Trouble starting

[Ric]

I'm still around. RoughSHOd, my 1993 SHO with 192.*** is difficult to start after shutting off and then trying to restart on high temperture days. Any time the engine is cold, it starts right up. On HOT days, if I shut it down, it will not start until I let the engine completely cool down. Any advice would appreciated.

 

[stevetatro]

Did you pull codes? Always a good idea.

Many people will disagree, but when my '93 ATX experienced the same symptoms, and got progressively worse, my problem was a bad Camshaft IDentification sensor.

If you have a code 214, you'll know for sure this is the problem.

A replacement is available at AutoZone for around $40 I believe. Couple of screws and an electrical connector and you're done!

Good luck.

 

[Ric]

stevetatro:
Did you pull codes? Always a good idea.

Many people will disagree, but when my '93 ATX experienced the same symptoms, and got progressively worse, my problem was a bad Camshaft IDentification sensor.

If you have a code 214, you'll know for sure this is the problem.

A replacement is available at AutoZone for around $40 I believe. Couple of screws and an electrical connector and you're done!

Good luck.

Thanks, Where is the Camshaft Identification sensor located?

 

[SilverSHO]

The camshaft ID sensor is on the passenger side of the rear head; it looks like a black cap with a plug in it on the end of the exhaust cam.

 

[Mike Kopstain]

I agree. A couple other places to look are the DIS module and the check valve on the fuel return line.

 

[sdpatt]

You didn't mention backfiring or rough cranking during startup, so it probably is not the cylinder idnetification (CID, aka camshaft position sensor) sensor. How old is your fuel pump? When you turn the ignition key to ON whe the car is hot, what do you hear? Is the fuel pump's noise a steady whine or does it lower its pitch over the 1.5 second it runs? This would be a problem with the internal valving in the fuel pump that is allowing the fuel system pressure to bleed off. You could allow the pump to build up pressure by turning the key to ON for about a second and a half before going all the way to START. The remedy for this condition is a new fuel pump. Does the pump sound like it is straining or pulsing? New pump time for this one too.

Do you hear rumbling from the fuel tank when the fuel pump is running? This usually happens after a hot start and is the result of the fuel return line check valve not holding the pressure in the return line. This allows the hot fuel to vaporize and bubble up through the fuel causing the rumble. The remedy for this is to replace the return line check valve. I have recently posted the link where I identified the part number for this valve. Search on fuel return check valve.

 

[Ric]

Originally posted by sdpatt:
[QB]You didn't mention backfiring or rough cranking during startup, so it probably is not the cylinder idnetification (CID, aka camshaft position sensor) sensor. How old is your fuel pump?

No backfiring or rough cranking during startup. Fuel pump is less than one year old (9 months).
Whe ignition is turned on hot, a low pitch is heard for 1.5 seconds. No noise at all after first attempt. No rumbling from the fuel tank when the fuel pump is running.
When the SHO does start, it runs at a very low RPM (400) until the accelerator is gently pressed to bring it to smooth running. It then idles nicely at 800 RPM. I have an Idea it is the fuel pump, as it was not very expensive from NAPA.

Ric