Hot start, well may be?

[kelvinwannell]

Please can one of you more iteligent guys help me, I do know if I have the hot start issue or not. I am unable to find a third relay.

Chim 4.0 1995, starts straight away, run it for 30 seconds, turn it off it will not start again. Fuel pump running ok, starter turning ok, but car will not restart until cold. It does try a tiny bit, the odd fire, but very little, not enough to start.

Any help would be greatly appreciated. Keep up the good work and thanks in advance.

[blaze_away]

Can you be a bit more specific, what do you mean wont start ?

Wont crank over on starter motor

Or

Crank but wont fire up

Either way its not the usual hot start issue, thats all to do with hot wiring becoming more electrically resistant.

Your issue here sounds more like ignition ie coil, or amp.

Pull the king lead off the centre of the distributor and put it near the engine block, hold with well insulated pliers, get someone to crank engine to see if you have spark when it wont start.

[kelvinwannell]

It does turn over ok, fuel pump running ok (3 secs) engine try's to start, but just the odd fire, just sounds very weak.

It has new coil (correct one) new alternator, new little black box thing on heat sink, new leads and dizzy cap, new plugs.

Can't get my head round it.

[Sir Paolo]

Agreed, it doesn’t sound like the typical hot start problem if the starter spins when you turn the key.

How long has it been running before this issue manifests itself?

Again traditional hot starts (as the name suggests), only become apparent when “hot”.

[kelvinwannell]

This morning started straight up ok, turned off after about 30 secs, would not restart.

[blaze_away]

kelvinwannell said:

It does turn over ok, fuel pump running ok (3 secs) engine try's to start, but just the odd fire, just sounds very weak.

It has new coil (correct one) new alternator, new little black box thing on heat sink, new leads and dizzy cap, new plugs.

Can't get my head round it.

Unfortunately these days "new" isn't always a good thing.

Suggest you do the check I suggested as a first step. Once we know result of that we can move forward.

[mk1fan]

If you have spark - test as above - to the dizzy, then check spark at each plug.

If you have spark, try spraying easy start into the induction. If it runs then stops. Repeat. If it runs then stops [when the easy start runs out] then you have a fuel issue.

If it runs fine and doesn't stop then you may have an air leak in the induction.

Simple checks and this is why my S3 wouldn't start on one Euro tour.

May of course be something else.

[kelvinwannell]

Thanks guys, will make some checks, as suggested.

[blaze_away]

In addition....

If you DO have a spark from king lead to engine block but NO spark at the plugs then it is either a dizzy cap, leads or rotor arm problem.

To test rotor arm.

Remove dizzy cap and move it to one side (make sure it can't be caught by rotating rotor arm.)

With Rotor Arm still in place, hold the king lead close to the centre of the metal part of the rotor arm

Get someone to crank the engine, if the spark jumps across the gap to the rotor arm then rotor arm is faulty, as it is earthing through the plastic via the centre of the distributor.

[kelvinwannell]

Thanks for your help so far.

I start it up for a min or so, try's to start but will not, does sound like it is firing a bit.

I have a good spark, I have plugs sparking, it seems like a fuel issue, but, the fuel pump fires up for the 3 secs and works fine until the car is turned off, it is then that it will not start again, fuel pump does the normal 3 secs, so I do not think this is the problem. My only thought is the computer getting wrong information from a sensor and limiting the fuel, is that poss?

aany help is always appreciated.

[MickC]

Long shot, is your stepper motor sticking?

That would usually cause the car to stall if hot rather than not start at all though, so probably not. Cleaning it may not fix the issue but cant hurt?

[sixor8]

It's a very reliable item usually, but what about the fuel pressure regulator? I seem to remember there being a thread on here where it was the culprit to somebody's failure to start.

[blaze_away]

You now need to establish if the injectorss are firing on the restart. Have a look at this video and get yourself a noid light.

https://m.youtube.com/watch?v=bROO1zanlRU

If you are near Rugby you can borrow my fuel pressure gauge to see if you also have fuel pressure on restart

[kelvinwannell]

Thanks for the reply's.

I don't think it's the fuel pressure regulator, it starts and runs when cold, the regulator would not work when cold, if it was that.

I also have installed a new temp gauge.

The only other thing I have found, when I start it cold and leave it running, it starts to miss and will eventually stop, then not restart.

Anyone near Horsham got a Rover gauge? Would that help?

rgards all.

[blaze_away]

Not saying its the pressure reg, trying to esyablish do you have fuel pressure at all when it wont start.

If yes then are the injectors firing to get that fuel into the engine.

[Paulprior]

Try looking at Steve D response a few threads ago as “no start”, the signal for the pump to continue running is different to the 3 second pulse from ignition on, so maybe you have fuel to start but after that the pump does not kick in again

[x 7usc]

Is it ok if you start it and just drive it? By default they run incredibly rich for a few mins on cold start, it could be wetting the plugs/flooding.
Mine does this but if i start it and let it idle for a min before i give it any revs its fine and will re start, before now ive stalled it and had to go out in something else as it won't re start lol

[spitfire4v8]

x 7usc said:

Is it ok if you start it and just drive it? By default they run incredibly rich for a few mins on cold start, it could be wetting the plugs/flooding.
Mine does this but if i start it and let it idle for a min before i give it any revs its fine and will re start, before now ive stalled it and had to go out in something else as it won't re start lol

I've got a resistor mod for that

[blitzracing]

Most likely flooding especially if the engine temp sensor is teading a bit higher resistance than it should. The fuel rail and water temp sensors are the same electrically so you can do a resistance check across both ( unplugged) on a cold engine and see if there is a significant difference between the two or RoverGauge will give you both readiings

Spitfires resistance mod fools the ECU into thinking the engine is warmer than it is so puts in less cold start fuel.

[Polly Grigora]

kelvinwannell said:

Please can one of you more iteligent guys help me, I do know if I have the hot start issue or not. I am unable to find a third relay.

Chim 4.0 1995, starts straight away, run it for 30 seconds, turn it off it will not start again. Fuel pump running ok, starter turning ok, but car will not restart until cold. It does try a tiny bit, the odd fire, but very little, not enough to start.

Any help would be greatly appreciated. Keep up the good work and thanks in advance.

Bearing in mind that more often than not a journey will last much longer than 30 seconds

What is the outcome after driving the vehicle for more than half an hour? It matters much