3.2 hard start - pls help solve

[rolls 912]

Hi
I have a 3.2 running a sw chip. Cat bypass. It's in a swb car. I'm not running a pressure valve on the fuel pump (my first suspicion).

Sometimes the car won't start after it has been driven for a while, full operating temp. When it plays up, Eventually the battery goes flat attempting to start. if I use a new battery + aerosol 'hardstart' fluid it starts again. My battery is newish. It cranks well.

Can Anyone offer some advice as to where I should start? Could the missing check valve on the pump cause this issue? I haven't fitted as its not compatible with the custom fittings I have used for the new fuel line.

TIA

Roland

[jmh61]

Check valve holds pressure in the fuel line so the injectors have fuel during start up.

I would check for spark. If you don't have spark, it's probably a different issue. If you have spark I'd fit the check valve.

[Quicksilver]

Originally Posted by jmh61

Check valve holds pressure in the fuel line so the injectors have fuel during start up.

I would check for spark. If you don't have spark, it's probably a different issue. If you have spark I'd fit the check valve.

More to the point: Hook a pressure gauge to the test port on the rear of the left injector rail and see if it is retaining pressure. I suspect that you will find that it isn't the issue as the car will start without initial pressure because the pump will pretty quickly build pressure.

There are really only four things:
- Do you have spark?
- Is the spark at the right time?
- Do you have fuel?
- Is it being spun fast enough?

Those four can be caused by a number of things but they are the basics.

[Chuck.H]

This is similar to the list I refer to, excellent post. Only add to the fuel line, the fuel needs to be within a range so the engine is not starved or flooded:

There are really only four things:
- Do you have spark?
- Is the spark at the right time?
- Do you have fuel --- and not too much or too little?
- Is it being spun fast enough?

Chuck.H
'89 TurboLookTarga, 336k miles

[rolls 912]

I have spark. I'm pretty confident it's fuel. When I had the problem on Sunday there was no hum coming from the pump.

I'm also going to instal a fuel filter between the tank and the pump.

[jmh61]

In a 3.2 the fuel pump won't run with just the ignition turned on. The engine has to be running or the starter engaged. The only way to test the pump is by jumpering it.

Quicksilvers suggestion is a good one, checking fuel rail pressure. I would still install the check valve, but you could have a bad pressure regulator.