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Normal acceleration

2K views 14 replies 4 participants last post by  B3NN3TT 
#1 ·
Video of my acceleration, is this normal?

I usually can’t get any faster than 102mph, and my rpms dip for a second if you look closely.
 
#2 ·
First - yes that is slow.

Second - automatics are slow anyway

Third - why is your check engine light on? Could be related.
 
#3 ·
First - yes that is slow.

Second - automatics are slow anyway

Third - why is your check engine light on? Could be related.
That’s not the CEL it’s the low coolant warning. The sensors broken, hence the auxiliary coolant temp gauge.

What system do you think could relate to this, I’m thinking air. It changes tone of the engine slightly when it revs up in the higher gears. Maybe unrelated, but the tps sensor never registers max open when the throttle plate is 100% open it registers 93%.

And it’s a car from 2000 that has 175k+ miles on it and it’s an auto, AAND it’s small displacement. So I don’t expect super crazy acceleration, but compared to my friends 4cyl corolla I drove. This thing is kinda slow for what it does have.
 
#5 ·
Is it this lever here, I looked on YouTube and some threads here, not such the best quality videos.

If I understand this correctly, troubleshooting should work like:

watch that forward lever and see if it actuates at higher rpms while someone revs, if so, good.

If not, look for rear one and see if it actuates or not. If so, replace front part. If not replace whole system.

I’m sure I’m wrong somewhere in that, any advice would be helpful. Thanks!
 
#6 ·
When that device fails, it takes about 40 hp with it, which is significant - almost 25%.

The actuator cable only pulls the rear bank. Both banks are connected to one another with a little wire rod running between the 2 banks, so when the rear bank pulls, the front should pull in parallel.

There are various kinds of failures.

Most commonly, the electronic box (bolted under the front plastic engine cover) just dies, and the linkage doesn't move at all. Car feels normal in stop-and-go driving, but has no top-end acceleration past 3500 RPMs. This is my suspicion regarding your situation.

Sometimes the little linkage between the 2 banks comes loose, so only the rear bank is opening/closing correctly. The front usually defaults closed. This feels mostly normal still, but just a little off, so most people don't even notice.

On rare occasions there can be a cable problem where it won't retract and the banks are stuck open, but this is definitely not that; stuck open condition will cause stuttering off-idle, but normal operation on hard acceleration.

Testing procedure : with engine running, add throttle to rev the engine (be certain the RPMs reach 4000 or more; the automatic has a standing rev limiter, so hopefully it's at least 4000, I honestly don't know). You should clearly be able to see both linkages move together as the revs build to 4000+. If there is no movement over 4000, you need to replace the IMRC actuator (under the front plastic engine cover, as mentioned).
 
#12 ·
When that device fails, it takes about 40 hp with it, which is significant - almost 25%.

The actuator cable only pulls the rear bank. Both banks are connected to one another with a little wire rod running between the 2 banks, so when the rear bank pulls, the front should pull in parallel.

There are various kinds of failures.

Most commonly, the electronic box (bolted under the front plastic engine cover) just dies, and the linkage doesn't move at all. Car feels normal in stop-and-go driving, but has no top-end acceleration past 3500 RPMs. This is my suspicion regarding your situation.

Sometimes the little linkage between the 2 banks comes loose, so only the rear bank is opening/closing correctly. The front usually defaults closed. This feels mostly normal still, but just a little off, so most people don't even notice.

On rare occasions there can be a cable problem where it won't retract and the banks are stuck open, but this is definitely not that; stuck open condition will cause stuttering off-idle, but normal operation on hard acceleration.

Testing procedure : with engine running, add throttle to rev the engine (be certain the RPMs reach 4000 or more; the automatic has a standing rev limiter, so hopefully it's at least 4000, I honestly don't know). You should clearly be able to see both linkages move together as the revs build to 4000+. If there is no movement over 4000, you need to replace the IMRC actuator (under the front plastic engine cover, as mentioned).
tested imrc while hot after a long drive and it the power rail that delivers 5v from the transistor wasn’t present. I replaced the assembly with a junkyard one today and it works great now thanks!
 
#10 ·
Alright! So. When I was testing the imrc the other day, I unplugged it to see if I could notice a performance drop. Which I did. But when I plugged it in and cleared the code. It ran pretty bad. And it still does. My idle is a bit different than it usually is, and the car all around it a bit more shaky.

I looked around for vacuum leaks and couldn’t find one. Any idea what could cause this?
 
#11 ·
it takes a bit of time to relearn it if you drove it broken.

simple things, check the spark plugs. pull the intake tube off and look into the uim past the TB. i would bet that if you have never done it, the uim is pretty gummed up. and like they said, the cats are probably a good bit plugged.

other thoughts are that its a ATX with 175k and the fluid probably hasnt been changed or checked.

what mods have been done to the motor?
 
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