96 Chevy S10 Blazer with 4.3 L engine vortex will turn over but won't start. Why?
The RPM's fluttered and it died. The PCM code read that it was the crankshaft sensor.
We have checked the following:
coil - replaced
fuses - good
control module (ecm) - replaced
plug wires - replaced
crankshaft sensor - replaced
voltage at connector to crankshaft sensor - is good
battery voltage while cranking - is good
spark - none (before we replaced the crankshaft)
vacuum lines - replaced
air filter - new
distributor cap and rotor - replaced
vent valve - is good
cranking voltage is good
battery ground - is good
coil wire - is good
MAP sensor - is good
PCV valve is good
The engine turns over fine, but will not start. We have disconnected the positive cable
to the battery for more than 10 minutes, and that did not resolve the issue. There are
no codes showing in the PCM any longer, but that might be because we replaced the
ECM. We don't know for sure. Shouldn't the PCM store the codes even though we
disconnected the battery? That is a side question. My biggest question is what do we
do next? We can hear the fuel pump come on. We do not smell fuel while we are
cranking the engine.
Check for fuel pressure. My silverado did about the same thing and needed the fuel pump replaced. But do no spray fuel or ether in the intake of a vortec engine because it will backfire and bust your intake manifold. They are plastic. I learned this the hard way with parts flying all over my back yard. So not only did I have to put in a new fuel pump but I also had to buy and install new intake as well.
Quick question. Did you test or replace the ignition control module. It might be your issue. Your injectors will not fire if the module is dead.
We have not checked the ignition control module yet. It's a throttle body injection and we replaced the ECM. Doesn't that take care of this?
Nope. It takes the signal from pickup on the distributor and the timing (advance) from the ecm and fires your coil. They are touchy, use the heat sink compound that come with the new one or buy some. They cook quickely with out it. Check the leads on the pick-up too. Never had a pick-up fail but I'm on my 4th one in my 92 TB 350. Both our S-10 4.3's have had there's changed recently.
Hi Yeti. Where is this ignition control module? We have two manuals and neither of them have this part listed. In 96 everything changed, so we can't figure out where this part is, we are discussing. Hi Dandy, We will be checking the fuel pressure and we will change the fuel filter while we are at it. It's probably never been done, but won't know until we get in there.
If it is a throttle body it is bolted to the bottom plate of the distributor. Takes a two wire plug internally from the pick-up, two wire to the coil and I believe it's a four wire from the ECM. You will be able to see the two wire plugs sticking out of the distributor. If it's a Vortec with MP I will have to look to see were it is. Trust me check this little POS. I got to the point that I carry one in my '92. I think there is still one in the door pocket
The camshaft sensor is under the distributor plate.
There is no cam shaft sensor on a TBI. It's called a pick-up coil. The module is bolted to the top of the plate and the pick up plugs into it.
If you have a multi port, not TBI, you have a cam position sensor on the bottom of the distributor and the ignition module is bolted to the coil. See the pic
Here is a scematic of the module on the TBI engine
Be sure to use heat sink compound when you install a new one.
Oh, that thing! : ) Ok. We will pull the cap and rotor and look at it again. Terry saw that, but didn't test it. Can you test it with an ohm volt meter?
Yes, we will use heat sink.
I seen some info on a web page, at camp with no manuals. Which one do you have the TBI unit mounted in the distributor or the Multi Port mounted to the coil. I will look.
The cm is mounted to the coil plate. (multi port?)
Doesn't look that bad. Try this http://easyautodiagnostics.com/gm_icm_test/gm_icm_diagnostic_1.php
Hi Yeti, Can you tell us if the PCM should be holding the error codes until they are reset? We think that disconnecting the battery would clear a check engine light, but not the the error codes. But now, however, we can't get any error codes to show up and it's been two days since disconnecting and reconnecting the battery.
I don't know. I'm thinking that unhooking the battery resets all codes. I don't own a scan tool as most of my efi vehicles are OBD 1 and you can't read live values with a cheap one. Saving up for some software though. Sick of the trial and error method, gets expensive changing sensors and parts that are not the problem. Atleast the parts you replaced should be good for spares?
Yett,i actron makes a scanner that reads live data, on obd 1 and 2, they are available and pretty cheap on Amazon.com. are you getting sparkwith the crank sensor replaced?
Hi John, No spark after crank sensor replaced.
Hey John. I checked. Yah the 9190 looks good for most people who need live data. Those vultures want to much to ship it to Canada. Looking at $550 to get it here. For what I will be doing I need the ability to burn new chips or run emulators. All in for 1200 then I can read and change what ever I want on my OBD 1's
Heather I put a crank sensor on my dads 99 Jimmy 4.3L and it worked once. After I shut off the engine and attempted to restart it there was no spark. It's a really common issue with these Chinese made parts. Yetti Get the software for a laptop and the adapter cable, as long as you have a laptop already the cable and software shouldn't be much more than a few hundred btw..., cp9150 is the exact same as the 9145 but with more cables. I have the 9150 and it reads live data on obd1..
Ok John, so what you are telling me is that the part may be bad to start with? We put it in, and never got it to start in the first place. How can we test the sensor to see if it's bad? Also, does anyone know how we can get the error codes back, so we can diagnose what's wrong now, instead of working blind?
isnt there a relearn procedure needed when replaceding the crank sensor?
Yes Andrew, but we had unplugged the battery for 10 minutes days ago, and that reset everything, so we can't get any error codes now. However, in this ongoing saga, today we went out, opened the passenger door and the dome light did not come on. We checked the brand new top of the line battery that just went in a couple months ago, and it is completely dead. In fact it seems to have been shorted out. It is completely ruined... We are at a total loss at this point.
Anyone want to buy a 96 Blazer as is, you tow it away. lol
The codes went away with the ecm. No relearn procedure needed. A bad crank sensor won't throw any codes because the ecm doesn't know the engine is cranking. Battery is probably dead from trying to start it.as for the buying as is what state/major city do you live near?
Correction.... The only time the crank sensor will throw a code is if it screws up while the engine is running.
I was joking about selling it. It is my son's and he would have to make that decision. I know he wants to sell it after we get it running. We live in Wisconsin. My family is full of mechanics ad they all say the battery apparently is bad. It will not take a charge. We are taking it back to advanced auto today. With all these mechanics, you'd think we could get this thing running in no time, but we don't have the newer diagnostic equipment $$. Once we get the new battery in, we will check the fuel pressure gauge and then look at the ignition control module.
You don't necessarily need a machine to tell you the issue, the machine will point you to the issue but regardless of how technologically advanced the engine ids it still needs air and fuel in a correct mixture, it needs to be compressed and ignited... spark, fuel, air, and compression, you don't have spark. Assuming the coil is good, ecm is the correct one, and all the wires are connected correctly, the crank sensor controls the spark. Those are your possibilities
update on the Blazer. We towed it to a trusted inexpensive mechanic and it needed a pick up coil (under the distributor cap. Parts and labor were $120. We now have a running Blazer. Thanks guys for helping!
Sweet. So hope you kept all the take off's of the other parts. They most likely still work and may get you out of a pinch in the future. Good luck.
I have a 99 Blazer 4.3. We just replaced the motor with a crated gm motor. We cant get it running. Has pressure its getting gas...sounds like it wants to start...but noting. Bought a new distributor today and still wont run. Any thoughts?? Also no codes are coming up when we scan it.
Timing on the distributor is set? It's it getting spark? You say it has fuel pressure but are the injectors opening? Turn the key on to print the fuel system with the gauge hooked up, pull the fuel pump relay, crank the engine, pressure should drop to almost 0 fairly quickly if the injectors are working.
Timing is set. Its getting spark...dont have tools to do that.
Prime not print, sorry for the typo. You can rent a fuel pressure gauge at your local AutoZone, they will put the full cost of the device on your credit card or bank card and fully refund the money once you return the tool. If the timing is set properly and its getting spark then it's a fuel issue. Not sure if you're aware of this but you can have the distributor 180° in the wrong direction and it will appear like the timing is perfect on the crankshaft timing mark with a timing light. Do not use any type of starting fluid in the intake, if it backfires it could blow your plastic intake onto pieces.
It ran for 3 blocks and died. Its getting gas. This is stupid!! Lol
How are you certain it's getting gas?
I had a question if anyone might be able to give me any insight on what to look at next! my SUV died on me while I was just idling in a drive thru, it's a 2002 GMC yukon denali XL 1500 has the v8 6.0L or Vortec 6000. I've replaced battery, fuel filter, fuel relay, fuel pump good, throttle postioning sensor, crankshaft sensor, had the alternator checked it is good as well can anyone help? any help is appreciated
Check fuel pressure, check for spark, check if the injectors are getting a pulse while cranking, if all those are good then do a compression check
My 1999 Chevy blazer v6 4.3 liter will not crank just make a clicking noise I replaced the starter and the replaced the battery and replaced the spark plugs and the fuel pressure regulator still makes the the clicking noise and won't crank or start help
You try turning the engine over by hand?
I have a 1998 chevy blazer v6 Vortec I was going down the road it started Spittering and sputtering and eventually died I am getting spark nice hot spark I am getting fuel and I have compression. I have changed the distributor, spark plugs, wires, rotor button, distributor cap, Sensors
ryan I am having the same issue with a 2000 gmc safari have spark fuel and compression fuel pressure I even went as far as to spray ether into the intake even tho I know its a no no I still cant get ignition I have no clue what to do now
Hey Ryan what was the fix to your problem as I'm having the same!
Ok, I have a 95 S10 with the 4.3, I bought the truck with a bad knock in the bottom end of the engine. The guy I bought it from found a running 4.3 of the same era and had it in the bed of the truck. I swapped the engines out and used the intake manifold and ignition pieces along with the distributor from the engine that was in the truck because I knew they worked when pulled. Now everything is back together and it doesn't start. It turns over but doesn't do anything beyond that. Checked and double checked the timing, and even swapped a couple parts out from the other engine to try different stuff and still nothing. any advise
Would assume that you would have verified that the dist timing is set for TDC on the compression stroke and not 180 deg out. How many miles on the orig motor. It's odd that a sensor/module would fail during the swap unless the plug or wiring was damaged. 95 - 96 was the transition to the Vortec does yours have the older TBI motor or the Vortec. For the TBI the pick-up coil in the dist or the ignition module might have been damaged (If the injectors do not spray fuel when turning over check these parts). Does it have spark. Maybe check all the plugs on the dist and coil -> contact cleaner. I clean mine and fill them with dielectric grease. Seems to help. Let me know. That's were I would start.
Its a multi port, the timing has been set with number piston TDC with the distributor rotor pointing at the number 6 one the distributor body. The truck has 204,XXX and the donor engine has 106,XXX. I visually checked the bearings and looked over the engine before I put it in, all looked good. It had good compression also. I swapped out the coil, ignition module and crank sensor just to see if it mattered and had no luck. I even set the distributor one tooth up and back just to try and still nothing. I just dont want to start throwing parts at this thing when it ran before the swap. I'm putting this together to drive back and forth to work so I can keep the miles off other vehicle. Yea I guess I'll go get some cleaner and dielectric grease and do all my connections. Thanks for your input
Did you verify that it was TDC after the compression stroke not the exhaust, if you checked all the sensors you may be 180 out of time with the dist. I usually pull a valve cover to verify, your intake valve on #1 will shut before BDC then both will remain seated as the piston travels up to TDC. I always go to TDC then roll back a few degrees (depends on motor and where you would like your rotor cap positioned) then re-tension the timing chain (If old and loose) by slightly rotating forward. Then install the dist with the rotor pointing towards or slightly advanced of the contact that feeds the plug for #1. This should leave enough room to set the final spark timing without having to pull the dist to catch a new gear on the cam.
I got it! I redid the TDC and distributor and it fired as soon as I hit the key. All is good. THANKS for your help
I have a 1999 Chevrolet blazer 4.3 we have replaced the fuel pump and it will turn over but will not start any suggestions?
i have the same issue on my 1992 chevrolet S10 blazer 4.3L vortex 4 x 4. code said fuel pump bad, but after replacing it, engine turns over but won't start. engine was running befor the new installation. i did't disconnect the battery cable and i think it blew the fuse, &also checking the ignition coil module, but not sure if thats my problem.
I have a 97 Chevy blazer. Not sure on the cylinders but anyways the car cut off on me on the road tried cranking it wouldn't start up but sounded like it wanted to. Replace the battery connected the wires to battery tried cranking the car wouldn't turn over but smoke was coming from the hood opened it and smoke was coming from the positive cable wire ? The car sounds like it wants to crank but can't can anyone help me ? I asked a few people and I'm getting different answers. I just wanna fix the problem so I can take it to the garage.
The starter is new and the alternatoris good yet....
did you try taping on fuel pump while you turning over engine? fuel pump is usualy located in fuel tank some were, so if you tap around on the back of fuel tank should work! let me know.
my problem was a bad fuel pump relay fuse. did a jumper test and it started.
i also disconnected my positive battery cable, was told at autozone the computer needed to be reset. not sure if that was correct or not, but somewhere between changing the new fuel pump and disconnecting the battery cable, it blew the fuel pump relay fuse, so thankful it didn't vapor lock on me..
michele, my battery cable did the same thing two years ago, the problem was the insulation near the starter had corroded away and was making contact against the frame. i replaced the positive cable and it solved my problem, 4 wheeling in sand and mud, is my guess that could have caused it.
If it starts up once in a while (won't start after the temperature heats up), and a weak spark from the spark plug wire to the plug, the problem is the igniter module. I just fixed the one I have by replacing the igniter module. - Andy Andy's Auto Center Glendora, CA
I have a 96 Chevy blazer that won't start I had to replace the heads because the cracked and now it won't start please help
check the spider fuel injectors I had same issues and had the right fuel pressure... hope that helps
2002 s10blazer not sure whats rong wont start cranks fine getting fuel spark good compression pulled pump relay thinking may be flooded tryed to start with out relay pluged in and it starts right up and will run fine with out a relay what could be rong
If the heat sensor goes out will it stop the motor from starting
In my 99 S10 blazer 4.3liter the code showed up heat sensor would that stop it from starting
Hi I have a 94 Chevy s10 blazer. Will not start. Throttle cable snapped in 2pieces. It has a kill switch for fuel pump it works works fine. Just dont know why it wont start up. first Tim driver and need advice. any help
How do i disconnect the alarm on my Chevy Blazer?
I just few my blazer 4.3 I had all those same kinds of problems it turned out so does a lot of blBlazer it turned out to be the fuse block was corroded cleaned and cut out bad wiring and replace with new one and it's working now just finished 10 minutes ago
I'm not sure witch fuse it the one that has a hole lot of different thing like 10 different things Fuel gauge all kinds of stuff to much for one fuse I got it time to a bud out of my yiti and enjoy thank you guys is much it was you guys that gave me the idea cold beer life is.Good
Hi guys. I'm a first time driver having problems with my 94 Chevy s10 blazer 4.3 vortec. it cranks but will not start. after 3rd try by turning key 3times. It starts. I want to get it fixed before driving in from fl to kanasas.
Hey Kendee take blazer to a mechanic they will pull the whole alarm system out. Took mine there a month ago. It cost me $20 for them to pull
Try the smoke machine see if you have a leak somewhere causing it to not get enough fuel to the engine
Try switching the ignition wire set if nothing else works
I have a 99 2 door Blazer 4 wheel drive with a 4-3 I just change the motor to a fresh one hook everything up got fuel got everything no spark coming out of coil why haven't I got spark coming out of the coil I've checked everything everything has power Dumbfoundead LOL
I cannot get my distributor to line up correctly to be bolted back in, I've got TDC and the the slot for the oil thing inside... but I've been stuck now having to take it back out check and recheck everything just to put it back in and the bolt hole won't line up.... this is my first attempt and self repair so sorry if I sound like an idiot... 96 chevy blazer vortec engine
From what iv heard is the cata converter can get clogged beating the piss out of it can fix it or drill a hole in it and use a screwdriver to tear the crap in there up. Start it u and let it blow that crap out u might have to go half throttle to make it start up
OK i have a 1995 jimmy with a 4.3 have good spark and 50psi fuel but will not start wire is hot going to injector when key is on .will run with starting fluid but then die don't know what else to try any help will be greatly appreciated
Mine didn't have a Voltage regulator,so i kept burning up control module. After 3 times in the shop we finally figured it out, hope this helps
50 psi isn't enough, don't use starting fluid you'll destroy your intake manifold. open upper plenum, if it's got clean spots you have a bad cpi if not check out your fuel pressure regulator, it's a trouble maker. My 95 4.3 blazer has been a total pain in my butt. my cpi failed, flooded the engine, which then hydrolocked the engine resulting in a clank when I turned the key. Took a month Of arguing with a man about the starter not being bad and buying a new One and getting the same result before I found the answer to that One, (pull the spark plugs out, let the gas evaporate out of the engine for a few days, Get new plugs, it will turn over fine, but if it flooded in the first place check under the upper plenum, clean spots around the injectors mean you need a new cpi. Clean spots at the back where the gas comes in mean you need a new fuel pressure regulator) new Voltage regulator is internal to the alternator, but before you replace that, check the 8 Gage wire running from the back of the alternator to the battery, that was my intermittent electrical problem. Replaced that and no more trouble with battery, now the truck won't start with my heavy key ring but starts right up with the light One or just the key, but that's a Chevy thing, they don't like weight On the ignition lock cylinder. Already replaced that once, just ditched the extra keys and it starts fine, but it's running like crap, pretty sure I need a new pcv valve, it has all the symptoms.
When you disconnect the battery, and leave it disconnected for 30 minutes, you WILL NEVER EVER GET THE CIDES BACK PERIOD, TAKE A HINT FROM YOUR COMPUTER if you scan your computer and they are there, then you disconnect the computer for 30 minutes or what ever and you rescan it and get no codes, THEY ARE GONE FOR EVER! USE A BLUETOOTH SCANNED, AND SAVE THE ERROR CODES TO YOUR SMART PHONE IF YOU THINK YOU MIGHT NEED THEM LATER!
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