Hard to start at times

[d_crosson]

My 2000 grand am 3.4L (128xxxkm) has been very hard to start at times. It is almost as if it doesn't want to catch. The gas pedal must be pushed down in order for it to start. But this doesn't happen all of the time, only once and awhile. I have replaced the plugs and wires recently and made no difference. Any suggestions what it might be?

[J-Ri]

Check the fuel pressure.

[rhino61466]

If it is related to your gas pedal I'm not sure; however, it could be your ignition switch or master lock cylinder. I have an 01 GA and had to replace my ignition switch at 98k. Apparently the ignition switches are not very good quality.

[d_crosson]

Is there anyway I could check to see if it is the ignition switch? I am wondering if this could be related to; I seem to use massive amounts of gas lately.

[g4life]

My 01 grand am 3.4 is hard to start as well it was idling sporradic when the engine was on idle. I changed out my MAF sensor and the Idle is back to normal. I also changed out my pcv valve cause the exaust smelled like wrotten egg and it was consuming allot of fuel. after i fixed that problem i got a p0305 code which is misfire on piston 5 So i checked my plugs and coil and changed out my wires and the code went away. but now im still left with the car hard to start and stumbles. I have been checking every where and it leads me to to believe that it might be my o2 censor or a fuel injector but first im going to change the fuel filter wich is the cheapest. I have been all week researching this problem. yours might be a combination of things like mine i hope this helps somewhat. If i find the problem ill post it.

[g4life]

I changed out my fuel filter today checked my fuel pressure regulator for leaks and disconnected my o2 sensor and started the car hot and cold a couple of times and still no change im going to have to check my injectors and i might have a leak in my intake gasket cause i do have a lifter noise.

[xeroinfinity]

Several things could cause this issue.

But Id replace the fuel filter if its not been in the last 20-30k miles, these are highly neglected areas. And check for vacum leaks in the sir intake and around the LI manifold.

Quiet possible an injector is acting up on both these GAs. If you dont run injector cleaner or have the system cleaned profesionaly every so often you can experiance these same problems.

Here is a link with several test procedures, including the ignition switch, O2 sensors etc etc.
Tips & Maintenance

[g4life]

I added a fuel Injector cleaner over the weekend and my wife reports that the car has been turning on fine when cold I will have to check tmrw to see if it does the same thing when engine is hot.

[3100]

remember ECT sensor is very important when starting. O2 sensor has nothing to do with starting since when ever you start system will always start in open loop and after several seconds depending on how hot the coolant is will go into closed loop. However if your ECT sensor is telling your pcm that engine is so and so degrees hot or cold pcm will lookup its tables and based on the temperature find the corresponding value for injector pulse width time on. So if your ect is a bit off your engine may not get enough gas pumped in for the start (remember cold engine needs more gas for start, hot engine less). Replace your ect it is only $14 and make sure all the wires and connectors are ok.. good luck.

[xeroinfinity]

This ECT realy has nothing to do with this issue. If it was failing the temp guage wouldnt read correctly.
Here is a link with those test procedures with the temp/resistance chart for this model GA.

IMO This is more likly a fuel (delivery) issue. Either the injectors are clogged/dirty or the fuel pumps weak, could also be the fuel filter clogged.
Even a dirty air filter can cause simular issues with start ups cold or hot.

[3100]

test resistances of your coils, if they get to hot resistance increases and will not send enough voltage to your plugs. someone must know resistance values for primary and secondary circuit I just remember that when you measure the resistance from the ICM side it should not be more than 1 ohm, but for the towers I am not sure.

[xeroinfinity]

Yeah you can check for good spark with a old plug, placed in the wires and cranking it over with the plug grounded, but dont touch it while cranking ! Spark should be bright blue.

If not disconnect the plug wire and test it. The resistance of a good plug wire should be around 600 ohms per foot, ie. 2ft=1200ohms.

If that checks out check the coil(s).
The secondary resistance, acrossed the towers, should be between 5000-7000 Ohms, if it's not replace the coil(s).

Also if no spark could test your crank sensors. Procedures for that are here... Tips & Maintenance

[d_crosson]

Took it to GM and got them to clean the injectors, very dirty. It starts well now and my mileage is back to normal, thanks.

[g4life]

I finally took the car to the shop, they put it on the machine and found nothing wrong. I asked if the Inectors were working and they said yes. so i took the car home and serviced my TB and IAC valve which was really dirty. the car starts good when cold now but it still doesnt start up good after its been running and i let it sit for a few. I noticed that the car starts acting up when the temp is 2 lines after half way point and i dont hear my fan cutting on so im going have to check on that. Does any one know at ehat temp is the fan supposed to cut on?

[xeroinfinity]

Originally Posted by g4life

I finally took the car to the shop, they put it on the machine and found nothing wrong. I asked if the Inectors were working and they said yes. so i took the car home and serviced my TB and IAC valve which was really dirty. the car starts good when cold now but it still doesnt start up good after its been running and i let it sit for a few. I noticed that the car starts acting up when the temp is 2 lines after half way point and i dont hear my fan cutting on so im going have to check on that. Does any one know at ehat temp is the fan supposed to cut on?

Here are how the fans work;

The PCM commands Low Speed Fans ON under the following conditions:

The engine coolant temperature exceeds approximately 106°C (223°F).
The A/C refrigerant pressure exceeds 1310 kPa (190 psi).
The vehicle is shut off when the engine coolant temperature is greater than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay ON for approximately 3 minutes.

The PCM commands High Speed Fans on under the following conditions:

The engine coolant temperature reaches 110°C (230°F).
The A/C refrigerant pressure exceeds 1655 kPa (240 psi).
And when certain DTCs set.