2001 Celica GT-S Issues

Thank you in advance for reading this. Bear with me as this will be long, but if I understood the sticky topics, more details here are better. Rather than have 50 threads about 50 issues, I wanted to try to keep as much of it in one spot as possible.

It should remain in my signature, but for posterity I have a 2001 Celica GT-S 6spd Standard which has a 2ZZ-GE 1.8L Engine. Everything is stock except the exhaust (which I’ll cover more later).

I covered it at length in my introduction, but I would say I am still pretty much a novice at automotive repair and at present out of work (so very limited budget). I do have a digital version of the repair manual, but it is geared towards more advanced technicians with a lot more specialized tools at their disposal. I really wanted to learn and fix all this on my own, but I after a year working at it, I kinda feel like it was time to reach out to a forum. What better one to go to than one of my favorite car video guys ETCG.

There are a number of small issues that aren’t necessarily related to the main issue, but I want to get them out of the way first.

The windshield washer fluid reservoir has a cracked hole in it. It’s placement makes it a minor pain to replace, more so than it’s worth at the current moment. The oddity here is that it is right near the passenger headlight but when the fluid drains out, it actually drains out near the passenger door. Of note, the car has a rear windshield wiper.

The battery is not secured. It tends to rest against the engine, but doesn’t actually impact anything because of the plastic engine cover.

The exhaust pipe is on the wrong side. It looks like the previous “mechanic” owner went through some gymnastics to do this and I have no idea why. If you look at a stock 7th gen GT-S the exhaust is on the passenger side, the spot for it is there on mine, but they actually cut out a half circle in the bumper on the driver side to place it there. Best I can tell, there’s nothing special about it, it’s not any particular aftermarket brand. This actually causes some complications though as it passes under the gas tank. This complicates getting to an already P.I.T.A EVAP canister which is a part I suspect as my main issue. ETCG doesn’t have a video on this specific part (that I could find) but this video shows what/where it is https://youtu.be/FQFULrEY3NE . There is also a rusted through hole in the exhaust pipe, probably 2ft from the muffler. I have a patch, but haven’t made it a priority to resolve.

The rear driver side caliper had a pin that stuck out. After some working at it I got it in and to stay put although this brake still grinds a little. The rear passenger brake is an atrocity. It had a loose pin that I could not get to go back in place. I tried to keep an eye on it so that it at least stayed in the hole, it only didn’t line up with the last hole, but I recently lost it. I tried some stuff to rig it for a while so that the pad wasn’t resting on the rotor, but the grinding seemed to get worse. That same caliper has always been missing its wire and retaining clip, so the pad flops around a bit. I would probably makeshift the wire, but I can’t make the clip. Given the situation, I really may as well replace both rear brakes and calipers, but it’s pricey.

AC doesn’t get cool, but likely just needs a recharge.

I noted this in my intro topic but I’m adding it here that the front end alignment has issues, steering wheel resting position is turned about 15 degrees counter clockwise. Along with some popping is either a ball joint or tie rod. The actual ride quality isn’t really affected by it in most instances. It could be both at there’s a bit of noise when the engine staggers or when making sharp turns. The ABS light is also on which is also part of that area in the CV axle, I suspect it’s related. ETCG Had a pretty good video covering this area.

On an interesting note, there’s a particular oddity where if I turn the steering wheel clockwise about say 5 degrees (not enough to turn the wheel, but enough to meet pressure) and release letting it turn back, the engine will surge about 500RPM and then drop back to normal. Not really something I think is a worrisome issue, but is worth noting for a small piece to the big issue to come.

I THINK the gas cap is a replacement. I’m not 100% but wanted to note it as a potential contributing factor. It seems to tighten down securely enough though.

The airbox is zip tied together where the previous mechanic owner broke the clips, but as I understand this is very easy to do. For a while I had removed the zip tie, particularly because I replaced the filter and wanted to try running without the tie but ultimately the box kept getting pulled open by the mass air elbow and normal vibration from engine. I ended up putting the zip tie back on. The air box itself isn’t actual secured well anyway because at least one of the plastic anchor bolts is missing, I think there’s one left holding it in place.

At one point one of the 1/2″ vacuum tubes had a blowout leaving a hole in it, this has since been replaced but is noteworthy towards the main issue.

Occasionally while parked idling at night I’ve noticed the overhead light dim slightly and only briefly. Noteworthy towards one of the CEL codes I’ve received but will go into more in a moment.

Another CEL code I received, basically was noted as an “Unknown Error”, but when I had looked it up seemed to be commonly related to the O2 sensor. I actually checked both O2 sensors and found that they had been replaced by previous mechanic owner. They used the cheap slice and splice ones and was very poorly wired. One had actually become disconnected behind the electrical tape and the other was close. I went ahead and reconnected them securely and made sure the electrical tape was bound good and tight. It was good to do but didn’t resolve anything. I did wonder if the being disconnected/loosely connected had maybe grounded/damaged the actual sensors. I have not replaced these as I want to use the more expensive OEM ones that are more reliable.

I think that cover majority of what I know has issues and the current situation. Which leave the MAIN ISSUE(S) which has been a fight, albeit great learning opportunity, to deal with. Everything with the main issue is intermittent but frequent, which is why I wanted to explain everything else first.

So the main issue started with a CEL about a year ago. At first it just ran (drive, idle, ect.) very subtly worse than before the CEL. The condition steadily declined but has never become terminal where it just died and wouldn’t start. When I had the CEL checked (I don’t have the tool for this) towards the beginning, it gave two codes which I don’t recall. However I know one was labeled as an unknown issue, the other was an open circuit. This is what lead me to investigate and rewire the O2 sensors as noted above.

The symptoms are hard for me to explain because of the inconsistency, so please bear with me.

For a while the car would not cold start on the first try, but almost always started perfect on the second try, but this hasn’t seemingly been an issue in the last few months. Outside temperature and weather did not seem to be a factor as it happened through winter and into summer. This also did not start happening until a few months after the CEL first lit.

For a few periods off and on, when I would go to take off when the engine was cold, the car would choke and act like it wasn’t getting gas, but never did it when the engine warmed up. In the periods where it wasn’t doing this, it would rarely do the same thing taking off from a stop after the engine was warm if I happened to try to take off a bit quicker than normal (pressing the gas a little more… quickly not so much hard and far from WOT). A lot of the time though, I can accelerate quickly without issue though. I don’t risk it obviously because I don’t want it to choke trying to turn through oncoming traffic.

Once the car is above 2000-2500RPMs it doesn’t seem to choke if I give it more gas (WOT excluded). So if I ease into taking of and then give it gas or don’t make a full stop, I’m golden.

Also when it chokes and acts like I’m not giving it gas, it will keep doing this until I release the gas, give it a second, and try again. Choke may also be the wrong word, because it will still idle, and even move for as I depress the clutch, but only at a idle speed.

Sometimes though, even now, while accelerating, it will jerk once or twice, but not actually choke. Occasionally this is accompanied by a light backfire. The jerking primary seems to be caused by momentarily not receiving gas and then catching up to the proper speed. While intermittent, unlike the starting choke issue and the 2nd time start issues, this has persisted pretty much the whole time. Notably this primarily happens during first gear acceleration when happen it does but not always. The higher the gear the less frequently this seems to happen, but it does happen.

Similar to the previous issue, when going a steady speed, sometimes it will jerk or even chug a little. This is more prevalent at the higher speeds, though much less frequent than the issue while accelerating.

An issue I’ve only really seen in 6th gear (primarily between 50-60mph) is that the car will stall. When it stalls, it will still roll idle, but receives no acceleration from any combination of pressing /releasing the gas. The stall will usually persist until the car has idled down to about 45mph and then pick back up like nothing happened. This usually happens about 10-15min driving on the highway. After it does it once though, it won’t do it again for the rest of the trip (up to 1.5hr trips from Louisville to Lexington). In fact usually once I’m over 65mph where my RPMs sit around 3k+ I never seem to have an issue.

Which really that’s more of a general thing really. The higher my RPMs, the less issues I have.

When I try to blip the RPMs while sitting idle, they drop from 1k to about 500 briefly before going up. If I quickly WOT from idle, it will pretty much always choke and hang around 300-500 RPM until I release the gas. With some recent more thorough cleaning, the WOT issue has seemed less prevalent. My last cleaning earlier today it seemed to WOT fine, but the other issues were still present.

The last symptom is dying. Most of the previous issue happen while giving it gas, but this happens if I’m not giving it gas. Primarily the car will only die while sitting idle at say a stoplight, but usually only in combination with times where it has been jerking a bit. While sitting at the example stoplight, if I give it gas and hold try to hold the RPMs at about 2k while it is trying to die, it’ll sound kinda like bubble wrap. However other times if I try to hold it at 2k at a stop, it will surge back and forth between about 1.5k and 2.5k RPMs. Of course sometimes it will idle fine or it will start to die, try to correct itself and jump to about 2.25k RPMs and ease back down to idle. Typically the car will not have an issue with trying to die until about 15-20min into a trip, notably similar to the high speed stall time. Unlike the high speed stall, one it starts trying to die, it will usually be a fight for about 5-10min trying to force feed it gas keeping it alive.

Speaking of idle, it’s idle over all is a hair high. Not concerning, but noteworthy. After cold start it usually idles at about 2k, a little over, until warm and then drops to a hair over 1k (like 1100RPMs). As I recall 900-1k is about normal idle.

So what have I tried?

Well as I mentioned the initial CEL pointed loosely to the OS sensor issue, which I repaired, but did not replace.

After I discovered the whole in the vacuum tube, which was about pea sized, I replaced it.

Tried cleaning them MAF sensor.

Used a 9v battery to test all the VSV attached to the air box, 3 total. One I don’t think was a vsv it was something else with a diaphragm about the same size the has a similar function. Also checked the airflow and vacuum through these based on the manual.

Tried cleaning the throttle body and the holes leading to that sensor. Did not actually remove these. According to the manual removing them would require replenishing the coolant (not hard but just haven’t done so yet). I cleaned around the circular plate top and bottom, or front and back depending on how you look at it as well as in the hole with cloth, toothbrush, and Q-tip. Notably this has seemed to be the most efficient way to keep the symptoms minimized but not fixed.

I replaced the air filter.

I replaced the pcv valve.

Tried flipping the blue vacuum test valve piece ( Bottom of this page ).. It didn’t seem to have a noticeable effect, although I didn’t realize it had a cleanable filter in it until looking for this image/page. Notable I had tested the airflow both directions and it did seem correct.

I tried running a spectrum of gas/fuel system/engine cleaners though it. It always seems to run better but not perfect. I chalk this one up primarily to increased octane boost though.

This engine requires premium, so I have only ever put 93 or 92 (whichever was highest at a given gas station) in it since I have owned it.

Turning the fan on or off manually doesn’t seem to have an impact. Something I noticed early on though was that when the engine was in the stage where it usually kicks the fans on and lowers idles a little, I think a cooling cycle, it would be most prone to trying to die.

I’ve not observed any issue with overheating while idling, driving street, or highway.

From a cold start leaving the car idling with no driving it will eventually die, usually 15-20min

Anytime it dies, it will start back up perfectly.

Tried resetting the efi by removing the fuses. Also inspected those fuses to make sure they were good. Resetting this usually makes the CEL go out. It will inevitably come back anywhere from immediately to the first time it has issues.

There was a period in time, I believe it was while I didn’t have the airbox zip tied and it slid open all the time (had to push it back together every trip or two), where occasionally the CEL would actually go off by itself. When the CEL went off though, the car was usually a lot rougher until it came back on.

Besides windshield wiper fluid, I’ve not noticed any fluid loss, no oil leaks, nothing like that.

I recently I Ohm tested all 4 ignition coils. Was going to test the distributor but it doesn’t have one..

I have not tested the spark plugs themselves. I got a spark plug wrench and gap tool earlier in the year for my lawnmower thinking I could use it for both, but unfortunately while it fits, the holes the plugs are in are too deep for the tool I got and I haven’t went out to get another yet.

I’ve not noticed any off color smoke or the sort.

That I think is all I know about the situation. If I overlooked something and remember I’ll try to come back and add it in. If stuck with reading this novel length issue, that you so much for sticking with it. It was a lot to unload and I’m sure a lot to read, but since the research I’ve done shows a lot of this can be virtually anything on the car, I just needed a second look.

As I noted in the beginning, I really want to check the evap cannister, but I’m nowhere near equipped to drop the muffler to get to it. Really I can’t jack up the car. I have a nice hydraulic jack, but a inclined driveway to a kinda busy street and no where else I can really work on it. Between that and the shoe string budget, it has made working on the car a slow progression.