Motor dies and stumbles

[slingslingbinks]

Been 5 months sence i had my other problem with my 91 Lumina 3.1. Heres the origional thread, http://www.automotiveforums.com/vbul....php?t=1022899
Sence then the car has been flawless with the exception of the enging developing a miss after replacing a p/s hose. Found the ign. Module not firing 1 coil pack and i installed a used Ign. Module and coil pack assy. only to find 1 coil not firing 1 plug. (it fires the other plug but not both of the plug's) Now the motor will die when taking off and stumbles and dies while going down the road. Sometimes it will die after starting it up as well. I hooked in my snap on scanner and code 42 was logged. Disconnected the battery and cleared the codes, Installed a fuel pres. gage and with it and the scanner i went for a ride. The motor still dies and stumbles, No codes logged and fuel pressure is 38 to 42 psi. It's a little low on fuel pres. I dead headed the pump, Pinched off the small return line and the pressure was 62. So the pump has the pressure. I haven't checked the f.p.r. yet and I did hook up a manual vac. gauge to tell if the cat is plugged and the vac. is good, But i did notice that the vac. gauge will read 17 inches and the scanner says the m.a.p. sensor is reading 7 inches. Soon after this test the scanner logged code 45: rich exhaust. The way it drives is like it's running out of fuel Or the ign. is turned off, But the spedo. still work's when this happens. Once it takes off it's ok. I did ohm check the circuit from the ign. module to the crank sensor and it was 1,041 ohm's. I don't know the speck on it. On the previous repair i did pull the motor and swap out the rod's and mains, while i had it apart i did check out and re loom all of the wiring to the crank sensor and the injectors and all is tied up and not shorting out. I have not bump tested the ecm yet. Nor have i checked the injectors. I'v tried to check back on this forum for any complaint's and there so many that are like my problem and so many have been repaired with crank, map sensors, injector's, ign. modules and ecm's that it's tough to trouble shoot and Sence i have no info from chevy to correctly diagnoise these circuit's. I don't want to start swapping these part's with out further trouble shooting them. Tks for any input u may for me to fix this daily driver. C-ya Scott

[maxwedge]

1k ohms in the harness between the connectors is way too high, look into that.

[slingslingbinks]

That is the ohm's through the cps as well. It's not the ohms in the wires as if i jumped the wires at the cps and ohm checked the circuit from 1 wire of the cps harness at the ign. module to the other wire. This circuit would be at max 5 ohm's then, but i don't know the speck. but it should be a closed circuit and no short's to ground as well.

[slingslingbinks]

Here's an update. Swapped out the 02 sensor and map sensor. Slight hesiation on off idle. No codes, thought i had it and went to test drive it and it died and after 10 attempt's it started only to die on take off. Tried another pcm and still no start, But i did notice there was no rpm reading on the scanner with the other pcm. Suspect it has a problem, so i'll return the other pcm. At this point i wanted to check the plenum for a vac. leak and swap out the injector's. No vac. leak's and i'm currently finishing up installing the injectors. I will check the egr and icv for sticking, clean the throttle assy. If this comes up as a no fix, i'll check the wiring and cps. Wish me luck, the day is warming up and soon it will b nice enough to work on it. Too many project's inside the shop to get it inside. C-ya Scott

[slingslingbinks]

Hell here goes, swapped out the 02 sen. The map and it still died. Tried another pcm and still died. So i thought, Let's check the injectors. Pulled the plenum and swapped them out. Later i learned to ohm check them, So i checked the old ones and 1 was 1.4 ohm's. Speck is 11 to 14. So that was it, also one checked out at 6.4. So between the 1 Bad and 1 low i figured i had it made. The i ohm'd the set i just put in and there was another low one 10.2 ohm's. So i yanked the set i just put in and heated up some atf in a pot on a burner to heat the oil to 220 degrees and rechecked them. None shorted out when hot and they all ohm'd at 11.7. SO i put them in and when i went to install the plenum i noticed the pcv hose bent in a 90 degree angle so bad it wasn't pulling the crankcase fumes good enough. (that would explane the oil film in the fresh air hose). I also checked the vac. side of the egr valve and it wasn't sealing. (making a vac leak there- no wonder my vac. reading was low) Any way i cheated for now and made a asbestos gasket to plug it off untill i can swap out the egr valve. It's starting good and running down the road fine, No cutting out like it did and no c.e.l. Thank's for your help. C-ya Scott

[slingslingbinks]

Well, making a new gasket to plug off the egr made the ses light come on 1/2 way to work this morning. Reinstalled the origional gasket and will give it a shot tomarrow. I figured the light would come on and i hate warning light's that coee on. C-ya Scott