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41Modified, Auto Service Technician
Category: Chevy
Satisfied Customers: 1
Experience:  ASE Master Tech,over 20 years experience in GMC truck Dealer
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Ignition problems, 94 S-10 pickup,4.3 vortec, 2 wheel

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Ignition problems, 94 S-10 pickup,4.3 vortec,XXXXX 205,000 miles. Recent history...replaced clutch, pp, release bearing, etc. Got it back together she would crank but if you turned her off after warm she wouldn't start again. Replaced coil, worked great for a few days then started skipping intermitantly. Replaced cap, roter button and coil wire. No better. Replaced pickup coil and things got better for a few days, then she started skipping again. Seemed to miss worse under light load. Now she will not fire from coil, but I do have voltage going into coil. I have a simple ohm meter but resistance testing is unclear insofar as decimal places and such.Did I miss something pertaining to the charge coil replacement...that was a first time thing for me?
Hello! If the problem started after replacing the clutch parts, i would double check to be sure that none of the wiring harness got trapped or pinched between the engine block and tranmission bell housing causing intermittent short circuits in the electrical system. Take a look and let me know...
41Modified and 5 other Chevy Specialists are ready to help you
Customer: replied 9 years ago.
No, the harness is ok although I remember it snagging the transmission as I was removing it. Looks like the oil pressure sensor is the most likely to have recieved undue tugging when that happened.
ok did you double check the bolts and studs that hold the bellhousing to the engine block? there is at one that is used as a grounding point for the engine harness, also there should be a bolt that is used as a grounding point on the back side of the left head...make sure all those wires got reconnected might also want to take a close look at the pole piece on the distributor shaft(the star shaped part that rotates inside the pick up coil...look at the 4 rivets on the pole piece and check for cracks around them, this allows cross firing inside the dist cap...if there are, then the entire distibutor shaft will need to be replaced...let me know ....
Customer: replied 9 years ago.
2 ground wires on rear of right head weren't disturbed. Didn't find another at bellhousing bolts, just harness tabs on 2. The 4 rivets and the pole piece look good.
can you check the terminals inside the connectors on the 2 wire harness that runs from the coil to the dist module, make sure they are clean and not stretched or deformed...also there should be battery voltage on the red wire at both sides of the coil and at the dist connector with the key on...
Customer: replied 9 years ago.
Reply to 41Modified's Post: Have 12 volts on both red wires at coil, haven't checked connections yet. If I were to run a jumper to the red input on the coil would that effectively bypass the harness, sensors and computer and let me know if the coil and distributor related parts were the problem or not?

you could try that bypass but it might not help in determining the problem...the spark is controlled by signals from the pick-up coil, dist module, crank sensor,engine computer,etc all working together... you must have removed the distributor to replace the pick-up coil,make sure you put a thin layer of dieletric grease on the bottom of the dist module when you put it back together, also be sure the clip that holds the pick up coil in place is fastened securely on the shaft housing,and please double check the timing and firing order...

Customer: replied 9 years ago.
Reply to 41Modified's Post: I'm going to give you a day or so off while I do your sugested steps. And check everything again. You've already earned your $ and I'm going to attempt to send it now. How can I get back to YOU for more details if needed?
Thank you for your generosity! I will also be away this weekend, not returning until late Sunday nite.I'm sure that working together we will get this problem figured out and repaired. I am new to this board so I am not real sure how to get back in contact but i will find out tonite and let you know. Enjoy the weekend!
I have added you to my JustAnswer buddy list and you wil be able to contact me using the PM feature at the top of the to you soon
Customer: replied 9 years ago.
Reply to 41Modified's Post: Got it to run again and found light pressure on 4 prong module connector into distributor killed her. Replaced that and she seems allright again. Will drive her a bit and see if dependability has returned. Sure hope so!! When i reinstalled the distributor after replacing thepulse coil I simply put it back at the previous mark and figured the computer would make fine adjustments as necessary. I did put my 70s vintage inductive timing light on her today and couldn't ever see the timing mark... but I never got into a position that was even marginal for viewing. Is there some sort of timing light that clips to the tube at the timing tab?
HelloCustomer..Hearing that you got the engine running again is great news! Your timing light should be ok to check and reset the timing, just remember that the 'set-timing' connector (a single tan wire with a black trace stripe, usually visible on the harness near the distrubutor) has to be disconnected while setting the timing, set the timing at 0 degrees, turn the engine off. Reconnect the the set-timing plug and when you resart the engine the computer will take over the spark control and timing functions. I realize that visibility is limited near the timing marks so you should try to find a way to be able to see down there. That tube on the tab is used at the factory, when they set the timing they use a probe that fits in there to read the timing, a very expensive and impractical tool for most people since it would be almost impossible to use once the engine is installed in the vehicle. Thank you again for your patience and generosity and I look forward to hearing from you again.
Customer: replied 9 years ago.
Reply to 41Modified's Post: I found a tan with black trace wire going to the 4 wire connector at distributor, but not a separate connector for just the one wire. The whole 4 wire connector at the module wouldn't be the proper alternative would it?? This vortec engine is an unusual throttle body version.
Hi again! Yes,the tan wire with the black trace stripe is the one that the computer uses to control timing functions, but it usually breaks out of the harness wih a single connector. Unpugging it at the dist module really isn't an option here, the other wires are needed by the computer. I'm going to have to do a little research and find out exactly where it will be located on your truck. Usually it's near the dist, but i have seen some that are located under the dash, just below the glove box area...I will be in and out over the weekend so it may take a day or so before i can get back to you... The TBI Vortec engine is a little strange...can you check the 8th digit of the VIN and let me know what it is? (should be W or Z)