Dear Scotty and Moderators. Firstly thanks for the awesome forum and quick responses to questions. Most recently I had been chasing down a strange WOT acceleration issue where it felt as if my brakes were grapping and then releasing every second or so. as suggested I replaced the battery terminals and this has fixed the issue mostly although I think I still need to replace the battery cables themselves due to the copper wire looking slightly black near the terminals and due for a change anyway as they are likely original with 150k miles.
The issue I still have is on initial takeoff from traffic lights with some moderate throttle the car seems to bog down quite a lot and a very audible noise starts to come from what sounds like the front left of the engine bay near the battery side. the best way to describe this noise would be it sounds like a water sprinkler going TSS TSS tSS TSS. I strongly believe it is not engine knock and I have no codes being thrown. This sound will go away if I back off the throttle howver so kind of acts like pinging. The noise will also occur If i accelerate hard causing a downshift to 2nd.
It's almost certainly a leak of some sort ( even almost an electrical arching type sound but with a constant frequency and more closely to a water sprinkler sound). I've conducted a vacuum test at idle and no indication of a vacuum leak exists.
The only item I have found to be leaking is the A/C Condenser which has a small crack in the pipe and is leaking out oil however the sound seems to happen with or without the A/C on and my A/C pulley is not stuck )
CAR
2001 corolla LE auto 4 speed.
156k miles
cylinder pressures around 170-180 PSI ( dry test only conducted ) still feels its got lots of power though just bogs down on initial take off
It does burn a little bit of oil. about half way down dip stick after about 1000 miles
Items replaced recently
Spark plugs
coil packs ( I've tried cheap Amazon and second hand denso's with same result)
fuel pump and filter ( second hand denso but clamed to be unsused)
Fuel pressure regulator ( goes inside with the in tank fuel pump and filter)
PCV Valve
Serpentine belt ( could not feel any damaged bearings in pullies when off)
oxygen sensor upstream ( new denso )
Oil+ filter changes every 3000 miles.
Intake gasket and valve cover gasket
ITEMS to Do
I plan to replace the VVT filter screen as I've heard this can cause issues with timing and perhaps its something related.
Thats about all I can think of for now. I appreciate you taking a look and hope you can help me figure this out.
@2001corolla
Hi! I bought a 2001 corolla brand new and still daily drive it. What you are describing I would test your upper passenger side engine mount by trying to move it with a crowbar or large screwdriver up and down. If you get any movement at all replace it. Note: if you replace it use OEM parts. I used an off brand part and the buzzing that resulted is not good. I recommend replacing the transmission mount too. If one is bad, the other probably is too. Both are easy to get to. There is also a lower front mount and if you do that you will probably need to remove the radiator hose to get to it so buy coolant beforehand. youtube has some good videos on it.
Thanks for commenting. I'll take a look at the mounts when I get home but this noise just doesnt seem like it would be from bad engine mounts. Did you have this noise also?
One key diagnostic question - if you accelerate briskly NOT from a stop, say uphill at 20 mph, does it bog and make that noise?
@glen_stet
Hi glen thanks for asking. No it does not. Brisk acceleration up a hill does at times produce a very distinct pinging (detonation) but the water sprinkler sound is very different to pinging. Does that help? Thanks again
@glen_stet
Sorry Glen, Brisk acceleration indeed does cause the noise. I was referring to accelerating slowly up a hill in my comment before. It only happens at a wider open throttle setting. this is a tough one right?
It is possible that the bogging and the noise are two different problems. You've checked and replaced a lot of stuff - how about cleaning the Mass Air Flow sensor and the throttle body? Any problem with them could give you bogging.
@glen_stetit bogs just on takeoff at lights with the noise but the noise also comes if I accelerate hard with a downshift so I think you're right they are two different issues. The MAF is brand new denso. I've only opened the butterfly by hand and cleaned it. Kve also seafoamed the car.
Well, I would say check the 02 sensor, but you're done that. If the throttle body is clean, I think you' might need to take it to a place with a high end scan tool (or buy one - Scotty lists recommended ones under TOOLS at the top of the page) This is the one that he recommends that won't break the bank - https://www.amazon.com/dp/B00652G4TS/?ref=exp_scottykilmer_dp_vv_d it uses your phone as a display, and to pull data from their database. Something is screwing up your air-fuel ratio to make for that bogging.
@glen_stet
I have a wired scanner. What should I be looking at when It bogs? I'll attach a screenshot later
Well, not knowing what it will show or not show it's kinda hard for me to say - you're reaching towards the edge of my amateur mechanic expertise. I would have a friend drive the car and watch the read outs for fuel trim, fuel pressure, load, spark advance - and see how things look when it is cold vs when the engine is warmed. You might want to look at this page - https://en.wikipedia.org/wiki/OBD-II_PIDs .You might also want to check out Toyotanation.com, as it probably has a thousand 01 corolla owners who may have had the same/similar problems.
You know, I just realized maybe your Throttle Position Sensor - or your connection to it - might lead to your bogging symptoms.
@glen_stet
Thanks again for taking your time to help me out with this issue. I'm going to remove the hole assembly in the next few days and give it a good clean. I'll report back with the results.