Chimaera 450 seems to cut out after driving up the same hill

[D_MWR]

I have a strange issue with my modified 450 (stage II heads, Megasquirt system, etc. etc.) where I drove 600km stopping in service stations, restarting without a problem and at the end of the journey I had to drive up a steep hill and into my drive which is also very steep. As the drive flattens out I tried to park in the garage and the engine cut out (immediately, no spluttering or intermittent power loss) and refused to restart until the car was cold. It has a 3/4 full fuel tank and if the ignition switch is turned straight after the cut-out, the fuel pump runs normally, but the engine wont turn over.

As the problem only happened once I wasn't too worried but yesterday I took the car out for a run (15km), driving up the same hill, the car died exactly the same conditions in exactly the same place ! the same inability to restart until the engine was cold again, at which point it starts 1st time, no issue with hunting or long cranking times

I can't get the 'common factor' of the hill out of my mind but also can't see with the car starting when cold how it could be related with fuel starvation. Possibility for a component failing under heat (impact of driving up the hill but its only 2km long) - but it doesn't seem to happen on the flat?

Apologies if this should be added to another thread but its my first post on PH and I'm still a bit green. Thanks a million for any advice you could offer..

[Polly Grigora]

Is there any chance that the engine earth is failing when climbing up the hill?

[D_MWR]

I'll check the earth tomorrow, but it seems strange that it doesn't happen as I drive up the hill, only when I get to the top of the drive where it flattens out. I will probably go for a drive again tomorrow to test it again, if it fails in the same place I may have to just move house !

[blaze_away]

Check your battery and terminals are secure.

[Jordie Barretts sock]

Check the obvious like the 100amp fuse and is the immobiliser still original?

Weird things can be attributed to either.

[Steve_D]

It has to be electrical IMHO because a fuel issue would give a more stuttering end rather than a dead cut.
Plus if the engine will not crank after the engine dies then it has to be in the start circuit with the prime candidate being the immobiliser.

Steve

[TwinKam]

Never experienced it myself, but I've heard tales of electrical interference from powerlines or substations preventing unlocking, could it also trigger an immobiliser?

[s p a c e m a n]

Had to have the missus discovery recovered a few years ago because we parked it next to a massive green box in a carpark and couldn't unlock the doors, not doing that again.

[ITVRI]

Steve_D said:

It has to be electrical IMHO because a fuel issue would give a more stuttering end rather than a dead cut.
Plus if the engine will not crank after the engine dies then it has to be in the start circuit with the prime candidate being the immobiliser.

Steve

Just reinforcing what’s been said. Based on your description of the engine not turning over the immobiliser circuit is your likely culprit there is a 20 amp fuse in the rats nest next to the battery from the immobiliser that supplies the starter solenoid and it’s worth checking and replacing the 100amp fuse located underneath the car as these can crack or corrode over time which could cause an intermittent problem.
Here’s a good thread with more info https://www.pistonheads.com/gassing/topic.asp?t=17...

[CubanPete]

TwinKam said:

Never experienced it myself, but I've heard tales of electrical interference from powerlines or substations preventing unlocking, could it also trigger an immobiliser?

I had a 90s golf GTi, that wouldn't start if the phone was plugging to charge. There were a couple of places I parked where it wouldn't start and I rolled it forwards a few feet, and started fine...

[gavgavgav]

To add to the list of potentials - if the fuse box is original, the cable to the battery box can jiggle the bottom right fuse out of the socket as it crosses the front of the fuse box, and in my case when the passenger lightly knocked the kick board the ignition simply turned off. The fuse could be flopping about a bit in your case.

[D_MWR]

Thanks everyone, I'm going to do some further investigation today, great advice and I hope it's something obvious! I had the car rebuilt from chassis up in France and since I've found a number of problems, the worst being loosing a brake caliper bolt on the A9, had to check the entire suspension and braking system to check they were all to spec...... apparently the garage closed and moved to Canada last year

Thanks again and I'll update later today

[Classic Chim]

D_MWR said:

Thanks everyone, I'm going to do some further investigation today, great advice and I hope it's something obvious! I had the car rebuilt from chassis up in France and since I've found a number of problems, the worst being loosing a brake caliper bolt on the A9, had to check the entire suspension and braking system to check they were all to spec...... apparently the garage closed and moved to Canada last year

Thanks again and I'll update later today

All brake Caliper retaining bolts should be loctited in place. That’s why it came loose!
Check all and re Loctite. Sounds like the mechanic was less than professional.
Check your rear engine Earth and Earth to outrigger.

[D_MWR]

Classic Chim said:

All brake Caliper retaining bolts should be loctited in place. That’s why it came loose!
Check all and re Loctite. Sounds like the mechanic was less than professional.
Check your rear engine Earth and Earth to outrigger.

Yes, I've now correctly loctited all calipers. Also found the engine earth could be undone by hand and they used the incorrect bolt thread so wasn't tightening up correctly. The 100amp fuse was falling to bits but the fuse itself and the connections were okay, will replace this also.

Thanks for the tip about the rear earth, I'll also check this tomorrow......yes it's a real shame about the garage as they were great guys, but over stretched himself I think and started missing bits in order to finish and get to the next 'bigger project'.

Thanks again

[D_MWR]

Polly Grigora said:

Is there any chance that the engine earth is failing when climbing up the hill?

Hi Polly,
Thanks for the tip, indeed I found the engine earth could be undone by hand when cold so probably very loose when the engine was hot. I'm hoping that may be it.

Thanks again