After 5 pages of threads I guess I missed where you replaced it. Thanks for the update.

 

what different modules communicate with the ECM through the BUSS?? And where are they?? Like is there a body module? And the ABS module? ATD module, anything that would use that BUSS wire. I`ll disconnect one at a time to see if it may take off.

 

Hello! My first post.
My car was doing the same thing.
I changed my coil and fixed my problem.
I know you tried that, but it won't hurt to try a brand new one again.

 

Hi, Welcome to the forums. Thanks for your imput. Your car would not start with the key but would bump start?
The coil works just fine, the car runs good when push started.
It`s no sort of voltage drop that`s causing it. I proved that with a second battery to the starter. So it must be something with the car rolling. The only things I can think of are the speed sensor in the tranny and the 4 wheel speed sensors for the ABS. I keep thinking security system is dissabling run durring crank.

 

What would change so the computer now needs to see inputs (wheel or VSS) in order to start?????? Think about your suggestion. If it needs to see VSS or the wheel sensors, why would any LT1 start with the key???? Or am I missing something you said?

I think your problem is 1 or more injectors dripping fuel and flooding the engine. But let's think about that for a second. IF that were the case, you should be able to immediately restart the engine after having been started by "push starting" it originally. So first question.

After having started it by push starting and run it for a while, have you ever tried to shut it off and immediately restart it with the key ????????

The reason I think there are injectors leaking is:
You stated before you added fuel at the intake and it still didn't start.
The starter can't crank it over fast enough to eject the fuel.
The nose cone broke off one of the replacement starters. I personally have done that as well on my P-up when I had 3 cylinders out and it loaded up with fuel.

Incidentally, if there are injectors leaking enough fuel you can see it a couple of ways.
One is a drop in fuel pressure after the fuel pump is shut off.
The other is fuel contamination in the oil. But not always.

Hope it helps.

 

I was thinking the security system thinks the car is being stolden so it`s keeping it from running durring crank.

yes I`ve tryed to restart right after push starting and it does not start with the key, even right after running from push starting.

Adding fuel to the intake does not effect it at all, no pops, no farts, no nothin.

The nose cone broke I`m sure cause the other guy hit the key when the motor was doing that backwards running thing and that exploded the nose cone. When it cranks, it cranks just fine and at a normal speed.

If the injectors were leaking bad enough to not allow it to start on it`s own, wouldn`t it run like dog meat after you pushed it??

 

bump, sure would love to fix this thing.

 

pursuing the weak to no injector pulse while cranking, I have a good + signal, the ground is what is weak. That comes from the ECM, where exactly does the ECM get it`s ground??

 

I am having almost the same problem. I havent tried push starting the car yet though. The oddity on mine is that it will start randomly after I mess with the wires going to the ICM.
Have you changed your ICM yet?? I have not seen it mentioned in this thread... http://shbox.com/1/coil_loc.jpg
I'm going to try swapping mine w/one of my running LT1s...I'll let you know how it worked.

-Neil

 

So I discovered last nite that the wire that goes from the ICM to the head was completely fried by the exhaust manifold... I changed it out, but still no engine start.. I really think my ICM is fried but didnt get a chance to swap it out b/c it took forever to go through all the wiring, find the bad wire, change it out, put everything back, and try to start the car..
I will try to swap ICMs over the weekend...

any luck on yours?

-Neil

 

Check the timing properly. Take the cover off. There are only a few things that will cause the engine to run backwards after you stop cranking, and a weak injector pulse is not one of em.

If the timing chain was off by one tooth it would be hard to tell just by looking at the valves and using a pencil to find TDC. It also explains why the engine would run when push started, since the RPMs would be higher than the starter manages, which would bump the spark advance far enough to compensate for the timing error.

 

To answer your question about the PCM grounds: There are 4 gounded pins on the PCM. Connector A (Red) pin# 2(blk/white wire) and pin# 18(tan/white wire) and connector D (Blue) pin # 1 (tan/white wire) and last connector C (clear color) pin # 32(black/white wire). Pin A-18 and D-1 are grounded to the engine near the ICM. Pins A-2 and C-32 are grounded near the knock sensor. by the starter.

However didn't you try squirting fuel directly in the intake back in May with no results? And while you may have a fuel delivery problem, that would indicate either you have no spark or it's occuring at the wrong time.

I believe your ignition timing is changeing.

How about doing something to curb All of our curiosity. Put number 1 at TDC (while looking at the valve movement would also be a good idea). Then pull the distributor cap off and see if the rotor is pointing very close to the 6 O'clock position.

Once you have that out of our mind as far as a cause. Let me run something else by you.

Didn't you say earlier that you measured some extremely low voltage while cranking the engine over????? Yeah post number 60 back in June. Stick with me on this. Once your voltage gets below 11 volts, weird things can happen with the PCM. When you crank it over, the voltage is dropping too low to everything connected to the 12 volt system. BUT when you push start it, it stays near the correct 12 volts because the starter is not engaged. YES or no.

So if you agree with that, let's find the drop and see if we can eliminate it. AFTER you confirm the rotor position.

BTW, in that same post you said it had 12 volts at idle and 10.4 cranking. As I stated earlier, it should never drop below 11 volts cranking and at idle, it should be around 14 volts. You got a problem there for sure.

But then you find post number 70 and it throws the whole voltage dropping thing out the window. So I'm sticking with ignition timing thing for now.

Last question, when you isolated the starter(post #70) from the battery in the car, did you disconnect the starter from the battery in the car when you jumped it from the "other" battery and did you have the key in the "on" position?

 

1 yes, adding fuel directly into the intake, no results.
2 me too, I believe the ECM is changing it.
3 yes, the cars voltage stays nears 12v when pushed
4 the original battery was completely disconnected from the starter so by rights the cars electrics should be identical to push starting, there should be no voltage drop to the cars harness while cranking with the second battery.

I`ll check the rotor here in the next day or two. I have a tranny out of a 2000 blazer right now I need to get together first.

 

The motor runs perfectly when push started. There is no mechanical advance in the distributer that would advance the timing due to increased RPMs.

 

12 volts at idle is a problem. Less than 12.6 volts means your alternator is DOA. It should be around 14 volts at idle.