cutting out
cutting out
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snookes

Original Poster:

262 posts

313 months

Monday 9th March 2009
quotequote all
on my 400 se it occasionally cuts out when the clutch is engaged or running on tickover. it has always done this but it seems to be getting worse. also it has started to be a bit kangarooie? between 1500 and 2000rpm when running at a constant speed. to cure this i have to either change down gear so i'm above 2000 rpm or put my foot down.can anybody point me in the right direction
thanks

anthony

firefox1712

1,772 posts

285 months

Monday 9th March 2009
quotequote all
Very strange -

My Aston Martin has a similar problem, and the Ferrari I had a few years back did similar too. We never solved the latter, but thought it might be the ECU.

At the moment with the Aston, the car has just recently refused to start after suddenly stopping following starting as usual on the first turn of the key.

The mobile mechanic has traced a fault to no power getting through to the fuel pump, and thinks that perhaps this was causing the cutting out when under way. The theory is that there is a perished wire that takes power to the pump and hopefully he will be able to replace that today and all will be well.

Good luck with getting it fixed.

JJ

pwd95

8,459 posts

268 months

Monday 9th March 2009
quotequote all
It started doing that just before I sold it to Lee. I think he said he had the timing adjusted & it cured it. I'd be surprised if it's anything too serious as it's a very well set up beast, having the Mark Adams map & all. yes

honestjohntoo

576 posts

246 months

Monday 9th March 2009
quotequote all
You may have two faults.

snookes said:
occasionally cuts out when the clutch is engaged or running on tickover. It has always done this but it seems to be getting worse.
Probably a weak mixture unable to sustain useful torque at low rpm, hence when a load is applied (or even randomly ticking over when hot) the engine dies. Likely cause, a rogue air leak into the plenum and even tho' it may run (near) normal at other times, an air leak has dominance at low rpm. Hence no torque and it stalls. Easily resolved - usually at nil cost:

http://www.vintagemodelairplane.com/pages/Rover_Te...

snookes said:
also it has started to be a bit kangarooie? Between 1500 and 2000rpm when running at a constant speed. To cure this I have to either change down gear so I'm above 2000 rpm or put my foot down.
Could be due to possible air leak but this symptom is also dead ringer for worn TPS randomly telling the ECU to fire acceleration enrichment circuits at its 1500-2000 rpm rotary position (ie: when cruising). Dropping a cog, or accelerating beyond that rpm moves the sensor away from a worn section of carbon track, random injections cease, symptoms disappear. Diagnosis and solution are quite straight-forward and can also be low cost depending upon how you choose to proceed:

http://www.vintagemodelairplane.com/pages/Rover_Te...

The links point to components in a system that is different to yours but the principles at play are the same.

Andy390

349 posts

306 months

Monday 9th March 2009
quotequote all
Agreed HonestJohn...were you a motor trader??!
This could be so many things but loose connections is the first thing to check. The TPS sounds like a decent guess in this case, but after having a similar fault(but mine was more random -only at high revs first,then at cruising and occasionally round corners) mine turned out to be a combination of old coil and a dodgy pickup unit in the old DLM8 Rover dizzy. ...A New dizzy cured it at last
(strangely a year before,on a trackday, the Rev counter started dropping revs when the engine was climbing. i thought it may have been the Guage, but i think it was probably ralated to the Dizzy/Pickup due to weak pulse.)
HTH Andy

Andy390

349 posts

306 months

Monday 9th March 2009
quotequote all
Agreed HonestJohn...were you a motor trader??!
This could be so many things but loose connections is the first thing to check. The TPS sounds like a decent guess in this case, but after having a similar fault(but mine was more random -only at high revs first,then at cruising and occasionally round corners) mine turned out to be a combination of old coil and a dodgy pickup unit in the old DLM8 Rover dizzy. ...A New dizzy cured it at last
(strangely a year before,on a trackday, the Rev counter started dropping revs when the engine was climbing. i thought it may have been the Guage, but i think it was probably ralated to the Dizzy/Pickup due to weak pulse.)
HTH Andy

leorest

2,346 posts

269 months

Monday 9th March 2009
quotequote all
Another easy one to check is loose connections to the ECU and also the resistor pack. Just make sure the connectors snap fully home.

TVRleigh_BBWR

6,553 posts

243 months

Monday 9th March 2009
quotequote all
Do you know if your 400SE is a flapper or Hotwire. if hotwire it could be the idle control valve these are known to become sticky.

honestjohntoo

576 posts

246 months

Monday 9th March 2009
quotequote all
Andy390 said:
Agreed HonestJohn...were you a motor trader??

My Goodness? No, What ever made you think that? There is an honestjohn on this forum, he's my son so I'm just a wrinkley version of him. Both RV8 hobbyists

The TPS sounds like a decent guess in this case

I really do try not to guess, preferring suggestions based entirely on the reported symptoms. TPS' have a finite life so when they wear out they may generate electrical noise that the ECU interprets as rapid throttle opening, responding by firing the enrichment circuits resulting in random surges. Hence a suggestion to read available material and do the tests. A potential problem with guesses is that OP's latch on to them, purchase new parts on the strength of the guess to subsequently discover a different cause. I personally like to advocate the "Testing" route. Probably comes from an entire career in electronic design, maintenance and semiconductor production testing.
Edited by honestjohntoo on Monday 9th March 21:51

adam quantrill

11,679 posts

272 months

Monday 9th March 2009
quotequote all
Then there's the problem I had where the alternator wasn't grounding properly. Try checking the voltage between the alternator casing and the engine block with the engine running. Anything over 0.1V is too high in my estimation, but easily cured by cleaning up the mating surfaces.

Another problem I had on another car was the rev limiter, that 'cut in' at random times apart from due to excessive revs, killing the spark. The rev limiter is now disconnected....

snookes

Original Poster:

262 posts

313 months

Tuesday 10th March 2009
quotequote all
it's a hotwire system leigh
TVRleigh_BBWR said:
Do you know if your 400SE is a flapper or Hotwire. if hotwire it could be the idle control valve these are known to become sticky.

snookes

Original Poster:

262 posts

313 months

Tuesday 10th March 2009
quotequote all
hi guys

thanks for all the input will let you know when it is sorted

anthony

rev-erend

21,623 posts

314 months

Tuesday 10th March 2009
quotequote all
Also worth checking that the pedal does not touch a wire that then causes the short.. the low tension from the coil does go to the key/barrel on the steering column .. and if an alarm has been installed may have rerouted this or extended it to the alarn..


Also worth checking the major earth points are OK ..

A jump lead can be added as a temp fix to see it it improves (battery earth to engine block)


Edited by rev-erend on Tuesday 10th March 09:51

Wedg1e

27,038 posts

295 months

Tuesday 10th March 2009
quotequote all
rev-erend said:
Also worth checking that the pedal does not touch a wire that then causes the short.. the low tension from the coil does go to the key/barrel on the steering column .. and if an alarm has been installed may have rerouted this or extended it to the alarn..


Also worth checking the major earth points are OK ..

A jump lead can be added as a temp fix to see it it improves (battery earth to engine block)
[pedant]
I think the coil feed is from one of the relays labelled 'Ignition' on the main relay board. Most later wedges have two relays in parallel and even though they're rated for something like 20A or even 30A each, the load-sharing is not equal and I've seen cars with both relays and the sockets melted due to heating effects of prolonged loads.
The early Tas was even worse as it only used one relay to handle most of the ignition switched loads... not helped by later owners adding uprated components and blinging ICE of course!

snookes

Original Poster:

262 posts

313 months

Wednesday 11th March 2009
quotequote all
rev
this happened to me the day i bought the wedge. every time i pushed the clutch pedal in, it stalled. the AA were passing and i flagged them down(i'm not a member) he spotted that the pedal was breaking the fuel pump cable. i just used a connector and problem solved. my problem at the mo is more a tickover problem
thanks
anthony
rev-erend said:
Also worth checking that the pedal does not touch a wire that then causes the short.. the low tension from the coil does go to the key/barrel on the steering column .. and if an alarm has been installed may have rerouted this or extended it to the alarn..


Also worth checking the major earth points are OK ..

A jump lead can be added as a temp fix to see it it improves (battery earth to engine block)


Edited by rev-erend on Tuesday 10th March 09:51