87 1500 Not Getting Power to TBI Injectors

[87 grey ghost]

Also just went out to check with it in and
got called to work for awhile! Should be
done after lunch. So I can retest with the
fuse in. Thanks for all the great help so far

 

[89Suburban]

newbie needs help

Yah test with the fuse in on the 2 little silver spots on the top of the fuse. If both those light up check for power at the splice I mentioned.


Posted From Hell

 

[87 grey ghost]

i got power to both sides of the fuse.
the red wire from one injector and the white wire from the other injector tie together
at a splice,then they turn into four pinkish colored wires with black tracers.
then the blue and green wires from both injectors run with out me seeing any splices
threw the fire wall on the passenger side.( i'm assumimg into the computer) thank you

 

[89Suburban]

Yup so you got power to the injectors after all. So it's the computer end of the line. I can't help you there but Jims86 should be able too give you some ideas. You might want to try to see if the computer spits out any codes. Those other pink/black striped wires out of the splice go to some of the other sensors on the top of the motor and one runs to the computer.

 

[87 grey ghost]

thanks so much for your help pawpaw.

 

[HotRodPC]

He said PawPaw !!!

Welcome to GMSB !!! Si Wannabe or what??? They blew that truck up you know.

So is this thing running now? If not, fire up a thread in the TBI Engine Section. Many of the other knowledgable guys, along with PawPaw can get it figured out with their heads together. But not everyone reads intro threads.

 

[77 K20]

You sure you just don't have injector wires that were pinched and grounded by the air cleaner assembly?
It was fairly common problem in the '87 throttle body injection.

I learned this the hard way in high school. Drove an hour to the girlfriend's house, picked her up and made it 50' in my dad's Blazer when it died. Checked for spark. Yep. Checked for fuel at the throttle body. Yep. Towed it all the way to town (30 miles) to find the injector wiring had been smashed by the air cleaner assembly.

 

[89Suburban]

You sure you just don't have injector wires that were pinched and grounded by the air cleaner assembly?
It was fairly common problem in the '87 throttle body injection.

I learned this the hard way in high school. Drove an hour to the girlfriend's house, picked her up and made it 50' in my dad's Blazer when it died. Checked for spark. Yep. Checked for fuel at the throttle body. Yep. Towed it all the way to town (30 miles) to find the injector wiring had been smashed by the air cleaner assembly.

Yup very common issue there. But that should be blowing the fuse if that were the case.


Posted From Hell

 

[87 grey ghost]

OK guys here is where i'm at now!! Got a new ecm ordered,It will be in tomorrow but probably won't get time to put it in do to kids activities. So after i get it in i'll let you
know how it's going. Thanks

 

[89Suburban]

newbie needs help

Damn it

Jim any ideas?




Posted from hell

 

[Jims86]

Yup, gonna have to unplug both plugs from the ecm and start testing for power.
A6, B1, and C 16 are the terminals you want to check for 12 volts.
B1, and C16 should be constant battery voltage, and a6 will be keyed power.
There is also a black or brown plug with 8 terminals coming off the wire harness from the ECM, make sure that is plugged in. That plug has the ALDL wires, and a constant power wire.

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[87 grey ghost]

Thanks guys, when I get home tomorrow
ill check it all out. And let ya know how
it turns out.

 

[89Suburban]

Can he use a test light in the injector sockets to test for a pulse somehow?

 

[MrMarty51]

Can he use a test light in the injector sockets to test for a pulse somehow?

Them plug in noid lights is best, I`d be a bit cautious using a probe/test lighton any of that ECM stuff.
The TBI circuit itself should be safe to test, I think, it goes through a relay and the ECM just grounds the signal side of the relay. I think that is how it works.
Wait until someone with more knowledge on these matters chimes in before using that 12 volt probing light.

 

[Jims86]

Them plug in noid lights is best, I`d be a bit cautious using a probe/test lighton any of that ECM stuff.
The TBI circuit itself should be safe to test, I think, it goes through a relay and the ECM just grounds the signal side of the relay. I think that is how it works.
Wait until someone with more knowledge on these matters chimes in before using that 12 volt probing light.

Not really a realay, but solid state circuitry/switch. It happens so fast, the noid light is the only way.