Allright guys....

I bought a built, 8.5:1 383 LT1 from a board member. This is a known good engine.... The motor was installed this weekend.

we tried to fire her up and no dice. Here are the symptoms:

1. Car cranks very laboriously.
2. some backfiring into the intake.
3. when we unplug the coil wire at the coil, the car cranks much smoother - does this suggest opti not installed properly?
4. the ground wire from the coil to the driver side fender gets very hot

Here are some other facts:

1. we are getting spark - we pulled a plug and checked
2. we are getting fuel, since the injectors are ticking - is the ticking enough to verify that we are getting fuel? any other ways to check this?
3. the roller rockers seem to be ok.... so i doubt it's a compression problem. the motor is VERY hard to turn over by hand, even harder then my stock 350 with 10.5:1 compression (this motor is 8.5:1).

There is one known problem right now - the ground wire that attaches to the block right near the starter motor is not connected.... coud this cause the problem? I doubt it since if the engine is cranking, the starter is obviously working. unless this wire is interfering with the spark......

 

First of all, you need to hook up that main ground near the starter or you will cook the other grounds.

If you are sure that you have spark and fuel, I would make sure the valves were adjusted correctly. The backfiring through the intake leads me to believe this may be your problem.

 

Jeez, that tiny little wire is the main ground? the one I am talking about is the one that mounts on a stud right under the #5 plug....

The big ground wire that bolts onto the engine cradle is connected.... is that the main ground?

I checked the valves, they look to be adjusted OK. I am thinking plug wires on the passenger side might be the culprit - can 2 crossed wires cause a non-start? the key fact here is that when the coil wire is unplugged, the cranking is smooth. When it is plugged in, the cranking is very laborious and erratic.

 

OK, I think I will focus on this wire. Apparently this wire grounds the MAF, PCM, fuel pump relay, and other things, and it is NOT connected because the wire broke.

Would this wire stop my car from firing if it were disconnected? Shoebox?

 

Sounds like a MAF problem or ECM. the car will run with the little black wire off, but im unsure what it grounds maybe ecm. When i installed the new motor i forgot it was off, but I also think it helped in burning my ECM.

 

It may or may not keep your car from running. I think there have been others that have not had that ground connected and their car ran. It really should be grounded, though. Rig something if only to ground it temporarily to see if there is any difference.

Your change in cranking labor sounds like not firing at the correct time. Maybe an opti install problem.

 

I was gonna say your opti isn't on right.

Make sure the notch on the opti matches the notch on the shaft. If you have to force even a little, its not on right.

 

Thanks guys


Will the opti throw a code if it's not on right? I am guessing it won't... but I have a laptop and can read the codes this afternoon. I will check the following things in order - feel free to add to the list:

1a. Scan for trouble codes

1b. Fix the ground wire by the starter, and check the battery ground and the braided ground strap on the coil. We put the coil on upside down... this isn't a problem is it? Also we got the braided ground strap wet when filling the coolant - this isn't a problem is it? There was smoke coming off it when we cranked the car

2. Check plug wires one more time

3. Check fuel pressure at the schraeder valve

4. Check opti install

 

There will be no code if the opti is not installed right.

Moisture won't hurt the strap. Coil upside down won't hurt.

Smoke from the braided ground strap? Either you were holding the starter too long at a time or the main ground from the battery is not making good contact to the block (it is just in front of the RH motor mount). You're gonna fry stuff if you don't get all the electrical stuff hooked up right.

 

the braided strap was wet from spilled coolant (don't ask lol).... I think the smoke was moisture (it was white, and not very smelly). However, that still tells me the strap is getting hot so I will check the battery ground.

Speaking of which, is the battery ground wire supposed to bolt onto the engine mount? There are three bolts holding the motor to the passenger motor mount thingy... currently I have that ground on the forwardmost bolt. Is this ok, or does it need to bolt directly to the block?

 

your ground is correct, it should be on a stud(2 bolts and a stud).

However, seeing that the ground strap is getting hot... sounds like the main ground is NOT hooke dup?

 

It should be right here. You might want to clean the connection up with a wire brush.

 

When you say "Main Ground"... is that the battery ground we have been talking about, or some other ground? (like the one that right now is NOT connected just above the starter motor). Just trying to make sure I'm not missing something silly here hehe.

I am going to be working on the car shortly.... hopefully this will work out . Thanks alot for all the help guys.

 

This is Draco at a friend's house....

Here is an update guys.... still need help here

we fixed all the ground wires, still won't start. still has very labored cranking, even with a fully charged battery and a jump start. fuel and spark are not a problem. the plugs are nicely coated in fuel. we tried holding the accelerator down while cranking, no dice

We also tried feeling the plug hole and looking at the spark. we got a spark right at the end of the compression (while cranking) which seems to tell me that the opti is on OK.

it is EXTREMELY difficult to turn the motor over by hand. we took all the plugs out, and it is still quite difficult to turn. with the plugs out and the belt off, it is about as hard to turn as my old motor with all plugs still installed. Could the big fat valve springs I have one be adding resistance making the motor really difficult to turn over?

the motor was sitting out of a car and hasn't been run for over a year - could this cause problems?