Need wiring diagram for 16151051 ecm

[belaw]

I picked up a harness from a 1988 full size truck with a 4.3 and a 16151051 ecm. Unfortunately this unit is listed in the ecm sub-forum and I need some help!

The harness is almost identical to a 7747 except for some different wire colors (grey instead of tan/white at B2 and yellow/black instead of black at B7). I traced the wires and they terminate at the same place as a 7747, so no problem there.

What has me scratching my head is that there is a circuit at pin C2 that isn't listed on the 7747 wiring diagram. Its a brown wire that I traced to a 2-pin connector (the other wire at the connector is pink/black feed wire). Is anyone familiar with this ecm or know what the brown wire at C2 is?

Also, I pulled a trottle body from a different vehicle ('92 van) because it was in much better condition, but the throttle position sensor connector doesn't match the one on the harness. The female connector on the van TBI has the 3 pins in a row, while the male connector on the truck harness has one pin above the other two (think of the three points of a triangle).

Should I grant a new male connector onto the harness, or can the female connector on the sensor be changed?
Brian

[RobertISaar]

if it is indeed based on the 7747, then C2 is used for "Select" as listed by Ludis. usually when i see that, it's referring to the AIR system.

i decided to look up a 1/2 ton 2WD 4.3 and came up with C2 being "EAC Solenoid", which also sounds like the AIR system.

[belaw]

if it is indeed based on the 7747, then C2 is used for "Select" as listed by Ludis. usually when i see that, it's referring to the AIR system.

i decided to look up a 1/2 ton 2WD 4.3 and came up with C2 being "EAC Solenoid", which also sounds like the AIR system.

Okay, let me show my ignorance: what is the AIR system? Any problems if I delete this circuit from that harness as part of a carb-to-TBI conversion? If it makes any difference I will be repinning for a 7427 PCM.

[EagleMark]

I beleive that is the service number for ECM number 16144288. You can plug in a 1227747 to that harness.

The EAC is the Air pump contlom soliniod but not used on most 1227747 trucks.

You can change the plug or TPS sensor.

Don't get worried about a wire color change, your good to go for 16197427 PCM swap from 1227747, just go by pins.

[RobertISaar]

i dug a little further, it is most definitely the AIR control.

EAC = Electric AIR Control.

anyways, it's an emissions device. in this instance it's used to switch between the AIR pump pumping air into the exhaust manifolds used to heat up the exhaust components faster(specfically the cat and O2 sensor), or it can pump into the air cleaner when it's been run long enough so that it won't throw off O2 sensor readings.

i'd wait for one of the TBI guys to chime in, but i'd assume it can be removed if going to the 7427.

[gregs78cam]

You can change the plug or TPS sensor.

Uuhhh, aren't the mounting boss and screw locations different between the the old weatherpack TPS (screws at 3&9) , and the MetriPak TPS(screws at 1&9)?

But yes just change connectors, I like the flat style connectors because you can find both a verticle plug and horizontal plug TPS for them.

[EagleMark]

Guess you showed me... Glad you guys watch me!

There's 2 flat ones you can change, one points up and one out for low clearence air filter. Round plug needs plug change as Greg as shown... sorry.

[belaw]

Dang, the level of knowledge of this forum is absolutely amazing! Thanks for helping me sort out my "new" harness.

I do have a question about the TPS sensor. Since I can't just swap sensors it looks like I need to change the connector on the harness. I hate to splice wire when I don't have to, and would rather cut the old connector on my harness and replace it with the correct connector. Does the flat-style TPS use a standard 3-way Metri-Pack 630 connector?

[EagleMark]

Not sure on the pins/connectors, but i splice them in, solder and shrink wrap and never had an issue. Pretty much any wire on harness can be done like this. Only one I don't is injector wires as I was told not to long ago, forgot why, never tried, don't know if that is accurate and stuck with what works.

[RobertISaar]

what's wrong with soldering injector wires? i've done it quite a bit with excellent results, even during a SFI to MPFI conversion.

[gregs78cam]

Does the flat-style TPS use a standard 3-way Metri-Pack 630 connector?

The flat style is the weatherpack(left pics above), the round plug (right pic above)(triangle pin layout) is a metripak 150(1.5mm pin/blade width)I believe.

[EagleMark]

what's wrong with soldering injector wires? i've done it quite a bit with excellent results, even during a SFI to MPFI conversion.

Like I said, I don't know, was told that long ago and stuck with it? You've proven it wrong...

[JeepsAndGuns]

Yea I used a junkyard mpfi injector harness and cut/spliced/soder/shrink wraped it to the length I needed, no problems. I also had to swap TPS plugs to that round style and lengthen my IAC wires. No problems spliceing as long as you do it right.

[gregs78cam]

I think the only difference in the TBI injector wires is the type of insulation, it is like a hard plastic, possibly due to probable contact with fuel/vapors/possible backfire.

[belaw]

The flat style is the weatherpack(left pics above), the round plug (right pic above)(triangle pin layout) is a metripak 150(1.5mm pin/blade width)I believe.

Okay, I'm off to the wrecking yard this weekend to find a Weatherpack TPS that will fit my throttle body. What year did GM switch over from Weatherpack to Metri-Pack fittings on the TPS? Any suggestions on what vehicles I should look for if I want the horizontal/low clearance weatherpack TPS?