Dead again... :(

[4xcrazy]

Gettin to the point, i'm about ready to strip it, and part it out.



Just went outside to head to the store, and no fire, i don't know why at the moment, it's cold, windy and dark...

figured i'd start my own griping bitching, complaining ready to blow it up thread...

here's what i have been messing with for any new comers...

http://coloradok5.com/forums/showthread.php?t=276340

 

[eagle mark]

Didn't I read in your old thread you can wiggle the harness and have an issue?

Are there any codes set this time?

 

[4xcrazy]

I had an issue when i moved out to Indiana from Arizona, where the gauges would all go dead, it would blow the fuse for them, i'd crawl up in the engine area, grab the harness towards the back and yank it around alittle and that would let whatever was shorting out,,,not, and i could go on down the road, which is alittle odd anyways, cause when i installed the new motor & trans, i cleaned up the harness, straightening things out, getting rid of the old brittle loom stuff and rewrapped all the wires, but i haven't had that problem since i have been here, since May...

As far as codes go, this is another issue i am unsure about, never had a computer controlled vehicle do what this one does and i have commented about it before, where i put the 2 prong code key in the port, turn the key on, and the SES light starts flashing, i get the 3-12 codes, and can usually get one more code which is the O2 sensor,,,which i already know is faulting due to the headers in this cold climate now.

But after that, the light will continues to want to flash, but it gets dimmer as it continues till it won't light anymore. Cannot retrieve any other codes. It appears like a light flashing on battery power, but the battery is dying, visualize that if it helps describe what it's doing. I have checked with a few auto parts stores around here about using their actual handheld scanners, but they all use the code key deal as well.

DaveW sent me a spare computer to check out, i still have it here cause i haven't had the cash to return it to him, i thought i had fixed this with the ignition control module. It has been running since the last post in that other injector pulse thread. Just out of the blue, it won't start.

Might try & head out there in a bit to kinda check a few things over, see if it's getting fuel, spark and whatnot and go from there, but damn it's only like 19* out, and i'm still not used to this cold weather yet

I'll end up doing what i always do with this truck though,,, i'll end up fingering it out and get it running again.

 

[4xcrazy]

Well, i just went out there to take a few pics of something, and decided to try and start it. It fired right up, ran for about 10 seconds and just died like i turned the key off. Basically doing the same thing again as it was before. after 3 ignition modules? granted they were all used, but still, what are the odds really. Guess i get to do some more digging.

I just wish the pig would fit in the garage, it's too damn cold and even colder with the breeze that's goin on out there.

 

[Mountain_man]

Ok. visually check the wires going down rear passenger side of block to the starter and knock sensor. These wires tend to get jacked up by going where they do on our vehicle. Also check where the harness comes out of distributor and down about 6-8". The other options are the set of wires going down passenger side of engine. going to spark module. If you isolate these wires you will probably find many of the gremlins I've been finding. I've fixed many suburban tbi's with these common locations of repair. Many of the wires have a small shaved side not the whole wire screwed up. wiggle wiggle wiggle and do it some more or you'll be chasing ghosts.

 

[dave w]

I had a 1986 Grand Am that would act just like your Suburban, except it was only 5 years at the time. When the Grand Am would not run / start, the problem was no fuel was spraying from the injector. Spark was fine, and fuel pressure was fine. Never got a code. I ended up replacing the computer to fix the Grand Am.

So as a guess, I think it is possible the ground / battery negative connections to the ECM might be corroded? Both the SES light and injectors are activated by the ECM sending Ground / battery negative pulses. The injectors will have +12 volts with the ignition switch in the "On / Start" position. The ECM will actually pulse ground to the injectors to make the injectors spray fuel. The SES light gets +12 volts from the ignition switch in the "On" position. The ECM will actually pulse ground to the SES light to make the SES light flash.

The only clue I have that the ground / battery negative connections to the ECM might be corroded is the way you describe how the SES light fades. As the SES light flashes more and more, the corroded connection gets worse.

Black wires with a white stripe are ground / battery negative wires on '7747 ECM's.

dave w

 

[eagle mark]

What year is your burb? I have a 90 so I can look to see where grounds are but you probably know?

 

[eagle mark]

Don't rule out other colors as I just looked at a harness here on the bench and it also has grey, brown wires tied into black. But from the looks of it there are 2 grounds with 2 wires each. One to the front of motorish and one to rear.

 

[4xcrazy]

What year is your burb? I have a 90 so I can look to see where grounds are but you probably know?

'89...

and as far as grounds, this was the next step basically was checking ALL wiring next, especially when you mention grounds. I have only been here for about 6 months, but as i was under the truck taking a few pics of some stuff and looking over things, i notices things are rusting up already.

This truck is originally from the southwest, no corrosive eating type rust at all, i'm starting to wonder now if some of this corrosive salt spray has made it's way to some of the wiring, grounds, and affected the connections in some way since i have been here.

UNFORTUNATELY,,,,today,,it's snowing out, and suppose to do it more tomorrow

as far as fuel injectors, that's what's going on, it'll start and run for a short time, but then the injectors just stop spraying, kills the engine instantly, then won't refire usually. This is why i swapped out the ignition control module originally.

Wiring is next on the list, i had even been tempted to just get a new harness.

 

[4xcrazy]

and Dave, thanks again for sending me that computer, i still have it here, gonna check over the wiring and see if i see anything obvious, then i may test with that unit and go from there.

I will still send it back to you either way though, if i end up needing a new one, i will buy a new one and get yours back to ya

Thanks a ton for the help on that

 

[eagle mark]

THAT WAS AWFULLY NICE OF YOU DAVE!

Your SES light is odd behaviour. Can't say I have ever seen that or heard of that before. Or can even figure out how it would do that? FYI the SES light comes from an ignition on power (key on) and runs through the ECM which grounds it.

 

[4xcrazy]

THAT WAS AWFULLY NICE OF YOU DAVE!

Your SES light is odd behaviour. Can't say I have ever seen that or heard of that before. Or can even figure out how it would do that? FYI the SES light comes from an ignition on power (key on) and runs through the ECM which grounds it.

yes, i know, as i said, i have never seen this before either, took me by suprise when it started doing it.

i really didn't think much of of it though, it actually was doing that out in Phoenix several months ago, but the truck ran great, so i didn't bother with it too much.