I’ve exhausted all avenues. Engine will not turn over

[canonc]

Afternoon all

I’ve re-built the top end of my Chimaera 450 and coming to the end now, but I can’t get the engine to turn over. I can turn the engine over on the crank bolt and socket, and the engine moves freely, but it won’t budge on the key!
I must have re-wired the electrics wrongly somewhere along the way.

1). It’s not the meta alarm because that was dispensed with years ago!
2). A new battery and fully charged.
3). New starter motor. I have bypassed the red battery cable and earth and jumped leads directly from the battery to the starter solenoid. There is a clunk from the starter when I do this, but won’t turn over the engine!
4). Have cleaned up the earth cable on the chassis horizontal to earthing point on the front of the engine and also the other two earthing wires there. Have also checked the earth at the back of the n/s cylinder head.
5). New 100 amp fuse between starter motor and alternator
6). Have checked over my wiring of the alternator and coil and they seem ok

Any help please. I’ve run out of ideas now.

Many thanks

[300bhp/ton]

Does it only do it with the new starter? Or was it doing it on the old one? Could be a faulty starter motor.

[canonc]

Hi 300bhp/ton. It’s the same with both starter motors. I had decided to change the starter motor before I completed the build, because it’s the original and about 22 years old

[Boosted LS1]

Seems as if the selonoid wants to engage but the starter won't rotate. Could be an earth issue or main power issue so I think you're on the right track. Have you changed the flywheel? I would test the starter on the bench.

[canonc]

Thanks Boosted LS1...I forgot to mention when the battery was connected to the car there was no clunk from either starter motor. All the lights and dash lights worked, and when I turned the key there there was no dimming of the headlights. I’ve bench tested the old motor and that worked, but not on the car!

[blaze_away]

Can you rotate the engine using the bottom crank pulley nut......just to make sure engine is not seized

[canonc]

Hi blaze_away. Yes the engine turns freely by rotating the engine from the crank bolt

[blaze_away]

Apologies for dumb question you already said that in opening post.

Anyway you need to now check out the ignition switch. Are you getting power to the switch ?

[MiseryStreak]

If the starter was operating correctly and drawing full current from the battery, then it would at least make a horrible noise as the pinion gear throws out onto the immobile flywheel. It must be a problem with the wiring to or the starter motor. I had an issue with a new starter on my Elan and it was a poor Earth connection. I wire brushed the connector and chassis point and then it was fine.

Edit: sorry, you’ve clearly stated you’ve checked the earthing!

[canonc]

No problems...yes the ignition switch is working. I might be way off in my thinking, but because the starter motor will not crank the engine when I bypass the ignition switch and jumping straight from the battery to the starter motor, then I’ve either got and earth problem or I’ve wired the electrics wrongly! Or possible something in the electrical loop.

[CAPP0]

Not sure what the access is like on the TVR but if you can get a jump lead onto the starter side of the solenoid, that would rule out the starter motor itself if it turns over then. Then work your way back, jump lead on the input side of the solenoid and turn the key, 12v onto the solenoid activator etc. I'm sure I have had one once where the low-current 12v connection onto the solenoid was faulty.

[derek.j]

Put a jump lead onto the engine block
To the negative terminal

Test for 12v at the thick red cable then bridge this 12v to the Solenoid

Should turn over if it’s not seized or faulty starter

[bearman68]

As the above poster says.
1) Put a big heavy duty jump lead or cable between the battery and the main positive terminal on the starter.
2) Put a smaller jumper wire from the main starter terminal to the solenoid terminal.

Report results.

[Englishman]

I was about to write the same thing. Bypass the car earth connections by connecting the battery -ve to the block.

[canonc]

Thanks guys. Would putting the negative to the block be different to earthing to the starter motor ears, or the chassis horizontal? I’ll give it a try tomorrow.
Thanks again...it’s driving me nuts!!

[Penelope Stopit]

Earth straight to the starter if you can

The thing is many jump lead sets are useless, you need to be sure the jump leads are good

The other way is to use a multimeter and check for a volt-drop first on the earth side when key is turned to crank and then on the positive side when @ crank

Max allowable volt-drop earth side = 0.25 volts

Max allowable volt-drop positive side = 0.75 volts

[canonc]

Thanks Penelope Stopit.....where would you suggest I earth direct to the starter motor? I’ve tried earthing from battery to the motor ears, but that didn’t work!

[Austin Seven]

There are several good suggestions here. One thing I would do in your position where you've tried several things without success, is to make up two wires (thin wire is fine) to connect your voltmeter to the starter as follows:

Connect the meter negative wire to the motor mounting ear, trap it under a motor mounting nut, making sure the wire is in good contact with the motor ear;
Connect the meter positive wire to the large solenoid terminal which is connected to the motor itself (not the one with the big red wire from the battery).

This will allow you to see exactly how many volts the motor itself is receiving. If, when you activate the starter, you don't see a good 10V on the meter, you know the motor will struggle to turn the engine, and you have an electrical supply problem. You can try the various suggestions above to identify and eliminate the cause of the poor power supply.

If you do see 10V or more, you know the motor is faulty and a strip down is needed, or the flywheel is jammed (but you have already checked the engine turns over OK).

[Penelope Stopit]

canonc said:

Thanks Boosted LS1...I forgot to mention when the battery was connected to the car there was no clunk from either starter motor. All the lights and dash lights worked, and when I turned the key there there was no dimming of the headlights. I’ve bench tested the old motor and that worked, but not on the car!

Ooops, only just read this

No clunk from 2 good starters

Once you know the engine earth and main battery positive are both good, find some 16 amp or higher rated cable and connect one of its ends to the starter solenoid crank terminal, now when you connect the other end of the wire to the battery positive the engine should crank, this is the same as a bench test

If engine doesn't crank with the above method, there is a big volt-drop or open circuit in the solenoid crank cable between ignition key/button and the starter, open circuit crank cables are often found in locations along the wiring harness where immobilisers or alarms have been previously connected

---

Regarding where to connect a engine earth jump lead, connect to a starter mounting bolt if possible or to the starter drive-end shield

[canonc]

Hello guy’s. I’ve followed your instructions and the solenoid is spinning, as if bench testing starter motor. I hate to say it...but I think my flywheel is seized. The car is on stands and Inhave engaged reverse gear and as much as possible rotated the rear wheels, and then 3rd gear and done the same. Not much movement!!
Does anyone have any idea how to free a possible seized flywheel?
Thanks for all your advise.