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Old 03-11-2012, 05:39 PM   #1
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Default Built engine won't start, intake mani is hot

Hey guys, so my stepdad and I's project Miata has been ever so close to running for some time now and we can't seem to get it fired.

The setup:
-95 1.8L with a forged bottom end and upgraded valve springs assembled at a local engine shop.
-Begi shanghai kit with an intercooler upgrade and a Megasquirt PnP
-Rx7 550cc injectors

The struggle:
So with the Megasquirt installed, the car would turn over, then hitch, then turn over, then hitch but never fire. The odd thing was that there was smoke coming out of the intake after trying to get it to fire, which led me to assume the timing was wrong.

To be absolutely sure the timing was wrong, we took it to the local Mazda dealership where they told us it was a couple teeth off. They fixed it and we tried again with similar results.

We double checked the plugs on the coil packs, the injectors, everything is hooked up correctly as far as we can tell.

Today:
We put the factory ecu back in and it seems to crank more uniformly but now the intake manifold gets hot when we do so and the exhaust is still ice cold.



Anyone have any idea what's wrong with this thing? I still think the timing is wrong somehow, but my experience with Miata engines isn't very substantial. Any help is MUCH appreciated!
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Old 03-11-2012, 06:27 PM   #2
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Engine turning the right direction?

You running stock injectors with the factory ecu?
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Old 03-11-2012, 06:34 PM   #3
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Update, the whole thing works backwards. It sucks air in the exhaust and blows out the intake. Is it possible to hook up the starter to where it spins backward?
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Old 03-11-2012, 06:43 PM   #4
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EEEPICCC!!! Look at the crank while some one inside is trying to start it. Remove the fuel injectors fuse to ensure its not kickback thats turning it backwards.
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Old 03-11-2012, 06:46 PM   #5
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The car is spinning the right way. The starter is fine. I'm pretty sure the geniuses at the engine shop and dealership screwed up the timing. The intake valves are opening when the exhaust valves are supposed to and vice versa.
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Old 03-11-2012, 07:04 PM   #6
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We need pictures of you valve cover off, with the crank at TDC and the cam wheels at what you believe are the correct positions. We will then tell you that your timing is off and what you need to do to fix it.
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Old 03-11-2012, 07:43 PM   #7
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As in this picture? Literally just took this picture and was going to post it to see what you guys thought. Glad we're on the same page. Thoughts on this?

The cam lobes on the number one cylinder are facing each other just about, which seems to me that they're wrong. Shouldn't they be facing away from each other?

For the sake of accuracy, TDC as defined here is when the #1 piston is at the peak of its travel and the timing marks are lined up yes.
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Old 03-11-2012, 07:51 PM   #8
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#1 lobes should be at 9 (int) and 3 (ex) when at TDC
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Old 03-11-2012, 07:54 PM   #9
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Yeah...ours are at 1 and 11.... How is this possible?
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Old 03-11-2012, 08:04 PM   #10
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A+ thread, would read again. Go get your money back from that pathetic shop.
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Old 03-11-2012, 08:06 PM   #11
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There are two slots on the cam gears, you put the pin in the wrong slot.
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Old 03-11-2012, 08:07 PM   #12
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Quote:
Originally Posted by gc8pat View Post
Yeah...ours are at 1 and 11.... How is this possible?
Your cam gears are both off. You need to remove the 14mm bolt that hold the gear to the cam and put them on correctly. For them to be correct on the intake side the "I" needs to be pointing straight up and the "E" mark needs to lined up with the timing mark on the plate. The lobes should point out towards the 9oclock position if you have it correct. On the exhaust side you need the "E" pointed straight up and the "I" lining up with timing mark. The exhaust cam lobes will be pointed towards 3oclock.

I am sure someone will come around and post a good picture that shows this correctly.

I would also go get your money back from the Mazda dealership you took the car to and had check the timing. They should have caught the cam gears being off.
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Old 03-11-2012, 08:12 PM   #13
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Thanks for the replies guys.

Shuiend, the cam gears are lined up with the I's and E's like they're supposed to be, I think the engine shop just put the exhaust cam gear on the intake cam and the intake cam gear on the exhaust cam. Currently disassembling to fix the issue. I'll post again after this is all sorted.

For those in the future. TAKE YOUR VALVE COVER OFF AND CHECK YOUR CAM POSITIONS AGAINST YOUR TIMING MARKS! Everything in the timing looks to be correct except where the cams are, which apparently every idiot who looked at the car and said it was ok overlooked.
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Old 03-11-2012, 08:18 PM   #14
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Correction Shuiend, you were right. I just read in the manual about the 3 holes that the cams can line up on. I'll post pics of where they put them in relation to where they're supposed to be.
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Old 03-11-2012, 08:46 PM   #15
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I always do timing by

piston 1 at TDC
front cam loaves pointing away from each other
crank mark lined up with that plastic timing thing.

I can't count so I don't count the teeth.
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Old 03-11-2012, 08:49 PM   #16
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Picture to show the fail.


Intake side on the exhaust slot, exhaust side on the intake slot. Nicely done. Almost back together, can't wait for this thing to beat ***.
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Old 03-11-2012, 08:51 PM   #17
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Are these cams identical in lift & duration?
Are the cams/gears just swapped? Are there any identifiers on the cams at all?
Need to follow your whole valvetrain actuation. Ie: make sure the order is correct.

Edit, I type way to slow...
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Old 03-11-2012, 09:13 PM   #18
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Quote:
Originally Posted by gc8pat View Post
Picture to show the fail.


Intake side on the exhaust slot, exhaust side on the intake slot. Nicely done. Almost back together, can't wait for this thing to beat ***.
Good job on getting it fixed now. I have had the same thing happen to me, hence why I know exactly what needed to be done.
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Old 03-12-2012, 12:30 AM   #19
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Fixed, started. Success. Always double check vital work done by others. Nobody is as careful with your car as you are.
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Old 03-12-2012, 01:37 AM   #20
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This thread has literally happened verbatim like 2 or 3 times in the last 6 months. We're getting good at this
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