Chevy & GMC Vans

so in my resent post i was having misfire issues and had taken it to a shop and drove fine for a day now my 99 safari will not start at all it turns over has spark has fuel has brand new cap rotor plugs wires coil ignition mod that was put on Friday got it back from the shop sat and drove it all day then went to leave and will not fire over any ideas

What is your fuel pressure? You need to hook a gauge up and see. Must be above 50 psi. You can't tell just by opening the schraeder valve to see if you get gas.

I will back up LiftedAWDAstro with this cool video of what he is getting at.

[youtube]http://www.youtube.com/watch?v=yjQY613s ... BC660C213A[/youtube]

so i checked the fuel pressure and it is good and watched the video and everything is good. van is now starting but still having the misfire code and ignition mod code thrown not sure what it could be and all spark related parts are new twice over i am starting the van and letting it run and cool down and repeat the steps but cant get it to do the not start thing again could it be the pcm?

You should list the codes so we have a better idea. The misfire history should be visible on your shop guys scanner to see if it is the same cylinder or random cylinders.

Your going to need to list the ignition mod code so some one who has experienced similar problems can help.

It seems now that you starting problem has stopped, you may want to check the area of where you measured your fuel pressure for something loose. Just a shot in the dark.

Drummernaut wrote:I will back up LiftedAWDAstro with this cool video of what he is getting at.

[youtube]http://www.youtube.com/watch?v=yjQY613s ... BC660C213A[/youtube]

Nice find Drummernaut, thanks for posting that...

the codes it is throwing now are po420, po340,p1351 and now it starts and runs fine minus the codes being thrown

1999 Astro/Safari

P0420 Catalyst System Low Efficiency Bank 1:

-The VCM determined that the oxygen storage capacity of the catalyst has degraded below a calibrated threshold.

P0340 Camshaft Position(CMP) Sensor Circuit:

-The CMP Sensor reference pulse is not detected once every two crankshaft revolutions.

P1351 IC Circuit High Voltage:

-The ignition voltage is more than 4.9 Volts.

There is allot more text that I just don't have time to type for this right now. It seems you have several conflicting problems or you have some type of wire/power problem.

I good shop should be able to route this out. There are long and distinct procedures for troubleshooting all of these issues. Of course, all of them list wiring as a possible problem.