Issue= The check engine light is flashing when car is running. The rpms surge up and down, and the engine is stumbling. Could she be misfiring? and Light comes on with the misfire, turns off, then comes back on when gets to that cylinder?

(Warning rap music playing in vid, turn speakers down now if offends)
http://www.youtube.com/watch?v=0Vbp0gKo-5s

Possibly unrelated = stalls if put in reverse and dont open the throttle, stalls at stops if dont keep rpms up. oil pressure sender looks like it went bad.
On some cars I see that if the relay for the fuel pump goes bad it will run the fuel pump through the oil pressure sender. Does this hapen on 86 firebird v6 2.8l Vin S? When I turn the key before starting engine, I still hear my fuel pump.

Only just orderd ALDL cable and Cabl1 from moates to be able to view and datalog in about a week.

When I jumper pin the aldl connection I get no codes and no handshake #12 after car has been running, with the flashing check engine light.

 

Don't think a single cylinder misfire would cause that noticable of a RPM jump, when we would disable 1 cylinder at school to perform a running compression check, my rpms did not jump like yours does(v6 too). Nor would the MIL flicker....
Im no mechanic so take it for what is worth...good luck tho

 

why bother posting a video if all that we're going to hear is rap music?

get to a quiet location, get under the hood and take another video

 

a bad case of eminem, that's the only conclusion I can draw

Your ecm is going in and out of limp mode and that's causing the rpm jump. Could also be that it's going in and out of field service mode if the aldl wire is grounding somewhere.

The fact that you don't get the code 12 9which is an est code so hard to diagnose if it's a valid code instead of set from KOEO) probably means that there's an issue with the ram power or the ECM itself.

 

My V8 has been having the same symptoms as yours (except not as bad of RPM surge and it doesnt stall on me, probably becasue there are extra cylinders, I think I am running on only 6 right now) and I have pinpointed it to be that it is missing (along with a few others) and will hopefully be getting new plugs and wires installed this weekend. If you dont figure it out by then and I have mine done then I will let you know the results.

Another cause for the SES to continue the flash is becasue it is grounded (like Twin Turbo said), make sure that you did not leave the paper clip in the ALDL, I did it once and all it did was flash at me until I saw I forgot about it.

 

Yeah I have definitly left the paper clip in a few times, and got the flashing light at same intervel. I was figuring probably a wiring issue, as problems I have with the car usually seem like a wireing issue.


Got the ALDL Cable and Datalogger from moates last night. Made a couple of short and then a long run datalogging. Using TunerPro RT v5 with A20.adx

Not sure exactly what the readings tell me yet.

Feedback I saw on tunerpro, with car deciding to act fairly normal ( wonder if the conections at the aldl interface could be toching each other sometimes, couse with ALDL cable plugged in seemd to run fairly normal.

I previously took my speedometer needle off, I see that the needle reads couple miles higher then the actual speed wich is good for me.

Looks like she runs in mainly OPEN LOOP, occasionally hitting closed loop
BLM Enable Looks like checks yes when it goes to closed to loop

More often Lean, but is switching back and forth between Rich/Lean

O2 Sensor seems to fluctuate around 500mv. (I gotta look up and see what it should be at)

Crank Pulse is mostly a Yes, but blinks nothing and yes ( is that suposed to register a pulse )

There was times that the power steering pressure shows excessive (looks like maybe only when stalled on start, and at end of my long run (when turned into parking spot likely

BLM Enable Looks like checks yes when it goes to closed to loop

 

interesting discovery ( no music ) http://www.youtube.com/watch?v=PaE8aVL2UjM

When ALDL cable is connected into the ALDL connection the RPM's do not fluctuate, and she does not stall in reverse. ( unplugged from compuer, so maye the pins on the ALDL cable are seperating the connection on the ALDL interface.

 

Went out data logging, Car driving fine, drove for only couple minutes, stopped in parking lot and idled for about 20minutes. Engine got warm, and eventually flashing Engine light and and car reving itself between 1K Rpm and 2K rpm. When I drove back home she stalled every 10 feet and did not want to start, but would try to turn over.

Engine light would stop blinking occasionally and RPM would be steady again at 1K. To note that when Engine reving and Flashing light, the Tuning software could not receive a signal from the ECM, but would start recieving information when the car would behave again.

http://www.youtube.com/watch?v=Y6spWBuYDI8

 

Replaced ECM, swapped my chips over, drove around in cool weather, let idle and warm up for a long time, drove around and got lost for a long time, highway speeds, and playing at all different gears, datalogging the whole time. Whatever O2 Crossover is freaking out all over the charts.

When I stopped in home, plauyed with the differnt gears, all was good. Till i unplugged my ALDL Cable. Instantly the rpms dropped, I put in reverse and she stalled

 

car was driving ok with ALDL cable connected to ALDL interface unplugged from netbook, short drive, threw a code 13 for a few minutes

 

today, when started car, o2 sensor read 1074mv steadily, and the o2 crossover read 01 and didnt change. Replaced o2, same thing and car just stalling after start.
Tunerpro showing code 13 "Oxygen sensor Open"

 

The light flashes in road test mode to indicate open or closed loop. In open loop it flashes 2.5 times per second. I closed loop it flashes once per second. The car's behavior makes me think that there is an intermittent short to ground in the ECM's diagnostic circuit. The diagnostic circuit is terminal B of the ALDL.

When the O2 sensor circuit is open, as in the sensor unplugged, the O2 circuit will default to .450 which is neutral. If you had the sensor unplugged at all with the ignition on, you will have set code 13 and it will stay for 50 key cycles or until it is cleared. Otherwise you may have an O2 circuit fault. As far as the high O2 voltage goes, that is not especially unusual. The O2 sensor will read gibberish until it reaches operating temp of 650degF. When the prolem is occurring, your engine is running as if it has a severe intake air leak or the MAF is reading low.

I would start by carefully examining ECM wiring. Especially the wiring to the ALDL. Is it chafing on the body somewhere? You may want to disconnect and remove the ECM, and using a ESD bracelet to avoid damaging it, open it up and look for loose components and broken solder joints. If you can verify that all wiring is good, you may choose to replace the ECM.

You can make an ESD bracelet by loosely wrapping a length of bare copper wire around your wrist and attaching it to the same metal table you are checking the ECM on or to the ECM case.

 

Thanks ASE.

Tryed following diagnostic flow chart for o2, still confused, first things seemed to read wrong, then apropropriate so probably intermitant, Sept car still just stalling out. Never knew were o2 sensor wire went to, followed it back to a wire harness that lays over transmission.

Does my single wire for the o2 go into this harness, and through firewall with the rest on drivers side, then behind my dash all the way back over to the ECM on passenger side?

One end of the wire harness I opend was full of a yellow powdery almost fiber like material, that fell apart when I touched. Thinking corrosion?

if all my wires go through on the drivers side and follow harness behind dash then i had a part were wires cut themselves on a peice of metal behind there before and I probably didnt fix them apropriatly.

 

The ECM harness is seperate from the main engine harness. The main engine harness passes through the firewall on the driver's side. That's connector C100. The ECM harness, which includes all sensor circuits, such as the O2, pass through the to the passenger compartment just in front of the passenger door. There is no break in the harness as there is in the main engine harness. The harness is one continuous run from the engine and each sensor to the ECM connectors. Where it passes through the body, there is just a bulkhead fitting that seals to the body and is held in place with a clamp from the inside. If you want to find the purple wire that is the O2 circuit, you need to look in the ECM harness.

The wires that you found cut on the body may be the source of your problem. You should inspect those to verify that there is no short to ground.

I am currently building a wiring diagram library on eaglemark.com. You can find a link to the site on my "wiring diagram" thread on the Electronics forum.