Struggling to start (O2 sensors?)

[omeara7]

Hi,
My 92' SHO has trouble starting at times (random times). It especially seems to struggle if I stall while trying not to ride the notoriously small and short-life clutch. The engine turns over so it's most likely not the starter but it just keeps turning and turning until it eventually slowly starts up with much hesitation (miss-firing as it slowly gets up to idle or 1500 rpm). I'm wondering if this could be a bad sensor of some sort. undefined Any suggestions would be appreciated. Thanks in advance
-Jon

 

[sdpatt]

Oxygen sensors? Absolutely not. They do not come into play until the engine reaches operatnig temperature and enters the closed loop mode of engine control operation.

With a misfire you have a mis-timed spark event. Have you checked the EEC codes? How old are the wires? The plugs? Does the engine ever stumble while driving that coincides with the tach dropping to zero? I'd suspect a CID sensor.

It could also be a leaking fuel injector flooding a cylinder, but that would only affect one cylinder and not make the remaining five reluctant to sustain combustion. Checked the fuel pressure at the fuel rails? Ever change the fuel filter? How old is the fuel pump?

The engine must have spark and fuel at the appropriate times to start and run. You must find out which is amiss.

 

[farley556]

Mine did that exact same thing and it eventually didnt start at all and it was the(IAC) idle air control valve. $75 at autozone

 

[ShadetreeSHOguy]

mine does the same thing, actually ran into doug lewis ttoday and he said it was the cam sensor

 

[rangerj]

Guys,

You can do a few very simple voltage and resistance tests with a DIGITAL Multi Meter (NOT ANALOG) in order to test the DIS (Distributorless Ignition System).

The crank and cam sensors, as well as the coil packs are parts tested. Do a search regarding testing the DIS. Then is you have questions just ask. Also check for any stored codes in the cars computer as an added diagnostic step. rangerj

 

[omeara7]

Thanks for the feedback. Unfortunately, I just recently bought the sho so I dont know when anything was last changed (fuel pump/filter). I don't think the ignition wires are too old but I could be wrong. Once the engine starts, it runs fine with no signs of miss-firing. I haven't checked the eec codes yet, but if the problem persists I will. Thanks again for the suggestions.