Hard starting from hot.
Turbo Mini Forums

Hi,

My mini starts fine from cold on the choke, but when it's up to temperature it's an absolute nightmare to start! Crank sensor is giving a signal (digital rev counter), spi fuel pump is buzzing away in the boot. Doesn't help if I pull the choke out, but does seem to help a bit if I hold my foot flat down on the throttle. Whipped the plugs out one time and they didn't look too bad really. The longer its left the worse it is. If I fill with fuel and run in and pay its not too bad, but if I go shopping for half an hour its a bastard to start again.

Good job its got a huge battery, because I have to just sit there cranking for ages until it goes.
Only think I can think is the fuel is evaporating from in the carb because of the hot turbo underneath? There is no heat shield fitted.

Any help please guys?!
Thanks, James.

It's normal dude, just have to live with it

Yep they all do it,

Audi s4 b5 - 470bhp & 486ft lbs

On 30th Apr, 2012 Brett said:
yeah stick the bit in and give it a wobble

A heat shield would help

In the 13's at last!.. Just

its the one thing that annoys me about my turbo

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

Side mount?

In the 13's at last!.. Just

Thanks for the help guys, its so embarrassing sat outside tesco for 20 minutes cranking it over with people staring / smirking. Didn't realise they all do it. Hasn't anyone found a cause?

The cause is, as you say, the hot turbo beneath, heating the fuel in the carb till it evaporates.

In the 13's at last!.. Just

The metro had a vent valve from the float chamber that opened to atmosphere when the ignition is turned off, I suspect for this very reason of poor hot starting. The Metro Turbo owners manual does advise that you should put the accelerator to the floor when hot starting.

we used the switch the pump off on the van for a few seconds before shutdown to drain the float chamber.

If something is worth doing, it's worth doing half of.

if your going to use the car on the road its definately worth adding the headsheild, and maybe a small 12v fan connected via a temperature switch.

I wasn't aware of this issue, however my engine came with the throttle linkage plate (that goes between the carb and the spacer) bent to go under the carb like this:





Car had no trouble what so ever getting started after it was on the rolling road giving it the beans. Maybe worth a try? That said I havent had mine on the road properly yet so may not be as effective as I am hoping.

P.s. What did the ERA turbo do to get around this?

Edited by Craigie-B on 7th Oct, 2012.

Possibly related to your issue as well, the SPi fuel pump isn't up to the job of any even lightly demanding turbo setup.

Swap it for an MPi pump ASAP!

If you get the car hot take the dash pot off and wait a little it become obvious what the cause is (well did to me) the heat from the manifold and turbo heats the fuel chamber on the carb boiling the fuel off... now for boosted use we block the vent off so this fuel only has one place to go... out the jet in to the inlet manifold where it collects
What i do is turn the fuel pump off and lett it idle the fuel out.. i run no heat sheild and aslong as i do this have no starting issues

There is tecnicaly one other place the fuel can go out into the plenum throught the float pressurising port but it all endsup into the carb

Yes i moved to the darkside

Instagram @jdm_brett

IMO it should never happen unless you have been driving the car hard and then stopped.

And usually sitting for 20-30 mins would allow sufficient cool down for it to restart as normal.

The Metro turbo and I presume ERA turbo had a proper heat shield underneath the carburettor. Nothing like that silly piece of bent metal in the picture above which would do nothing.

Google images brings up this picture, someone has strangely painted it red. This is the OEM heat shield though



But you really need a heat shield AND some method of venting the hot air.

ie a vent in the bonnet like the ERA had.

Also, Renault 5 turbos had a small fan to blow cool air around the carburettor for this same reason

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

That's the van! The heat shield was read when we got it and had been repaired.

If something is worth doing, it's worth doing half of.

Another google pic



As these are a little fragile, by the time the engine gets fitted into another vehicle, they are usually destroyed so people dont bother.

I made one from some heatshield material from Demon Tweeks. And it did make a huge difference.
The only times I experienced problems was if I stopped after a good thrashing. And when I did so, rarely would I switch the engine off because I knew it wouldnt restart.
I had holes in my bonnet above the carb, and also an electric fan in the wing which helped some air circulating through the engine compartment when stationary.

But under normal circumstances or even a little abuse it always started first time hot or cold.

And some more pics via google images

http://uk.images.search.yahoo.com/images/v...umb=d9wx0k0NJK4

Edited by stevieturbo on 7th Oct, 2012.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

May be for another reason, but my hot starting problems with the T3 disappeared immediately after I fitted the GT17.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Flol at "silly piece of bent metal"

Using a none bi-metallic jet holder in the carb don´t help with the hot start?

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=311

Pedro Silva

http://miniciados.blogspot.pt/

Stevie, same manifolds but there is a lot more chance for air to get round the GT17 with it being smaller.

Mine is an inline engine installation and I have a 4" duct direct from the front of the car , feeding cool air to the turbo area, which obviously was not as effective with the T3.

I suspect that the greater mass of cast iron in the T3 was holding so much more heat that it aggravated an endemic problem of a carb full of fuel sitting very close to a very hot object !

After a good run with my car after being switched off for about 15 minutes the car would need half throttle and spinning over a few times before it would start, but starts great at all other times, as Steve says its the heat from the turbo..

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A small motorbike cooling fan suitably placed to circulate air around the carb, or to try and blow the heat away from it might make a good difference. There are plenty on egay etc.

This is the R5 Turbo fan. It ducts cool air onto the carburettor.
http://www.ebay.co.uk/itm/RENAULT-5-GT-TUR...4f#ht_730wt_729

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

To be honest Steve, hasn't been that bad to start really, you just notice that difference when the car is hot, but the fan idea may be something to look into at a later date, got more pressing things to do on the car first as you know, will be over to see you shortly.. Alan

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