ADM

This started about a month ago. First assumed it was the battery, took it in for charging and it failed the load test which meant it was dying anyways. I got me a brand new battery and removed the starter to test it too, and it worked. Put the battery in and car started and used it normally.

Then it has happened randomly. Once 2 weeks ago after I drove it back home, it would engage but not crank. I left it alone for a day, next morning it started normally.

Today after a long drive, I park the car at home. Decide I need to go out again, starter cranks but car doesn't fire up first go. 2nd attempt all I hear is the starter engaging but no crank.

I hit it with a mallet, nothing. Thought it might be heat soaked from the headers. Let the car cool for a few hours, try again and nothing changes.

When I bought the car it always had the security light on constantly during driving, but the car started so I assumed system must have been bypassed.

Could it possibly be a security system problem?

If it were a problem with the VATS system, can it be completely disabled?

96capricemgr

iTrader: (1)

by "starter engages but does not crank", what do you mean?
Is the engine turning over but not firing or does the starter engage but then not turn the engine?

To me what you are saying is the solenoid engages but then the starter isn't rotating the engine. In which case I would look for loose connections or worst case fuel or water is hydrolocking the engine shortly after shutdown and it then leaking out and later allowing you to turn the engine over.

ADM

The solenoid engages the gear forward to mesh with the flywheel, but the starter does not rotate the engine. There is no movement whatsoever, it doesn't even try to rotate the engine.

Water inside would be quite odd, flat deck, flat cylinder heads, brand new head gaskets and brand new ARP bolts with ARP thread sealant paste on the threads and torqued correctly. Nothing coming out of the tail pipes suggesting coolant burn off, and no loss of coolant in the radiator either.

I will remove the fuel injectors for testing and cleaning to confirm I don't have any leaking.

The Outlaw Kid

iTrader: (1)

Sounds like a VATS issue. Yes it can be disabled. You can do it through a tune or by soldering the correct ohm resistor in one of the wires. I've never done it so that's about where my knowledge stops.

Your key can go bad though, so it might just be a key. If the keys good I bet the wires on the ignition lock cylinder are broken. It's a common problem, you'll have to take the column apart to look at it though.

If it were my car I would just replace what's not working.
ONLY USE THE GM PARTS! Parts store ignition lock cylinders are junk.

shbox

If the solenoid is engaging, it's not VATS keeping the starter from spinning. It's either weak voltage, poor connection, battery, starter motor or something physically keeping the engine from rotating ( ex. hydrolock).

The Outlaw Kid

iTrader: (1)

So VATS will keep the starter from engaging the flywheel. Good to know makes me wonder why the light is on though.

Here's an idea for the OP check to see if the teeth are broken off the flywheel/flexplate. If you have an A4 it's a matter of pulling the dust cover and checking the flexplate. Assuming you haven't done this already.

sleeperLT1Z28

iTrader: (1)

I had similar issues in my 93. It turned out to be the ignition switch. After replaceing it, I took the old one apart. The contacts inside were worn and slightly charred. The problem was solved. My guess is full voltage was not being sent to the solenoid, as it would click but not roll the motor over. $17 and 1.5 hour fixed the issue.

ADM

UPDATE:

I checked the new battery, it turned out OK. Checked all the power cables and they were in good shape. None of the cables were loose at any terminals or corroded.

Rotated the engine using a ratchet by the crank hub bolt and it rotates freely.

So I jacked up the car and had a better try at hitting the solenoid this time but with a brass hammer. A few good solid hits, put the battery back in and it started.

Guess I need to replace the starter.

A big thank you to everyone who shared their knowledge and experience