cold start Question??

[jonysho]

When the temp is cold outside my 91 MTX has a very hard time starting. But ony when it's cold. It will crank over just fine but won't start.
Last winter if I turned the ignition on then off then back on and cranked it, it would start right up. But this year that doesn't even work.

Is there some sort of sensor or something that could be going bad?

 

[pete c]

couple of winters ago my slo wagon wouldn't start worthashit in very cold weather. The next summer it crapped out while on vacation altogether. The culprit was a clogged fuel filter. This causes reduced fuel pressure at the injectors. Change your filter.

Next time you get into the car, turn the key to the run position (don't start it). You should hear the fuel pump come on, run a few seconds and shut off. If your filter is a clogged as mine was the pump will stay on because it never reaches cutoff pressure at the fuel manifold.

 

[Mr Anonymous]

Fred Hurder and a couple of other members discussing this recently: http://www.shoforum.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=17;t=003936. It seems to be becoming more common on Gen 1's. Some speculation was that it could be due to a 'tired' coil pack.

 

[projectSHO89]

pete,

The initial pump running sequence is for about 1.5-2.0 seconds based on time. That is why several ON-OFF cycles of the ignition switch can help build up proper pressure before hitting the START position. There is no pressure feedback circuitry that cycles the pump at any point during engine operation.

Once the engine starts, the fuel pump runs continuously with the fuel pressure regulator maintaining the appropriate pressure at the fuel rail.

With the cold weather setting in for many, contaminants and other crap trapped in the fuel filter can start to thicken and lead to fuel delivery problems. Replacing the filter will definately help in these cases. Cheap, not to difficult.

Steve

 

[sdpatt]

The topic that was referenced was not about starting, but rather about engine hesitation when cold. Nothing in that topic discussed starting difficulties. Different subject. I also doubt that a "tired" coil pack is the cause. Old wires maybe, but not the coil pack.

Check the fuel system (filter, pump) to ensure that it generates the proper pressure and flow. From the behavior you mentioned from last winter, this sounds to be a factor. The other culprit could be a weak spark. How old are those plug wires and plugs? If the wires are older than 6-8 years and 120,000 miles, they have long ago served their best and are due for replacement.

 

[jonysho]

The wires are brand new. About two months old. and the plugs the same. The coil is good I know that for a fact. Fuel filter is brand new also. This really does puzzle me. Every electronic piece on the ignition system cps; cam pos. sens;computer; DIS module. All are about two months old with about 1000 miles on them.

Any other suggestions. Or is this just a characteristic of the GEN I's

 

[jcostantino]

What about the fuel pump? You should invest in or borrow a fuel pressure gauge. I need to do the same. Perhaps our problems are related?

If you crank your car continuously, does it eventually start? I get that problem with my 95 even when it's hot out (90o or more) and I suspect some sort of fuel pressure problem.

Jeff

 

[sdpatt]

The engine should fire (spark igniting fuel) by the first complete revolution of the engine in all years and versions of the SHO V6.

 

[snowwind1990]

I'm speculating here, just like everyone else.
Fuel pump relay..1990,1991 only located IN the CCRM......
You can e-mail me privately, 'cause I'm getting into a peeing contest with other speculators..

but I will say the cold weather has a lot to do with your/our problem.
Ma Ma M.......not a know it all by any stretch, but very experienced with the "possession of the SHO" shoot