Tough Ignition Problem 1996 C2500 5.7 L Vortech
Hi my name is Nick, from rusty truck ohio. Having troubles looking for advice and the logging of information I get to maybe help someone else in the future.
Background info that may be applicable.
-Had the truck about 4 months. Always kinda ran slightly rough around 2k to 3k rpms. Seems like a misfire or studder. Was able to gas it and rev past it. about 15 mpg average the time ive owned it.
-Purchased a really bad tune up kit off eBay (never again) which consisted of plugs,wires, cap, rotor.
-installed about a month ago with no change to performance. Rough running was still there at those rpms. did not matter how much pedal i had at those rpms, would still seem to miss and hesitate till past 3k about.
Last friday the truck died while taking off from a stop sign. I suspected fuel issues but i was wrong. What actually happend was the rotor tab that contacts the distributor cap had broken off and was laying in my distributor.
I did not realize I had no spark until after I had tested the fuel system (Showed 60 fuel pressure from a guage I rented) so i flooded the truck. BAD
I was able to get a free tow to my house to look at the ignition.
Before I found out the rotor tab broke I purchased a new ICM and New Coil. Oreily gave me a bad ICM. My Original was still good.
I also purchased new plugs and wires because I had no faith in the tune up kit i bought so I wanted to eliminate that variable.
I was able to get spark to the plug wires after making sure CPS was sending signal to ICM, ICM was sending signal to coil and had good ground and power. I can take wire off distributor and put next to bolt but its showing orange spark not blue. But it will jump about a half an inch to the bolt.
First question is: Ya I have spark but shouldnt that be a bright white or blue? This is a new coil but its BWD brand and the BWD brand ICM i had was returned because it wasnt sending signal to the coil right out of the box. Thats when i went back to my original ICM. Still have new BWD coil installed.
Okay so at this point I can get a spark tester (not the one that jumps gap, but the inline one that uses a light bulb) to light up.
My engine had been flooded so I took all plugs out, ran starter to blow the fuel out. Put new plugs in. Still no start. turns out plugs were fouled.
Clean plugs again, run starter to clear fuel out, take out fuel pump relay, and try to start with alittle starting fluid again to try to avoid fouling plugs.
Turns out ive got no spark to plugs again.... check coil for spark and sure enough same orange spark that will gap about half and inch to an engine bolt. Auto parts store says if its gapping that big, the coil is good.
So i know coil is sending out some high votage to the distributor cap.
Check timing by finding TDC and comparing rotor position and harmonic balancer position. I rotate crank by hand until HB mark lined up on the 2 o clock position where i can see a greasy tab sticking up on the timing cover. First time it lined up rotor possition was on the 6th cylinder post inside the distributor cap. Rotate the crank around one for time and it lined up on the 1st cylinder post inside the distributor cap. I now know I did not slip a timing chain. I think. I cant see that mark on the timing cover from the top, but i painted the HB line and put it in the center of the tab sticking out of the timing cover that sits about the 2 o clock position. the tab on the timing cover is about and inch and a half big and looks like "\___/" from the bottom view. too much **** in the way i cant find it from the top. So Im pretty sure im in time.
the only part i have not verified good is the distributor itself. Its shaft driven with a spline drive. I cannot spin the rotor freely which is good but i can twist it and it "spins" while moving up and down alittle. From my research this is normal. but it does not snap back into place. I can leave it in the spun up or spun doewn possition and it stays till I crank starter and it always reverts back to one of the possitions after cranking. But could exesive play cause timing issued and generate weak spark to plugs?
I verified all igniotion up to distributor cap and I still cant get this truck to run. In the morning im going to set to TDC and remove and inspect the distributor. Everything else is new and checking out. I dont understand this and im running out of time and money like everyone else that does their own work.
Would love to see if someone has experience with these distributors or has tested a coil the way I am and is getting a nice blue spark. Auto parts store has talked me out of buying a new coil twice and kept telling me to check plugs. I have cleaned and reinstalled plugs after blowing out cylinders and I still have no go.
I'm thinking my distributor is worn and is causing my problems. Should make a difference but the mount for the rotor is dry but has surface rust all on it.
Im 4 days working on this so im sure im leaving something out but I need second opinions from guys who have actually worked on these motors.
Thanks
-Nick
Background info that may be applicable.
-Had the truck about 4 months. Always kinda ran slightly rough around 2k to 3k rpms. Seems like a misfire or studder. Was able to gas it and rev past it. about 15 mpg average the time ive owned it.
-Purchased a really bad tune up kit off eBay (never again) which consisted of plugs,wires, cap, rotor.
-installed about a month ago with no change to performance. Rough running was still there at those rpms. did not matter how much pedal i had at those rpms, would still seem to miss and hesitate till past 3k about.
Last friday the truck died while taking off from a stop sign. I suspected fuel issues but i was wrong. What actually happend was the rotor tab that contacts the distributor cap had broken off and was laying in my distributor.
I did not realize I had no spark until after I had tested the fuel system (Showed 60 fuel pressure from a guage I rented) so i flooded the truck. BAD
I was able to get a free tow to my house to look at the ignition.
Before I found out the rotor tab broke I purchased a new ICM and New Coil. Oreily gave me a bad ICM. My Original was still good.
I also purchased new plugs and wires because I had no faith in the tune up kit i bought so I wanted to eliminate that variable.
I was able to get spark to the plug wires after making sure CPS was sending signal to ICM, ICM was sending signal to coil and had good ground and power. I can take wire off distributor and put next to bolt but its showing orange spark not blue. But it will jump about a half an inch to the bolt.
First question is: Ya I have spark but shouldnt that be a bright white or blue? This is a new coil but its BWD brand and the BWD brand ICM i had was returned because it wasnt sending signal to the coil right out of the box. Thats when i went back to my original ICM. Still have new BWD coil installed.
Okay so at this point I can get a spark tester (not the one that jumps gap, but the inline one that uses a light bulb) to light up.
My engine had been flooded so I took all plugs out, ran starter to blow the fuel out. Put new plugs in. Still no start. turns out plugs were fouled.
Clean plugs again, run starter to clear fuel out, take out fuel pump relay, and try to start with alittle starting fluid again to try to avoid fouling plugs.
Turns out ive got no spark to plugs again.... check coil for spark and sure enough same orange spark that will gap about half and inch to an engine bolt. Auto parts store says if its gapping that big, the coil is good.
So i know coil is sending out some high votage to the distributor cap.
Check timing by finding TDC and comparing rotor position and harmonic balancer position. I rotate crank by hand until HB mark lined up on the 2 o clock position where i can see a greasy tab sticking up on the timing cover. First time it lined up rotor possition was on the 6th cylinder post inside the distributor cap. Rotate the crank around one for time and it lined up on the 1st cylinder post inside the distributor cap. I now know I did not slip a timing chain. I think. I cant see that mark on the timing cover from the top, but i painted the HB line and put it in the center of the tab sticking out of the timing cover that sits about the 2 o clock position. the tab on the timing cover is about and inch and a half big and looks like "\___/" from the bottom view. too much **** in the way i cant find it from the top. So Im pretty sure im in time.
the only part i have not verified good is the distributor itself. Its shaft driven with a spline drive. I cannot spin the rotor freely which is good but i can twist it and it "spins" while moving up and down alittle. From my research this is normal. but it does not snap back into place. I can leave it in the spun up or spun doewn possition and it stays till I crank starter and it always reverts back to one of the possitions after cranking. But could exesive play cause timing issued and generate weak spark to plugs?
I verified all igniotion up to distributor cap and I still cant get this truck to run. In the morning im going to set to TDC and remove and inspect the distributor. Everything else is new and checking out. I dont understand this and im running out of time and money like everyone else that does their own work.
Would love to see if someone has experience with these distributors or has tested a coil the way I am and is getting a nice blue spark. Auto parts store has talked me out of buying a new coil twice and kept telling me to check plugs. I have cleaned and reinstalled plugs after blowing out cylinders and I still have no go.
I'm thinking my distributor is worn and is causing my problems. Should make a difference but the mount for the rotor is dry but has surface rust all on it.
Im 4 days working on this so im sure im leaving something out but I need second opinions from guys who have actually worked on these motors.
Thanks
-Nick




