Hard Starting Sho

[John L. Mickevich]

I was just wondering, the last year or so there have been times when the
Sho has been hard to start. Like last Saturday, after doing some shopping, it took (5) times for the engine to engage. The first (3) times, nothing, the fourth time, it ran for a second, then died. The fifth time it started up ok.

Should I be thinking about changing the crank sensor or is there anything else that I should check first?

Thanx,
John

 

[93rev2sev]

What maintenance is it due for in the next 10,000 miles?

 

[LJRuddy]

Hard starts are a known symptom of a cam sensor going bad. Does your tach needle move when cranking?

Being EXTREMELY broad (as I forget the detailed details) the cam sensor tells the computer which cylinder is on the compression stroke. Since 2 cylinders are always being sent a spark at the exact same time, the cam sensor basically decides between cylinder pair 1, 2 or 3 to send spark to. When the cam sensor fails, the computer does not have this information so it "guesses" which pair is next to be ignited. Thus, you can get difficult starts as the computer guesses incorrectly on which pair of cylinders needs the spark.

So uhm yea... Check for a bad cam sensor.

EDIT: I re-read your post... Based on what I typed above, the SHO engine should start perfectly no later than the 3rd try. Since you said it took 5 attempts for it to start, I'd say something else is wrong here... How is your fuel pressure? Do you hear the fuel pump prime with the key on but engine off? Does the engine accelerate well on the top end or does it feel abnormally sluggish? How old are your plugs and wires? Any error codes?

 

[John L. Mickevich]

What maintenance is it due for in the next 10,000 miles?

I hadn't really planned on any major work on the sho, but earlier last year
a mechanic suggested having the lower portion of the engine worked on
(water pump, cps, etc.) since the sho had relatively low mileage but still
getting up there in years.

John

 

[John L. Mickevich]

Hard starts are a known symptom of a cam sensor going bad. Does your tach needle move when cranking?

Being EXTREMELY broad (as I forget the detailed details) the cam sensor tells the computer which cylinder is on the compression stroke. Since 2 cylinders are always being sent a spark at the exact same time, the cam sensor basically decides between cylinder pair 1, 2 or 3 to send spark to. When the cam sensor fails, the computer does not have this information so it "guesses" which pair is next to be ignited. Thus, you can get difficult starts as the computer guesses incorrectly on which pair of cylinders needs the spark.

So uhm yea... Check for a bad cam sensor.

EDIT: I re-read your post... Based on what I typed above, the SHO engine should start perfectly no later than the 3rd try. Since you said it took 5 attempts for it to start, I'd say something else is wrong here... How is your fuel pressure? Do you hear the fuel pump prime with the key on but engine off? Does the engine accelerate well on the top end or does it feel abnormally sluggish? How old are your plugs and wires? Any error codes?

The tach moves when starting, I can hear the fuel pump prime, it doesn't seem to be sluggish, but the plugs and wires are original.

John

 

[tompumped]

Something i'd suggest is to step on the gas while cranking when it happens see if that helps. I had this problem, I suspect a leaky injector. Worth a try.

 

[medgraphsho]

check the fuel regulator too