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Cold Start Valve On 1st Gen 400's


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I finally got a straight answer about why my car takes either a long crank or two short ones to start if it has been sitting for more than a half hour. There is a cold start valve that can go bad. I ordered one just now that is new in box off the net and wanted to know where I should look for it on the engine :huh: and what tools/time I should be lining up for the replacement of the valve. Is fuel going to be spilling all over me or anything?

Thanks for any info you guys have, my Dad loves that his daughter can work on her cars, but I won't tell him where I get the best tech advice; it certainly is not from him! (No Dad the shop was wrong, your muffler bearings did not need to be replaced... )

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You should do a residual fuel pressure check to diagnose the system first, before throwing parts at it. I seem to recall the cold start valve is under the intake manifold, but I'm not sure.

Let's see, a part that costs $40 and designed to start the car when it is cold and my car does not start on the first crank when it is cold. If it walks like a duck and quacks like a duck... I spent a long time (almost a year) asking on this forum what my issue could be and lo and behold my latest blind search on the web let me to a BMW site that had a former lexus mechanic. "It is your cold start valve, they are over $100 at lexus, find a seller on ebay..."

At least someone knew there even is a cold start valve. How many others here knew about it? I bet not many.

Don't forget that when the car is very hot in blazing heat while I am at work, is starts right up too. If the fuel pressure in the rail was leaking down it would leak down no matter what the outside temperature is. Kind of like our failed climate control displays showing perfectly in the same kind of heat soak conditions. Increased resistance due to increased heat gives the capacitor the right output to fire the display. I am betting on the valve solving the cold start issue...

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So you're sure it's the valve, but you're not sure what happens when you disconnect it?

Throw the valve at it. You still won't know if the pressure regulator is working, or if the fuel pump is getting weak, or if you have a leaky injector (other than the start valve).

Stand back.

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I finally got a straight answer about why my car takes either a long crank or two short ones to start if it has been sitting for more than a half hour. There is a cold start valve that can go bad. I ordered one just now that is new in box off the net and wanted to know where I should look for it on the engine :huh: and what tools/time I should be lining up for the replacement of the valve. Is fuel going to be spilling all over me or anything?

Thanks for any info you guys have, my Dad loves that his daughter can work on her cars, but I won't tell him where I get the best tech advice; it certainly is not from him! (No Dad the shop was wrong, your muffler bearings did not need to be replaced... )

It could be the injector or it could be inj time switch at the front of the engine on the water bridge.

I don't have any diagrams, but I'm sure any Lexus dealer will fax you one. They've always obliged me whenever I've asked for any part location or part breakdown diagrams.

Here's a link I think will help you out:

http://lextreme.com/forums/showthread.php?...hlight=starting

PS: Good onya for making pops proud of his daughter! :cheers:

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So you're sure it's the valve, but you're not sure what happens when you disconnect it?

Ahem. Lets see... ...I did ask about the location and any issues with its installation did I not? SRK, are you just trying to scare me? Sounds like it.

Thanks eatingupblacktop! I like all your posts. You are very constructive in your comments. VERY cool!

Hey killerfatty, I will post my results as soon as I investigate the repair and get the info I was looking for.

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I'm not trying to scare you. When the valve is disconnected, the residual pressure will be released, unless it has bled down. Wear eye protection. My point was that diagnosing such things is tougher than replacing them - a "cart before the horse" situation. Which is why I wonder how you have diagnosed this problem. Maybe you're right. Maybe not. I just don't like replacing parts - I like to know that the part WILL fix the problem.

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I'm not trying to scare you. When the valve is disconnected, the residual pressure will be released, unless it has bled down. Wear eye protection. My point was that diagnosing such things is tougher than replacing them - a "cart before the horse" situation. Which is why I wonder how you have diagnosed this problem. Maybe you're right. Maybe not. I just don't like replacing parts - I like to know that the part WILL fix the problem.

Point taken. Thanks for the heads up on the line pressure and need for eye protection.

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