Pwnage1337

First off let me begin by saying that I am extremely frustrated with the car.

Second, I'd like to thank everyone who has been following my thread, helping me along the way (you guys know who you are, without you it wouldn't have been possible)

Third. I need more help. I know this is the right place to ask.

Let the story begin,

Put the car away last fall. After having the exhaust setup welded in place, the car ran fine. I drove it for 3 days, pretty gently just cause I am cautious about the first few thousand miles. The car ran great for 3 days, then out of nowhere just took a total dump. Dumping fuel, running very rich and crappy. I put the car away for the year because the snow was coming.

Flash to spring time.

Go over to start the car, and get it out of storage. At this point I didn't notice whether or not there was a check engine light, but it started, ran like total crap, so I drove it 100 yards to my house, and parked it in the driveway. It has been sitting there since.

For the past couple of days I have been troubleshooting with my FSM, the main problem is that I have no Check Engine Light. Using Chart A-1, in driveability and emissions section, (6E3-18) I followed the flow chart and landed on "Open Circuit 419, Open Circuit 39 to bulb, Faulty light bulb"

So the first thing I did was pulled the DIC, and checked the bulb on the CEL. the bulb is good. Just for ***** and giggles, I pulled the bulb from the Door Ajar location, and put it into the CEL location. It didn't work either. Upon reinstalling the bulb into the Door Ajar location, now the door ajar bulb won't light. Not sure if there is a separate issue here or not. Is it possible I'm getting a check engine light, but I just can't see it due to a faulty DIC? Checked all of the fuses, and they are all good.

Now here comes the weird part. When I crank the car, the BRAKE! bulb lights up on the DIC. Leads me to believe the DIC is faulty, or the ECM is doing some pretty wild things.

I have fuel (watching fuel pressure gauge needle bounce, plus plugs are wet), have spark, and obviously there is air.

When I jumper the ALDL connector the cooling fan comes on, so I know the ECM is doing some of its job, how much of it I don't know. The car gets fuel pressure when I turn the key to "on" and when I crank, it almost catches but doesn't want to run.

I would just read the ECM with tunerpro, but I am unable to connect to the ECM through Tunerpro. I would jump the ALDL with a paperclip to pull codes, but I'm unable to do that as well....

When I tried connecting to the ECM through tunerpro, I was getting crazy readings. Things like 9000 rpm, 24 volts, readings were jumping all over the place. This is with the key-on, car off.



Any help is greatly appreciated. I will probably add more to the pile of BS as I remember it.


Thanks again for everything guys,


Jeremy.

cgantner5150

Check the fuseable links behind the battery - when I had no CEL that was the cause. Maybe it's not completely blown or corroded?
It could also be a ground issue (always seems to be a ground issue on these Vettes). A bad ground can cause all kind of craziness.
Have a multimeter? Check volts at the battery, the ECM (orange lead - which is the feed/fuse able link, continuity of the ECM grounds (little to no resistance). The 24v in tuner pro is odd but I trust a meter more.
Suddenly running like garbage - maybe it is in "limp" mode?

VetteMed

recent welding done, no check engine light -- that screams bad ECM to me.

Pwnage1337

I love this place and worship the keyboards you guys type on.

I will check my fuseable links tomorrow, I looked at my ECM ground (at the back of the drivers head) and it's tight.

Thanks for the swift response!!

Pwnage1337

Battery was disconnected, and the ECM wasn't in the car when it was welded. It was reinstalled and ran good for three days after the welding was done, any other ideas?

Thanks for your input.

-js-

I agree check that you have power and ground at the ECM.
I doubt that limp home would even operate as expected if the wiring for the power into the ECM has left the room.

AGENT 86

What ECM are you using ?
Is there 12v on one side of bulb socket with ignition on ?
Did you test for open circuit between bulb socket and ECM ?

-js-

Here is a thought I have not followed your other threads.
Did you change the programming in the ECM?
If so how was it done?
I have played with these and recall if the ECM eprom Is not seating things like your describing would happen.

Pwnage1337

Its a 165 ECM.

I have not tested any circuits as of yet, I ran out of time today but will jump on it tomorrow. Damn work, always getting in the way. lol.

Yes the programming has been changed, i have a startup chip from bjankuski that ran the car fine. I had two chips, one i made some alterations to, just minor things, but the one that originally ran the car (brians chip) is in the ECM. Running a moates memory adapter

Thanks again for all the suggestions guys, this place is great.

cgantner5150

I didn't think about the chip
. It will go in backwards and it will run - like crap and the fan always runs. Been there done that.
I have not experienced it coming loose or partially out but I am sure that it would not be good.
Voltage and grounds are VERY IMPORTANT.

Kubs

Since the chip adapter is not locked in like the OEM chip and it hangs upsidedown in the car it can wiggle loose. That happened on my car and it was running rough had no power and was spitting fuel out the tail pipe. I also did not have a check engine light.

VetteMed

Another thought, check the ECM fuse, it's a 3A or 5A fuse, if blown or missing it will prevent power from getting to the ECM (and give the above symptoms). Silly, but worth checking.

merlot566jka

Using this, I would check A5 for 12v key on, engine off.

and test anything else thats quick for errors. Kinda sounds like your memcal lost its mem. lol. (which should only happen in the event of uv errasing or emp blast or just bad luck)

I would really check things with a meter. Check the batt voltage, check voltage on ecm, AND CONTINUITY GROUND CHECK to all ecm ground connections. Just checking to see if a ground is clean on the outside doesnt tell the condition under the connection. Corrosion happens, and its usually galvonic, where the steel/aluminum/copper touch. If there was any moisture during storage times, there is a good chance corrosion happened. And by moisture, I mean even humidity.



totally possible!! check it. Remember ESD sensitivity!

The ebrake light should have no relation to the ecm. I cant remember the last time i was in a vette of your year, but some of the idiot lights come on during cranking, and go away once the car is started. I dont remember which. Try taking off the ebrake, and see if the light is still there. I know on the 92-96 they have two brake lights, pressure and ebrake. the pressure comes from a sensor on the actual brake system, while the ebrake is from the switch on the handle of the ebrake.

Pwnage1337

Made some progress here in the last few days. Weather hasn't been cooperating with me very well. Gale force winds, rain/hail.

I checked the ECM, have 12v at A5, fusible link tested out good. Put the battery back in.

Just going over some things, i decided to pull all the plugs. They were all basically fouled. I cleaned each one of them, put them back in. Keyed on, there was still no check engine light, but I had fuel pressure so I cranked the car. It popped right off, started within the first half second of cranking.

The car ran very well for the first three seconds, then started to go rich again. My AFR gauge read 14.3 for about 3 seconds, then slowly crawled its way down to 12.0 so I shut it down. Why does it run so well for three seconds and then just start dumping fuel?

I'm guessing the car is in closed loop operation for a few seconds, then once it starts taking information from the sensors it goes into open loop and that's when everything goes all silly.

I pulled the plugs again right after running it, and they were a bit wet. Not what I want to do with this engine, if the rings keep getting washed like this I might have a 8000 dollar paperweight.

I still need to check my bulb circuits to see if there is actually a check engine light and I'm just not seeing it. I did try connecting with tunerpro again, and it was giving me tons of messed up readings. It may be my cable, however I am not sure how to test it.

If I jumper terminals A+B, the fan does kick on.

The quest continues.


Thanks for all the help,

Jeremy.

illenema

Did you check fuel pressure?

383vett

12:1 afr is not that rich for a cold motor. A cold motor needs more fuel (carburator choke) to keep running. Mine is in the 11:1 range on startup. Are your plugs hot enough to keep a cold motor running. Sounds like they are fouling out and not burning the fuel. Depending on what plugs you are using, might want to go up one or two ranges and see if that helps. I went through this a while ago and my plugs were too cold. Hotter plugs helped.

85MikeTPI

Sorry I haven't been following along, but in over half the weird problems I get called in for, the problem always comes down to a bad ground. I've seen people put grounds back onto painted surfaces, exhaust bolts, A/C lines or gang them all together, but then never ground the gang to the body and engine.

I wouldn't waste time doing any troubleshooting until you can get the ECM communicating with your scan tool/software, otherwise you're just guessing.. Run new, temporary grounds between the battery,frame,heads, and directly back to the ECM as a start..

Cliff Harris

When you first turn on the ignition the ECM powers up in a default hardware mode where the SES light is on. As the ECM goes through its power-on reset process it turns the SES light off. After it realizes that the engine is not running (no DRPs - Distributor Reference Pulses), it turns the SES light back on. That little sequence is known as "SES bounce", which is obviously not happening in your case. For those of you following along at home, I've had my car for 26 years and never noticed the SES bounce until I read about it around 6 months ago.

According to my '86 shop manual, page 6E3-A-6, the SES light gets its power from the ignition switch through the INJ 1 fuse. The ECM applies ground on pin A5 to turn it on. Seems to be a wiring/bulb problem. It could be an ECM ground problem. I like to check it by connecting an ohmmeter between the ECM case and a screw on the door sill (goes straight into the frame).

LD85

I can mail you my 165 ECM today, no chip though, for a test.

Larry

Pwnage1337

Made some progress!

I cleaned the ground on the back of the head, it was slightly corroded. Smothered it with grease this time.

Reconnected the grounds, put everything back together, and put new wires/wire loom on.

Looks much better than before, I don't even want to post before pictures because it is embarrassing.

The car starts, idles, runs, and even DRIVES, but there is still no CEL. I'm guessing its an open to the circuit behind the DIC.

When I say runs/drives, it runs and drives, but has very poor manners. Tuning needs to be taken care of. It will sit there and idle all day, but as soon as I put it in gear, it wants to die unless i keep my foot in it a little bit.