Engine not running on all cyls. - help!

FL911 · 07-13-2009, 04:38 AM

Ok, here is my problem/question:

1981 911SC 3.0 - 14 months in the process and I finally got the engine in last night..........triple checked everything and she fired right up.....but after checking the timing it sounded like it was only running on 4 cylinders or so.
We checked the spark and all of the cylinders are firing so I was wandering what else it could be?

For the record everything is new: plugs, plug wires, cap, rotor, all EXCEPT for the fuel injectors........could this be the problem?
Does the fuel distributor have to be timed with the engine and if so how do I do that?
I am quite sure I have all of the fuel inj. lines in the same order as they were before but just in case does anyone have the correct orientation of these?

I need some help from you all so I can get this thing running right! Other than this I have no leaks and it should run strong when I get this issue taken care of.

Thanks for any input!!!
Frank

Flat6pac · 07-13-2009, 05:12 AM

First you have to figure whick cyls are not firing. go under the car with it running and a spray bottle of glass cleaner or water. Spray the exhaust pipes at the heads and you ll see which are cold.
You can switch injectors easily enough from one line to another to acertain if you have a bad injector. You can also pull out the injector with the key on and lift the air flow sensor and see how the injector is spraying.
14 months is too long a time to do an engine as you forgot where you left off and where to start again. Building is a 40 hour job and there is too much to remember over a year.
Bruce

Sigurd · 07-13-2009, 05:21 AM

Has the engine been apart? If so, is one cam 180 deg wrong?

When checking if all the injectors spray, make sure you don't fill the engine with raw fuel.

FL911 · 07-13-2009, 05:34 AM

Yes, the entire engine has been totally rebuit. I know 14 months is too long but one week was not even close to being a reality for me....thank god for digital cameras!
The cams were triple checked at the machine shop so they should be ok.
I will start with the spray bottle technique and then go from there.
I may just go ahead and buy all new injectors, after all of the time and money spent on this project I am mad at myself for not doing this in the first place!!

Thank you both for your input!!

Flat6pac · 07-13-2009, 05:59 AM

Dont buy injectors until you know thats the problem
Bruce

Britwrench · 07-13-2009, 05:13 PM

" The cams were triple checked at the machine shop so they should be ok"

That doesn't mean the cam timing is correct, as previously posted, it's probably 180 degrees out.

FL911 · 07-14-2009, 03:47 AM

Update:
Last night I pulled all of the plugs and found that the #2 and 4 cylinders were the ones not firing..........I should say they were not getting fuel. All of the other plugs were noticeably getting fuel as well as firing, but these 2 were bone dry.

So I pulled those 2 injectors and they were indeed clogged, I put them in my ultrasonic parts cleaner and then cleaned them out with some injector cleaner spray and they are ok now.

It was to late to fire it up but all should be good to go!
I will keep you all up to date tomorrow.

Thanks again for all of your input.

FL911 · 07-15-2009, 05:04 AM

July 14, the night of, I got everything back in order and MY ENGINE RUNS OUTSTANDING!!!!!!
Took it out for about a 5 mile cruise and I could not be happier! Now, time for the first oil change!

Thanks again to you all.