Truck just quit first time while driving coasted to stop. Replaced coil, truck ran, was idling in driveway truck quit again and will not fire?
Ignition module in the distrb or a bad module
SOURCE: 1994 GMC Jimmy hard to start and runs rough when first started
did you do a fuel pressure test? if you havent do it its cheep an at least you can elimanate that. if thats not an issue, then there is only two other things crank sensor, and if there is one cam sensor.
SOURCE: 1994 GMC Jimmy hard to start and runs rough when first started
i think if you checked the sparking plugs and map sensors then check your distributer its maybe not delivering the current nedded to perform the spark to some of the cylinders
SOURCE: GMC 2500 P/U 350 Vortec.. Installed rebuilt
Have you checked to see if your distributor is aligned properly? I just had to change out a distributor on a 1997 GMC 3/4 ton that has the V8 Vortec in it as well and you need to pay attention to the (2) numbers around the mating surface / rim of the distributor. You should see a number 8 and a number 6. You need to find TDC on your number 1 cyl. You can either slowly crank the motor over or turn the motor over with a ratchet and socket on the bolt securing the main pully to the crank while another person places their finger over the spark plug hole and when it just starts to Stop pushing air out past your finger then stop. Is the rotor aligned with the number what ever size engine you have in your truck (i.e. 6 or 8)? If not then your timing is off. You will need to remove the distributor and rotor, then install your rotor (before re-installing the distributor) and align the rotor pointer with either the number 8 or 6 stamped on the lip of the distributor where the cap sits down and creates the seal. I have found that they run both numbers on the distributor because they use the same distributor in both the V6 and V8 Vortec motors or a least the plastic base of the distributor. There will be (2) numbers here and sometimes hard to see. Align the pointer with what size engine you have and lower the distributor down into the hole. If the end of the shaft starts to turn the rotor as it aligns with the oil pump causing the pointer to no longer be pointed at the number that indicates which engine this is being installed in then you need to remove the distributor and look down into the hole where the distributor goes in and you'll see the end of the oil pump shaft with a slot (perfect for a big flat head screwdriver) staring back up at you. You'll need to insert a long shanked large flat head screwdriver down into the hole and turn the slotted oil pump shaft until you can successfully lower the distrubutor into place and not lose your mark. I also found that you'll need to have to pointer of the rotor a bit retarted from where it is suppose to be. This is because the distributor shaft gear is swirled and will cause the rotor to turn as it finds its mark, aligns and lowers down into a seated position. When it is seated and the rotor has stopped turning it should be pointing at the indicated cylinder Stamp in the lip that is your size motor (V6 or V8). Now it should be on time. The computer will take care of advancing and retarding.
If not the timing, then I would also consider that you may have a bad crank shaft sensor. These are merley suggestions because there is no more to go on than what you've submitted.
SOURCE: I am having ongoing problems with the truck miss
Misfire is a common driveability problem that may or may not be easy to diagnose, depending on the cause. A misfiring cylinder in a four-cylinder engine is, pardon the pun, hard to miss. The loss of 25% of the engine's power output is the equivalent of a horse trying to run on three legs. The engine may shake so badly at idle that it causes vibrations that can be felt in the steering wheel and throughout the vehicle. The engine also may be hard to start and may even stall at idle, depending on the accessory load (air conditioning, headlights and electric rear defroster, for example).
When misfire occurs, performance suffers along with fuel economy, emissions and idle quality. And, when a misfiring vehicle is subjected to an emissions test, it will usually fail because of the unusually high levels of hydrocarbons (HC) in the exhaust.
What causes a cylinder to misfire? Basically, it's one of three things: loss of spark; the air/fuel mixture is too far out of balance to ignite; or loss of compression. Loss of spark includes anything that prevents coil voltage from jumping the electrode gap at the end of the spark plug. Causes include worn, fouled or damaged spark plugs, bad spark plug wires or even a cracked distributor cap. A weak coil or excessive rotor gas inside a distributor would affect all cylinders, not just a single cylinder.
"Lean misfire" can occur when the air/fuel mixture is too lean (not enough gasoline in the mixture) to burn. This can be caused by a dirty, clogged or inoperative fuel injector; air leaks; or low fuel pressure because of a weak pump, restricted filter or leaky pressure regulator. Low fuel pressure would affect all cylinders rather than an individual cylinder, as would most air leaks. A leaky EGR valve can also have the same effect as an air leak.
Loss of compression means the cylinder loses most of its air/fuel mixture before it can be ignited. The most likely causes here are a leaky (burned) exhaust valve or a blown head gasket. If two adjacent cylinders are misfiring, it's likely the head gasket between them has failed. Also, if an engine is overheating or losing coolant, it's likely the head gasket is the culprit.
Intermittent misfires are the worst kind to diagnose because the misfire comes and goes depending on engine load or operating conditions. They seem to occur for no apparent reason. The engine may only misfire and run rough when cold but then smooth out as it warms up. Or, it may start and idle fine but then misfire or hesitate when it comes under load. Also, it may run fine most of the time but suddenly misfire or cut out for no apparent reason. Intermittent misfires can be a real challenge to diagnose, so let's start with a steady misfire in one cylinder before moving on to intermittent misfires.
Hope this help.
SOURCE: 1994 gmc sierra 1/2 ton 350
Replace the pickup coil in the distributor,this pulsates the injectors.
294 views
Usually answered in minutes!
×