rodder Posted March 26, 2011 Report Share Posted March 26, 2011 (edited) i installed my rebuilt motor finished today, however when i tried to start it, it turns has plenty of fuel , and spark but wont run can anyone sugest anything to try thanks guys Edited March 26, 2011 by rodder (see edit history) Quote Link to comment Share on other sites More sharing options...
hottelboy Posted March 26, 2011 Report Share Posted March 26, 2011 i installed my rebuilt motor finished today, however when i tried to start it, it turns has plenty of fuel , and spark but wont run can anyone sugest anything to try thanks guys timing?pcm? Quote Link to comment Share on other sites More sharing options...
chpspecial Posted March 29, 2011 Report Share Posted March 29, 2011 check all your grounds and make sure all sensors are plugged in. Quote Link to comment Share on other sites More sharing options...
misterp Posted March 29, 2011 Report Share Posted March 29, 2011 Will it 'caugh' or 'chug' at all, or does it not even 'light-off'? An issue that got me last week, make sure your TB works - with the engine still and key on 'run' you should be able to press the gas pedal and hear/feel the throttle body butterfly moving, no TB = no run! Mr. P. Quote Link to comment Share on other sites More sharing options...
hottelboy Posted March 29, 2011 Report Share Posted March 29, 2011 crank sensor? i had an 89 olds cutlass supreme (turd) that would run just fine and die out of nowhere finally it would just crank but never fire. just so ya know its on the back of the block opposite of the oil filter (I believe)easily missed on an install, out of site out of mind! Quote Link to comment Share on other sites More sharing options...
misterp Posted March 29, 2011 Report Share Posted March 29, 2011 check all your grounds and make sure all sensors are plugged in. However, if there is a sensor missing the PCM *should* turn-on the check-engine light. Easy-to-miss are the two harness grounds at the back of the engine block, one is to the same bolt that anchors the firewall/chassis ground strap, the second is to the passenger-side of the oil pressure sending unit & cam sensor... Mr. P. Quote Link to comment Share on other sites More sharing options...
rodder Posted March 29, 2011 Author Report Share Posted March 29, 2011 (edited) However, if there is a sensor missing the PCM *should* turn-on the check-engine light. Easy-to-miss are the two harness grounds at the back of the engine block, one is to the same bolt that anchors the firewall/chassis ground strap, the second is to the passenger-side of the oil pressure sending unit & cam sensor... Mr. P. i put both grounds on 1 stud should i seperate them Edited March 29, 2011 by rodder (see edit history) Quote Link to comment Share on other sites More sharing options...
rodder Posted March 29, 2011 Author Report Share Posted March 29, 2011 Will it 'caugh' or 'chug' at all, or does it not even 'light-off'? An issue that got me last week, make sure your TB works - with the engine still and key on 'run' you should be able to press the gas pedal and hear/feel the throttle body butterfly moving, no TB = no run! Mr. P. it wont cough or chug an throttle body is working Quote Link to comment Share on other sites More sharing options...
hottelboy Posted March 30, 2011 Report Share Posted March 30, 2011 (edited) check the plug directly above the starter opposite the oil filter! and no you don't need to seperate them thats how it comes from factory as well. Edited March 30, 2011 by hottelsss (see edit history) Quote Link to comment Share on other sites More sharing options...
rodder Posted March 30, 2011 Author Report Share Posted March 30, 2011 check the plug directly above the starter opposite the oil filter! and no you don't need to seperate them thats how it comes from factory as well. installed new crank sensor checked all grounds still will not run Quote Link to comment Share on other sites More sharing options...
misterp Posted March 31, 2011 Report Share Posted March 31, 2011 (edited) installed new crank sensor checked all grounds still will not run I do not know for sure, but I believe you can attach both harness grounds to the same bolt at the back of the block and be OK - going by memory, one is ground for the PCM and the other is ground for the coils. I would have to look at the service manual... It may not help, but if you want to eliminate all possible 'variables' you can take a few minutes and redo those two round wires, Delco may have discovered they needed to be separated for the PCM to work right, I dunno... OK you have functioning TB - good. Even assuming your tune is WAY off the mark, you should get at least a cough out of the motor; gasoline is very forgiving, the PCM tune can be a mile out of whack and the motor may not run but you should still get *something* like a cough, or sneeze, or attempted start. Verify fuel at the rail - easily checked, with the key on 'Run' but the motor still the fuel pump should be sending fuel up to the fuel rail; crack open a fuel fitting (or on a stock fuel rail press the schrader/tire valve) and see if liquid gasoline comes out under pressure, if it spits air let it bleed all the air out of the fuel rail. Once you have fuel at the rail and still not getting even a sneeze from the motor then you are not getting spark and that is two basic suspects - bad coils or coil grounds, OR the PCM is not commanding the coils to fire, which could be anything from failed sensor to security interlock. If the PCM is not firing the coils then there SHOULD be check-engine codes and/or the CEL light lit on the dash. Do you have DTS codes? Do you positively know you have pressurized fuel at the injectors? Mr. P. Edited March 31, 2011 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
rodder Posted April 13, 2011 Author Report Share Posted April 13, 2011 I do not know for sure, but I believe you can attach both harness grounds to the same bolt at the back of the block and be OK - going by memory, one is ground for the PCM and the other is ground for the coils. I would have to look at the service manual... It may not help, but if you want to eliminate all possible 'variables' you can take a few minutes and redo those two round wires, Delco may have discovered they needed to be separated for the PCM to work right, I dunno... OK you have functioning TB - good. Even assuming your tune is WAY off the mark, you should get at least a cough out of the motor; gasoline is very forgiving, the PCM tune can be a mile out of whack and the motor may not run but you should still get *something* like a cough, or sneeze, or attempted start. Verify fuel at the rail - easily checked, with the key on 'Run' but the motor still the fuel pump should be sending fuel up to the fuel rail; crack open a fuel fitting (or on a stock fuel rail press the schrader/tire valve) and see if liquid gasoline comes out under pressure, if it spits air let it bleed all the air out of the fuel rail. Once you have fuel at the rail and still not getting even a sneeze from the motor then you are not getting spark and that is two basic suspects - bad coils or coil grounds, OR the PCM is not commanding the coils to fire, which could be anything from failed sensor to security interlock. If the PCM is not firing the coils then there SHOULD be check-engine codes and/or the CEL light lit on the dash. Do you have DTS codes? Do you positively know you have pressurized fuel at the injectors? Mr. P. thank you for all your help i found the problem ground wire near p.s. pump runs like a bear now im gonna get a tune should help even more thanks again Quote Link to comment Share on other sites More sharing options...
misterp Posted April 14, 2011 Report Share Posted April 14, 2011 Ahh cool man Glad to hear it! Mr. P. Quote Link to comment Share on other sites More sharing options...
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