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Discussion Starter #1
New to this forum because I'm out of ideas. Please can someone help? My wife 2011 Sienna XLE is having delay cranking. On a very cold start, meaning van has been sitting over night, it starts up fine. If it runs and then stops, and I turn the ignition on immediately, it starts fine. However, if it's been sitting there for 10 minutes or more, the start/crank is a little rough/long but it always starts. I've checked the battery and it is good. The starter has been checked and it seems ok. The long crank/rough start is very intermittent. Sometimes there is no problem, other times, it's a long crank but it will always start. I've also changed out the starter relay. Also recently replaced the sparks plug. My mechanic thinks that it could be plugged fuel injector so I am currently treating the gas with Techron. We like to take our van on long road trip and am afraid it will not start one day where we are in the middle of nowhere. Any ideas?
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Has your mechanic checked fuel pressure? I'm wondering if it could be weak fuel delivery.
 

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Has your mechanic checked fuel pressure? I'm wondering if it could be weak fuel delivery.
Just had the mechanic check the fuel pressure. He said it's supposed to be 25 psig. It dropped to 22.5 pig so he doesn't feel like it warrants checking out the fuel pump. I kinda of agree because if it was pressure loss, why would it have no problem on a cold start, ie the van has been parked overnight but starts right up. Checking the crank angel sensor next.
 

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I ended up replacing the fuel pump and the problem is gone. Mechanic said after several tries he was able to see the fuel pressure drop. It's been a few days since the fuel pump has been replaced and the car is back to normal again.
 

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Most of the time fuel pumps just die and the problem is easy to diagnose. But sometimes the pump accumulates so much internal wear that the output pressure is below spec and strange drivability problems occur. I went through this with my old GMC pickup a few years ago. My mechanic didn't want to recommend replacing the pump because he could measure pressure at the lower acceptable limit. I wasn't convinced his gauge was accurate, since it was designed to measure higher pressure multiport systems and my truck has low pressure throttle body fuel injection. I finally told him to replace the fuel pump at my risk if that didn't solve the problem. He installed the new pump and the truck ran great.
 
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