1987 K10 No start

[Fleetwood]

Hello! About a week ago I accidentally left my lights on on my 1987 K10. When I came back to it it was stone dead. I tried jumping it to no avail. I took a battery out of a family member's '90 blazer and it fired right up. I then drove it home, got a new battery in it, and now it won't start. It cranks good, there is plenty of fuel coming out of the injectors, and it has an orange spark. I have replaced the ignition coil but that didn't help. What could be wrong?

 

[AuroraGirl]

Hello! About a week ago I accidentally left my lights on on my 1987 K10. When I came back to it it was stone dead. I tried jumping it to no avail. I took a battery out of a family member's '90 blazer and it fired right up. I then drove it home, got a new battery in it, and now it won't start. It cranks good, there is plenty of fuel coming out of the injectors, and it has an orange spark. I have replaced the ignition coil but that didn't help. What could be wrong?

How are your wires, plugs. how about ignition.. module..?(you have a TBI distributor, im not familiar with them) how is the wiring to your distributor. How are your engine block grounds, your negative post connections to all points(chassis, engine, frame) how about voltage drop, corrosion points, freyed cables

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what im getting at is your cables dont look like this I hope

 

[Bextreme04]

You probably blew a fuse while trying to jump start it. I'd check the ECM fuses.

 

[SirRobyn0]

Orange spark? Generally that would be considered weak spark, how are you testing the spark? Gap jump test tool? Light firing tool? screw drivers? Spare spark plug? Especially on a GM HEI system that thing should produce a nice blue spark.

The best way is with a gap jump spark testing tool, second best is a new spark plug gapped correctly. If you're not using one of those methods, please retest with a new or at least clean and in good shape spark plug. If you get anything less than a nice blue spark, it's weak and if you're in the orange or mostly orange color range that could certainly get you a no start.

IF the test results in a diagnosis of weak spark, check the tune up stuff first. If it's been a while since the last cap and rotor just go ahead and change them. Sometimes the button that contacts the coil in the cap gets corroded between the button and coil so you can't see it and will cause weak spark. If that doesn't do the trick you are probably looking at a worn out pick up coil in the distributor, which honestly is the most common cause of weak spark. Bad coils, and modules typically manifest themselves as total spark loose or intermittent total spark loss, not weak spark.

 

[Fleetwood]

Just checked my ECM fuses. ECM B and ECM I are good. However, ECM B had a 30amp fuse in it (i'm not the one who put it there), and my fuse box says 15a by where it says ECM B. Do you think I toasted my ECM?

Edit: I think its probably not the ECM due to the fact that I literally drove it home with a new battery after it started at random

 

[SirRobyn0]

Just checked my ECM fuses. ECM B and ECM I are good. However, ECM B had a 30amp fuse in it (i'm not the one who put it there), and my fuse box says 15a by where it says ECM B. Do you think I toasted my ECM?

No. If you toasted your ECM you'd have no spark at all. No injector pulse ect.

See my post above about weak spark.

 

[Fleetwood]

No. If you toasted your ECM you'd have no spark at all. No injector pulse ect.

See my post above about weak spark.

I just tested it by removing a spark plug and grounding it

I attached a picture of the spark
the spark plugs do not seemed to be fouled up and the truck was running fine before with them

What do you mean by the button that contacts the coil?

Thanks!

 

[AuroraGirl]

see the center hole in the plastic cap? there is a small button that goes through there which I believe ... has a spring? that connects the top of the rotor tab thing that sends spark from the coil above it down to the rotor which turns with the distributor and the button presumably does to(?) or something, and that when the rotor nears the cap terminal inside and the coil built up energy it passes that terminal, sparks through the circuit which lands it in the spark plug wire attached on top, which you know the path from there. that was oversimplication but if you changed the coil they come with a little button and a seal or pad thing that goes around the bottom, too.

 

[AuroraGirl]

Why are you using an R43TS?

"letter S which would indicate the plug has an extended tip."

this shouldnt hurt your spark situation, but is your truck call for r43t originally? it seems a little cold but it seems there are times they are called for.. but its hit and miss if it was or not

 

[AuroraGirl]

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Now called CR43TS / 19354425 (conventional) apparently.
OE; GAP .035

Did you gap them?

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19307139
too bad you would need new wires but these rapid fires apparently are popular replacements for those. not related to the spark problem, unless you have bad wire to plug interface. you didnt show us the condition of the end of the plug

 

[Fleetwood]

see the center hole in the plastic cap? there is a small button that goes through there which I believe ... has a spring? that connects the top of the rotor tab thing that sends spark from the coil above it down to the rotor which turns with the distributor and the button presumably does to(?) or something, and that when the rotor nears the cap terminal inside and the coil built up energy it passes that terminal, sparks through the circuit which lands it in the spark plug wire attached on top, which you know the path from there. that was oversimplication but if you changed the coil they come with a little button and a seal or pad thing that goes around the bottom, too.

Oh I see what you mean now I don't have that kind of distributor my coil is separate from the dist cap tomorrow when there is light ill remove that cap and see whats up

here what mine looks like

 

[AuroraGirl]

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this is a ford, but can you pop one of your cap towers and pop the coil wire on both ends, also pull the connectors and show us the terminals/towers/pins/end of spark plug(one) where the wire goes. So this picture here its blurry but the coil, center of cap, and at least 1 plug and 1 tower post are visible. take a picture like that if you could? (the connectors Just pull them and check for corrosion, if good put them back on)

 

[Fleetwood]

I don't know if this mean anything, but if I wait a day or so, it will start and run for about 1 second before it dies.

 

[AuroraGirl]

I don't know if this mean anything, but if I wait a day or so, it will start and run for about 1 second before it dies.

sounds like fuel issue or heat related issue almost. but it would be easier if you just helped me help you for the third time now lol

 

[SirRobyn0]

@Fleetwood I still don't think it's fuel related, but if you have access to a fuel pressure gauge you should check the fuel pressure. If you don't try this. Spray 2 seconds worth of starting fluid into the throttle body and try to start it, see if it'll run. If it does let it stall spray more in a try again. If it'll run twice like that then it's most likely fuel, but I really doubt it, still you should check it.

Ok the picture of the spark. One issue is photos of light sources, and a spark is essentially that, pictures can sometimes misrepresent color but that is not good spark at all. To me going on the picture it looks like orange. Also in the picture see how it is only jumping on one edge of the electrode, assuming the picture is taken at the peak of the spark, not as it is ramping up or falling off. A video would be better, but you'd have to up load that to a video hosting platform and link it and it's not really necessary unless you really want to. If you watch the spark in real time while the engine is cracking see if it fully engulfs the electrode.

One thing I didn't get to type earlier is if we do decide that it's weak spark and not related to the coil / button or cap and rotor, in other words we decide it's the pick up in the distributor then you will need to decide how much distributor work you want to do or if you'd rather just drop in a new distributor.

@AuroraGirl gives a good description of how the coil to button is setup.

I can't come up with a diagram, but from the top of the coil down, it is plastic cover, coil, rubber isolator, and then the button. The "button" is the terminal in the middle of the cap when you turn it up side down. On the other side of that terminal or "button" is a spring which contacts the coil terminal. I've seen those get rusty or even the actual terminal on the coil. It's not common really for that to happen, but it does and is one of the few things that can cause a weak spark in this system.

Still you should do one of the fuel tests so we can know for sure about that end of things.