Still having trouble starting

[S7Paul]

I added to someone else's starting-related thread a week or so ago, detailing the problems I was having, but (probably unsurprisingly) didn't get too far with a resolution.

My 450 has always started very easily, but I began to have problems recently which IIRC pretty much came on overnight. Now, it'll just sit there with the starter spinning but no sign of actually bursting into life, or else it fires for a second and then stops again (which it will do repeatedly). Eventually, if I'm lucky, it'll keep running. It's predominantly a cold-start problem, though still needs more cranking than previously to get it started when hot. Once running, it still drives fine.

Within the last 1000 miles it's had new Dist Cap, Rotor Arm, Ignition Module & HT Leads (all Lucas), NGK plugs, Bosch coil, Stepper Motor (Britpart item from Paddock Spares) & had the AFM & Throttle Position Sensor set-up as per the book.

The battery & starter motor seem fine (judging by the speed at which the engine cranks over).

I'm now getting stuck for ideas. Any advice would be appreciated.

Edited by S7Paul on Thursday 9th October 19:47

[drew.h]

Have you taken a spark plug out to see what its like?

If its wet then the car has flooded. I had a similar problem recently. Searching the forum suggests putting your foot to the boards and try to start. This should dry the plugs off, due to the larger air flow at full throttle.

Also worth checking the temperature sensor, mine was faulty, reading to high.

[nig-gtv]

Can you hear the fuel pump prime?

[M@H]

nig-gtv said:

Can you hear the fuel pump prime?

good point - sounds like an intermitent alarm issue to me.. (not knowing any othey symptoms)

[BBR]

Don't want to teach grandmother to suck eggs but have you checked the basics? I have had similar probs in the past ie engine turns over but does not start, in my experience there are several causes that are easily remedied.

1 Check that the plug leads and extenders are on properly.
2 I had this problem shortly after fitting a new dizzy cap, on inspection it had actually cracked
3 Is your battery fully charged, if I forget to plug mine in to trickle charger it will not start first time

As has been said faulty alarm/immobiliser, wet plugs, could also be at fault.

[AlexB]

S7Paul said:

The battery & starter motor seem fine (judging by the speed at which the engine cranks over).

If you can, try leaving the battery on charge overnight, or swap the battery for a new one (ar at least connect one up from the footwell rather than fully install) - I had a problem with the Chim where it was cranking over with a reasonable pace, but not catching - new battery installed and she cranked over much faster and started very easily. Worth trying the simple stuff first to rule them out rather than pay a garage to trouble shoot the expensive stuff....
Good Luck
Alex

Edited by AlexB on Friday 10th October 14:59

[S7Paul]

Thanks for all your replies. Taking them in turn:-

drew.h

I haven't removed a plug yet, or checked the temperature sensor. That's probably the next job.

nig-gtv / M@H

Yes, the fuel pump primes as normal.

BBR

I've checked that the plugs & extenders are on OK. I had the dizzy cap off again the other night, didn't see any cracks but I will double check.

The battery is fully charged as I keep it hooked up to an AccuMate all the time I'm not actually driving it. Last time I checked the voltage (about a week ago) it was reading 13.08V. I haven't checked the SG of the cells yet 'cos it's a pain to get access to (as you all know). What I can say is that it seems to be cranking over as fast as it has always done. Overall, I don't suspect the battery as it often fires for a second (and then cuts out).

I'll post again as things develop........

[M@H]

..perhaps multimeter test the low tension 12v supply to the coil, a new coil isn't going to work with no 12v free to check and will tell you if if it is spark or fuel. If thats not conclusive, better still take a 12v feed from the battery to that coil contact and see if it will run (you'll need to disconnect it again to stop the engine).

Cheers,
Matt.

[S7Paul]

Latest developments:-

I swapped the temp sensor for a known good one - made no difference.

Despite the things I had swapped/checked, the engine was still taking too long cranking before starting, but it would always fire eventually. I did a shortish journey this morning (around 10 miles) and left the car on the drive when I got home. About 20 minutes later I went to start it to put it in the garage and this time the starter didn't operate at all (first time that's happened). I could hear the fuel pump running, but the starter seemed completely dead. Tried it a couple more times and eventually the starter spun and the engine started. So, it sounds like the problem is narrowed down to the starter, solenoid & associated wiring. Looks like I'll be spending some time under the car within the next day or so!

[pringli]

Dont want to add to your woes but sounds like two problems now - the starter/solenoid problem being the usual hotstart problem. The other sounds like no enrichment when cold - equivalent to choke on a carburettor engine. You have changed the temp sensor so what else can cause that guys.