Celica Forums General Discussion Engine and Performance engine ping and pulsing idle problem, Helps!

Hi everyone!
I have been having an issue with my 2001 Toyota Celica GT-S where the engine is pinging and also after the car warms up, the idle pulses between about 1000 and 500 rpm.

History - Car was overheating, diagnosis from mechanic says new head gasket needed.
What i got done was: new head gasket, new valve job, new lifters, oil pump, timing chain, water pump, spark plugs.Still same issue. Then replaced Idle Air controller, Mass air sensor, knock sensor, camshaft sensor. Each new sensor showed no change.
EDIT: also oil control valve was cleaned.

Took it into Toyota dealership, after many hours, they tell me it it was either the ECM or "you need a new engine".
Changed ECM, but same symptoms of pulsing idle and engine ping persists. Returned the new ECM.
Brought my mechanic down to speak to their lead tech who diagnosed the car. He says, has your car ever overheated? - yes, before all these issues started happening, which led to all this work being done.
He says, if the 2zz-ge engine EVER overheats, it warped the head and you need new one to fix problem.

I'm at wits end! 3,500 spend to find out i need to go in and spend another k on a new head and repeat the install??

Is this accurate? is any celica geniuses out there had this problem before? any other ideas on what to try?

Any and all help graciously accepted, and Thanks in advance for reading through this

best,
kenny

Hey, welcome.

Sorry to hear about your troubles but I'm sure you're not alone here.

How many miles on the car? How long do you think it ran before realizing it was overheating? How many times did it overheat? Has it overheated since the head gasket was done? Was your head not resurfaced and inspected before being reinstalled?

That info will help as well. Hope to hear back!

-Connor

Thanks for the reply Connor,
car has about 138k miles on it. i have had it since 2004 and it maybe has overheated 4 times over the years. the overheating just before the head gasket was done, i ran it maybe a block before shutting off car. since the head gasket/valve job was done it has not overheated. at the time of the valve job the head was cleaned up and from what i hear, lightly sanded but not resurfaced. Toyota says any resurfacing of the head will make engine throw codes and not run properly. not sure if they are speaking truths or if they were trying to get me to buy a new head from them.

If it has overheated 4 times, especially on these engines with light aluminum heads, I wouldn't be surprised if there isn't a deeper internal issue. If the head wasn't completely gone over and resurfaced and all, it may be out of spec or still be damaged.

BUT

Are there any codes?

Yes, it shows P0340 as CEL code

Ah, good to know. It continues to show that even after replacing the cam sensor before?

Yes, it was one of the last sensors changed, about 3 weeks back, before taking it to the toyota dealer.

And all of the sensors/parts you replaced were new OEM genuine Toyota?

No, most come from 1aauto.com and rockauto.com

That could be a contributor. I use RockAuto for a lot of stuff, but mostly things that don't move/affect performance. (Things like brake pads, body parts, sway bar links, etc.) The problem arises when these aftermarket parts are less than perfect, which happens often. They can easily provide a reading or draw power that is out of spec.

I understand your desire to save money, but sometimes you just gotta bite the bullet. Just something to consider.

Aside from the cam sensor, all were done before it was taken to toyota for diagnostics. they did not report any problems with those sensors. re-buying already new parts, kind of not ready for that yet. Again though Connor, i really do appreciate all this help and input!