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Have the listed truck I'm looking at for someone and I have no spark to the plugs, went backwards and no spark to dist cap, no spark coming from coil (coil lead was corroded in where wire from coil to dist cap is, went ahead and replaced as it would need anyways).
If I'm understanding things properly from danner's video then I should have power from to the positive and control wire? I've checked these which I had to Pierce the wires because it was a sealed plug and couldn't backprobe as it was bending the t-pins. I want to make sure the control is the wire from the dist cap to the coil or am I probing the wrong wires.
I'm not wanting to rule the coil pack bad yet because I feel the no power to the positive and control wire when cranking isn't proper.
IS there something else I should be looking for? The owner said he'd checked all the fuses.
Also how do I disable the fuel to the engine to keep from flooding it while trying to crank?
A little history is they replaced the fuel pump after the vehicle quit running a while back in August. Is there something with the wiring that goes to the fuel pump that can control the ignition if something is improper I don't want to have to drop the fuel tank on this to verify the pump but he did say when he replaced the fuel pump the screen was out on it.
He also said before he replaced the fuel pump he would hear the pump kick in when he turn the ignition forward. Right now the ignition is stuck in the forward position so he has to disconnect the battery he's time he's not working on it because the lever below the ignition key in the steering column will not move and allow the key to rotate backwards.
Have a feeling I have a few problems here that maybe tight end and related to each other?
Back to the fuel pump for a second, he did mention that since they replace the fuel pump he doesn't hear the pump kick in when they turn the ignition key forward. Is there a test I can do to verify the pump without having to crawl Down Under the vehicle in the snow? There is no Schrader port on this vehicle going into the throttle body assembly as it looks there's two lines that are metal that are similar to break lines screwed into the back side driver and passenger side corners
It does have the little injector thingies in the top but I don't see no fuel being sprayed in when he is cranking as well.
Another thing has came to mind which is fusible links if I'm understanding them properly because I've never had to work on a vehicle this old. With the fusible links on the firewall coming off of the PowerBlock how do I test them from one side to the other without Pearson the wire and can you visually tell if one is bad or not it looks as if it's a white plastic it's a little bit larger than the line? That's what I'm guessing is the fusible link.
I'm sure Paul is smiling right now saying he has to work on one from the old days because honestly other than older carbureted a couple times I've never had to mess with these type of engines but the theory is the same in all of them is my guess and if I recollect properly this was at a cross point in time where they were going from carbureted to just a few years before OBD2.
Also when I hook in the gm1 adapter to the plug in the OBD1 port with a da5 adapter and power to the gm1 port to power the connection I get no communication message from the scan tool as well.
The guy that bought the vehicle said he had just bought it a couple weeks prior to the fuel pump going out back in August and the guy he bought it from said it was a good solid truck and there was nothing wrong with it. When I ask the guy how much you paid for it he said $2,000. He's only ran the vehicle 2 dimes driving at home and then the next day when he was going down the road and it just quit running no sputtering or anything.
Sorry about the lengthy message but wanted to give as much information as possible.
Last edit: 8 years 2 weeks ago by Dtnel. Reason: Typos...
Old Chevy V8, no spark at all? Is the distributor turning when you crank the engine? I have seen many where the gear on the distributor gets chewed up & it no longer turns, or skips. If the dist turns, then look at the tach (if it has one), does the tack move? Common failures would be the coil or the ignition module.
If you don't have fuel spraying out of the fuel injector "thingie" (TBI Unit?), this also may indicate that the dist isn't turning, or the pickup is bad. Let us know of the dist turns & if you have a tach or rpm reading. Check your ignition power to the coil & let us know what you get.
To disable fuel you should be able to pull the fuel pump relay or fuse. Should be in the under hood fuse box. If your not spraying fuel, you don't need to worry about this now.
"Right now the ignition is stuck in the forward position so he has to disconnect the battery he's time he's not working on it because the lever below the ignition key in the steering column will not move and allow the key to rotate backwards."
That, coupled with the (missing) power feed for the coil coming from ignition positive sounds suspicious.
I'd want to see if there's power from the pink wire right out of the ignition switch with the key on.
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