XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

Hard or no warm start

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Old Apr 4, 2013 | 03:52 PM
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Default Hard or no warm start

My 86 5.3 always starts perfectly when cold or after sitting overnight. Recently, and occasionally, it will not start after a short trip. Sometimes there is just a click and other times the engine turns over for about 10 seconds before, reluctantly, starting. The battery is new and the volt meter is dead on. I can understand a hard warm start problem, but just the click is where I have having difficulty. All connections are perfectly tight. I was thinking starter or starter solenoid, but that would occur all the time, not just when warm -- correct?

Thoughts?

Thanks!
 
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Old Apr 4, 2013 | 08:22 PM
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there are a lot of stories circulating about difficult warm starts. and i have also experienced a similar symptom, especially when the engine is running on the warm side.

the prevailing explanation is fuel vaporization in the fuel rail--did i get that right?--from the heat of the engine after shutdown.

following others' suggestions i've been able to get over this by turning the key to the on position for several seconds to allow the fuel pump to run, then switching back to off, and repeating 2-3 times, prior to actually turning to the start position.

if i don't do this, the start will be rough, and will only stay on if i hold the accelerator down and continue to keep the throttle open for a a minute or 2. then it tends to normalize.
 
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Old Apr 5, 2013 | 12:41 AM
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@ Jagxjs

Sounds like you have 2 problems..... your "clicking" would appear to be a separate issue from the "cranking and cranking before spluttering into life"

The latter is as per DrScientists suspicions, ie fuel vapour lock most probably

The former sounds like something to do with the starter for sure.....
 
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Old Apr 5, 2013 | 01:22 AM
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Agreed on two different issues: A) a cranking problem and B) cranks, but hard to start problem.

As for the later, IMHO, vapor lock would seem unlikely after a "short trip" as menioned in the original post...unless perhaps the engine was running on the hot side and/or ambient conditions were extreme. And in theory (heh heh) the fuel temp switch (if functioning) would prevent thisby dumping vauum to the regulator and thereby increasing fuel pressure to clear the fuel rail.

I'm thinking more of an overfueling problem: a cold engine likes extra fuel (which would explain the easy starting when cold, as mentioned) but a warm engine certainly doesn't.

Drippy injectors? Excessive fuel pressure? Skewed coolant temp sensor? The temp sensor is easiest to check...or even replace for $20. As guesses go, that isn't too hateful.

Cheers
DD
 
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Old Apr 5, 2013 | 01:25 AM
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Originally Posted by Jagxjs
I can understand a hard warm start problem, but just the click is where I have having difficulty. All connections are perfectly tight. I was thinking starter or starter solenoid, but that would occur all the time, not just when warm -- correct?

Thoughts?
Please clarify what's included in "...all connections".

Assuming the clicking you hear is the starter itslef, and not just the starter relay, I'd agree that the starter is probably giving up.

Cheers
DD
 
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Old Apr 5, 2013 | 05:51 PM
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Thanks Doug. I was planning to replace the coolant temp sensor anyway as part of clear the valley strategy. Might as well do it now.

As always, thanks again!
 
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Old Apr 5, 2013 | 06:06 PM
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Good point Doug. I meant battery connections only. "All connections" was unintentionally misleading.
 
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