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New Problem, Hard Start In The Morning

andy95'R33GTR

By andy95'R33GTR,
in General Maintenance

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andy95'R33GTR Rising Star

andy95'R33GTR

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im having a hard start during a morning, battery is ok, i need to crank the engine 5 times, after no idle.. i need to press the accelarator, and the engine runs very unstable, for at least 1 minute before it will sit flat idle on 950.... but when the engine is already heated up, no problem starting .......... =( help

andy95'R33GTR Rising Star

andy95'R33GTR

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may also be the cold start valve. they are a pain to get to.

also try letting the fuel pump prime fully before trying to start the car and see if that changes things at all.

i observe it will pickup when first starting, but can't fire up the engine...hmmm... il check everything.. could also be a timing belt... i haven't replaced it yet... i already have the replacement.. but haven't find time to install it...

andy95'R33GTR Rising Star

andy95'R33GTR

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ok i tried, removing my return line... and after i turn the key to on position the gas just flow thru the return hose...meaning, my fuel regulator is open??? will this really need to close in morning just switch on, not cranking the engine?

blind_elk Grand Master

blind_elk

Posted
Posted
ok i tried, removing my return line... and after i turn the key to on position the gas just flow thru the return hose...meaning, my fuel regulator is open???
No. The fpr is designed to maintain the correct pressure behind the injectors. If there is too much pressure, the fpr simply releases excess pressure, ie fuel, back to the fuel return line.
andy95'R33GTR Rising Star

andy95'R33GTR

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No. The fpr is designed to maintain the correct pressure behind the injectors. If there is too much pressure, the fpr simply releases excess pressure, ie fuel, back to the fuel return line.

even the engine is not running? yet? or the engine is not cranking yet?? how come the fpr will open, there is no vaccum yet..

blind_elk Grand Master

blind_elk

Posted
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The fpr controls fuel pressure by an internal spring acting against a diaphragm. The fuel pressure in the rail is varied by applying vacuum or boost to the diaphragm in the fpr. When the engine is not even running, the fpr sees atmospheric pressure.

If the fpr simply opened because the engine was not running, it is unlikely that the engine would start because there would not be enough fuel pressure in the rail to squirt properly through the injectors.

According to my workshop manual, cold start problems can be caused by:

- cold start enrichment from the engine temp sensor is not working

-- try starting with the engine temp sensor disconnected

-- check engine temp sensor resistance

-- check engine temp sensor output voltage

- idle speed controller is not working

- start time enrichment is not working

- cranking speed too slow

Then combine with the poor cold idle:

- idle control system not working correctly

- cold start valve not working properly

- engine temp sensor not working correctly.

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