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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Chevrolet r1500: 87 chevy pickup with a 350 tbi...I have injector

Customer Question

87 chevy pickup with a 350 tbi...I have injector pulse and food fuel pressure but no spark. Have replaced coil new wires rotor cap and plugs
Submitted: 2 years ago.
Category: Chevy
Customer: replied 2 years ago.
Hello??
Expert:  Dave Nova replied 2 years ago.
Hello and thank you for trusting me with your question. My name is ***** ***** I will do my best to help you with your Chevy problem.
Do you have voltage to the pink wire at the coil with the key in the on position?
Customer: replied 2 years ago.
Yup
Customer: replied 2 years ago.
I assume with injector pulse that the new module is working and recieving the signal from pickup cool right?? My next guess would be pickup coil but I'm not convinced
Expert:  Dave Nova replied 2 years ago.
So the ignition control module in the distributor has been replaced?
Customer: replied 2 years ago.
Replaced the icm, coil, wires, rotor bug and cap
Expert:  Dave Nova replied 2 years ago.
If you have injector pulse then the pickup coil and icm should be operational. Connect test light across pink and white wires at the coil and crank the engine. Light should flash, does it?
Customer: replied 2 years ago.
Nope
Customer: replied 2 years ago.
Wait a sec. What do you mean connect test light across the white and pink wires? I know your talking about plug at coil but how do you lay test light??
Expert:  Dave Nova replied 2 years ago.
Connect clip of test light to pink wire and probe of test light to white wire. Then crank the engine and look for the light to flash.
Customer: replied 2 years ago.
And if we don't have the flash?
Expert:  Dave Nova replied 2 years ago.
If you have power on the pink wire but no flash, this would indicate a faulty ICM.
Customer: replied 2 years ago.
Ok thanks. I'll get back to you later
Expert:  Dave Nova replied 2 years ago.
Thanks I will look forward to your reply.
Dave
Customer: replied 2 years ago.
Ok I have confirmed 12 volt power to both the white an pink wires. When I prob the the wires as requested in either direction there is no flash. This is a brand new module also...
Expert:  Dave Nova replied 2 years ago.
Does your truck have a tach?
Customer: replied 2 years ago.
Nope. Just tested module at slow reillys and confirmed good....this one I'd gonna drive me nuts
Expert:  Dave Nova replied 2 years ago.
With coil and module unplugged, do you have 12 volts on white wire?
Customer: replied 2 years ago.
Does ground placement matter? The engine ground is on frame. Isn't it supposed to be a body ground??
Expert:  Dave Nova replied 2 years ago.
Main ground cable should attach from battery to engine block. You should also have a ground strap from the engine to the body at firewall, a second ground strap from engine to frame.
Customer: replied 2 years ago.
Module unplugged? You mean the 4 wire plug?
Customer: replied 2 years ago.
Ok with 2 wire unplugged from coil I have 12vlots on tach wire and power wire plug if that's what your asking. Replaced the 2 wire plug from coil to module and confirmed all grounds. with key on if I unplug the 2 wire plug from distributor from coil and hook it up it will trip injectors
Expert:  Dave Nova replied 2 years ago.
If you unplug 4 wire connector and crank the engine, do you get spark?
Customer: replied 2 years ago.
Nope. Tried it
Expert:  Dave Nova replied 2 years ago.
I am about out of options on this one. Likely something wrong with the wiring where the white wire is shorted to voltage, but the schematics for these older vehicles are hard to come by. I am going to opt out and allow other experts to chime in on this one. Perhaps one has some direct experience with this issue. Best of luck on your repairs.
Dave