C4 spark testing
Thread Starter
4th Gear
Joined: Oct 2017
Posts: 4
Likes: 0
From: South Jordan Utah
C4 spark testing
This may sound dumb but I bought a 1990 C4 that didn't start. Ok they told me it has water damage and was totaled. When I looked into it the water damage was minimal but the engine had thrown a rod. How do you throw a rod parked at the Beach?? Anyway after a rebuilt engine I've gone through most of the electronics, new ECU, relay's, distributor cap roter wire's +. The engine will crank over, fuel pressure up, but won't start? I've tested voltage to the ECU the Fan's come on the vats light goes off when cranking but have no spark, checked all fuses (twice) in line fuses (twice) power to the distributor cap.
I don't know what else to check, is there something I've missed??
I don't know what else to check, is there something I've missed??
Instructor
Joined: Mar 2017
Posts: 193
Likes: 13
From: Florence SC
This may sound dumb but I bought a 1990 C4 that didn't start. Ok they told me it has water damage and was totaled. When I looked into it the water damage was minimal but the engine had thrown a rod. How do you throw a rod parked at the Beach?? Anyway after a rebuilt engine I've gone through most of the electronics, new ECU, relay's, distributor cap roter wire's +. The engine will crank over, fuel pressure up, but won't start? I've tested voltage to the ECU the Fan's come on the vats light goes off when cranking but have no spark, checked all fuses (twice) in line fuses (twice) power to the distributor cap.
I don't know what else to check, is there something I've missed??
I don't know what else to check, is there something I've missed??
Safety Car
Joined: Sep 2001
Posts: 4,137
Likes: 531
From: Glenbeulah Wi
This may sound dumb but I bought a 1990 C4 that didn't start. Ok they told me it has water damage and was totaled. When I looked into it the water damage was minimal but the engine had thrown a rod. How do you throw a rod parked at the Beach?? Anyway after a rebuilt engine I've gone through most of the electronics, new ECU, relay's, distributor cap roter wire's +. The engine will crank over, fuel pressure up, but won't start? I've tested voltage to the ECU the Fan's come on the vats light goes off when cranking but have no spark, checked all fuses (twice) in line fuses (twice) power to the distributor cap.
I don't know what else to check, is there something I've missed??
I don't know what else to check, is there something I've missed??
Thread Starter
4th Gear
Joined: Oct 2017
Posts: 4
Likes: 0
From: South Jordan Utah
C4
Ok I pulled up the codes and it says the ECM is bad so I ordered a new one and I'll see what that does 🤔.
Cruising
Joined: Aug 2014
Posts: 10
Likes: 0
Does it start if you give it a sniff of gasoline in the air intake? If it turns over. Your problem is fuel delivery. Don’t assume spark. Try and eliminate the cheap stuff. Spark is super tricky. What code did you say you got?
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