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Is a non working SES light from a bad computer always? Plus a miss or lugging problem by johnt671
Started on: 06-12-2019 02:56 PM
Replies: 10 (176 views)
Last post by: johnt671 on 06-18-2019 09:11 AM
johnt671
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Report this Post06-12-2019 02:56 PM Click Here to See the Profile for johnt671Send a Private Message to johnt671Edit/Delete MessageReply w/QuoteDirect Link to This Post
I've been working on a lugging problem for a few days now, and just noticed the SES light isn't lighting at all. While I was working on it over the winter I forgot to turn the dome lights off and killed the battery, and had to jump start it. Could this mess the computer up? I tried two different bulbs in it but still no light. I don't suspect a wiring problem because nothing along those line has been touched. What do you think?

The car ran great on it's first trip this season that was over an hour and a half one way. After that trip the problem started. It only seems to happen If I'm going 40 to 45 MPH in 4th gear which is around 2,000 RPM for my car. When I press on the gas to keep my speed up the car starts bucking. It almost feels like bad gas at this point and once it get up the hill she runs fine. At higher speeds it does better, only bucking if I floor the pedal and only a little bit. Riding around it runs as good as always with no hesitation miss or buck even with the gas to the floor. Could this also have anything to do with the computer?

The car is an 84 SE four speed with over 236,000 miles in her.
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Report this Post06-13-2019 09:20 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
No MIL doesn't = bad ECM even if you install new bulb.
Socket and/or "Board" on back of dash can be crap and not making connections.

But ECM can be "Bad" from a number of reasons and never set codes and MIL works too.

Sounds like ignition problems.
try Discon the tach filter and See my Cave, HE Ignition

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johnt671
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Report this Post06-13-2019 10:15 AM Click Here to See the Profile for johnt671Send a Private Message to johnt671Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks Ogre. There is no tach filter on mine. Years ago I installed a an aftermarket tach with a shift light so the factory tach isn'y connected anymore. I read the cave section you suggested and I also have an MSD box on it. I'm going to unplug it since its been on it for around 15 years and see what happens. The dist. cap and rotor have also been on it for a long time so I'll check those out and replace them. Since I'm going that far I'll also replace the plug wires and see what happens.

I wish I knew when the SES light stopped working since that might have give me a clue as to what happened. I also think I'm going to take the cover off of the ECM and see if I can see anything. The last one I replaced years ago had scorch marks on the outside of the case. It's worth a try.
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Report this Post06-13-2019 11:47 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Disconnect the tack then. Iffy tach and wiring to it can to same as a bad filter.

MSD is crap hype to start with. On a stock engine way more so.
And Not just the "box."
Many MSD and Accel parts are crap and been so for 20+ Years.
Is made to sell to fools that think GM Ford and others are too stupid to make engines and ignitions to run them. That's why GM "stupid" engineering eats Millions of $ per year...

Is likely burned the cap and rotor. Replace both.
If plug wires are 3+ years old. replace them too.
If coil is MSD/Accel... replace it. Use Wells or AZ (AZ ignition parts are Wells.)
And use standard or maybe Platinum plugs. Simple Platinum not gimmick plugs or Bosh 2 or 4 ground tips. (I mainy use better plugs only because has better metal parts that don't rust easy.)

Check base timing too. Iffy base timing will cause ECM problems to set actual timing to run the car.

[This message has been edited by theogre (edited 06-13-2019).]

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Report this Post06-13-2019 12:27 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by theogre:

Many MSD and Accel parts are crap and been so for 20+ Years.
Is made to sell to fools that think GM Ford and others are too stupid to make engines and ignitions to run them.
Is likely burned the cap and rotor. Replace both.
If plug wires are 3+ years old. replace them too.
If coil is MSD/Accel... replace it. Use Wells or AZ (AZ ignition parts are Wells.)



Repeated for emphasis....

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johnt671
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Report this Post06-13-2019 01:10 PM Click Here to See the Profile for johnt671Send a Private Message to johnt671Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by theogre:

Disconnect the tack then. Iffy tach and wiring to it can to same as a bad filter.

MSD is crap hype to start with. On a stock engine way more so.
And Not just the "box."
Many MSD and Accel parts are crap and been so for 20+ Years.
Is made to sell to fools that think GM Ford and others are too stupid to make engines and ignitions to run them. That's why GM "stupid" engineering eats Millions of $ per year...

Is likely burned the cap and rotor. Replace both.
If plug wires are 3+ years old. replace them too.
If coil is MSD/Accel... replace it. Use Wells or AZ (AZ ignition parts are Wells.)
And use standard or maybe Platinum plugs. Simple Platinum not gimmick plugs or Bosh 2 or 4 ground tips. (I mainy use better plugs only because has better metal parts that don't rust easy.)

Check base timing too. Iffy base timing will cause ECM problems to set actual timing to run the car.



This is a huge co-inkiedink. When the two posts came through on my phone I had just finished pulling the MSD box off the car. The timing was great because I was thinking about swapping the MSD coil out. I have a couple of almost new ones I picked up years ago, so I'll swap them in too. All of the ignition parts are years old because I don't drive the car as much as I use to. I do have a new set of plug wires and an almost new cap and rotor some in the garage too. The last time I tuned it, I used GM Rapidfire plugs which I was happy with, so a tune up will begin tomorrow afternoon. I'm part way through removing the console the see if if their are any signs of a toasted ECM. When I replaced the last on it had scorch marks on the outside of the case and was melted inside. I have a spare ECM so I might try plugging it in without starting the car to see if the light comes back on. I don't want to run it until I replace the ignition parts.

Thank to both of you.
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Report this Post06-13-2019 04:11 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Dead ECM almost never have signs it burned a part.
Any crack solder joint is enough to "kill" an ECM even when ECM seems good. Common example is "dead" injector driver(s). Part might be dead or just crack joint to/from it on the board.

If you have nonGM PROM in The ECM... May cause MIL problems and/or disable ECM scanner tools.
2 screws hold cover over the PROM or "MEMCAL" GM PROM have small labels w/ GM "broadcast" codes.

When removed console...
See my Cave, ECM Heat
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johnt671
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Report this Post06-14-2019 03:25 PM Click Here to See the Profile for johnt671Send a Private Message to johnt671Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks again guys. Yesterday I took the MSD box and coil off the car, plus swapped the dist cap and rotor out for my slightly used one I had to order the Rapidfire plugs so when they get here I'll put them in along with the new plug wires. I also changed my computer out for my spare since that is easy enough to do. Man, the dist cap was a mess inside. I just took it for a ride and the bucking problem is gone. That was the main thing I was worried about because there is a big car show and cruise Sunday. So big that the local TV station broadcasts it and when you register they give a a number for your windshield and a fact sheet for you to fill out with info on your car. When the cruise starts the local radio station have the fact sheet on all the cars and they broadcast it live so people watching not only see the cars, the hear about them also. At least for one day Kulpmont PA is a real car town.

Now on to the SES light problem. I recalled I took the dash apart to remove the white face gauges, so I may have caused the problem myself. I know I checked the lights and turn signals when I put it back together, but I don't remember if I looked for the SES> Is there a fix if I messed the circuit board or should I look for an 84 instrument panel?
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Report this Post06-15-2019 12:23 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
put bulb and socket from another light that works then try.

Sockets go bad but look same to most people. Metal parts can bend or crack w/o being obvious.
Plastic dash can compress for pressure when socket metal crushes is. Try rotate socket a bit like turn to out may help to get batter connection.
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johnt671
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Report this Post06-15-2019 12:09 PM Click Here to See the Profile for johnt671Send a Private Message to johnt671Edit/Delete MessageReply w/QuoteDirect Link to This Post
I did swap two bulbs in but nothing. I have a bunch of spare bulbs and sockets to try. I'll also use a mirror to see if the circuit board looks in that area. Also pry the connectors on the sockets up a little. Fingers crossed.
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Report this Post06-18-2019 09:11 AM Click Here to See the Profile for johnt671Send a Private Message to johnt671Edit/Delete MessageReply w/QuoteDirect Link to This Post
Worked on it yesterday. No luck. I tried a few different bulbs and sockets, bent the contact points up and swapped bulbs in from other lights in the dash that I knew work.

If I make a jumper wire with a bulb in it and jump the A and B terminals the bulb should flash if the ECM is good, right?
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