c3500 No Spark.

[Jrgunn5150]

I'm trying to help a friend out, over the phone, which is even more difficult than over the internet lol.

He has an 89 C3500, 454 TBI.
Say's it was running fine and he backed it into the driveway one night, came out in the morning, no start. Says the injectors are spraying so he has fuel.
Say's he's replaced the distributor completely.
Say's he found one burned fusible link and fixed it.
Says' his 5 amp crank fuse gives no power either way.


I suggested he swap relays around under the hood and see if he can get it to spark with no fuel, I really don't know what else to tell him as far as trouble shooting. I can't think of what he might have wrong with the thing if the distributor and everything is new.

 

[skylark]

He needs to check for spark. If he replaced the distributor the next most logical step is to see if he has power to the distributor and coil. If so then check the coil and coil wire.

 

[frito-bandito]

Definitely check if he has spark, Ive had a damn distributor cap throw me for a loop before. Even if its new, don't assume that its good

 

[Jrgunn5150]

Well he's in Detroit, about 2.5 hours from my home, if it comes to that, I'll head down there, but I'm hoping not lol. He's an older guy, even a TBI is out of his comfort zone. His lone diagnostic tool is a test light.

So in this pic, he says with the key on, he get's a light from the left plug, but it's very weak compared to anywhere else he hit's it,

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He's say's none of these light up at all, which makes me think he has a bad module, but I'm honestly not super familiar with the TBI ignition system at all.

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[skylark]

Well he's in Detroit, about 2.5 hours from my home, if it comes to that, I'll head down there, but I'm hoping not lol. He's an older guy, even a TBI is out of his comfort zone. His lone diagnostic tool is a test light.

So in this pic, he says with the key on, he get's a light from the left plug, but it's very weak compared to anywhere else he hit's it,

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He's say's none of these light up at all, which makes me think he has a bad module, but I'm honestly not super familiar with the TBI ignition system at all.

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The top picture is the map sensor. He would get a 5v reference from the ecm, that is why his light is dim. As for the distributor power, going from memory here, I BELIEVE that the pink wire is the power wire.

 

[Jrgunn5150]

From my research it looks like he need's 12v at the pink wire. I just told him to check the pink wire, if no voltage, run it straight to the batterer and hit it to see if she fire's. I guess we'll go from there.

 

[geolow97]

Let me know what you find out because I have a TBI 350 that is doing the same thing. Found lighting issues to be a separate problem but I have a jumper to my distributor to get it to run . I have to twist it together to start it then pull it apart to shut er down. Kinda janky. I have been told that it is probably the ICM under the rotor?

Sent from Charleston SC

 

[Jrgunn5150]

Let me know what you find out because I have a TBI 350 that is doing the same thing. Found lighting issues to be a separate problem but I have a jumper to my distributor to get it to run . I have to twist it together to start it then pull it apart to shut er down. Kinda janky. I have been told that it is probably the ICM under the rotor?

Sent from Charleston SC

Will do, part of my reasoning for helping him is so if I have trouble I already have a leg up lmao.

 

[geolow97]

Lmao! Good strategy!

Sent from Charleston SC

 

[skylark]

From my research it looks like he need's 12v at the pink wire. I just told him to check the pink wire, if no voltage, run it straight to the batterer and hit it to see if she fire's. I guess we'll go from there.

If I recall correctly the coil and the distributor are on the same circuit. He will want to check for power at both.