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-   -   Full throttle randomly feels like the brakes were applied, not sure why? (https://www.miataturbo.net/general-miata-chat-9/full-throttle-randomly-feels-like-brakes-were-applied-not-sure-why-78030/)

Nagase 03-23-2014 04:53 PM


Originally Posted by Joe Perez (Post 1114213)
It's actually a VR sensor with a built in conditioner, not a hall sensor, which is an important distinction in this case.

The sensor is unlikely to be damaged by having a 1-2mm gouge in it from the wheel. The electronics are located back within it some distance, the visible tip is just steel.

That said, your problem certainly sounds electronic rather than mechanical, and the NB cam sensor is notorious, with the crank sensor slightly less so.

Yes, my problem sounds electronic.

But if there's a sensor, and four prongs, and they're all a different distance, that cannot be right. Look at any trigger wheel. All prongs are supposed to be the same distance.

Joe Perez 03-23-2014 04:59 PM

You mean the gap between the sensor and the tooth is different for each of the four teeth at it passes by the sensor?

If so then yeah, that's a problem. One I've never seen, in fact.

sixshooter 03-23-2014 08:20 PM


Originally Posted by Joe Perez (Post 1114213)
It's actually a VR sensor with a built in conditioner, not a hall sensor, which is an important distinction in this case.

I'm...well aware of that. What an odd comment.

Nagase 03-25-2014 02:27 AM

Yeah, just checked it again. At least one of the nubs is noticably further away from the sensor than the other.

Put a 21mm ratchet on the pulley, and couldn't really get it to turn that much, but didn't feel wobbly. There some better way to test for wobbles?

Savington 03-25-2014 02:39 AM

Sensor gap errors cause massive, undriveable misfires at a repeatable RPM independent of throttle application.

EO2K 03-25-2014 11:36 AM

Well, not sure my regulator is going to help. Sounds like Andrew has your number there.

Nagase 03-25-2014 12:05 PM


Originally Posted by EO2K (Post 1114836)
Well, not sure my regulator is going to help. Sounds like Andrew has your number there.

I'm not so sure. At first the breakup was just at WOT, but now it's starting to happen at cruise as well. I'll probably try gapping the sensor once more, making sure it's a credit card's width out from the furthest prong, after clearing codes.

Reverant 03-25-2014 12:40 PM

Swap MS3 in, test?

Nagase 03-25-2014 12:46 PM

I haven't wanted to swap in the MS3, I'm not quite sure what to do with it as per the last PM.

M.Adamovits 03-25-2014 12:50 PM

Install the WB to see how AFR reacts during the stumble. Might help explain if its fuel, spark, sensory..

Install MS after and log, that should reveal sensor issues.

Nagase 03-25-2014 01:27 PM

Checked, the crank doesn't seem wobbly, and the nut seems to be on there decently. Put a prybar on it a touch and saw the timing disk flex but nothing else moved. All seems solid.

TheScaryOne 03-25-2014 01:51 PM

If you were down here in Tucson I'd have a spare four tooth wheel you could use for diag. Maybe try calling Mike's Place? It's just weird that yours got damaged somehow.

Nagase 03-25-2014 01:55 PM


Originally Posted by TheScaryOne (Post 1114894)
If you were down here in Tucson I'd have a spare four tooth wheel you could use for diag. Maybe try calling Mike's Place? It's just weird that yours got damaged somehow.

Yeah, I could have just been imagining it. I'm not good with spacial relationships. Just gapped it all again, and seems like it should be working, but now it's not starting. Might have the gap a little too far now.

Codes are:

P0031
P0037
P0128
P0134
P0300
P0301
P0304
P1345

The second O2 sensor makes sense, I've removed the one that just checks up on the cat.

However, it says sensor 1 isn't active, which I thought was the primary O2 sensor. Odd.

P1345 is what I've been operating off, with putting in a new cam and crank sensor.

Nagase 03-25-2014 02:09 PM

Well, I wasn't imagining the gap distance changing. I gapped it just so a credit card (my .030 feeler gauge) just had a bit of tension, then turned the crank... and the next prong scraped into the plastic of the sensor again. So I found the longest prong, set it so it just barely doesn't hit that one, and tried to start... no start.

Savington 03-25-2014 02:23 PM

What is the difference in length between the shortest and the longest tooth?

Nagase 03-25-2014 02:39 PM

Right now, it's gapped so:

2x teeth ~.005 gap
1x tooth ~.01 gap
1x tooth ~.08 gap

Which is well outside of the .029-.059 gap spec.

Nagase 03-25-2014 03:23 PM

Okay, just gapped it to ~.025 from one of the 3 longer teeth, and it's at least starting again. Time to see what happens.

Edit: What happened is that the O2 heater errors are back, as is P0300 random misfire and P1345 crank/cam signal data error.

TheScaryOne 03-25-2014 06:27 PM

The O2 codes are probably because you have one of them unplugged.

The Random Misfire and Crank/Cam code are probably due to your trigger wheel. I'm guessing that it's only seeing three out of four pulses per revolution because of the worn down nub being .07 shorter than the others, and the spec for gap is only .03 wide (.059 - .029).

Either get another 4 tooth wheel from Mike's Place or Mazda, or get the 36-1 Trigger wheel from a 1.6L Protege from the dealer, and install your MS3.

Reverant 03-25-2014 06:29 PM

Will you people stop STOP advising others to install a 36-1 trigger wheel with an MS3, especially on a 01-05? It doesn't work.

EO2K 03-25-2014 06:32 PM

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