8v digi slow to fire up and low power when cold

[Steve_B]

Am having issues starting from cold recently and am trying to track down the cause. If I leave the car for a couple of days or so it will turn over when I try to start it but take ages to fire into life. It's also low on power, seems reluctant when pressing on the accelerator, this goes when engine is warmed up. If I run the car for even 10 mins or so then re-start the problem has gone.

As its turning over ok I don't suspect the starter motor, it's a 2 year old bosch unit anyway
Battery is more or less new, as it starts fine again after 10 mins this seems to rule it out for me
Recent service so new oil, oil and air filter, and plugs
Have checked all the earths and cleaned them up
Replaced the ecu recently as the old one blew and was flooding the engine

Am only getting about 13v when running so the alternator needs looking at, could this cause the issues I'm seeing?
Does an 8v digi have a cold start valve, this seemed to come up in my searches but not even sure what it looks like or how to test it

Any other suggestions welcome

Steve

[analogue_rogue]

when running with the lights off it should have 13-14.5 volts at battery so I wouldn't worry too much about alternator yet.

It sounds like your fuel is primed on cranking. have you got a fuel smell anywhere? is the sender seated correctly?

run a fuel pressure test.

If your fuel system is at the right pressure and isn't leaking move onto air.. as an air leak can alter the mixture and cause the same issues..

[Sgt_Lemon]

To me this only happening with the cold would suggest an air leak somewhere that is plugging itself once the engine warms and expands.

[Steve_B]

When you say air leak are you talking abut the vacuum pipes?

Can hear the fuel pump priming for a couple of seconds, fuel filter was replaced about a year ago.
Not sure which sender you're referring to, can't smell any fuel from the cabin will have a snifter at the bay this weekend.

[analogue_rogue]

Even if you can here the fuel pump you need to make sure its delivering the fuel at the right pressure or you will struggle to start and run.

When cold the fuel air is roughly 8/1. When warm its closer to 16/1

So any changes to these ratios can affect the running. 

So if your fuel is at a lower pressure youll get a weak mixture

If your air intake is letting in extra air you also get a weak mixture.


Hence cold running and starting issues :-)

[X4MGS]

have you reset the ecu or changed the blue temp sender?

[Steve_B]

Problem is from before i swapped the ecu so won't be that, if anything it's running smoother since once its warmed up. Will try disconnecting the temp sender and see if it makes any difference to running. Looks like i also have to source a fuel pressure guage from somewhere, any recommendations?

[analogue_rogue]

I have one if you can get over to oxford one day?

[Steve_B]

I have one if you can get over to oxford one day?

Thanks, may take you up on that some time.

[Steve_B]

After some poking around there was a slight build up of oil in the throttle body. Is that normal or a symptom of something?

Also, can hear the fuel pump in the cabin when engine is running, definitely seems louder than it used to be.