Im stumped 98 Grand Cherokee 5.9 crank no start

[Blair Warner]

Posting for a friend of mine. About two weeks ago he came home and shut the jeep off came out next morning and crank no start. Pulled codes and replaced a crank sensor (very common on these and I had a spare from my ZJ) got rid of the P0320(I think no CKPS signal was the description) but still no start. Tested for spark and it was there. Tested compression and its what I would call normal for being cold. Fuel pressure seems off to me it primes to 45psi but as soon as you start cranking it drops to about 20psi and slowly builds back to around 40. Its also cranking slowly and needs a starter box on to crank for more than 10 seconds.

I know this isnt well typed sorry Im rushing but if anybody has any suggestions I could pass along it would be appreciated.

Thanks

Topic

[college man]

pull the vacuum line off the fuel pressure regulator
and look for fuel in the line or coming out the fpr.
see if fuel pressure increases.

http://www.ericthecarguy.com/faq/solving-automotive-no-start-problems

[Kevin Criswell]

[quote=”BoneYard-Racing” post=82228] Its also cranking slowly and needs a starter box on to crank for more than 10 seconds.

[/quote]

Get the battery out and take it to a parts store for a charge and test.

If battery voltage is dropping low enough (slowly cranking) the PCM will start to shut down from low voltage and the fuel pump will kick off.

You have to find out why the engine is cranking really slow before going any further in your diagnosis.

[Author]

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