Ok guys,
It has been awhile since I have been on this forum. I sold my 1980 Vette back in April of 2016 and decided to buy a C4, yesterday.

The guy that I got it from put an LT1 from a 1996 Caprice Police car. Steel heads. The key will not turn the car over. The security light stops blinking and turns off when you turn the key on and I verified that the ignition has the correct ohms down to the connector under the dash on the column.

I have installed a jumper switch on the starter and it turns over when I hit it. I turn on the key and hit the button and it spins but it will not start. It sounds like the timing is off. I can only get to one cylinder (4) and the compression is a little of 100 PSI. Close quarters has prevented me from checking the others up to now. I have only had the car at my house for a few hours now and will probably pull the motor to check everything if I cannot find a quick fix. I hate taking over from someone else, don't really know if they did things correctly.

I have checked to make sure that it has spark, but I'm unsure if the timing was correctly set, he changed the timing chain when he installed the engine. and stated that he did not move anything when he did it. How can I verify timing on the car? The Haynes manual states that it cannot be checked.

So I have two questions really.

1. What else besides the VATS can cause the key not to turn the engine over?
2. How do I check the timing without pulling the entire front of the motor off and verifying crank and cam position?

Thanx for your assistance ahead of time.

Fred

 

First thought is the neutral safety switch on the Auotmatics





Assuming you mean Cam timing as it's pretty much impossible to get the opti out of time.


If you can get the starter turning, You could run compression tests. Can't get compression if cam timing is off. Also you could pull a valve cover and check the valve positions with a piston at TDC.

 

The car is a 1995, the engine is out of a 1996 caprice, the wiring harness is the one from the Vette to include the ECM.

Update: I have checked the wiring under the dash. The schematics state that the yellow wire should be hot during starting and it is. I checked the neutral safety switch and it shows continuity when in the park position and power is present when the key is turned to start. I don't know where the starter interrupt relay is located and the wire that is connected to the starter from the key is brown, not purple like the schematics shows. I need to find the starter interrupt relay and see what color the wires going in/out and the voltages.

 

Have been finding too many issues with the install of the motor. I am going to pull it, check the timing and compression out of the car on a stand. This way, I can clean up everything and ensure that the work is completed correctly.

I am probably going to drop the tranny and have it gone through as well.


Will let you know how it goes. I only have to drop the exhaust and a couple of other things to get the motor out.

Oh, and I need to pick up a cherry picker and engine stand.
Fred

 

Pulling the engine to fix under dash ing seems like and odd way to solve the problem.

 

That is serious cover compensation and will require a lot of dedication. I get cranky if I have to take a tire off.

 

And does not address the wiring problem.

 

The under the dash is just one of the problems with the car. They are several things wrong with the manner in which the motor was put in. The way the engine sounds when it turns over sounds like the timing is 180 out. I am a big guy and also been in the military for a little while. My feelings on things are, if you do not know for sure what someone did, take everything they could have done and start over. This will give me peace of mind and I will know that the motor is installed correctly.

As I said, I was just going to pull the motor and start over. I have found a bolt connecting the flywheel to the torque converter cross threaded and there was a gap between the torque converter and the flywheel. I found connectors not attached to anything and just zip tied to the frame, bolts that he did not tighten, broken bolts and just other shady stuff.

It may be overkill, but if I am going to drive this car and will let my daughter drive it to school every now and then, I will be right.

 

I will get er done. Don't mind the work at all.

 

You are correct. I will read out everything when I can get to it easier and see what is what. Pulling a motor to get to everything is a whole lot easier than being bent over cramming my hand in places too small for anything.

Just my thoughts, plus I will be able to really clean the entire engine bay.

I have a large shop, so having room to get everything done is not an issue.

 

Well, I have the motor out and the number one piston is at TDC. The Harmonic balancer is 45 degrees advanced. The distributer housing is cracked, Not sure if the crack will make a difference yet. I'm sure I will get some good advice on this issue. I don't have the correct pullers for to get to the timing chain tonight. I will try to hit it in the morning.

Still haven't started looking for the wiring issues.

New question. what will make the climate control stay on all of the time, even with the key off? It drains the battery.

Thanx in advance for any assistance.

Freddie B

 

I didn't answer your question earlier about the service engine soon light. It does come on.

Also, After taking the engine out and fixing the timing issue, I am including the pic of compression for each cylinder and one of the engine broken down all the way to send to the machine shop.

It will have aluminum heads again and a hot cam. Not too much, just something to let you know work has been done.

I will start reading wires tomorrow and cleaning up the rest of the car, inside and out.

I still don't know whee the start interrupt relay is located. I want to read to there then to the starter.

Thanx brother for you input.

Freddie B

 

Thanx brother for you input and I forgot to add the pics. I am pretty tired.

Freddie B

[/QUOTE]

 

Your compression pressures are all over the place. The low ones are suspect and the high ones also. I would expect them to be about 100 to 120 PSI.

How did you measure the compression? I have a compression gauge that screws into the spark plug hole. Is that similar to what you used?

 

I don't own an LT1 so I'm just throwing a thought our there based on something I read....

I wonder if the crack in the Opti is due to someone installing it with the timing notch (can't think of a better term) not lined up properly and then tightening the bolts?

 

Motor out, rebuilt with corvette cam and heads, motor is back in car and all of the issue that I wrote about in the first post have cleared up. Car starts and runs perfect.

I figured out the vacuum line issues.

The Change Oil light is on and I just put in new oil with the new motor.


Any assistance with these items would be greatly appreciated.

Have a great day.

Thanx,
Fred

 

That could be. The housing is made of pot metal and like a thermostat housing if you tighten down one and then the others, it will break.

Who knows... I have it running now. Just a couple of issues that I put in the post above.

 

I have the same compression checker. I rebuilt the motor and all is well for now... Well at least with the compression.

 

before

After

 

Hope this helps with the oil light.