91 325ix No Start After Timing Belt Change

[Steiner]

Car ran fine before timing belt replacement. I recently purchased the car and noticed the belt had exceeded the 4 mark, so figured I'd replace it. At the same time, I replaced the water pump and ignition rotor (due to a stuck bolt).

After re-assembling everything, the car will crank and fire up for a second and then quickly die. If I hit the gas right after ignition, it will speed up and and still die. It won't stay started for longer than 1 or 2 seconds and sounds muted - not the normal exhaust note.

I disassembled everything down to the timing belt and double checked the camshaft and crankshaft were both lined up correctly with the timing marks. I rotated the engine a couple of times by hand and the marks lined up every 720 degrees.

Frankly, I'm at a loss for the cause of this problem. Any suggestions would be helpful. I'm sure it's something really stupid...

Below, please find a link to a video of the starting problem (with sound):
https://youtu.be/0pSAE8eatKQ

[Steiner]

91 325ix No Start After Timing Belt Change

Car ran fine before timing belt replacement. I recently purchased the car and noticed the belt had exceeded the 4 mark, so figured I'd replace it. At the same time, I replaced the water pump and ignition rotor (due to a stuck bolt).

After re-assembling everything, the car will crank and fire up for a second and then quickly die. If I hit the gas right after ignition, it will speed up and and still die. It won't stay started for longer than 1 or 2 seconds and sounds muted - not the normal exhaust note.

I disassembled everything down to the timing belt and double checked the camshaft and crankshaft were both lined up correctly with the timing marks. I rotated the engine a couple of times by hand and the marks lined up every 720 degrees.

Frankly, I'm at a loss for the cause of this problem. Any suggestions would be helpful. I'm sure it's something really stupid...

Below, please find a link to a video of the starting problem (with sound):
https://youtu.be/0pSAE8eatKQ

[e30austin]

Crank position sensor? Did you possibly reverse the pulse sensor and the crank sensor connectors? Is the front balancer properly orientated?

[Steiner]

Crank position sensor? Did you possibly reverse the pulse sensor and the crank sensor connectors? Is the front balancer properly orientated?

I did not disconnect the crank position sensor other than removing the bracket and replacing it:



The balancer is also properly oriented:

[Steiner]

I did not disconnect the battery when I did all of this work. I went outside, disconnected the negative terminal to the battery and let the car sit for 30 minutes. I came back out, started the car and initially had the same problem. I turned the car off, then attempted to restart it and it actually caught and stayed started - though it was running rough. I didn't have the radiator in, so I turned it off pretty quickly.

My plan is going to be to re-assemble the cooling system and see where that gets me.

[Steiner]

Fixed the rough idling issue - it sounded as though there was backfire in the manifold along with the smell of gas - i.e. running rich. Apparently in the process of working on the car, I disconnected a vacuum line at the time of the manifold. Once I realized this (after staring at the engine for an hour), I fired it back up and it purrs like a kitten.

[101]

Glad you found your issue. These M20 engines are stupid sensitive to vacuum leaks.

I don't believe we've seen pictures of your rig yet, have we? ;)

[RWD BLOWS]

I'm having the same exact issue after doing the exact same job on my car and I cannot get my car to start.

[Steiner]

I'm having the same exact issue after doing the exact same job on my car and I cannot get my car to start.

It's frustrating. I tried documenting my steps and checks as close as I could above.

The first thing I would do is go unplug the battery from the back of the car. I don't know if it makes a difference or not, but my thought is that it might reset the computer.

While the battery is unplugged, I would re-check my timing marks. It's annoying to have to take everything apart again, but worth the piece of mind. Make sure you spin the crank 720 to ensure the marks line up. Also check to make sure your crank sprocket is re-installed the correct direction (timing marks toward engine).

Third, when putting things back together after checking the timing marks, make sure your crank sensor is in place and secured.

Fourth, check to make sure your ignition rotor is secured and if you disconnected your spark plug wires are reconnected to the right locations on your cap.

Finally, check the top of the engine to make sure all of your vacuum connections are secure. This was my problem - I inadvertently bumped one and it came loose. Once I found that, the car started right up.

Hope that helps!

[Steiner]

Glad you found your issue. These M20 engines are stupid sensitive to vacuum leaks.

I don't believe we've seen pictures of your rig yet, have we? ;)

Here it is:



...and no, not all of those white cars are mine - just the important one.

[RWD BLOWS]

I took everything apart 4 times to check the timing Mark's. I rotated the crank 2 revolutions for every 1 revolution on the cam shaft sprocket and the marks lined up. I replaced the intake manifold and the bitch tube prints and used brand new intake manifold gaskets....

[Mpolito3355]

I took everything apart 4 times to check the timing Mark's. I rotated the crank 2 revolutions for every 1 revolution on the cam shaft sprocket and the marks lined up. I replaced the intake manifold and the bitch tube prints and used brand new intake manifold gaskets....

i know it might sound dumb but have you tried to see about the ignition rotor being put on backwards .... a member here did that a few months ago and thats what it turned out to be ......kinda hard to do but its been done

[Alpinerunner]

Doing some diagnostic work might help narrow it down. Pull the plugs first. If they are wet with fuel, you have a spark problem. Check the crank reference sensor and make sure the ignition wires are routed properly from cap to cylinders.

If you have no fuel-soaked plugs, it's possible you created a vacuum leak somewhere in the intake tract and it's too lean to run.