Code 43 ESC problems.

So i just put in a new thermostat, long overdue, because my car wasn't warming up to what it should (1st bar on indicator), and had barely any heat. well now its heating itself perfectly.
Anyways, had to step on it to get through a light, no problems, then when i started to head home the engine light came on, then no power, (retarded timing?) checked it. code 43, esc. turned it off, started it up, ran and drove fine, light off but code still stored, then as soon as i go up a hill around 2000 rpm, mechanical noise then light back on, no power, just chugging along. Oh how I love fixing one thing, then another pops right up  :O

I had this happen once in the summer getting onto the freeway, same noise and everything. but i just unplugged the battery to reset and it hasn't popped up until now.

Trouble Code 43 indicates that there may be a malfunction in the Electronic Spark Control (ESC) circuit.

So should i go about replacing most of my ignition, such as coil, Ignition control module, knock sensor, and the Electronic spark control. I'm sure its all from 1991, so a year older than I. lol

Maybe check the timing? loose chain or something. my car makes a spinning clickey noise at about 1100 rpm, always has, and only at that range.
As for gas i usually go for "top tier" rated suppliers but always put 87 octane in it.

1991 rmw with the 5.0 L03
im at about 117,800 so I've put about 20,000 miles on the car the year I've had it.

any insight on this problem would be greatly appreciated, im kinda stumped as to what i need to be looking for or replacing.

find the wire for the spark advance, the one u have to disconnect to get base timing,.
when you replaced the T stat you may have disturbed it;'

You could have a malfunctioning knock sensor, or the ESC module itself. The knock sensor is below the passenger's side exhaust manifold, and the ESC is located on the relay bracket at the rear of the passenger's side of the engine compartment.

Phantom - yeah, my dad and i checked that first time it happened, pulled that wire to check the base timing which is right where it should be 0, but when that was plugged in it jumped ahead to 12, so im hoping just a faulty esc. I dont think my car was getting hot enough to enter closed loop, and the esc functions during closed loop from what i heard.

Fred- yup, i just changed the knock sensor yesterday to see if that'd help, which it runs a little smoother but still threw the code under strain. I'm going to take the esc module out and get it tested today. i hope this works!

well, they could not test it. so i put on a new module, which made a tiny bit of difference but not enough to fix code 43. still popped up when i tested it up a hill, and made a grindy noise around 2000 rpm, then retarded the timing a large amount.

I wonder if my timing chain could be all stretched out by now. cause this is just an odd problem.

Could this noise you mentioned be a torque convertor shuddering to unlock on the hill.This shuddering could be confusing the knock sensor which retards the timing creating the code 43?Dont think its a stretched timing chain either.

hmm, good idea, could be a possibility. would you still be able to duplicate the noise in park if you goosed it? cause i can get it to do it occasionally, but not as bad as during the driving ive been doing to check it, if im gentle it doesnt do it as much.

ive read somewhere that the torque converter got a little bulked up after the 91 model :O I'll have to pinpoint the noise this weekend.

Dont think so but we have some very sharp guys here who love a challenge.The 91s dont have much power and I know from mine that everything has to be perfect or it can start acting up."Phantom 309"
actually said something a few years back about the 91s that made a ton of sense to me.I went out and bumped the timing which completely eliminated the shudder/odd noise going up hills.Not sure if the convertor could be made to make the noise at idle.I read on the TBI forum where a shuddering convertor was tricking the knock sensor into thinking there was detonation.The 91s are great on trips where there are no hills but they do struggle up the hills empty or loaded.Fairly sure your timing chain is good,please dont start tearing the engine down until the SMART guys have had time to diagnose your problems.

yeah definitely not ripping the car apart anytime soon, at 118,000 i dont think much should be wrong. I'm pretty gentle on it, with the occasional moderate acceleration to get on the freeway or pass, almost never floor it, I drive probably 3/4 freeway and then around the city on the weekend, i get about 18mpg.

May need to rebuild the tranny within the year though, shifts kinda hard, and especially when cold (below or around freezing), torque converter takes FOREVER to lock up. 20 mile drive to work on a really cold day and maybe it'd lock up by time im getting to work.

going the check the wiring to the esc this weekend with a meter. the esc is mainly, the knock sensor, the esc module, and computer (ecm). i would think my computer is still fine as i can still read the data and see codes with the scan tool. ive read on another tbi forum that it does a "forced knock test" when youre in closed loop, and floor it. and that code 43 can pop up when it thinks its failed. assuming the l03 in the firebirds are close to ours.

Ive done just about everything i can think of to this car maintenance wise, new tires when i bought it, alternator, 100,000 mile tune up, new fluids, filter and seals - tranny and diff. cap, rotor, delco rapidfire plugs, wires, fuel filter, front bearings, idler arm, Bosch 02 sensor, and now a knock sensor and new esc. seafoamed the engine when i bought it, no smoke came out so it should be super clean. oil change about every 5000 miles with high mileage partial synthetic. maybe i should look into suspension, and possibly u joints soon.

for the meantime im stuck driving a 86 monte carlo ss, that reeks like rat pee and runs crappily.
I miss my big beautiful comfy land yacht :/

sorry for the life story, just wanting to be thorough. lol

Did you check the actuator for the EGR valve. Mine will stumble like it is lean when I try to accelerate even at speeds over 45mph. It only happens after I run at a steady speed for a period of time. If I give the throttle a good stab, it will clear up and accelerate normally. I am going to temporarily block the action of the EGR valve to see if it is the actuator.

Hope you are running at least a 195 degree thermostat,I switched to a 180 and it started running rough and mileage fell.Went back to 195 and it immeidiately began to run much better,these engines need heat to run smoothly.They were designed this way,so keep them this way.

Everything is in stock configuration.

yeah the car is bone stock, just put in a 195 degree t-stat. before it was running about 30-40 degrees cooler, first bar on the heat index past 100. it looked like the original thermo. so i think it hasn't been running in closed loop for a while based on that.

My dad said i should put the old t-stat back in but that's just avoiding the problem, and dumb sounding. haha

Egr is definitely on my list of things to look at. if my car was running cold for so long i wouldn't be surprised if something may have gotten gunked up.

Alright, so long story short, new ground wire installed from the engine to esc today, couldn't find where the original went, and it didn't light up with the test probe. so far so good, just tested it on a couple big hills, gunned it a couple times with way better response and no problems, and running like a clock.

Im going back to driving it to work this week and will report if anything comes up.

thanks for all of your guys' help and knowledge! Not to mention a profound love of these cars that most people dont understand