Starting problem

[SsHaDyGt]

Hello all,

My car is having trouble starting, when I turn the key it turns over fine but it won't start unless I give it some gas and even then it takes a bit.

Once the car is started it runs fine and there is no power loss.

Any ideas?

Thanks

Andy

[tblake]

classic symptoms of a bad IAC motor. I had one go out on my 3100 and it would only start at part throttle and would stay running if i left my foot off slowly. but after warmed up would run totally fine. im not familiar with the 3.8 much yet, so someone else like gtp dad will be along shortly to help you out more.

[SsHaDyGt]

I replaced the IAC with no luck.

I also did plugs, wires, pcv, oil change, and put a bottle of techron in.

I am still having starting trouble.

I am going to clean the throttle body.

Any other suggestions?

Andy

[BNaylor]

Long starting/turnover can be caused by a fuel supply problem so check the fuel pressure at the left hand side of the front fuel injector rail. There is a Schrader valve to connect an automotive fuel pressure tester. Check fuel pump prime at ignition to on and then at idle with and without the vacuum line connected to the fuel pressure regulator. You may have a fuel pressure regulator problem or low fuel pressure. Also, how old is the fuel filter?

[richtazz]

check the vacuum line to the fuel pressure regulator, and look for fuel in it. That's a tell-tale sign of a bad FPR, which will cause hard starting.

[SsHaDyGt]

The fuel filter was replaced not to long ago.

I talked to a guy who works at a dealership and he said to check the regulator for fuel under the vacuum hose, there wasn't any.

My uncle is going to let me use his fuel pressure tester to check that, what should it read?

Thanks for the help.

I will let you know the outcome.

Andy

[richtazz]

fuel pressure spec is 48-55 psi, key on engine off, and 3-10 psi lower than that with the car running and the vacuum connected.

[SsHaDyGt]

The pressure jumps to between 40-50 when I turn the key on but when I hear the fuel pump stop the pressure drops back down to zero.

Does this sound like a fuel pump?

Thanks for the help

Andy

[tblake]

It sounds like you have a leak somewhere. Wheather it be an injector, fuel pressure regulator, or a bad check valve on the pump. Did you pull the vacuum line off of the FPR and check for gas like bnaylor and richtazz said to?

[richtazz]

you could have a leaking injector(s). Check your spark plugs for any that look wet or fuel fouled. you can ohm out the injectors, and even though there isn't a "true spec", any that are way off from the others are where your problem may be. It's called an injector balance test, and you want all 6 injectors to be close in resistance.

[tblake]

you really cant do a true injector balance test if fuel pressure drops off very quick. Also im not quite sure if an ohm check would be very beneficial here. Richtaz, you are saying that maybe electrically an injector is being turned constantly on? almost as though the pcm is messed up or a wire a shorted to ground. If this were the case, if he unplugged all the electrical connectors to the injectors it in theory should hold fuel pressure.

How elaborate of a fuel pressure gauge set is that? Does it have a ton of fittings and things? or just a few? There is a rather easy way to diagnose this, but it requires a rather expensive fuel pressure guage set and the know how.

[richtazz]

a stuck or clogged injector will read different resistance than a good one will. One way out of spec from the rest would be the leaking culprit. This would be independent of whether powered or grounded, as you do an ohm test with the injector disconnected.

My other suggestion to resolve the issue is to hook a hand held vacuum pump to the FPR and see if it holds vacuum. If not, then even though there is no fuel present in the hose, it's leaking (possibly internally) and bleeding off the fuel pressure.

[SsHaDyGt]

Thanks for all the help on this issue.

In the end it ended up being the fuel pump which cost me around $600 just for the ACDelco pump.

Andy