84CUCV
3/4 ton status
after i made one with a dash bulb. thanks dyeager535. no light. not sure were to go from here. does that mean that something with the computer is messed up??
thanks
thanks
CK5
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no light with the noid test.
- Thread starter 84CUCV
- Start date
dave w
1/2 ton status
Normally the TBI injector wires white and red will have + (positive) battery voltage, when the ignition switch is in the on and start position. Both TBI injector wires white and red are supplied power from the injector fuse. I would make sure the white and red wires have + (positive) power when the ignition switch is in the on or start position.
The noid light should be connected to either white / green or red / blue wires.
Both green and blue wires are routed to the ECM, and supply - (negative) battery voltage pulses to the injectors when the engine is starting or running.
I would use an ohm meter to make sure both the green and blue wires are good (not broken or corroded) to the ECM.
Before calling the ECM bad, I would use data logging software to see if things like to TPS, CTS were working. If the data logging software showed TPS, CTS were working then I would think the power and ground wires to the ECM were good. I might even remove the distributor from the engine and use a variable speed electric drill to spin the distributor (be sure the distributor is grounded and reconnect all the electrical plugs) to see if the data logging shows different RPM's while changing speeds of the distributor with the variable speed electric drill. If the data logging show different RPM's, then I would PRONOUNCE the ECM Injector Circuit DEAD
dave w
The noid light should be connected to either white / green or red / blue wires.
Both green and blue wires are routed to the ECM, and supply - (negative) battery voltage pulses to the injectors when the engine is starting or running.
I would use an ohm meter to make sure both the green and blue wires are good (not broken or corroded) to the ECM.
Before calling the ECM bad, I would use data logging software to see if things like to TPS, CTS were working. If the data logging software showed TPS, CTS were working then I would think the power and ground wires to the ECM were good. I might even remove the distributor from the engine and use a variable speed electric drill to spin the distributor (be sure the distributor is grounded and reconnect all the electrical plugs) to see if the data logging shows different RPM's while changing speeds of the distributor with the variable speed electric drill. If the data logging show different RPM's, then I would PRONOUNCE the ECM Injector Circuit DEAD
dave w
84CUCV
3/4 ton status
wow ok thanks. pretty sure i got all that
Keep in mind that the ignition module sends a signal to the ECM for the injectors to pulse, a bad module can create no injector pulse. This is the more probable issue.
84CUCV
3/4 ton status
ok how do i check the ignition module? anyone know a book on chevy FI? think that would help me out a bit thanks
dave w
1/2 ton status
I think maybe a parts store will have the ability to test the ignition module? Seems like some of the parts stores where I live (would / used to) test the ignition module.
The first EFI book I purchased was titled "How to Tune & Modify Chevrolet Fuel Injection" Authored by Ben Watson ISBN # 0-7603-0442. http://www.amazon.com/Modify-Chevro...=sr_1_1?ie=UTF8&s=books&qid=1253463985&sr=8-1
dave w
84CUCV
3/4 ton status
i will call around and see. know of any book just on the stock tbi? thanks
dave w
1/2 ton status
Haynes Techbook Fuel Injection 1978 thru 1985
http://www.amazon.com/gp/offer-list...?ie=UTF8&qid=1253506588&sr=1-3&condition=used
http://www.amazon.com/gp/offer-list...?ie=UTF8&qid=1253506588&sr=1-3&condition=used
twiget
1/2 ton status
I am having the same issue with my 'burban. I replaced the ignition module and that did not do the trick (didnt know they could be tested...). It looks like the problem is the pickup coil that connects to the back of the ignition module.
Since your going to be in the area when you remove the ignition module, it would not hurt to check the resistance of the pickup coil with an ohm meter. From either pin to ground should be an open. If it is anything less than open, the pickup is bad. Also measure from one pin to the other. The resistance should be between 500 ohms - 1500 ohms. My pickup coil was around 5,000 ohms on all three measurements, so I'm pretty confident this is my problem.
I don't think anyone else has said it yet, but dont forget to check your fuse's too.
Since your going to be in the area when you remove the ignition module, it would not hurt to check the resistance of the pickup coil with an ohm meter. From either pin to ground should be an open. If it is anything less than open, the pickup is bad. Also measure from one pin to the other. The resistance should be between 500 ohms - 1500 ohms. My pickup coil was around 5,000 ohms on all three measurements, so I'm pretty confident this is my problem.
I don't think anyone else has said it yet, but dont forget to check your fuse's too.
