What is my next move?
 

Vehicle: 1999 Boxster; 28K miles; original engine; no IMS replacement

Symptoms: No start; Turn key and hear clicking noise at starter. Starter motor does not turn. Dashboard lights dim with key at start position. Car running fine previously.

Diagnosis (so far):

• Confirmed battery good charge
• DME no fault codes per Durametric
• Starting system OK (ignition switch; starter relay; starter)
• Removed serpentine belt to see if anything else is locked -> nothing else is locked
• Removed all 6 spark plugs -> all spark plugs dry; crankshaft rotates only +/- 5 degrees with all plugs out

What is the next step for diagnosis?

• drain oil: inspect oil filter for metal; remove oil pan and inspect for metal?
• inspect inside of cylinders using endoscope / borescope through spark plug holes?

Engine locked by itself. Removed starter for inspection.

Sounds good for the next steps. How are you trying to rotate the engine, only with the starter or with a socket on the crankshaft... or rolling the car while in gear?

Crank Position Sensor failure?

Are you sure you can't rotate the engine any more than just plus/minus 5 degrees? For an engine to lock up like that with no signs of any engine distress before it was shut off and the cylinders free of any oil or water is not a behavior I have ever come across.

If the engine is truly locked then you need to verify the starter is not stuck engaged.

If it is not then don't bother draining the oil or removing the pan or inspecting the bores. If engine is locked up and there is not an external explanation for this: Stuck starter, a transmission not in neutral, the engine has to come out of the car and the engine torn down to determine what caused the engine to lock up.

A broken cam chain, a snapped cam, something internal and something major and something expensive to address has gone wrong.

If the engine is not locked, that reads like power to the starter solenoid is not good and the clicking is the starter solenoid moving back and forth but not making it far enough to activate the starter.

If you are sure about the battery being good -- and they can "look" good but when called upon to produce the electrical power necessary to start an engine show their true condition -- then I would suspect the power/ground connections between the battery and the starter and the chassis are suspect.

Clicking, not clunking? maybe the starter has given up

Did you have the warm start issue before? By this I mean the car would have difficulty cranking after the engine was warm? The starter/generator wiring harness on early 986s were too small and a thicker upgraded harness is now available.

https://rennlist.com/forums/997-foru...when-warm.html

From the 997 forum but applicable to 986

lights dim and starter clicking sounds like a bad battery to me. how many volts is the battery producing?

it wouldn't explain why you can't rotate the engine. I'll defer to more knowledgeable minds on that one

My opinion is you have something broken inside the engine--a rod or rod bearing? Or a timing chain? Or a IMS bearing failure.

Time to pull the engine and investigate ant then decide whether to fix/replace the engine. One of those situations where it really helps to be an adventurous DYI'er.

Sorry, sorta been there, done that. The pain in the wallet still is giving me trouble--or is that a back ache?

Thanks everyone for your feedback and comments.
UPDATE TODAY:

• removed starter/solenoid from car to confirm that is not causing issue -> CONFIRMED
• inspected all 6 cylinders using endoscope/borescope video camera through spark plug holes -> NOTHING UNUSUAL
• removed oil filter cartridge & inspected along with oil in filter housing -> NOTHING UNUSUAL
• confirmed no oil leaks under car at bellhousing/block flange
• crankshaft only rotates +/- 5-10 degrees using wrench on crank bolt and ~75 ft*lb torque (estimated) -> SAME AS YESTERDAY
  • transmission in neutral
  • same with clutch pedal up or down

Are there any more diagnostics I can do while engine is still in the car?
I assume first step is transmission removal to inspect clutch and IMS area?

I would drop the pan and see what treasures await you! And please include pics.

If you are 110% confident you are unable to rotate the engine at least 2 full revolutions with the plugs out, and you are sure there is nothing locking up at the accessory drive to prevent the engine from turning (you should remove the serpentine belt) and you are sure there is nothing inside the back hollow of the crank pulley which can possibly jam and "lock" the engine you will need to remove the transmission to ensure there is nothing with the clutch or with transmission that is preventing the engine from turning.

If the engine can't be rotated there is something horribly amiss inside the engine. You are not going to find and fix this with the engine is the car.

How the hell could a car go from 'running great, parked it' to 'seized motor'? That's insane.

28k miles on a 20 year old car? That's also insane. Nowhere near enough exercise...