas as to what the issue could be now?

Maybe a recommendation to a shop that deals with electrical gremlins in the south Orange County California area (I am near 949 Racing, as a point of reference)?

The exhaust looks to be 1 tooth off clock wise, but it could be the camera angle also. Even if that was the case it would start and run fine. You have never said if you rechecked to see if you had spark. If no spark the above doesn't matter. Have you also checked to make sure your getting fuel????

Exhaust cam looks off a tooth to me. Timing belt also looks WAY too loose. I'll bet it slipped.

Jmann beat me to it.

before I ripped the timing belt off I'd see if the injectors are firing and if plugs are lighting up, if neither then CAS sensor or wiring to it.

20 teeth between the cam marks - it should be 19. The positions are right but there is too much slack between the exhaust and crank.

When you slip the belt on, put the crank mark at 11:30 position, then slip the belt on the exhaust (I use clamps to hold it) and bring the crank to 12:00 to remove the slack. At that point, the exhaust should be at 12:00 and then you focus on getting the intake at 19 teeth between marks with a wrench. To make it easy on myself I cut 19 teeth out of the old timing belt and lay it over top to eyeball it quickly.

All the slack needs to be between the intake cam and crank. Once I have 19 teeth between the marks you then stuff the belt behind the tensioner, doublecheck your marks and spacing, then rotate the engine clockwise 3 turns letting the spring hold all the belt tension and taking up all the slack then tighten down the 14mm bold on the idler.

You can take a plug out and lay it on the valve cover with the plug wire attached and see if you get spark. Some don't like to do that so for a few bucks you can get an inline tester at autozone, walmart, harbor freight, that well tell you if you if it is electrical.
Inline Ignition Spark Checker Again the timing belt has ZERO to do with it not firing.

Okay so I pulled the injectors after trying to start the car several times after buttoning back up the front after rechecking timing. Fuel spilled from the two rail holes that I pulled the injector from. I am not sure if that is a sure way of knowing it spit fuel or not.

As stated earlier I get the smell of fuel from the dipstick when I pulled it so I imagine that the unburned fuel slips past the rings and gets in to the oil. Is this enough to confirm that it delivers fuel?

Nope. It does not tell you if all the injectors are firing or if any of them are firing. It ran once before. Fuel in the rail does not mean much, it could be from when it ran previously or just the the priming pulse.

You still haven't seen if you are getting spark and that is the easiest of all to do. Sounds like you are getting fuel, in fact you need to be careful as you can get so much in the oil that it ignites and well blow the oil cap or the weakest outlet off. The 99 up have a fuse in the box in the engine compartment pass. side that has a 30 amp fuse for the fuel pump, I don't know if NA years have the same thing but you need to stop the fuel from injecting if you can smell gas in the oil. Check the spark!!!!!, I'll bet you don't have any. Get that cheapo tester I linked, plug the one end onto the plug [leaving it installed] and plug the sparkplug wire on the other end an see if spark jumps across in the clear viewing barrel.

I will get on that as soon as I get the tester.

Wrap a wire around the plug threads, and run it to a ground location. Check for spark. No tester needed.

So I bought the spark tester and had a chance to test to see if there was spark. Nothing. Tried all 4 cylinders and got jack squat.

I rechecked the timing to be sure it was still set correctly and it is.

I am thinking maybe the cam angle sensor might have gone out? I may try getting one and throwing it in for shits just to see if that is the issue.

I really do not know where to go from here. I have re checked fuses and relays, rechecked resistance and voltage on sensors and ignition system components. Any further advice is greatly appreciated.

Weren't you advised to change the cam angle sensor, like three weeks ago?

Well it only took a month to get you to check what was the easiest to check all along. I am not the brightest bulb in the chandelier when it comes to checking out this stuff with multi meters and other test equip.. If you have a spare CAS I would try it first. After that I wouldn't know what to do. Atleast now you know what you don't have.
Also did you reset your cams one tooth and put some more tension on the belt, it looked loose. Loosen your tensioner and use a long screw driver or bar and put a little extra tension on the belt above what the spring alone does. I think with like 20# of pressure in the middle of the belt with a straight edge laying across it you are supposed to have around 3/8" slack. It ain't brain surgery, just be around those figures.

No spare CAS so, unfortunately, that is not an option.

I figured that if the timing light was not triggered on any plug wire while cranking the motor then the spark test would yield the same results. It did.

I will reset the tension per your advice. Thanks for the tip.

I was but I don't want to throw 100+ dollars at a guess before trying other solutions that are free. Now that I have ruled many possibilities out, it is time to go for the CAS.

I have one for a 95. Not sure if it will work for you. If it does, 50 bucks.

I would also change the oil after you get this to start for as much cranking as you have been doing with unseated rings and smelling fuel in the oil. You are breaking it in with non detergent oil right?, and if you installed new cams you need to use break in oil for the zinc content, if not just buy some cheap 30w non detergent oil and run for atleast 500 miles.

30W non detergent was put in originally. I have some on deck for when I get spark. I want to wait til I get spark before I drop the new oil and filter in.

I am poor :cry:

PM'd

If it's still what it was in either of the "correct" pictures you posted it's still wrong. 19 teeth between the marks on the timing gears is what you want. 18 is wrong, 20 is wrong, 19 is right.

It might run with the timing off, but you might as well time it right before getting it running. You're certainly not doing your freshly built motor any favors by trying to get it running with your cams obviously out of time.

https://www.miataturbo.net/attachmen...1&d=1455298317

Installed the cam angle sensor and it still has the same no start/ no spark condition.

I have no idea what to do next.

Does anyone have any suggestions? Maybe miata shops near orange county California that you guys recommend?

Sounds like what you need to do, I don't live down there so can't help you locate a shop. If you can't find one that dynos or specializes in tuning miatas try finding a good tuning shop for any car

Did you ever fix the timing belt to have the 19 teeth?

Yes I did. That was first before installing sensor. Tried the spark tester again as well and still dead.

Do you get a spark signal at the plug that goes into the coils?

I have used a multi meter and checked the coil packs and also have used a spark tester to test the ignition system.

How do you suggest I check them?

i cant help but wonder when i see the pictures, is the tensioner making the timing belt tight? the pictures only show a belt thats about as loose as a motor with no tension on the belt at all.

the other thing we should know is did you do any wiring projects while the car was apart. i had a car not run when the owner installed his racepak improperly.

with the CAS removed and plugged in and the coils both disconnected with the key on, do you hear the injectors click one at a time when you rotate the CAS?

We have determined he has fuel and he has replaced the CAS. He has no spark. He has fixed the cams and the belt he said, besides they would have nothing to do with no spark.

cas->ecu->coils. we dont know if trigger is coming from ecu to fire the coils. so by seeing if they trigger the injectors we will know if the ecu is interpreting the data and firing its outputs. just trying to narrow down the possibilities.

Another thing is are all the grounds attached? one at the TB, behind the intake manifold, the one from the engine to the body by the drivers side firewall, and the ppf

If the oil has gas in it from all the cranking doesn't that say the injectors are being triggered?

It did run initially. so that's where you fuel smell came from?