99 head swap backfires won't start
I swapped out my warped 96 head for a 99 head. I had the 99 head taken to a machine shop and had them shave.008 off to make sure it was straight. Then put it on the car. everything went smoothly with the installation except that we had to take about a 1/4 inch off the bottom of the passenger side chain cover mounting bracket(the stamped steel one that sits behind the cam gears).
Now the car will not start. And is back firing through the intake when cranking. I really think that it is the ignition timing but i'm not sure of a great way to verify that it is sparking at TDC of compression stroke. Ive tried moving the cam sensor to see if it would help. and it can stop the backfire, or it can cause a flame to shoot out of the throttle body depending on where it's positioned. The car is a 92 with 96 block, 99 head, 90-93 MSPNP. any advice would be appreciated. |
Flip the ignition wires. Sounds like you've got the 1/4 plugs connected to the 2/3 coils and vise-versa.
The relative positions of the two coils are reversed on the 1.6 engine as compared to all of 94-00 1.8s. It actually doesn't matter which coil is which, so long as the correct path of ECU wire -> coil -> plugs is maintained. EDIT: just noticed that this was only a head swap, not an engine swap. Are the ignition wires hooked up the same as when this was working with the '96 head? |
Did you install the timing belt correctly.?
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I bet the cam gear on one of the cams is off. When crank is at tdc the front cam lobes on both cams should be pointed outwards.
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(zack morris's phone)
Sounds familiar doesn't it lars.... |
I would check the cam timing.
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Another vote for cam timing.
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Cam timing.
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We checked it a few times. The cam timing seems spot on.
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Originally Posted by AredMiata
(Post 764029)
We checked it a few times. The cam timing seems spot on.
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If you want to check ignition timing:
Disconnect the injector connectors. Pull out the spark-plugs Put the spark-plugs in the Spark-plug-connector and ground them to the engine block. Now check timing with the timinglamp. As for the cams: you can mount the cam-sprocket wrong. The wheel for the exhaust and intake are the same but they are mounted specificly for their function. Check the manual. |
Originally Posted by AredMiata
(Post 764029)
We checked it a few times. The cam timing seems spot on.
The only other thing it could be is if you crossed the spark plug leads or the coil plugs (plugging the 1/4 coil harness into the 2/3 coil) |
In for failed timing pics. Some one should figure out what it takes to time it to run the intake as exhaust and vise versa. I'm surprised some timing belt first timers havent stumbled upon it yet.
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Thanks for the lack of confidence fellas, lol. Seriously hope you guys are right! I will go check and take pics.
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we doubt because we care.
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Originally Posted by AredMiata
(Post 764029)
The cam timing seems spot on.
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2 Attachment(s)
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Thanks fellas, guess I decided that it would be good to line them up without reading the letter on the stamped steel plate. Yay For Miata Turbo And All Those Who Doubted! Thanks Everyone!
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Originally Posted by guestlive85
(Post 764146)
Well, you did it wrong as we thought. you have E lined up with I on the intake side, and I lined up with E on the exhaust side... when you do it correctly, I and E will point veritcally and you should have 19 belt teeth between those two marks. the Cam lobes will also point away from each other. |
Originally Posted by guestlive85
(Post 764146)
Crank
Cams Cylinder # 1 Lobes E = Exhaust, I = Intake, both point to 12 O'Clock whan the crank points to 12. |
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