2003 Buick Century

[graceful ocean]

I'm experiencing some throttle issues with my 03 Century, my current thought is that it's the throttle body being dirty. I'm led to believe that because occasionally when I press the gas the car will rev higher but not accelerate, but if I pump the gas it will start going again, which makes me think the butterfly is getting stuck closed and I can kinda jimmy it open by pushing the gas a few times.

Is this a sensible train of thought to come to the conclusion that it's possibly a dirty throttle body? Maybe clogged fuel filter or injectors?

[vagrant jay]

Yep! That train of thought makes sense. You can take off the TB and clean it with carb cleaner and a brush, that should de-gunk it if it is getting sticky. That said, replacing the in line fuel filter is also a good strategy, if nothing else it’s probably due. You get any check engine lights?

[fallow wasp]

Sorry, there is a conflict that need to be identified first.
In general, no drivetrain will allow an engine to accelerate(IE RPMs go up), and yet not accelerate the car itself. If this is the case, you have a clutch (or torque converter) issue.
IMHO

[graceful ocean]

would a faulty tc only cause it to happen sometimes?

or would it be all the time? because it acts normal 90% of the time but then occasionally it will rev without moving the car

[obtuse river]

Possibly a downshift, knowing that transmission they like slipping

[fallow wasp]

Clearer minds prevail (IE I was drunk last night)!
Intermittent is possible if it is on the cusp of failing. Check your transmission fluid first (does it smell burnt?). Beyond that, what I said stands, but in addition it could also be the bands inside the transmission that are slipping.
If your fluids are okay, then my next stop would be a transmission shop for a professional diagnostics.
Sorry, not a big fan of automatic transmissions so my knowledge is limited to understanding the most basic functionality, apposed to actual experience working on them.
Hope others have more ideas for you, but I think a shop is needed.

[graceful ocean]

okay so 6 days later but

this same issue expressed above occured

however it happened a little differently this time, I've been having issues with electrical more specifically the alternator. The issue with acceleration this time started and I wasn't able to unstick it, it continued revving while not accelerating when I push the gas until the car totally bogged down and died

I tried turning it back on and nothing, let it sit for a while and tried again and it, begrudgingly, started up

however with a battery light, which had previously been on but turned off when I replaced the alternator

[graceful ocean]

^

[vagrant jay]

Bad news - listen to Clever Old Guy. This is a trans or torque converter issue and, unfortunately, not likely something you can fix yourself. At the very least, you can start by checking the fluid level and condition, this is a bit more complex than checking oil as it usually needs to be running, in park, at operating temp but confirm in owners manual. If it smells burnt or is brown or black, you may be toast. Ideally it should be ruby red.

[graceful ocean]

Is there a chance that checking the fluid while the car is cold would show me good fluid while the bad fluid is hidden inside the transmission and not visible on my dipstick

The last time I checked while experiencing this problem the fluid looked like it just came out of the bottle

And if the fluid is perfectly clean, would I default to assuming it’s the t/c that has failed/ is failing?

[vagrant jay]

Cold vs hot should change the level, but the condition wouldn’t change. If it’s clean that is a good sign. What happens when you start the car, put it in neutral, and rev it? Does the engine respond correctly as you would expect?

[graceful ocean]

okay so I checked again

perfectly clean fluid and no smell of burning.

the engine revs properly aside from a slight misfire

which im unsure of the cause of, replaced plugs and wires to no avail

I currently have codes for the EGR valve, o2 sensor, vapor canister vent valve solenoid, oil pressure sensor and fuel level sensor

there's also a wiring short presumably

if that might have any effect, I'm not sure

[vagrant jay]

Yep, those could definitely cause throttle response challenges and misfires and other suboptimal running conditions. What are the specific codes? Possible/probable one of them is causing some others.

What leads you to suspect a wiring short?

[graceful ocean]

one sec I can send a pic of the code reader results

my car might not be totaled 🔥

well technically it is if you ask insurance, performed 1.6k of repairs on a 1.2k car

but I dont have insurance! so its not totaled at heart

[vagrant jay]

Hahaha I’ve done many repairs worth more than my cars themselves. We are in an exclusive club haha

Ok those are all circuit related, just as a sanity check, test battery and alternator. Voltage test while running and at rest will be ideal.

A borderline low voltage could cause some of these

[graceful ocean]

oh yea

the alternator is bad asf lol, I've been having issues with alternators, they just die

I have them tested before I leave the store, they test all good but then after I put them on my car they die

the most recent alternator I put on worked for like 3 days and then died which was the longest one lasted so far

and dw I've been taking advantge of warranties not spending $800 on 3 alternators

[graceful ocean]

big note

I forgot about kinda until now. the previous owner had a sound system and it appears they half-assed uninstalling it, there's still some loose wiring hanging from the radio

it kinda smacked me in the face when I realised thats probably the cause of all the electrical issues

kinda felt like an idiot cause I knew about it the whole time I just never made the connection for some reason

[vagrant jay]

Hey sometimes that’s how stuff works. “Rubber Duck debugging” is a fun concept https://en.m.wikipedia.org/wiki/Rubber_duck_debugging

First order of business is to sort the stereo wiring. If there’s any cabling connected to the battery that was not put there by GM, remove it. Then; inside the dash, cap off any wires that are unused

[graceful ocean]

sounds good

cap off the wires with like those little rubber sleeve things they got at autoparts stores

I need a heat gun to shrink them, right?

[vagrant jay]

Then get the alternator and battery tested with them in the car - good that you confirm them working before you leave the store but helpful if they test good on a bench but are suboptimal in the car

[graceful ocean]

how would you suggest getting them tested while in the car?

[vagrant jay]

You can get regular crimp style caps if you prefer

[graceful ocean]

the car can't really make it to a parts store to be tested

would a multimeter test work? I can do that myself at home

[vagrant jay]

Yep, if you’ve got a multimeter that’s perfect

https://www.youtube.com/watch?v=HNGA6u18K8w

[graceful ocean]

cool

so would you say with the new facts I've brought up, it is maybe not the trans/tc

could these issues end up causing damage if not fixed considering the electrical issues are causing throttle problems

[vagrant jay]

Trans is still likely a problem, because old guy is still correct: it should never allow the rpms to rise while you’re in drive without pulling the car forward

[graceful ocean]

could a faulty shift solenoid cause the same issue?

[graceful ocean]

I'd also like to say that it does but like 1% power

[vagrant jay]

I don’t think so but can’t be certain. Electrical issues can get weird and have unpredictable side effects. Only thing I could theorize would be the solenoid telling the trans it’s in park when the shift selector is in drive; but then I wouldn’t expect hitting the gas a few times to bring it back to being in drive

[graceful ocean]

I noticed the last time it happened I was on an incline while pushing the pedal and I was holding steady speed but it wasn't going up either

very very very slight incline I'll say

but an incline nontheless, so it seems like theres SOME power going to the wheels

[vagrant jay]

It’s at least free to sort out your cabling and confirm the health of your electrical system, start there and let us know what you find. I’m especially interested if there’s a stereo cable attached to the battery that could be causing a drain or some other issues.

[graceful ocean]

I haven't noticed anything attached to the battery, I swapped it out twice

maybe I've missed something though since I haven't exactly been searching, could also be spliced in further down the cable maybe and not directly on the connect

spitballing on the last part idrk what Im talking about tbf

once it warms up later today I'll head out and see what I can pull off the stereo and give the battery another check and come back

[graceful ocean]

I found a mystery connector with no visible spot to be plugged in nearby? It’s also full of water

It’s in behind the front bumper, in front of the radiator

The harness it’s connected to leads to the relay box

And what I thought was remnants of their sound system was actually some LEDs they weren’t even hardwired in

However there is still aftermarket speakers in the back and I found an amp when I was cleaning out the car so it’s still a possibility it was removed halfhazardly

[graceful ocean]

there appears to be nothing foreign connected to the battery

Just plain old battery connectors

there is an aftermarket stereo installed as well

that could maybe be causing some power drain depending on how demanding it is

but its just a pretty run of the mill stereo, nothing super special

[vagrant jay]

This is all good news. No additional wires on the battery means there wasn’t another amp drawing, or whatever amp you found above wasn’t connected. Cool.

That mystery connector is likely for something like washer fluid level sensor or horn or something, it’s OEM. Clean it up, dry it off, and try to cap it to keep water out.

[graceful ocean]

What would you suggest doing from here in terms of the wiring?

Is there anywhere I could take it to have a thorough physical inspection of the wiring?

[vagrant jay]

At the moment, get some baseline readings about the health of your electrical system. Use that multimeter to test battery and alternator, let’s see where they are and go from there

[obtuse river]

Probably cheaper to buy a whole new harness

[graceful ocean]

reads 11-11.5v when idling under low load

reads 11.5-12.00 when under load

[graceful ocean]

well as your bio says, theres the right way the wrong way and the janky way

Im going for the janky way cause I also dont have the brains or the money to do the right way

I wont be spending any money actually until it visits a trans shop for a diag

I got a fuel pump and an egr valve waiting to go in but after that I dont really plan on spending anymore money until I'm advised by a professional

[vagrant jay]

This is good news. Battery should be 12.5 or higher when the car is off, and 13.8 or higher when it’s running. At a minimum you may have a bad or failing battery, and the alternator may be borderline but don’t trust an alternator test until the battery is known/confirmed good. M

[graceful ocean]

alright so do spend more money

new battery it is

cause I did get a sub-par battery to replace the old dead one

$70 battery from walmart lmao

[vagrant jay]

Hang on. Take the battery out, have parts store check it. It might be good and it’s a borderline alternator, never hurts to double check your work

[graceful ocean]

I will probably take both out and have both tested on their own

I really wish I could take the car itself with both hooked up to be tested

[vagrant jay]

Yep! That’s perfect. And if both test good at the store when out of the vehicle, then we suspect a wiring issue somewhere and it’s more diag there.

[graceful ocean]

do you know if I can buy the testers that autoparts stores use?

for on-car battery and alternator tests

[vagrant jay]

Your multimeter will do the job just fine, I wouldn’t worry about trying to replicate their setup.

[graceful ocean]

can I test the battery with a multimeter while its not hooked up to the car?

or do I need the autoparts store to test it for me when its off the car

[vagrant jay]

You can definitely test it with your multimeter, I forgot you had one when I mentioned having the parts store check it 👍

[graceful ocean]

The car is not starting so I went and got a warranty on my battery at Walmart

Gonna get it in and see if that gets it starting and I’ll be back soon with multimeter results

[graceful ocean]

Alright so new battery in

Battery light turned off, so it was just the battery that caused the car to shut off the last time, I hope at least

Which would mean the alternator is still good

Alright so test results are in

It’s testing 12-12.2v at idle, however 11.9-12v under load not the needed 13-14.5v

Oh and the previous battery tested bad at the parts store, hence why I got a warranty replacement

[vagrant jay]

Sweet. Sounds like alternator time. Bring the old one with you and have the parts store test it, then that way you’ve already got the core if you need to get a replacement. And if it tests good at the parts store, then we are jumping back into wiring issues

[graceful ocean]

okay so considering last time I swapped the alternator it was fine until the car died last and then it turned out to be the battery this time

could I safely assume it was the battery this time because the alternator failed again and wasn't charging the battery

I've been through 3 alternators that tested good before leaving the store and then they all tested bad after installation