Crazy choking power loss after shifting under hard acceleration?

[chwood]

This happened during 2 drives last night and then some again this morning.

I was on the gas hard in third, pulling nicely up until about 5.5k or so, shifted to fourth and kept on it only to find my rpms sluggish and then lurching and bucking like I was choking out or something! Very disconcerting.

I experimented and I could get it to repeat in all gears AFTER a shift coming from hard acceleration/boost. Drive gentle and it feels normal - push it and you're fine until you shift and then it feels like the car is running out of gas or something.

I do have one step colder plugs and one of Joe's MBC's on, but I'm peaking at like .70 so nothing outrageous.

what might be causing this?

 

[Heathen23]

That's interesting because I was having a similar buck or power surge and loss, today I found out my turbo was leaking oil. I had the dealer looking for a coolant leak and they found the turbo was leaking oil. I also have colder plugs and running a similar boost so possibly a similar problem? My car has been difficult to get a good read on lately because of a cracked exhaust but your description sounds like what I was experiencing breifly. Maybe have the dealer check it out or try inspecting it yourself. It sounds like my turbo was getting slightly starved based on what the dealer described.

Are there any sounds associated with the problem?

 

[chwood]

That's interesting because I was having a similar buck or power surge and loss, today I found out my turbo was leaking oil. I had the dealer looking for a coolant leak and they found the turbo was leaking oil. I also have colder plugs and running a similar boost so possibly a similar problem? My car has been difficult to get a good read on lately because of a cracked exhaust but your description sounds like what I was experiencing breifly. Maybe have the dealer check it out or try inspecting it yourself. It sounds like my turbo was getting slightly starved based on what the dealer described.

Are there any sounds associated with the problem?

I was listening this morning and I didn't hear anything unusual.
I haven't noticed any oil in the garage, but I really haven't looked that closely either. I'll check when I leave here today and see if the oil is low or if there is any on the pavement.

 

[Heathen23]

I didn't see any oil on the ground anywhere and I park in the same spot every night. I am also very attentive to my engine bay and did not see it so it may not be in plain sight. I would just get it into the dealer and describe the problem because I had no clue until the dealer found it. Who knows, they could be completely unrelated but the fact that they description you wrote sounded similar I think it's a decent stab in the dark.

 

[SoniCraze]

i also had a turbo oil leek. It was a pool of oil that would collect on the bottom of the turbo, wouldnt really drip but if you wipe it off it would be back the next day. Its a loose banjo screw that just needs to be tightned.

 

[chwood]

would an oil leak of that degree cause this kind of drastic impact on performance though?

 

[Heathen23]

would an oil leak of that degree cause this kind of drastic impact on performance though?

Honestly I don't know. But my leak is more serious than just tightening a loose banjo screw because they are replacing my turbo.

 

[SoniCraze]

o dam!

 

[CustomMSP]

My car does that sometimes as well if I get on the gas very fast/hard after I shift. This fees like the ecu is dumping fuel in the engine before the air can get back in the engine after the BPV vents...Something like running an open BPV? Hope that makes sense.

 

[chwood]

This was a startling new thing for me - always had been smooth before.

Well...other than the hesitation, but that disappeared after I went from 5.5psi to 9psi.

 

[CustomMSP]

With this car running as rich as it does, these things can pop up randomly I guess. I've never owned a turbo car before so...

 

[505zoom]

I had the same thing start happening after I installed my SSQV. I thought that it just needed adjustment, but it still does it sometimes and it's exactly like you described. The first time it happened, I was extremely concerned. I didn't want to take it to the dealer though and have them tell me that it was the BOV. If a bunch of these turbos are leaking, I sure hope they don't make it real hard for us that have modded our cars to get a replacement. I have not raised the boost, but I still worry that I will be denied any major warranty work due to the FMIC and SSQV.

 

[flat_black]

I've heard of this problem before; Not on a Mazdaspeed Protege, but rather a Protege5; It consisted of the VTCS butterflies in the manifold being stuck; I'd say get out of the car after starting it, give it throttle manually with the throttle control beside the throttle body, and keep an eye on the VTCS valve controller; It looks more or less like a wastegate actuator for cars with a built in wastegate. It should click open around 5 - 6k RPM, but you won't be able to see the tach from outside, so just do it by ear, and wait for the thing to click. If it doesn't, then it's stuck closed; Manually push/pull the plunger to see if you can free it, then if that doesn't allow it to come on, it's probably an electrical fault, and you'll have to bring it in to be serviced.

Hope this helps!

 

[Heathen23]

With this car running as rich as it does, these things can pop up randomly I guess. I've never owned a turbo car before so...

Although it may be a result of design (just like the common coolant leak) I think it might have more to do with the crap install at the ports. Everytime I work on the car I seem to find another part that was installed half assed.

 

[CustomMSP]

Although it may be a result of design (just like the common coolant leak) I think it might have more to do with the crap install at the ports. Everytime I work on the car I seem to find another part that was installed half assed.

Or that...it's like the cars back in Russia...after you buy it you have to finish assembling it yourself lol

 

[TheMAN]

somebody didn't search about the hessitation

 

[Heathen23]

somebody didn't search about the hessitation

Somebody uses icon too much, read the thread and his description. It's not the hesitation based on his description.

 

[chwood]

somebody didn't search about the hessitation

(roll) yourself - somebody didn't read the POST.

(lol)

its not the hesitation thanks - shoot even the DESCRIPTION doesn't match the hesitation.

I've got 15k miles on the car and its flashed and running at 9psi - I don't have the hesitation and haven't for some time.

Besides, I've been around here for quite some time and I don't remember reading one like this before.

 

[505zoom]

Yep, for sure not the hesitation here. That was a totally different thing altogether. This is like a MAJOR power surge, whereas the hesitation was more of an annoyance.

 

[BremertonMSP]

This happened during 2 drives last night and then some again this morning.

I was on the gas hard in third, pulling nicely up until about 5.5k or so, shifted to fourth and kept on it only to find my rpms sluggish and then lurching and bucking like I was choking out or something! Very disconcerting.

I experimented and I could get it to repeat in all gears AFTER a shift coming from hard acceleration/boost. Drive gentle and it feels normal - push it and you're fine until you shift and then it feels like the car is running out of gas or something.

I do have one step colder plugs and one of Joe's MBC's on, but I'm peaking at like .70 so nothing outrageous.

what might be causing this?

Here you say you are peaking at .70 but later on you say you are running 9psi? I'm a bit confussed at what you are saying.

So this is an intermittant problem that only occurs after hard boost and then when you get on it hard again right? But that is only "after" you where able to get on it hard once, like to 9 psi.

flat_black may be on to something with his idea with the VTCS.