Crazy choking power loss after shifting under hard acceleration?

[CustomMSP]

Everybody, see what happends as your accelerating a little past 4k rpm, like 4.2k or so, and let off the gas. Than get back to me with a detailed report! (drive)

 

[Emode]

also try different throttle positions to get there
like full on to 4 or partially

 

[Dr.Sound]

ok, i'll try tomorrow

 

[505zoom]

Everybody, see what happends as your accelerating a little past 4k rpm, like 4.2k or so, and let off the gas. Than get back to me with a detailed report! (drive)

Don't even need to go check. Above 4k, at anything more than half throttle, I can not let off the gas unless I do it very very slowly witout the car bucking. And this problem is every time. I won't let anyone else drive my car untill it's fixed, and all my friends have been bugging me.

 

[CustomMSP]

Don't even need to go check. Above 4k, at anything more than half throttle, I can not let off the gas unless I do it very very slowly witout the car bucking. And this problem is every time. I won't let anyone else drive my car untill it's fixed, and all my friends have been bugging me.

Ding Ding Ding !! You're the winner of today's show 505zoom! Now go unplug your VICS and see what happends. This is what I wanted everybody who say they're having a "problem" with bucking or whatever else people are referring to to experience. If 95% of the people with an MSP are experiencing the same thing as we are here, we should get mazda to come out with another "flash" and this time with the correct a/f ratio and not timing advance. Ok, I need to stop dreaming now...

 

[505zoom]

I'll do that and report tomorrow... If it ever stops freakin raining

 

[CustomMSP]

Well you don't have to drive fast just "right"

 

[Striker187]

what gear should i try this in?

 

[Delivery_Guy]

Yeah...definitely much better with VICS off. Accelerated up to 4200rpm, then let off the throttle...very smooth deceleration. With VICS plugged in on the way back to the office, accelerated to 4200rpm , then let off the throttle and got the "normal" lurch from the car. I also didn't notice much difference in performance between the two.

 

[CustomMSP]

what gear should i try this in?

It will happend in any gear, but from gear #3 on it's noticable the most. I actually like driving the car with the VICS off because in everyday driving I don't really need too much power down low because I would just spin in first gear if I had to accelerate fast out of a parking lot or something like that. Now the car has a little less power from start to about 4.5k rpm, but all the high end. This would probably be good for track people as well. A little more traction when taking off. It's like having a two stage boost controller

The VICS is there for a reason, otherwise Mazda engineers wouldn't have included it. Turning it off is not a perminant solution guys. Getting Mazda to redesign the ECU is. Just want to throw that out there

I did't mean to thread jack if that's what it looks like

 

[Delivery_Guy]

But only if it could be, wouldn't that be a perfect world...where turning one thing off makes another thing work.

 

[Glowmunkey]

Damn, I have the same problem... and here I was just hoping and praying it was because my shifting technique was a little off (haven't owned a turbo-charged car for the past 5 years...). I figured I was just a little rusty.

Maybe I'll have to use the Joe P. FPR kit even though I got the ECU flashed...

 

[CustomMSP]

I found out that the kit made it even more pronounced. Just my observation.

 

[chwood]

hm - like I said though, I've got 15k on the car and I've had the boost up around 9/10 for the past 2k or so and this had never happend before the other night.

This morning on the drive to work it seemed fine though - I pushed it hard though 2nd and 3rd a couple of times and everything felt normal.

wtf?
(dunno)

 

[BremertonMSP]

New Bucking problem

So I'm curious who all is having this problem, and what mods we have.

I've experienced this "bucking" problem twice. Both times it was when I got off the gas just as boost was coming on. Also, It was a really hard jolt that shook the car hard enough to make me worry.

I never had this problem until I upped my boost to 10psi.


Now, I've only hit fuel/spark cut once, and that was last May at the track. It was at the top of third gear at about 7krpm.

I had the pre PCM flash stumble also.

This was neither of those. It's a new beast. Similar to what Heathen23 said about driving in a parking lot real slow, and give it just a touch of throttle and the car wants to jerk all over the place. That's not it, but similar in feeling.

I'm still leaning towards the BPV being part of the problem. The reason is, I had this same kind of problem with my turbo Mustang when I tried to run without a BPV one time. I was still in the configuration phase of my buildup, and I hadn't gotten t the BPV install yet. Went for a test drive, and the car would buck all over the place when getting on and off the gas.

Something for us to keep in mind.

 

[Delivery_Guy]

It does seem like there are two issues here.

1. The huge buck which occurs after shifting.

2. The little buck which occurs when you get on and off the gas.

For #1, I think BremertonMSP might be on to something with the BPV. I only have had this problem twice, the first month that I had the car...I thought the front end was going to fall off. It sure does feel like what I would expect a turbo that suddenly stops due to back pressure to feel like.

For #2, I have no idea.

 

[chwood]

It does seem like there are two issues here.

1. The huge buck which occurs after shifting.

2. The little buck which occurs when you get on and off the gas.

For #1, I think BremertonMSP might be on to something with the BPV. I only have had this problem twice, the first month that I had the car...I thought the front end was going to fall off. It sure does feel like what I would expect a turbo that suddenly stops due to back pressure to feel like.

For #2, I have no idea.

ditto - #2 isn't really an issue for me, it happens rarely and not with much severity.

#1 SUCKS though - but this explanation sounds plausible at least. how to confirm or fix though?

 

[SaaBaaDoo]

I felt it as well, I thought I was hitting fuel cut at stock boost (in my car, peaks at 8psi). (dunno)

 

[turboge]

Didn't we already go over this?

 

[chwood]

Didn't we already go over this?

re: bpv? just glanced over the previous pages and didn't see much there - lots re: vtcs, vics and ecu though.

If this is a symptom of the over-rich ecu settings, why would it just now have appeared after 15k miles? Also, I didn't experience anything that could possibly be confused with the "hesitation" it felt more like my car was suddenly not breathing at all - drastic and sudden loss of power. WOT the rpms would rise slowly and then randomly drop back down.