Hard start

[Burgundy8]

Had my truck for about a week now and been trying to go through and address all the minor cosmetic stuff. Noticed however on first start in the mornings or if it has been parked for a long time, it's a little hard to start. It will crank for a good 5 seconds before it fire and sometimes only starts if I give it a little gas. If I turn the ignition to position 1 and wait the 5 seconds it starts immediately, its almost like the fuel line has no pressure at first start but if I pressurize the line by waiting the 5 sec she will start.

She is a "99 4.0 SE, any ideas where to start looking.

Mike

[Keithy P38]

You pretty much answered your own question!

I'd be replacing the fuel pump if I were you!

Cheers
Keithy

[Burgundy8]

Fuel pump is abount 3 months old.

[Keithy P38]

Next question, if its a Gems, have you replaced the fuel filter recently?

Other things to check are:
- Spark plugs might need replacing (don't use britpart ones, they are a waste of money, get NGK).
- Fuel injectors may need a clean. Easy fix would be to run a few tanks of premium unleaded (95 octane) and an injector cleaner with each tank.
- Spark plug leads may be wearing
- Is your battery voltage and all earth points in good condition?
- Is the air filter clean?
- Are the fuel hoses properly clamped in the tank?

How does it run while driving? Is it sluggish or just seems normal?

Cheers
Keithy

[RR P38]

Pretty much all that Keithy says.

Fuel pressure is easily checked, via the injector rail, get a work shop to do it for you unless you are pretty handy and have the guage. It only takes a minute or two.

[Burgundy8]

Ok..guess I have a couple stuff to check.

Keithy thanks for the check-list. She is a '99 GEM, the battery is new (optima Yel), I am running Techron from day 1, will check plugs, leads and fuel filter over the weekend and report back. It drives great, though I have nothing to compare it with as my other vehicle is a Audi A8

Thanks again.

Mike

[Keithy P38]

Thanks mate, definitely let us know how you go!

[Burgundy8]

Ok..had a chance to do a fuel preasure test on the truck today and with key in position 1, I got 38psi, what is strange is with the key turned off the preasure falls to zero. The fuel rail is not holding any preasure, this could explain why on first start in the mornings, if I let it sit in position ! for 5-6 seconds before starting, she fires up - no problem. So why is the pressure falling to zore once the fuel pump is turned off, there is no fuel leaks so obviously its bleeding back into the tank through the return line. Could this be a bad fuel regulator?

Thoughts?

Mike

[benji]

My guess would be the pressure regulator - cheapest too. Second guess would be pump, though that's brand new. How quicky does it go back to zero?

Leaky injectors or injector orings are another possible cause but I suppose it would take some time to drop to zero if it were these.

Sent from my GT-I9305T using AULRO mobile app

[wayneg]

When the fuel pump was changed was it just the pump or the whole pump sender unit?
If just the pump, what hose was used within the tank. If not the correct submersible type, SAE30R10, the hose will soften and swell and lose the seal. With the pump running the pressure will hold enough to run the engine, as soon as the pump stops the pressure will drop off very quickly. Sooner or later the hose will burst.


http://www.ebay.com.au/itm/5-16-SUBMERSIBLE-IN-TANK-FUEL-LINE-HOSE-SAE30R10-SPECS-/161054405966?pt=AU_Car_Parts_Accessories&hash=item257f97354e

[Burgundy8]

As per the PO, it was just the pump. We did pull the pump a couple of weeks ago and from what I can remember they re-used the factory hoses. How can I check the regulator, if I pull the vacuum hose during testing what will happen?

[benji]

Nothing will happen, you can drive without it.
Best to hook up a fuel pressure guage and see what the pressure does in relation to the manifold vacum.

Sent from my GT-I9305T using AULRO mobile app

[wayneg]

As per the PO, it was just the pump. We did pull the pump a couple of weeks ago and from what I can remember they re-used the factory hoses. How can I check the regulator, if I pull the vacuum hose during testing what will happen?

From the sender unit / fuel pumps I have seen, the factory hoses are heat shrunk hard plastic. These would not be re-usable, they need to be cut off.

I have had exactly the same symptoms after fitting a pump with the wrong hose. Sounds implausible, I thought the same when advised by Bee-utey . He was 100% on the money. Lesson learnt.

https://www.aulro.com/afvb/images/imported/2013/11/1228.jpg