Hi guys, new here but I've been reading and searching the forums the last week. I am having some issues with my 1993 Corolla LE (1.8L) that I need help or advice. Here's the story:
I can start the car fine in the morning or after letting it sit for hours. Everything seems normal, I can rev the engine, everything is smooth and such. After about 5 minutes idle, I assume the engine warms up, the idle drops down to about 850 and is stable. However, if I rev the engine fast (gas the pedal quickly), the engine will stumble and RPMs drop and car stalls. Then I will have trouble cranking, I will crank and crank, the (tha-tha-tha cranking sound is fast,but engine doesn't turn over). I will do this a few times, wait a few minute or so, and eventually the car may start again. Once started, it idles fine. If I SLOWLY gas the pedal, I can rev it smoothly up to 4k RPM and hold it there, if I slowly ease off the gas pedal, it will be smooth too. However, if I gas it hard, it stumbles and stalls. If I release the pedal fast from 4k RPM, it may stumble when the RPM dips and stall as well.
Now, the issue has changed a bit. Today I started it up again, played with it, trying to narrow down the issue. Anyways, after it stalled, I cannot start it again, but this time the cranking is a lot different. The crank is VERY Slow. The tha-tha sound is very slow, as if it is not having enough power. But the battery is new. Inititally, my assumptions was that it may be fuel related, due to cranking but no turning over. Now that the crank is really weird, I think I may have a different issue. I have included a youtube video, hopefully you guys can help me narrow down the problem.
This is the car cranking after it has stalled. This is hooked up to a new batter with higher than the required CCA.
The starting issue seems like an electrical problem, since all your lights go out as soon as the starter is engaged. Two things that come to mind are:
1. Bad ground somewhere. Are the cables and clamps that connect to the battery clean and tight?
2. The starter motor may be half dead, so it just draws a lot of current without turning over.
Does the car start if you push-start it? Or is it auto transmission so you can't check?
Given the stalling when quickly applying throttle, I am leaning towards bad ground, but the starting issue and stalling may not necessarily be related.
Hi gandaif, Thank you for the reply! The car is an automatic, sorry I forgot to mention that. I also think it is electrical, so a bad ground is possible. I will have to check. The battery clamps are clean and new, snuggly clamped onto battery. I hope its not the starter, had that replaced about a year ago.
Keep suggestions coming, I will check in the morning. I will update.
AS gandalf pointed out about the lights... You have a battery to car power issue. Lights may dim a little when starting but not as much as what you have in your video. The only ground engine/body I know of is under the airbox near or on the engine mount.
You may also have a "worn out" + battery cable. They oxidize over time and wont flow enough electricity.
Oil level?
Drain the oil and check for metal in the oil. If you spin a bearing it will be difficult to turn over.
After reading I was going to say tps sensor but now that it wont start and the rpms dropped, im thinking you lost a bearing. As the engine warms the parts expand with heat, and this would be tighting (squeezing/binding the crank) and would make it difficult to rev or hold idle
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Oil level?
Drain the oil and check for metal in the oil. If you spin a bearing it will be difficult to turn over.
After reading I was going to say tps sensor but now that it wont start and the rpms dropped, im thinking you lost a bearing. As the engine warms the parts expand with heat, and this would be tighting (squeezing/binding the crank) and would make it difficult to rev or hold idle
Which bearing are you talking about? Is it easy to check? It is only difficult to rev if I gas the pedal fast, but if I go easy on it, I can rev as high as I want, and if I ease off on it, it will come down and idle fine. But any sudden gas/letting go of gas, will cause the stall.
Last edited by Streetmagus; 06-12-2011 at 05:02 PM.
Okay guys, heres an update. I cleaned the terminals and clamped everything down tightly. I gave it new spark plugs and cleaned the throttle body. Was wondering if this car has a air mass sensor? The air duct between filter and throttle body seems to have this weird attachment that has nothing in it or connected to it. The air filter box itself has a sensor, my assumptions are its the Intake Air Temperature sensor.
Well, now I can start the car, cranks normal regardless of temperature of car. It still stalls however. I am wondering if it is idle related now. Let me describe:
Car is idling on the first hatch mark under 1K, so around 800'ish? If I gas it hard and let go immediately, car will shudder but catch itself and not stall. If I gas it hard and keep my foot on pedal, car will shudder and eventually stall after a about 5 seconds. After that, I will have difficulty starting the car, it takes 1-3 cranks to start up. Otherwise, it starts up normally.
Now, if I simulate a higher RPM (around first hatch above 1K) and gas it hard from there, it does not shudder or stall. It revs up normal regardless if I hold pedal down or release if it starts from ~1.1K RPM. If I turn off engine with key (not by killing it by stalling), the car starts up normal.
Here is another video of me demonstrating what I just described. Toward the end is where I gas'd it hard and held foot on pedal. It stalls like that. Around middle of video is where I gas it hard from idle and immediately release the pedal. As you can see the RPM dips, causing the shuddering but it catches itself and does not stall.
Was wondering if this car has a air mass sensor? The air duct between filter and throttle body seems to have this weird attachment that has nothing in it or connected to it.
You have a Manifold Absolute Pressure (MAP) sensor. The attachment is a resonator.
Quote:
Originally Posted by Streetmagus
The air filter box itself has a sensor, my assumptions are its the Intake Air Temperature sensor.
Yes, it is Intake Air Temperature sensor.
Quote:
Originally Posted by Streetmagus
Car is idling on the first hatch mark under 1K, so around 800'ish?
Correct, this is where the idle should be when the engine is warmed up.
Quote:
Originally Posted by Streetmagus
If I gas it hard and let go immediately, car will shudder but catch itself and not stall. If I gas it hard and keep my foot on pedal, car will shudder and eventually stall after a about 5 seconds. After that, I will have difficulty starting the car, it takes 1-3 cranks to start up.
When you stall it like that, check the spark plugs before attempting to restart. Are they wet from fuel or dry?
Possible problems if dry:
1. The ECU is not told to deliver more fuel. Faulty throttle position sensor (TPS) or bad connection.
2. Injectors not supplying enough fuel. When you rev it slowly, there is quite little throtle applied, thus not much fuel needs to be delivered.
3. Too low fuel pressure.
It would be interesting to know how the car behaves when you repeat the full throttle experiment with engine under load, while driving the car. Just don't crash doing it.
Difficulty to restart makes me think the engine gets flooded.
Perhaps you have weak spark. Plugs do not fire, maybe the leads have broken insulation and the spark jumps before reaching the combustion chamber.
When you stall it like that, check the spark plugs before attempting to restart. Are they wet from fuel or dry?
Possible problems if dry:
1. The ECU is not told to deliver more fuel. Faulty throttle position sensor (TPS) or bad connection.
2. Injectors not supplying enough fuel. When you rev it slowly, there is quite little throtle applied, thus not much fuel needs to be delivered.
3. Too low fuel pressure.
It would be interesting to know how the car behaves when you repeat the full throttle experiment with engine under load, while driving the car. Just don't crash doing it.
Difficulty to restart makes me think the engine gets flooded.
Perhaps you have weak spark. Plugs do not fire, maybe the leads have broken insulation and the spark jumps before reaching the combustion chamber.
Heres an update:
Stalled it, Cranked and couldn't start. Checked spark plug and it was wet, smelled of fuel. I then checked distributor rotor and cap. The cap contact points were all white with corrosion, the rotor contact point was dark and nasty too. So I replaced distributor cap and rotor and spark plug wires. I then tested for spark with 1 spark plug out, it sparks and the car started on first crank. I immediately turned it off due to horrible shaking with 1 spark plug out.
Now the car starts everytime, even after stalling it. However, the problem still exists. I can still stall it by revving it hard from idle. What confuses me now is that it is very difficult to stall now. It will shudder, but will catch itself and not stall. It seems to be getting better. Out of 10 times of hard revving with shudders each time, I can probably stall it once. I then am able to start it right up. I don't know if it is due to my fuel injector cleaner, maybe it cleaned the injectors up a bit and thus its getting better?
I tried flooring it under load (taking it for a test drive). While accelerating, I get shudders, so its not a consistent acceleration. It does not stall, but I get shudders throughout the RPM band, but I can get up to 70mph.
Could it be dirty fuel? I also read it might be water contamination in fuel. I did have the car park for a week without much fuel in there. Maybe around E. That morning I went and filled about 3-4 gallons of gas, everything was fine drove about 5 miles, parked. That when I couldn't started and then all of this happened. I've never had this issue before though, and I always run down to E etc. How likely is this?
It appears that you had two problems.
1. Worn out distributor cap/rotor, causing poor ignition. Together with fueling problems this prevented the car from starting.
2. Fueling problems causing the shudder.
From your description it seems that problem 1 is now solved. As for number 2, I doubt it is water contamination. I do not think it could happen in just one week.
Not sure what to think about the shuddering. It is still interesting to know whether the engine stalls due to lack of fuel or flooding.
When it stalls, do not try to restart it but check the spark plugs right away.
If they are wet, I doubt that the injectors are clogged since the engine is getting too much and not too little fuel, if anything.
I am leaning towards the engine being flooded. When there is too little fuel, nothing much happens when the throttle is opened. Pretty quick the RPM will drop and engine may stall.
Shuddering and coughing on the other hand is usually caused by cylinders not firing at all, due to one reason or another. For instance because of spark plugs getting flooded.
Your ignition timing could be wrong. It should be 10 degrees BeforeTopDeadCentre with the engine fully warmed up and TE1 and E1 terminals in the diagnostic connector jumpered. You will need a timing light to check that.
Few guesses as to what else could be wrong:
Perhaps someone experienced with the following parts malfunctioning could comment on these theories.
1. Maybe a problem with the Fuel Pressure Regulator. Not sure though if it could cause flooding of the engine.
2. ECU is pulsing the injectors too long because of false information from some sensor. Possibly coolant temp sensor? If this sensor reports a way colder engine than it actually is, it will throw the mixture as the ECU will overcompensate for fuel condensing on the cold walls of the intake. And for cold air being denser. This sensor sits in the thermostat housing. Is there any difference if the engine is cold vs warmed up? The sensor can be checked with an ohm-meter, some hot water and a resistance-temperature chart. The chart has been posted on the forum, run a search.
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