Help! Crank but no start (sorta)
 

I picked up my second MSM 2 days ago since I couldn't pass it up. It's got basically full FM bolt ons, MSPNP Pro, bigger turbo, 700cc injectors, etc.

Car apparently ran great for a long time, then it started to stall in neutral, and eventually just died and he couldn't start it.

Here's what I've tried:
-checked height of all pistons, all 4 are same height at TDC (no bent rod then ya?)
-compression 100-110 all 4 cylinders (a little low ya? but consistent)
-cam sensor is good
-Spark on at least cyl1 (checked spark on just the 1)
-Pulled valve cover, and the timing marks look...odd. At cyl1 TDC the valves are closed, so that's good, but it looks off a bit.
I'll post a picture that hopefully is helpful(though its hard to tell in the pic). I'm wondering if it skipped a tooth or two?

The car tries to fire, and I actually got it running after pumping the gas while starting it over and over, and it finally fired up but wouldn't run on it's own. Sounded rough too, but it was only a few seconds and then couldn't get it to fire up again.


my thoughts of possibilities:
-skipped timing, needs adjusting.
-TPS?
-tune messed up (though he said it ran on this dyne tuned tune for over a year)
-bent rod (though all pistons seem to be same exact height)
-spun bearing
-fuel pump (but it sounds like it's coming on)

Let me know if you guys think of anything I can do or check. Any help is greatly appreciated! Thanks!
-Also, I'm new to Megasquirt. I don't think the car came with the cable to hook it up.. but I'll look. Maybe I can log attempted fire ups and it'll help diagnose?

I'll send someone a $10 amazon card who gets it right https://forum.miata.net/vb/images/sm...smiley-014.gif
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It's hard to tell, but the timing marks seem off. Intake is lined up, but exhaust is lower than the mark by a couple teeth.

I would retime the engine if it visually looks off.

also, get the stuff you need to connect to MS.

sounds like youre in the same boat I am right now, subscribing for answers

Yeah, there's a good chance the timing is the culprit. I'm hoping to try some easy stuff before I rip it all out to set the timing, only to find out it wasn't it. I'm assuming advancing the timing would impact both cams at the same time as opposed to just the exhaust, right? I would check the timing but it's hard since it doesn't crank very well right now as it's not running on it's own power, I'm not sure the timing light would work. It might be worth a shot though.

No, I mean the timing belt, not the ignition timing. Do the cam marks line up in the right spot when at TDC? Do you have the correct number of belt teeth between the cam gears? A corrupted intake charge can make it hard to start. Incorrect valve timing can produce low compression numbers.

It doesn't look like the timing marks are quite right at TDC, but the cam lobes aren't pressing on the valves, so they are closed. I'll have to count belt teeth.

Use the marks on the cam gears. IIRC, each CAM tooth is like 7 deg, plus the valves dont open/close right at TDC, so I wouldn't thing eyeballing the cam lobes would be at all insightful outside of a gross issue.

PO probably ~forgot~ to tell you that he replaced the timing belt or waterpump right before the car started running like $hit.

I can't really see anything in your first pic. The angle is wrong. Use the SM for proper timing mark alignment, not pictures from forum space. Mellens should have the SM you need. That is a BP4W head, which is also found on NB1 (1999-2000) vehicles.

Could be something as simple as the Main Relay or the EGI Main Relay on the passenger side of the engine bay. I'm hoping that's my problem, and it's a known issue with the NB

I would consider pulling the cam gears off and re-indexing them. The I on the intake cam should be at the top, with the cam lobes pointing towards fenders, E on exhaust cam should be up, with cam lobes pointing towards fenders. Because the cam gear has multiple slots for the indexing pin on the cam, there are multiple orientations for the gear. Make sure yours are correct.

Gears look correct orientation in post 7, but can't see cam lobes.

Unfortunately I can't find a Mellens manual for the MSM, and the cam gear is a little different it would appear than in the NB1. The Mellens manual for 99-2000 shows the E as the marker, but there's no E on the intake cam gear for the MSM- just like in that second picture from the inter webs. I know the intake cam is different on the MSM, it would appear the cam gear is as well. So unfortunately Mellens didn't help for this one. :/

Yea I was thinking that.. Might need to pull them off and reorient, but I'm afraid of getting them wrong and then trying to align based off of incorrect marks. :/

Well, I think it may need a full rebuild. I got it to fire and got a video (though it's sideways and crappy). But it sounds like it's knocking hard. When I measured the piston height, all 4 were the same. Could that be the case and still have a bent rod?

I can't hear any knocking over the belt squeal. I'd go back to marking things off the list before you decide it's toast.

It takes less than 10 minutes to pull the covers and check cam timing. My recommendation would be to stop speculating and do that.

yeah it's the last couple seconds where the knocking is very audible. I did check the timing as stated above and the mark on the exhaust cam isn't lined up. So timing is an issue, but that knocking is ferocious. Open to ideas of their correlation- timing off is causing it to fire at the wrong time and thus the knock? If timing is fixed it should be ok? Or- even fixed, it's screwed?

No one can tell what is going on with the timing from the picture you posted. Ted already mentioned that.

I can't hear anything over the squeal in the video.

If you believe the timing is off then take the 15 minutes necessary to fix it. You were four fasteners away from doing it properly when you took that picture. Once you fix the timing and the belt squeal post another video of the knocking.

I really do appreciate the help and time. I was thinking I would have to remove accessory belts, harmonic balancer/crank pulley, timing covers, to get to the tensioner to pull the belt to adjust the cams. Am i missing something? what 4 fasteners are you thinking of? if that's the case I'll definitely do it.

Unless the MSM is completely different than my NA8 the front timing cover is 3 different pieces.

Remove the valve cover, remove the top timing cover (4 fasteners), then you can reach down to the bolt that locks down the timing belt tensioner with an open end wrench. you can access the tensioning spring with a standard needle nose pliers.

Edit: To clarify, pulling the belt would require more disassembly but you don't need to pull the belt to correct the timing.

I'm assuming I'll just be hoping the mark lines up at the crank at TDC with the timing gear since I won't be able to get a visual on it? Aside from that, it makes sense, I'll give that a shot. Thanks