Between when it was running fine and now, have any changes been made?

 

I didn't touch anything on the car for awhile that I think would cause the issue.

I replaced spark plugs/wires with oem
Replaced o2 sensor
Replaced transmission and differential fluids.


But even before this recent tune up I was experiencing the problems before but I wasn't concern as I am now because it's a little more violent now.

I tightened the throttle cable because it was like a jump rope for my fingers. That didn't work.

I do have some boosting issues. I'm was currently at a pattern of 6-5-6 because Pettit said I was going to boost lower levels but gain hp when they removed the airpump, warm up idle, disconnected the boost solenoids that's under the IM to the very left right under the vacuum chamber. Both unplugged and the hardliners to them capped.

Installed pettits intake filters.

 

Any porting?
ECU stock?
Aftermarket boost controller?

 

What RPM is the bucking happening at? There's a TSB to clean grounds that sort of remedies that. Is it more prominent with electrical load?

Matt

 

@TomU Stock motor, no boost controller, Prewg solenoids are disconnected, stock eco


@Mrmatt3465 bucking happens 3,050 rpms +/-

Not sure what you mean by electrical load, I do notice that the lights dim slightly and get brighter when driving at night.

I replaced the Alternator with a 100amp beck and Arnley Oem remanufactured.

Oil temp gauge flips around though and I replaced the sensor brand new oem.

Trying to help give you as much information as possible as I am limited in my knowledge and skill with the vehicle.

 

On the stock ECU w/o the solenoids wonder what''s controlling the turbos

You may want to revert back to the stock control, get it running good and then go from there on any mods if you want. IMHO stock is very well balanced and unless you track it, there''s no reason to mess with it

 

I'm all for going back to stock but Pettit Racing did the work a year ago. I'd like to correct what they did I can show pictures of the work and hoses they looped and left open.

This is a reason I don't order or have work done by them.

 

By electrical load, I mean, does the bucking get worse with the AC/headlights on? Or is it equally as harsh and prominent without the load? On a stock ECU, I know the fuel system transitions to secondaries around 3k Rpms and the fuel pump gets its voltage upped. The stock fuel control system uses a resistor located under the brake booster (silver in color and looks like a heat sink) and the resistor is bypassed and battery voltage is sent when the ECU grounds the fuel pump speed relay. If you have a lazy fuel pump speed relay, it could be causing you to lean out around 3k RPM.

Also, if the stock boost solenoids are unplugged, then you're only running on waste gate pressure. Plugging the waste gate and pre control solenoids will increase boost (probably beyond control depending on intake and exhaust mods.)

matt

 

It doesn't buck worse under electrical load. It does so with a/c on or off.


When we hooked up a boost gauge that we used to check it out, it wouldn't boost over 6 psi
But I hear what your saying. I might need a manual boost controller to hook the solenoids up. .

My mods are intake filters, Megan downpipe, and racingbeat catback with a Stock midpipe and intercooler.

I replaced the fuel pump with a new oem. If you suggest to check out the relay, I'll check it out and order one today.

 

You may have several things going on that may or may not be related. My guess is the bucking is probably a fuel issue. If the stock fuel system is related to boost and you are having boost issues, that could be a culprit. You may want to start a new thread on this issue to get a wider audience of experts that may pinpoint the problem (list all the symptoms and everything done to the car). My rec is to revert the boost control back to stock and make sure all your controllers are up to snuff (that at least will rule out a variable and may fix your boost issues). Another culprit could be sticky injectors. Have they been cleaned/replaced?

 

The injectors were cleaned in 2004. I have documentation on that from the first owners records at 91k miles.

The car is now at 145k


Untitled by Gerald Mugar, on Flickr

Untitled by Gerald Mugar, on Flickr

 

That was a while ago, but they could be ok. Before going through the trouble of taking them out, you may want to test your fuel pressure to rule out the pump. I hooked up a tester (https://actron.com/content/fuel-pressure-tester-kit) using Rob Robinette's instructions (Fuel Pressure Gauge). This will test pressure at idle, but is hard to use driving to test at load (i.e. boost). I later installed an electrical sender that I tied into my wideband multi-gauge.

 

@TomU I'm ordering a used Apexi ECU probably today and a New OLED separate purchase.

 

Just purchased a new serial number ecu and OLED

 

This Is Interesting but It still doesn't click with me. Maybe it'll shed some light.



IMG_1927 3 by Gerald Mugar, on Flickr






All the Voltage Numbers are on this specific page he wrote.










IMG_1929 by Gerald Mugar, on Flickr

 

The bucking and hesitation you're getting is the O2 sensor. A lazy O2 sensor will slowly sweep lean and rich around stoich and you'll feel it when cruising. I know you just replaced it, but there's a lot of factors there, how good the ground is the O2 sensor gets (since it's one wire, it grounds to the exhaust), how good the aftermarket O2 sensor is, how hot it gets, etc.

I know you have a PFC coming, I would just disable it. PFC drives great with O2 feedback off and gives great fuel economy.

The trouble codes are fine, that's just the factory boost control that's removed or unplugged.

TPS voltages seem OK, with the PFC you can easily double-check that in the Sensor Check screen. Not sure on the knock sensor voltage deal.

I would take everything Mazda says with a grain of salt, they aren't used to FD's and aren't used to troubleshooting them.

Dale

 

My knock sensor goo all leaked out and was unresponsive to the "hammer test". Even with the new sensor, "hammer test" didn't cause my volt meter to jump and it honestly drives the same. So I would chuck knock sensor out as an issue.

Dale you're making me want to try something with mine. I still have my slight bucking issue myself however I have a universal o2 installed on my jet hot coated down pipe. Considering an OEM o2 and cleaning up the mating surface on the bung to see if it might help myself.

With the EGR as well, just grab the new style gasket for it that has a pin hole sized opening. It's basically an EGR block off in essence :P There is so much natural EGR that it does nothing for us. It's not even on 95 Rx7s. TPS looks fine. Grounds are likely an issue. Clean the one on the AC bracket. Clean it good. Like super shiny good. With sandpaper. Then relocate it here.


Let us know how it goes.

Matt

 

Sweet matt and dale, I am appreciative of your help.

 

With a coated downpipe, you will definitely have problems getting the stock 1-wire O2 sensor to ground. You would have to grind down the O2 flange as well as the flange to the engine, and Jet-Hot is REALLY damn hard to grind off.

You could go with another O2 sensor that has a ground wire and/or a heating element from another vehicle, but that would require some wiring work.

Or, PFC, turn feedback off, and done. I have NO O2 sensor on my car (save for the wideband) and haven't missed it.

Dale

 

Would having the downpipe wrapped cause the same issue?

 

A wrapped down pipe will not cause ground issues. This might though

Looks like I know what my next project is. Where the o2 sensor meets the bung is still coated in coating. This stuff is probably not very conductive.

Matt

 

I just placed an order for Motormounts from Mazda Motorsports and made the commitment on the price. Wowza they are expensive!

They were the last bushing I need to replace on the car and I'm hoping they arrive before Deals Gap Rotary Rally April 17. They are going to manufacture them since they have no availability at this time. It'll be anywhere from 30-90 days. Fingers are crossed.

PFC is on its way from Japan.

 

Now, just waiting on the Commander



Untitled by Gerald Mugar, on Flickr

 

As NEW as Used can BE


Untitled by Gerald Mugar, on Flickr

 

Todays task consist of unlooping and un capping the lines that route to the Duty Valve.

The other day in doing so, I had broken the nipple off the old solenoid and I ordered a new one from Mazda. What a difference visually.



Untitled by Gerald Mugar, on Flickr