Help hard start after 20mins
Help hard start after 20mins
Hey everyone I have a strange issue my 91 starts fine normally but if you drive it get it fully warmed up and then stop somewhere and the car sits for about 20mins it is really hard to start and smells like fuel. Any ideas ?
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Lokim
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- Car: 1994 Infiniti Q45 acquired 4/25/10 w/192K
Now at 222K and going strong! - Location: Seattle, WA
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Re: Help hard start after 20mins
Look into the ignition system...
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Q451990
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Re: Help hard start after 20mins
I had this exact issue after installing "remanufactured" injectors into my first Q back in the late 1990s.
Your car is probably flooding due to an injector bleeding down. Usually this is a slightly pinched or cut lower o-ring. At night when it bleeds down, all of the fuel in that rail seeps past your piston rings, so you don't know that it happened - but after a hot soak (your 20 minute stop) you're into the peak time for the fuel to have accumulated in the combustion chamber but it hasn't had time to seep away.
I would fix this quickly, since diluting your oil isn't a good thing - and if it gets worse you could hydrolock your engine.
Heath
Your car is probably flooding due to an injector bleeding down. Usually this is a slightly pinched or cut lower o-ring. At night when it bleeds down, all of the fuel in that rail seeps past your piston rings, so you don't know that it happened - but after a hot soak (your 20 minute stop) you're into the peak time for the fuel to have accumulated in the combustion chamber but it hasn't had time to seep away.
I would fix this quickly, since diluting your oil isn't a good thing - and if it gets worse you could hydrolock your engine.
Heath
Re: Help hard start after 20mins
Hey thanks for the response I am going to tear the upper intake off tonight and go to the dealer tomorrow (they are holding the seals in my name) and replace them tomorrow night should I go ahead and do both the upper and lower seals or just the lowers ?
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Lokim
- Posts: 681
- Joined: Mon May 10, 2010 12:47 am
- Car: 1994 Infiniti Q45 acquired 4/25/10 w/192K
Now at 222K and going strong! - Location: Seattle, WA
- Contact:
Re: Help hard start after 20mins
Give your dipstick a sniff. Does the oil smell like fuel?
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Q451990
- Moderator
- Posts: 11030
- Joined: Tue Jul 23, 2002 8:21 am
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- Location: Columbia, SC
- Contact:
Re: Help hard start after 20mins
After you have the fun of taking the plenum off, you'll probably answer this question "yes" out of fear of having to remove it again... not a lot of fun. I have found the best way to get the injectors out without damaging them is to remove the entire fuel rail with the injectors in them. Then put a deep well socket over the tip end of the injector and put it in a vice with some screws in the threads for the cap to give space for the injector to pop out. I don't remember the size of the socket, but it needs to fit in a way that won't damage the tip of the injector, but presses on the metal area around the tip without catching on the bottom of the fuel rail. These things are a real pain to get out, and brittle - so you're guaranteed to break them if you start prying them out with a screw driver or grabbing them with plyers.
I would ohm test them as well... it's very likely you have some on the way out... http://www.q45.org has instructions under the technical section. Once they're out you can just test them with an ohm meter. Should be about 12-14 ohms cold. If you get over that they are beginning to fail due to ethanol exposure and will probably need to be replaced in the near future.
I think you're going to find that a lot of hoses and the runner gaskets will all need to be replaced if they haven't been done already. Many people try to avoid duplicating plenum labor by replacing all of the hoses, knock sensors if they're cracked or ohm incorrectly, the knock sensor subharness, etc. while they're in there. I spent over a week on my injector job cleaning and replacing everything, but that's just me.
At a minimum I would replace those runner gaskets, your throttle body gasket, and all o-rings with new ones. Be sure to lubricate the o-rings and mating surfaces in the fuel rails before you install the new injectors, and avoid twisting the injectors too much while inserting them to help avoid pinching or cutting your new o-rings.
Good luck!
Heath
I would ohm test them as well... it's very likely you have some on the way out... http://www.q45.org has instructions under the technical section. Once they're out you can just test them with an ohm meter. Should be about 12-14 ohms cold. If you get over that they are beginning to fail due to ethanol exposure and will probably need to be replaced in the near future.
I think you're going to find that a lot of hoses and the runner gaskets will all need to be replaced if they haven't been done already. Many people try to avoid duplicating plenum labor by replacing all of the hoses, knock sensors if they're cracked or ohm incorrectly, the knock sensor subharness, etc. while they're in there. I spent over a week on my injector job cleaning and replacing everything, but that's just me.
At a minimum I would replace those runner gaskets, your throttle body gasket, and all o-rings with new ones. Be sure to lubricate the o-rings and mating surfaces in the fuel rails before you install the new injectors, and avoid twisting the injectors too much while inserting them to help avoid pinching or cutting your new o-rings.
Good luck!
Heath
Re: Help hard start after 20mins
Thanks for the info Heath, I have already had the intake off and back on the other day so last night when I did it, it only took me 20 mins I don't think it is that bad of a job. Anyway what are you lubing the seals with ? Thanks again for everybodies help !
Re: Help hard start after 20mins
I used a product from Harbor Freight named - Super Lube - Synthetic Grease.
This is the product that Deatsch Werks provides with o-rings for their injector kits.
It is also a good dielectric grease. It provides a slick coverage area that helps prevent the seal from pinching during the tightening process.
Also, as I tighten down the injector cap tops, I rotate one full turn between each side of the cap to evenly balance the force -- again to avoid pinching the seals.
http://www.harborfreight.com/85-gram-su ... 93744.html
This is the product that Deatsch Werks provides with o-rings for their injector kits.
It is also a good dielectric grease. It provides a slick coverage area that helps prevent the seal from pinching during the tightening process.
Also, as I tighten down the injector cap tops, I rotate one full turn between each side of the cap to evenly balance the force -- again to avoid pinching the seals.
http://www.harborfreight.com/85-gram-su ... 93744.html