1994 Infiniti Q45 Hard Starting

SANDEE WON

MEMBER
1994 INFINITI Q45
130,000 MILES

Engine starts on the first turn, then dies. It starts again, only with the gaccelerator held down and 5 to 10 seconds cranking, sputtering a few seconds, some dark smoke from exhaust, then it runs fine, but I picked up the idle so it wouldn't die at a red light. Fuel filter and pump check out alright. I removed a small hose from below the fuel regulator and some gas came out. I think it is a vacuum line. I could not find a vacuum leak. Where do I go from here? Many blessings on your house, thank you.

7 Replies

KHLOW2008

MECHANIC
41,815 POSTS

The vacuum hose for the fuel pressure regulator should be dry. If gas is present, it means a bad pressure regulator.

Do a vacuum test to determine if pressure regulator is holding vacuum. If it fails to hold vacuum, the engine would be running too rich at idle causing stalling.

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Monday, August 26th, 2013 AT 10:44 AM

SANDEE WON

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Ok, I did the Test and It did not hold pressure. It slowly went down. I removed a vacuum line from the back side, under the regulator. It is a :Y: shape, and it was full of gas, as was the line from the bottom of the regulator. I was not able to break loose the screws on the regulator. Not much room there. Is there a special tool for that? Am I even going in the right direction? I have to do this myself, because all the men won't give me a fair deal. They treat me like an idiot. Thank you, You are wonderful.

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Monday, August 26th, 2013 AT 7:17 PM

KHLOW2008

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Yes you are on the right track and sorry that you had bad experiences with men, lol.

No, there are no special tools and you have to be careful not to damage the bolts head if they are too tight. You need a good grip and righht amount of force to get them loose.

Good luck.

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Tuesday, August 27th, 2013 AT 8:29 AM

SANDEE WON

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9 POSTS

Will I need to remove the intake manifold and fuel rail to change the fuel regulator? It looks like a big job but there is not much room for a screw driver.
Thank you, sandee won

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Tuesday, August 27th, 2013 AT 11:03 PM

KHLOW2008

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I can't remember the exact procedure as it was a long time ago that I last did this but you would need to remove whatever that is restricting access.

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Wednesday, August 28th, 2013 AT 5:10 AM

SANDEE WON

MEMBER
9 POSTS

Thanks! I replaced the fuel pressure regulator. I did have to remove the intake manifold and fuel rail to get at it. I carefully connected all fuel and vacuum hoses. I must have missed something. It will start up on first turn, but idles way down and dies. I hold the trottle up and keeep it running. If I rev it, a back-fire in the manifold. No power brake vacuum and black smoke too. What clould I have done wrong? Please tell me the truth, I can take it.

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Saturday, September 7th, 2013 AT 11:11 AM

KHLOW2008

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Seems something was not installed correctly resulting in vacuum losses. Ensure manifolds are flush and was the manifold gasket replaced or was it cleaned?
Check the brake booster hose for leakages and proper installation.

Btw if the battery was disconnected. It results in computer memory losses and this would cause excessively low idling. When throttle body and IAC valves are dirty, air flow is restricted and the engine computer needs to relearn before the idling stabilizes. One quick way is to have the throttle body and IAC cleaned.

Excessively low idling can reduce efficiency of the brake booster if it is repeatedly used within a short time frame.

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Sunday, September 8th, 2013 AT 12:39 AM