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87 tbi issue after tune up truck died!!!! UPDATE BLAZER IS RUNNING!!!!

I

isaac

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so as the title says i recently gave my truck a tune up 2 weeks ago wires, plugs, cap, and rotor. got everything all changed out adjusted the timing everthing is running great. so today i go out get on the freeway and about 4 miles down the road the truck just dies shuts off.... so i get off the nearest exit and had to tow it home. i sounds like it wants to turn over but i have no idea what the problem is. there is gas in the tank but i have no idea how to check on tbi how to check if the engine getting gas. so i dont know if its the fuel pump? i dont wanna just swapping out a $250 dollar part out and that not be the problem. could it be the ignition module? i dont know any help would be greatly appreciated just trying to get ready for my september elk hunt..... :(

isaac
 
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Could be ignition module.

You say "wants to turn over". Cranking/turning over means the engine is rotating. I assume you mean it is turning over, but will not start.

Pop the air cleaner off, have someone crank the engine over while watching down the TBI for fuel spray. If it's the module, you will likely not have any fuel spraying.

You can also test with a "noid" light (which you can make from a 192 dash bulb) on the injector wiring connector, one wire to each of the two terminals on the connector, then watch the light as it cranks. If it doesn't blink, it's not getting the signal from the ECM, also indicating that the module may have issues.
 
Ok step one.

Pull the air cleaner off. The injectors sit right ontop, have someone crank it. If you dont see fuel spraying down into the throttle body then your lacking fuel. Could be fuel pump, or could be fuel regulator. CHECK YOUR FUSES FIRST. There is a safety fuse in the panel that will cut the injectors if something archs. I've had it happen in a mudhole before, replace it and fired right up.

Step two if you have fuel.

Begin checking your spark. Take a wire off and hold it next to something metal, turn the motor over. Did it arch? If no your lacking spark.

Now theres 4 things that can lead to no spark. Cap/rotor, coil, ign module and ecu.

ECU is very doubtful. Seeing as how you just did a tune up I would double check that the cap seated properly and something didnt go wrong.

What brand coil is it?

To be honest your problem is more than likely the ign module but I would take that coil to the store and tell them they gave you a bad one and your truck died. If it still dont start at least you ruled the coil out and it didnt cost you anything. (or test it if you have a meter)
 
dyeager535 said:
Could be ignition module.

You say "wants to turn over". Cranking/turning over means the engine is rotating. I assume you mean it is turning over, but will not start.

Pop the air cleaner off, have someone crank the engine over while watching down the TBI for fuel spray. If it's the module, you will likely not have any fuel spraying.

You can also test with a "noid" light (which you can make from a 192 dash bulb) on the injector wiring connector, one wire to each of the two terminals on the connector, then watch the light as it cranks. If it doesn't blink, it's not getting the signal from the ECM, also indicating that the module may have issues.
Click to expand...


I thought the ign module only cut spark not fuel?
 
Nope. Ignition module sends a reference pulse to the ECM indicating the engine is cranking/running. This is used by the ECM to trigger the fuel pump relay, at which time the ECM also grounds the leads from the injectors to pulse them for fuel.

Even without the signal you'll get fuel pressure after cranking for a bit (oil pressure switch) but it will never fire if the ECM doesn't see the reference signal from the module.
 
dyeager535 said:
Nope. Ignition module sends a reference pulse to the ECM indicating the engine is cranking/running. This is used by the ECM to trigger the fuel pump relay, at which time the ECM also grounds the leads from the injectors to pulse them for fuel.

Even without the signal you'll get fuel pressure after cranking for a bit (oil pressure switch) but it will never fire if the ECM doesn't see the reference signal from the module.
Click to expand...

Good to know.

for some reason I thought it cut spark...
 
spray a couple of shots of ether down the intake, then try and start it, if it fires, you have spark and no fuel.
 
great thanks for all the replys i will check all these things as soon as i can get someone over to the house and help me turn the key over... just my luck home alone and cant get ahold of anyone...
 
did you put the coil ground strap from the old cap in the new cap?
 
If it was recently tuned up check distrubutor hold down bolt. If the timing was adjusted the dist. hold down may not be tight and loosened up enough to allow the dist to rotate ( retard ). Engine vibration and rotational torque from the shaft may be the culprit. See if the dist can be turned by hand, if it moves turn it about one inch opposite the direction of rotor rotation ( advance ). See if the engine starts.
 
Also when you timed it. Did you disconnect the timing bypass wire? Prolly not related to your problem but your timing will be way out if you did not disconnect the bypass wire when setting the base timing.
 
timing was done correctly with the brown/tan wire disconnected, but good idea. distrubitor bolt down tight no movement from distrubitor. i checked for spark no spark and i aslo watched if there was gas flowing from injectors and nothing from either. so no gas or spark. i checked all of the fuse's under the dash they all were good. is there any other fuses on the truck? should i try to switch the cap and see if thats the issue. its a jegs brand cap/rotor? i dont know i thought i would try their brand. bad rotor? i just realized i didnt change the coil could this be the problem? but everything was working good thats what thorws me for a loop? i am thinking about changing out the ignition module? i dont know? :confused: what is the coil grounding strap? where dose it go dose anyone have a pic of it?
 
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the exact same thing happened to my truck... it turned out to be the ignition module. all of the same symptoms you're describing
 
When it happened to me first time, module failed.
Second time, coil low voltage lead came off.
(towed it all the back to my shop, too! ):mad:
 
think i am going to change the coil tomorrow and see if thats the issue. and if that dosent fix it i guess try to change out the ignition module. how hard is it to change the ignition module?
 
changing the module is a no brainer, and cheap. i think they are like 50 bucks. just be sure to put the thermal grease on it before you install it (directions will tell you what im talkin about)
 
i hope its as easy to change that module as you guys say it is....
 
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