car still has starting issues???

[jeff983000gt]

well my 2000 trans am ws6 is acting up agian..ive changed my spark plugs..fuel filter..air temp. sensor..and cleaned out all the other sensors and my car still occasionally still wont start right away..i have a new set of msd wires coming in and a new throttle position sensor..but i dont know if those will fix it..the car is completly random as to when it starts or doesnt..it will start right up probly 75% of the time..but for that 25% its gay!!! and it usually happens in pairs, when it doesnt start right up..it takes probly 3-4 times of cranking it to get going..like it will go days without the problem then a day it will act up..i took the air filter off to see if moisture was in it..but it was dry..any ideas as to what would be causing this problem??? there are no check engine lights either..so no help there..you think its sensor related or more involved..the car has only 34000 miles on it! any help would be appreciated!

[muff34]

Have you actually verified that it is getting spark even tho it is not starting. One thing I was told that if the crank position sensor starts to go awol ,the tach will not register as it is cranking over. I can not verify that tho as being correct. At the time I was looking at a `98 Grand Prix GTP. it would quit and not reatart. Good luck . Just my two cents

[jeff983000gt]

ya there all deff getting spark cuz the power doesnt lie..its deff on all 8 cylinders! ill have to check out about the crankshaft sensor thought..thanks

[wrightz28]

What he meant was are you sure your getting spark when it's not starting, IE cranks but no start means either lack of fuel, spark or compression.

[jeff983000gt]

well i had checked the feul rails for gas and there was gas for sure..none of the old spark plugs were wet or anything when i changed them so i dont see why they wouldnt be sparking..i guess thats a possibilty thought..what do you mean by compression?

[wrightz28]

Since it does eventually start and run well, compression can be eliminated, to your answer you question tho, part of the stroke cycle, compression is when your compressing the air/fuel mixture to be ignited, sparked into explosion, hence the combustion engine.

The question regarding having spark, is if the ignition system is comanding the plugs to fire when the no start condition occurs.

[gmack221]

Sounds like your fuel pump may be acting up ... I'd check the fuel pressure ... with a gauge not a screwdriver!

[jeff983000gt]

ya fuel pump could be a possibility..im just trying to get the easy cheap stuff out of the way to see if anything fixes it.. cars been fine for the past 2 days again..but who knows if it will do it again.i put the msd wires on today, throttle position sensor tomorow..wouldnt it be more of a consistant problem if it was something as serious as the fuel pump?

[wrightz28]

Originally Posted by jeff983000gt

, throttle position sensor tomorow..wouldnt it be more of a consistant problem if it was something as serious as the fuel pump?

For the cost of the TPS why not jsut a fuel pressure guage?

If you plan on working on EFI car, which obviously you do, it is a must have tool in your tool box.

[gmack221]

I've seen vehicles act up when the fuel pump is going out, run fine one min & the next its almost impossible to get started. I recomend either buying a gauge or paying a shop to put one on for you ... should be cheap if you tell them thats all you want is for them to put the gauge on & tell you what the pressure is. I had a grand am that would get warm if I was sitting in a drive thru, then when I went to leave it would die, or just die for no reason, replaced the fuel pump & its been fine for the last 2 months.

[jeff983000gt]

well ive read in a few forums about people with fuel pump issues..and they seem to have stalling issues not starting issues..so im not leaning towards fuel pump...

[jeff983000gt]

well ive today im gonna check my fuel pressure with a gauge..say it does read low..basically meaning it is the fuel pump? how hard is it to change..im pretty machinacally inclined..i do everything myself..how hard is it..and how long does it usually take?

[wrightz28]

Have you bought the gauge already? A quality one should come with instructions on how to use it properly (if it doesn't, Autozone has some nice instructions on their site. There are several different test you can perform to narrow down wich componenet of a fuel system may be faulty, thus no, if your pressure is low it does not mean it's the pump. It could be leaky injectors, faulty pressure regulator, and if applicable, check valve.

[gmack221]

A bad fuel pressure regulator will usually leak thru the vacume hose (if these are the same as the one on my grand am), make the car starve for fuel thus the plugs will be bright white. A leaky injector will make the plugs carbon up (black). If the fuel pressure is low change the fuel filter, check again, if its still low & the plugs looks ok & the pressure regulator isn't leaking thru the vacume hose, most likely its a bad fuel pump.

[jeff983000gt]

well i checked my fuel pressure ( with a gauge ) about 3-4 days ago..it was fine..with key just on "on" position" it was around 55...then while running on idle about 50..which is what the book says it should be running at..i checked it multiple times that day and it was consistant..so i figure its not fuel pump..or anything fuel related really..BUT the car has started fine everytime for the past 5-6 days now..its wierd it will go a while being fine then out of the blue just not wanna start, but it hasnt done it in a while sooooo