V8 won´t start: Help needed: Engine cranks, pump noise good and battery is OK. What should I look for?

[2000V8Esprit]

Hello! I took the car yesterday for a drive and all was good and parked it in my garage as usual. Today the car won´t start. The battery is in good condition (always in tender when car not in use), I can hear the pump activate, but it wont start. It also cranks well. At first, I thought it could be something related with the Cobra alarm and engine immobilizer. But since it cranks, I´ve been told that it is not the immobilizer. (Is that true?)
I have checked fuses and relays and also the inertia switch. All seem good.

I need your help to get this thing started again.
What else should I be checking? I appreciate any leads. Thanks!

[Barrykearley]

Immob is a twin cut.

one cut does stuff like fuel pumps and spark

other cut does electrics and ignition 

doesnt sound like an immobiliser issue.

[2000V8Esprit]

Thanks Barry.  Yes, it seems like if its an electrical issue, not the immobilizer.  Any help is appreciated!  Regards

[sailorbob]

It could be the immobiliser as that cuts two circuits; the starter and the ignition coils. Assuming there's no 'check engine light' indication of an ECU fault code I would check for spark first.

[Espritv8black]

I had the same issue years ago on my 98 V8.  If I remember correctly mine just stalled in the driveway and would crank but not start.  My immobilizer had been bypassed by a previous owner.  After checking everything it ended up being where the immobilizer was bypassed by the ECU.   A paperclip was used and it was loose.  So you checked everything I checked, but now that I think I know a bit more I would do the following;  We know it is air, spark and fuel.  I think we can probably rule out air, so that leaves spark and fuel.  If you take the engine cover off you can test the fuel pressure with a fuel pressure gauge.  It is a Schrader valve located at the front of the engine on the right side looking from back of car.  Pressure should be about 53lbs once you turn the key and the system pressures up.  If that is OK I would check the spark by attaching an inductive timing light that clamps to the spark plug wires.  This is harder to do as you would need to take off the top cover on the valve cover.  Not hard just more work.  If there is spark the light should be flashing and the flashing should be the same basically on all cylinders.  There are others that are definitely sharper that me on here who hopefully can help.  Mark

[v8GTmac1]

Everybody needs an obd2 code reader. It will give you trouble codes if the computer can see something wrong.

In some model readers  you will even get RPm signal reading which rules out the ckp and cam sensors. 

But you can skip this by checking for spark. Spark will tell you the ecu is reading RPM correctly. 

You can actually pull out a coil wire off the spark plug and listen to the sparks jump during cranking provides there is not much ambient noise. Not too far off the plug that the spark won’t jump and instead hit a different ground point. This method could be aided by using a stethoscope to listen closely. 

 

Timing light method is safer overall. 

Edited May 23, 2021 by v8GTmac1

[2000V8Esprit]

Hello, so here is an update:

After checking all the basic and easy stuff, the car will still not start. Our conclusion is not a good one, it is probably a worst case scenario.  When cranking, the passangers side camshaft will not turn.  I believe that the belf must have broke at one time.  The cranking noisy seems like the car has no compression... and there is no fuel injecting in.   I do not know what to think on this one, but I am worried..

[mike_sekinger]

You have cause for concern. 

The 918 is an interference engine meaning that if your crank is turning and your RH bank camshafts are not, then the piston crowns will have made impact with some of the valves of that bank.  Regardless of the actual reason behind the original failure, there will be damage to that bank caused by continuing to turn the engine.   The RH bank also houses the cam sensor, hence the reason why the engine is not firing at all (thank heavens for that).

If the LH bank continues to turn over, then you must have virtually no tension on the shared primary drive/IMS for the RH belt and it is just skipping.

Stop cranking the engine and prepare to extract for a top-end rebuild of the right bank.

[Barrykearley]

My thoughts are with you and your wallet at this troubling time 😢

[mike_sekinger]

@2000V8Esprit

Did you get a chance to understand the cause and extent of the damage?

[2000V8Esprit]

Hello!  So here´s an update.  I will need to pull the engine out, as my mechanic says that we need to check the valves and see other possible extent of the damage.  I will upload pictures of all this process...   hopefully we will get it done and fixed

[2000V8Esprit]

So here are a few first pictures.  The big screw was completely loose and snapped the plastic cover

[mike_sekinger]

That external damage is the least of your worries.   Sadly, you are going to discover damage most likely to valves in both cylinder heads.

On the bright side, everything can be fixed and hopefully before too long you will be enjoying the thrill of driving again.

[Espritv8black]

Hopefully, you caught the issue quickly and you can start driving again soon.  It sucks that this happened so quickly.

[alanlambert]

I am rebuilding my engine at present and i am having a keyway cut into the intermediate shaft and both pulleys as the original design relies on the bolt being FT to transmit the drive from shaft to both cam belts.( Far from ideal)

Wonder why that bolt came loose ??

[ramjet]

On 17/05/2021 at 00:30, 2000V8Esprit said:

Hello! I took the car yesterday for a drive and all was good and parked it in my garage as usual. Today the car won´t start. The battery is in good condition (always in tender when car not in use), I can hear the pump activate, but it wont start. It also cranks well. At first, I thought it could be something related with the Cobra alarm and engine immobilizer. But since it cranks, I´ve been told that it is not the immobilizer. (Is that true?)
I have checked fuses and relays and also the inertia switch. All seem good.

I need your help to get this thing started again.
What else should I be checking? I appreciate any leads. Thanks!

Welcome to TLF.

Hope you get it all fixed up. MikeS knows a heck of a lot about these engines. So does BarryK, come to think of it.

You should duck over to the Introductions area and say hi in there as well. Also look forward to seeing some more photos of your car.  

[mike_sekinger]

This one is up for an engine rebuild.

[2000V8Esprit]

Here is an update on how I am moving.... slowly but steady .... 

[alanlambert]

Good luck working on that with the engine in situ 😬

[mike_sekinger]

If it's a shop doing the work, they will burn through more hours with this approach.

Given that you had the engine cranking over with one bank locked, it is hopeless to imagine that a full top-end rebuild on at least one bank will not be required.  Depending on the impressions in the piston crowns, you may also have some remedial work there.

 

[Chillidoggy]

I wouldn’t be putting too many engine parts on that glass roof. The engine rebuild is going to cost enough as it is.

[2000V8Esprit]

47 minutes ago, Chillidoggy said:

I wouldn’t be putting too many engine parts on that glass roof. The engine rebuild is going to cost enough as it is.

Good advice my friend!  I will allocate the engine parts elsewhere, I just left them there when I got tired...