Won't start after rebuild - help!

[75-911S]

Edited 1/16/06 - Engine is running but this is still a good read.

My 2.7 CIS won't start after my rebuild. It turns over freely and seems to "catch" like it wants to start but doesn't.

After going through three dozen or more pages of others people's problems on both the engine rebuild and this forum here's what I've done/tried.

1. Checked for spark at the plugs - lots of it.
2. Checked for fuel flow by pulling a couple injectors to see if gas came out when the fuel pump was running - lots of it.
3. Doubled checked to insure TDC was at the right mark on the front pulley - yep.
4. Double checked that the rotor lines up with the mark on the distributor when the engine is at TDC (and 5 degrees each way) - yep.
4a. Pulled the distributor and moved it forward and backward one tooth at a time - no change.
5. Changed distributors for another - no difference.
5a Changed distributors caps and rotors - no change.
6. Checked that the right wires (new) were on the right plugs and at the right place in the distributor cap - yep.
7. Doubled checked plug and points gaps - okay.
8. Changed the new WUR that I had installed for the one that came off the engine (which was running before the rebuild) - no change.
9. Changed the new fuel distributor that I had installed for the one that came off the engine (which was running before the rebuild) - no change.
10. Installed a new fuel pump - no change.

(By the way I "charged" the fuel suystem back up after all fuel related changes by lifting the plate in the mass air sensor for a few second with the fuel pump running.)

11. Put in a new cold start valve - no change.
12. Jumped the battery with the one from my running truck - no help.
13. Put a 10 amp charger on the battery while trying to start the motor - no help.

I can smell gas which makes me think I'm flooding the engine, but I don't know what else I can do to change that, if its the problem.

I feel like I'm sooo close to having it run but I just can't make it do it.

I even put my new specialty license plate on (75 911S) to make the car feel special. But nothing.....

Anyone have a suggestion?

Jack

[1974carrera]

Jack, On your item #4 you mention that you you lined the rotor up with the mark on the distributor while the engine was at TDC. Are you sure that you did that with #1 cylinder at TDC? Also be sure to use a test light or meter and set the static timing before you try to start it.
Good luck!

[Ron.G]

Also check the firing order. I had the same problem. then I realized the rotation is supposed to be counter clockwise on the distributor for my SC.

[schamp]

Some good ideas. Are the plugs new? I would imagine they are. After you are cranking the engine have you pulled a plug to see if its wet. The counter clockwise, clockwise is a really good thing to check. I spent a week once working on an engine once I put the wires right it started right up. Good luck.

[75-911S]

Thanks for the first round of suggestions.

I had bumped the distributor rotor with the starter to make of the rotation direction.

I had doubled checked the firing order when I traced the plug wires to make sure they were on right.

I had smelled gas on the new plugs that I pulled to make sure fuel was getting to the cylinders.

Top dead center on number one was checked when I pulled that plug.

Keep the ideas coming - I'm out of them.

Jack

[David Goodman]

Is it possible that the cam timing is off ?

[HFR_Racer]

I would guess that if the plug wires were mis-routed that you would hear backfiring. Correct? Sounds like you have plenty of fuel getting to the cylinders. You say that the engine is catching? Maybe if you describe exactly what you mean by catching this could help.

[Rick V]

Compression good?
If you have spark and you have fuel all you need is compression. Also is there any chance that youe exhaust has become stopped up? Mouse nest built in muffler during re build. You know the potato in the tail pipe senereo

[Early_S_Man]

Jack,

You need to pull the left side valve covers and check to see if both valves have the normal clearance at TDC on the firing stroke for cylinder #1 ... when the distributor rotor is pointed to the mark/notch on the distributor body. Then check your wires for correct firing order!

[schamp]

All good ideas. You might want to get someone to ground a plug and turn the key. Trying to check and see if getting consistant spark.

[aigel]

Originally posted by 75-911S
Thanks for the first round of suggestions.

Top dead center on number one was checked when I pulled that plug.

Jack

Jack:

Are you sure that is TDC COMPRESSION? That means, are both valves closed? You can find out by putting your thumb over the spark plug hole. Well, you could on a pushrod engine. On the flat six, you can screw a hose from a compression checker into the spark plug hole and keep the other end open. Then turn over the engine and if the chanber builds pressure when you come up to TDC, you are on the compression stroke. Alternatively, as mentioned above, you could pull the valve covers and check if both valves for #1 are closed.

If you are off, you need to move your distributor. This means, pull it out, move the crank one rotation and put it back.

I have built a lot of engines in my time as a wrencher I can not tell you how often I had the distributor out 180. I know about it and still have messed it up.

George

[75-911S]

George, Early_S_Man - Good ideas. I'll recheck is valves.
Also, I forgot to mention that I did turn the distributor 180 degrees and the engine backfired as expected.

Schamp - a did the plug grounding/firing test and had lots of spark.

HFR_Racer - What I meant by almost "catching" is that the engine seems to sound like its occasionaly firing - like when you try to start a car on a really cold day and it "puffs" a few times before it actually begins to run.

David - The cam timing was checked multiple times when that phase of the rebuild was accomplished.

Isn't this a great puzzle guys? I'm glad I have some time to try to figure it out right now. But I have to say I'm super frustrated at this point and living in a very small town in South Carolina have no one else but you guys to help me out.

Jack

[aigel]

Are your cams in the correct location? Left and right?

From what you are telling us there is spark and fuel. What is possibly missing is compression and we are not too sure about the timing of all the events.

At this point in time I would take the valve covers off and check for TDC compresssion. I would also check cam location and cam timing together with an experienced 911 person for sanity check.

George

George

[75-911S]

I read all the pages of Kelly Bell's thread titled "Still won't run well," and tried several of the fuel system suggestions included in it.

Today's tests included:

A check to see that the manual throttle in the cabin was opening the engine throttle enough to let the micro switch to open. okay

A check to see if the mass air sensor arm was moving when the key is turned. okay

A fuel system and WUR pressure check - both within tolerances

A compression check on #1 cyclinder to insure that I had some and that the distributor was set at TDC on the compression stroke. - all okay

A double check for spark on different cylinders and to insure that all plug wires were firmly attached - okay.

Turned the engine over for three entended period without fuel pump running to try to "blow" some of the accumulated fuel out of the cylinders and to let the plugs dry a bit, in case I had flooded everything.

Tried to start it again after this and it seemed to fire several times but not enough to keep it running.

It sounds so much likes it's flooded that I guess I'll pull all the plugs and let things dry out some - then try it again.

I probably also need to check the valve settings to make sure I have them at the right clearance and on the right stroke.

Thanks for all the suggestions so far. I'm not giving up yet.

Jack

[75-911S]

IT'S RUNNING.

Apparently it was flooded after all the fuel system and other tests. I aired all the cylinders out a bit and after a long turn of the starter it fired up and I was able to do the first 20 minute break in run at 2000 rpm.

Needless to say, I'm tickled to death despite finding a couple of sizeable oil leaks.

But that's tomorrow's problem.

Again, thanks to the forum members who have helped me get it running.

Jack

[Rick V]

Glad to hear good luck