Odd new problem on starting

[gixxer1000]

My 2000, 4.5 LW has developed a new quirk. Sometimes when I go to start it I don't get much of a response (as if the battery is dead or starter motor kapput) and then it bursts into life a moment later.

Could this be:

* duff battery
* duff alternator
* duff starter motor
* duff other

There is no clicking or whirring coming from the starter motor when this happens. It feels like the battery has low power but then bursts into life.

Also, it only seems to happen when the car is hot (e.g. after stopping for petrol).

Any thoughts folks?

Thanks,
gixxer.

[Nickccc]

loose batery connection, or earth maybe.

[AndyTather]

Have a similar problem with a brand new starter motor from TVR (looks very different, could for the cerbera MkII ) Problem is it sucks the battery dead each time it starts. Yesterday, it started okay, then did some short runs then at the petrol station it really died whilst starting like you said, only just starting. Then got home, tried to start it again and the battery/starting is completely dead. (New battery and start motor fitted this week)

There must be something wrong with these starters on old cerberas.

Just tried it now it starts okay.....

>> Edited by AndyTather on Thursday 13th October 19:00

[marcus1970]

Sounds to me like you need a new battery as well as a new starter motor!

Trouble is with the Cerb starter motors, I'm lead to believe, that they are really meant for starting racing engines and not for the daily rigours of stopping starting, shopping, getting your newspaper etc..

They will pack up eventually and its best to get a new one.

MB

[PetrolTed]

Interesting... See this thread

[Julian64]

I'd go for the obvious first. You say this is a hot problem. Is the fan on your engine running at the time you turn the starter motor on?

[gixxer1000]

Julian64 said:

I'd go for the obvious first. You say this is a hot problem. Is the fan on your engine running at the time you turn the starter motor on?

Not sure really, but it could well be. Would that make a difference to what could be causing it?

[Julian64]

gixxer1000 said:

Julian64 said: I'd go for the obvious first. You say this is a hot problem. Is the fan on your engine running at the time you turn the starter motor on? Not sure really, but it could well be. Would that make a difference to what could be causing it?

Yep, fans will take it out of your battery, because they take quite high current, only really meant to be running with the engine on. That gives you a slight problem in a petrol forecourt. Really could do with an inhibit switch.

[PetrolTed]

How old is the starter motor?

[mike_e]

AndyTather said:

Have a similar problem with a brand new starter motor from TVR

I had the same issue when my 2nd starter died the inevitable death. Went through 2 more Tilton supplied starters at the dealers in the same day, would start when cold, locked up when hot. 3rd starter of the day, supplied new from TVR, was OK.

Battery was only months old and the 2 starters were brand new, not recons, so clearly was heat related. The expansion due to heating when the car stopped made the gap between the teeth far too small to mesh correctly.

Sounded like the pinions where the wrong spec.

[trackcar]

I know the company that makes the all-black shrink-wrapped starter motors, in fact about a year or more ago I had the fabricated/welded pre-production version to try on a car for a while to make sure it was ok.

the motors are something like 1.2kw as opposed to .9kw of the originals, the one way clutch is an open but improved design and they have better solonoids as std .. I'm inclined to think along the same lines as julian64 .. go for more obvious eliminations first .. also is your big fuse on the way out? cos sounds to me like your battery is only occasionally getting charged up .. ?

I used to fit plenty of starter motors but rarely had any problems with the uprated units, they really were an improvement.

[gixxer1000]

PetrolTed said:

How old is the starter motor?

No idea Ted. I've had the car for two and a half years and I haven't changed it. Could be the original (from Jan 2000).

[gixxer1000]

trackcar said:

.. also is your big fuse on the way out? cos sounds to me like your battery is only occasionally getting charged up .. ?

I had this replaced as a matter of caution around a year ago, so I wouldn't have thought it would be that (but then what do I know).

The thing about this problem is that it has only just started to happen - i.e. it used to start fine when hot, including when the fans were on, so something must be failing I would have thought.

[mikesr]

Julian64 said:

Yep, fans will take it out of your battery, because they take quite high current, only really meant to be running with the engine on. That gives you a slight problem in a petrol forecourt. Really could do with an inhibit switch.

Joo (Trackcar Solutions) is offering various ECU tweaks including getting the fans to kick in at a lower temperature. I believe the ECU can be also be tweaked to turn the fans on only above a specific RPM. If it was set to 800 or 850 then the fans wouldn't come on until the engine was above cranking speed - ie after its started.

That would reduce the load on the battery during a hot start since I'm reliably informed that both fans together pull about 30amps

[apprentice]

From our experience, the problem seems to centre on the ones coming via TVRs suppliers.

Liase with Andy @ APM who utilises exchange units via another third party - 5 day turnaround and change from £200. No inherent failures reported.

On early Cerbs check that you have the later chip in the ECU.

apprentice

(NB:- copied and pasted over from parallel thread on Cerb starter motors)