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1G Inconsistent acceleration

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hoonigane

5+ Year Contributor
123
10
Jan 4, 2018
Siauliai, Europe
Hello, I need some help with my car. To whoever that doesn't want to read long essay here are the problems and questions (I dont want to start 5 threads :/) :

1. Performance is unstable (change from day to day without doing anything to the car)
2. Climbs high rpms very slowly (from 5k to 7k. I don't even push it after 7k because car sounds like its struggling hard). It accelerates faster if you shift at 5-6k rpm than if I let it reach redline.
3. I noticed changes in MPG's too, because I travel a lot with it. I drive same distance (150km) and it uses up different amounts of fuel. And yes I use cruise control to travel at same speed.
4. Does 1G gs has o2 sensor after cat? I think 2G does. Im thinking maybe it could be clogged cat and thinking of removing it, because I will change the exhaust when I turbo it anyway..
5. Does oil pan check work for gs and is it accurate? My oil pan is flat where it meets transmission, some article said that meant it was 6 bolt.
6. If there is an issue with fuel delivery like fuel filter, pump or injector clogged, power loss would be constant right?

Car is 92 GS. I have plans to turbo it, but I want to make it stable and driveable in the first place. My problem is pretty weird and I'm not too sure where to start. So my problem is that the car's performance feel very unstable. I mean one day it pulls really nicely troughout whole rpm range and another day it feels super slugish even after 3k rpm acceleration is slow feels like driving on 1.5k or something. Car used to die sometimes when I pressed clutch. Idle surges, sounds like a misfire on idle (again sometimes it does that, sometimes it doesn't). I used to buy cheaper fuel (same octane) just from different station. Recently I changed gas stations and noticed the car doesn't die anymore when i press the clutch. So I poured those snake oil injector cleaners thinking maybe bad quality fuel was clogging up something and it would clean it. Car hasn't died since on idle so I thought that bad fuel was the cause of performance loss too, but even when using good quality fuel acceleration differs a lot. I'm thinking maybe misfire, it would make sense that it's not constant, but it doesn't feel like it, engine isn't shaking or anything. I tried like 3 sets of different plugs 2 ngk's and 1 beru, new spark wires, new air filter, new water pump, new timing belt (changed it myself couple months ago, but didn't had that light to check the timing, but performance wouldn't change from day to day if timing was off im thinking). Car is not modified, it has turbo camshafts, egr delete, intake silencer removed, fart can and thats about it. Anyone faced anything similar and could tell me where to look? You guys are more experienced than me so tell me please. If needed I will upload couple pulls tomorrow.

Edit: You can smell gasoline in interior sometimes really badly when idling in place. Doesn't happen often but sometimes. Few of my friends noticed it too and we all agree that it wasn't doing it before.
 
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Is there any codes? Any signs of a fuel leak anywhere?

No O2 sensor after the cat on a 1g. You can tell if it's a 6 or 7 bolt by the lower timing cover.

If you mean CEL no its not on. 1g has obd 1 port so can't really scan shit. I know that you can check codes with small light, but if there are any codes shouldn't CEL be on? Should have checked if its 6 bolt when replacing timing belt :(. Thx for quick reply thought if Colts have 2 o2 sensors 1g Eclipses might have them too. Gonna delete the cat later then :)

No signs of fuel leak anywhere. Doesn't smell like gasoline when you open hood too.. Fuel isn't dissapearing anywhere after leaving car sitting for few days too.
 
It could be a few things or just one thing wrong. You ever change the fuel filter? It is the black cylinder just near the battery on the fire wall. There is a breather for the gas tank that relives excess pressure. It's line that runs from the tank to the charcoal canister under the battery. It is for emissions. If that gets clogged or a line leaks, it can smell like gas. Your injectors could be old and clogged if they are the 20+ year old originals. Do you have access to another set that you could swap, or a business that can clean them with an ultra-sonic cleaner?

Getting bad quality gas isn't something I would have thought of, as gas quality over here is consistent and federally regulated. But if the poor running conditions and acceleration is caused by bad gas, I would think a lot of people's cars would be running poorly.
 
It could be a few things or just one thing wrong. You ever change the fuel filter? It is the black cylinder just near the battery on the fire wall. There is a breather for the gas tank that relives excess pressure. It's line that runs from the tank to the charcoal canister under the battery. It is for emissions. If that gets clogged or a line leaks, it can smell like gas. Your injectors could be old and clogged if they are the 20+ year old originals. Do you have access to another set that you could swap, or a business that can clean them with an ultra-sonic cleaner?

Getting bad quality gas isn't something I would have thought of, as gas quality over here is consistent and federally regulated. But if the poor running conditions and acceleration is caused by bad gas, I would think a lot of people's cars would be running poorly.

I changed fuel filter bout a year ago and I remember it wasn't as easy as it seemed :D I will check the breather for gas tank, because in summer when it was hot if you'd unscrew fuel cap you can hear pressure escaping. That probably shouldn't be the case if gas tank is ventilating properly, but who knows my friend has 2012 car and it did same stuff. If its injectors, I don't want to replace them without knowing for sure, because I will need other ones if im going turbo route. Any way to check injectors without a new set? When I had laptop connected to obd there was an option to disable fuel injectors 1 by 1. It seemed to work identical by disabling any injector.
 
Yeah the fuel filter on these cars is a pain.

Gas cap hissing a little bit isn't a concern. Just means the tank is holding pressure, but that being said, I would check those evap lines that run from the gas tank to the charcoal canister up front. I think a lot of newer cars will throw a CEL if the gas tank isn't pressurized. There's a light for loose gas cap on my newer Ford, but I've never seen light up cause I never leave my gas cap off :D

If your injectors were bad, it would throw a code. As you already know, the 1g is OBDI, so there's only a dozen or so codes. But bad injector is one of those codes. However if they're gummed up and not spraying as they should, it wouldn't throw a code because the ECU wouldn't see a fault in the electrical properties of the injector.
If you want to check them one by one, just unplug them one at a time while the car is idling. If the car gets worse when you pull an injector, then that injector is working. If the car continues to idle poorly, that injector isn't working. But I don't really think that's your issue.

Have you done any kind of leak down test or searched for vacuum leaks? Misfires and dying when you push the clutch in sounds like it could be leak related.
Also, not sure if those turbo cams are helping the situation. They would let more air in per revolution and the stock n/t injectors might not be able to keep up. Just a thought.
 
Yeah the fuel filter on these cars is a pain.

Gas cap hissing a little bit isn't a concern. Just means the tank is holding pressure, but that being said, I would check those evap lines that run from the gas tank to the charcoal canister up front. I think a lot of newer cars will throw a CEL if the gas tank isn't pressurized. There's a light for loose gas cap on my newer Ford, but I've never seen light up cause I never leave my gas cap off :D

If your injectors were bad, it would throw a code. As you already know, the 1g is OBDI, so there's only a dozen or so codes. But bad injector is one of those codes. However if they're gummed up and not spraying as they should, it wouldn't throw a code because the ECU wouldn't see a fault in the electrical properties of the injector.
If you want to check them one by one, just unplug them one at a time while the car is idling. If the car gets worse when you pull an injector, then that injector is working. If the car continues to idle poorly, that injector isn't working. But I don't really think that's your issue.

Have you done any kind of leak down test or searched for vacuum leaks? Misfires and dying when you push the clutch in sounds like it could be leak related.
Also, not sure if those turbo cams are helping the situation. They would let more air in per revolution and the stock n/t injectors might not be able to keep up. Just a thought.

As I mentioned I have checked injectors by disabling them and the car was idling same with any of the injectors disabled. I don't have a compressor to do good vacuum test. I have blown smoke into intake when engine is off, and it didn't seem to leak anywhere around intake. Any ideas where to check leaks next? Or only with a compressor can you do this properly? Turbo cams actually ain't that bad I noticed better acceleration on low end (1.5k-3k) after installing them. Not much but an easy mod and it will help when I'd install turbo.
 
-Dying when you push the clutch
This problem was fixed by switching up gas stations. Yesterday rpm's were surging and dropping, but that's because there wasn't a lot of fuel in the tank. My gas tank is bent slightly (after driving over a rock :( ) so im pretty sure it was surging a lot because of that. Low gas light stopped working after gas tank was bent aswell. It aint a huge dent but still probably shook something up. Although it once came up recently when i was low on gas, so im lost here too.
 
Engine was cold thats why its smoking. Tho when its up to working temperature it misfires even more usually.

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3rd gear pull at wot. From low rpms. Wasnt climbing over 7k rpms, cant even reach redline.

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I don't think the cams would cause any issues. I have BC street cams for a future turbo build and my car is running just fine.

I know I had a problem with my maf but it was a 1.8 maf from when I did my swap. I would go over what. Is free, check your timing, check spark plug gaps and stuff like that. A misfire is usually fuel or ignition related.
 
It actually doesn't sound bad in those videos. The 4g63 engine is a slow revving motor in general in my opinion. When I say "slow revving", I literally mean the time it takes for the needle to go from low to high RPMs. I don't know all the engineering factors, but I'd imagine it has to do with the motor's rotational inertia- weight of parts (like flywheel, accessory belts, pistons, rods, etc). Compared to my old Toyota MR2 and my current CBR600 motorcycle, my DSM is a slow revving sloth. Again, different rotational masses at play in those motors.

Your changing MPGs day to day could be because of the differing ambient humidity and pressure conditions. It shouldn't be a huge change though. If you're getting 25 MPGs one day and like 8 MPGs the next day, something is wrong.

Aside from a compressor, I'm not sure how else to do a leak-down test (which is different than a compression test). The old farmer's method is to light up a cigarette and blow into the intake and see where the smoke leaks out. Sounds like you already tried something similar with smoke.
I'd do what Cherry recommended though- set your base timing by rotating the CAS and use a timing light hooked off the number 1 spark plug. It is 5° BTDC (before top dead center) on the 2.0L motors. This must be done and is one of the first steps to getting the thing to run right. Buy, borrow, steal, whatever and get a timing light.

Edit: Also, the rubber rings around the injectors is a trouble spot for me. I always get leaks around there and now always replace those rubber rings.
 
Does the car have a cat installed? If yes then take the exhaust off and drive without it. Other wise back to the basics. Check fuel pressure at all rpm range. Check ignition timing and mechanical timing. Compression and leak down. Data. As funny as it sounds, you could connect a scanner to it but you won't find too much data but maybe some. I believe with modis I could not even see fuel trims but the temps sensors and mass could be seen.
 
It actually doesn't sound bad in those videos. The 4g63 engine is a slow revving motor in general in my opinion. When I say "slow revving", I literally mean the time it takes for the needle to go from low to high RPMs. I don't know all the engineering factors, but I'd imagine it has to do with the motor's rotational inertia- weight of parts (like flywheel, accessory belts, pistons, rods, etc). Compared to my old Toyota MR2 and my current CBR600 motorcycle, my DSM is a slow revving sloth. Again, different rotational masses at play in those motors.

Your changing MPGs day to day could be because of the differing ambient humidity and pressure conditions. It shouldn't be a huge change though. If you're getting 25 MPGs one day and like 8 MPGs the next day, something is wrong.

Aside from a compressor, I'm not sure how else to do a leak-down test (which is different than a compression test). The old farmer's method is to light up a cigarette and blow into the intake and see where the smoke leaks out. Sounds like you already tried something similar with smoke.
I'd do what Cherry recommended though- set your base timing by rotating the CAS and use a timing light hooked off the number 1 spark plug. It is 5° BTDC (before top dead center) on the 2.0L motors. This must be done and is one of the first steps to getting the thing to run right. Buy, borrow, steal, whatever and get a timing light.

Edit: Also, the rubber rings around the injectors is a trouble spot for me. I always get leaks around there and now always replace those rubber rings.

I have to agree. I have replaced the seals and added another fuel oring (brown) on top of oe seal to have a tighter seal. Would not stop leaking for me.
 
The rubber seals on the bottom of the injectors are called injector insulators and if they are hard then change them out. I had a ton of issues with my engine, base timing was out of wack, IPS wasnt set right, injector insulators were hard and leaking, FPR vacuum line was leaking, EGR blockoff was leaking and those were from the previous owner of the engine. I didnt swap out the 1.8 MAF to the 2.0 MAF when I did the engine swap so that was my fault.

It really doesnt sound that bad and the non-turbo versions dont have a lot of power to them. You are probably lucky to get into the 200 hp range with a n/t 4g63.

Spark plug gaps, base timing are 2 good places to start though. The O2 could also be on its way out too though it should throw a code. I had gotten a bosch O2 sensor and I just recently got a CEL code that came back as the O2, its brand new almost though so it would be strange for it to go out already. I reset the code, keeping an eye on the fuel consumption and watching to see if the CEL comes back on.
 
Im getting new battery tomorrow ill update if there are any changes. I'll try to find someone with a timing light near my area asap then. Also I wanted to ask you guys, on nt I heard people saying that you should gap sparks 11mm, others saying 7mm. I have tried both spark plugs bpr6es-11 (11mm) and bpr6es (which is 7mm) and I haven't noticed any difference at all. Which is weird because gap difference is pretty big.. It was bpr 6 or 7 i don't remember but it was the same only gap changed.
 
Update: bought a new Bosch battery, didn't fix anything really, but it needed changing anyway. Next step im trying to find anyone with a timing light nearby. Called nearly all shops and nobody has them
 
So found a place where it had the timing light. Guys didn't even knew how to use it. Timing was set at around 5 degrees. Advanced it to around 8 ish. Car running much better, no sound of knock or anything so I think im good.
 
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