No spark at the coil

read and switch some relays around in fuse box. look for bad or loose connections under hood AND frayed wires,,, MAF,,,,connections PCM? maybe! seems when it is closed loop you have trouble

i would make sure the wires to the coil arn't messed up. 2 possibilities i'm thinking is the ign switch or PCM

I already checked connections and fuses, swapped relays. I did the wiggle wires test. Didn't think it could be ignition switch. I will further check wiring and ignition switch,PCM. I found on the web a site how to test sensors (troubleshootmyvehicle.com) this helped and I did found power going to sensors according to procedures.

Did you ever find the cause of this? My blazer is doing the same exact thing. I'm on coil pack number 4 in about a month and a half. 1999 Chevy Blazer 4x4 4.3 Vortec I have replaced the following parts: Fuel filter Distributor Cap Rotor Button Spark Plug Wires Crank Shaft Sensor Cam Shaft Sensor Ignition Control Module x2 Oxygen Sensor Battery Coil Pack x3 Cleaned the throttle body, Idle Air Control Valve and EGR valve Fuel Injector cleaner x2 Had fuel pressure tested and it tested perfectly. Fuel pumps comes on, primes and shuts off This morning it died on me and wouldn't start back up, went and got another coil pack because I wasn't getting any fire and it ran enough to get it home. The O2 sensor had came in the mail so I went ahead and put that on as well. Now when you are driving it spits and sputters and sometimes dies. It idles at .6 which is where it has always idled and from what I have researched is where it should be for this model. The engine is quiet and it does not blow black smoke, smell like rotten eggs, the cat does not glow red, the oil and transmission fluid both look and smell normal. I am at a complete loss on how to go any further. There are no codes showing at this point. Before changing out the coil pack again, it would just die when coming to a stop light or if you left it sitting still and running. But 3 coil packs in about a month and a half, something has to be messing them up. Also when I had the throttle body off I could see down inside the top of the motor where the spider injectors are and it was completely black inside except for a small gold spot to the right, which from what I've read means there is a fuel leak. Can anyone please give me some ideas on where to go from here? Update : It will not start again, no fire at the coil pack, putting coil pack number 4 on .

Check the voltage on the pig tails to the ignition module and coil with a digital multi meter it cold be low voltage if so Change it

I'm not saying that this will help you out,but3 out of 5 4x4 blazer I have had lately,was ignition switch NOT tumbler, but the wiring harness switch, it takes about a hour for a beginner, and 30 to 45 for e experienced mechanic this part runs about $ 50. At local parts store, the quality of aftermarket parts are a bit cheesy,but I have bad goodluch with Oriellys partz& help. I hope this cures your problem I have went to auto parts junk yard & removed one from a total wreck, and it worked great price was $ 10.. The damage on vehicle showed it was running when it hit a ditch. I went home & tur ex switb on for twenty mins & off for 30 to 50 seconds,and it fired right up!! U can call itluck ifu like but I a.Running again for less. Than$ 45.00. Good luck.

Our 1999 GMC Suburban is doing the same as well. Our mechanic said it could be the engine control unit ( computer ). We replaced engine control module, coil, & crankshaft sensor. We now have to replace the pick up coil. There may have been a power surge, ( think that's what he called it). Well, anyway, those parts were affected . Good luck!!

I changed ignition switch, altanaor, ignition module, crank sensor,altanorand bunch of other stuff my blazer won't start it was working just fine no hiccups and I went to start it no start

Is the security light on?

I have a 99 Blazer 2 door 4 wheel drive just put a new motor in it now have no spark check every wire on it twice can't figure it outit ran before I change the motor LOL

I have a 99 Blazer 2 door 4 wheel drive just put a new motor in it now have no spark check every wire on it twice can't figure it outit ran before I change the motor LOLnow I have no spark coming out of the coil have juice everywhere with test light

Jeff , I was going thru this forum and seen this old problem , I was thinking g bout how Cheated I was when my blazer quit running. Again I'm very glad I haD your help. I replacing that switch has been a job saved , thank you again.. still running strong!!best 45 bucks ever spent!!

Hi dan did you check for power going into the coil ?

I got a 1995 s10 blazer im getting power to coil bit its not getting spark when i start the engine my test light just stays constantpower ive changed everything im stumped

Hello Wes, I don't know how mechanically inclined you are , but seems if you have power at coil , and you have replaced everything ,turn ignition switch to run position , And if you have a remote starter switch ,try to see if it will run by starting it that way., I have done it by using old broke screwdriver. NOTE !! If you are not familiar with this method DONT TRY IT! A remote starter switch at parts store is generally around 12 to 15 dollars. A real handy tool to have ! You can go under right front fender to get to starter , connect one lead to purple wire & other to large main power cable from battery . Good luck & be careful. Use parking brake if manual trans.

Have 2000 GMC Sonoma crank no spark until on position cleaned ignition control module with small wire brush mounted with dielectric grease now starts good, I replaced ignition switch, key set, crank sensor, still had no spark while cranking cleaned control module works great .

theres a connection under the drivers side by all them relays pull it apart 2 different s10s i worked on had the ground wire burned i could wiggle the connection and it woul fire right back up thats how i found it in the first place,try that

On the blazers i have found a ground wire coming out of the fire wall to the back of the engine was damaged.

mine was ECM took it to auto zone had them test it was bab changed it and started right up.

Ok SERIOUS QUESTION HERE : IM VERYOLD SCHOOL AND DONE THIS MORE Xs than I can remember but all chevys but much older like 94 and below I would get bad coil or connection possibly and just run a jumper wire straight off pos term on bat right to positive on coil itself but mainly if I was trying to narrow it down on diagnosis or had to have thing running immediately ...my question is can I do this on my 2000 S10 Blazer 4.3 vortec ??? Thanks for feed back really need to know ???

I have 2000 Blazer...Crank no start. Watched a lot of video. Read a few articles and tried the steps on easyautodiagnostics.com. , listen for the fuel pump to come on checked the fuse, ingnition switch, relay, bought replacement coil and tried plugging it in temporally and layed it on top of the engine. the next day it started? I was baffled. The ignition signal was going to the coil but no spark? but it started. I thought ok let me try the old coil. guess what blazer started...still baffled. I thought i'll save myself some money and didn't replace anything. Used the blazer for a while one day crank no start...got towed home, next day it started again and was ready to replace pcm/ecm from flagship one but i thought before i go through all that i need to make sure what the problem was and i was ready to go through all the connections to the pcm/ecm and test crank shaft sensor....was preparing to do that when i went outside started her up and decide to check for loose wiring. Wiggled the wires at the coil then decided to check the connector....Yep the car shut off when i wiggled coil ignition connector. All along it was that connector causing crank no start. Lesson learned. Check everything, components, wiring, and connectors before you start replacing everything till you find the fault! I don't feel bad about missing the bad connector...don't work on cars everyday and now i have a much better sense of how to fix my own car...who know how much a shop would have charged me before finding the problem;')

Gurut2jlt we are having the same problem our 2001 gmc sonoma 4.3 will crank but not start we have replaced fuel pump distributer cap fuel filter and control module we are at a lost any suggestions?

you sound like you have a crack head that a small crack opens up when the motor gets up to running tempuerture

A word of caution when probing wire connector terminals directly with a test light or similar .. You expand the wire terminals to the point they no longer engage the pin terminals of the component the connector hook up to. Even if you have already fixed the original problem you have just created another! .. Y’all think about it.

first thing i would do is get a brand new battery, then run a ground wire over to the engine. then look underneath the relay block for burnt connection, replace relays. then replace ig module and coil. sooooooooooooooo could be a security issue, if somebody tried to steal it it will shut itself down. then you must get a skeleton key from GM.....!@#$%^&* my next car will have no wires.