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As the title stats, when driving my 04 MT just simply won't rev past 5800-5900 rpm. I feel like i have checked all of the basic problem areas and just cannot figure it out. It is not a rough jerky feeling when it happens, it just stops climbing and sounds like its hitting a soft rev limiter. I held my foot to the floor for about 20 seconds one time and it did not go past or feel/sound rough at all.
Here's what's been done to car. (There is AlOT more but this stuff can relate to these issues)
BHR coils/plugs/wires (less than 2k miles)
BHR Midpipe
AEM Intake
S2 Fuel Pump (less than 2k miles)
I have done/checked the following
All solenoids work when bench tested. I even heated them up a touch
SSV and VDI valves are clean and in working order
APV motor spins on bench test and when hooked to car (acc 2 testing with key)
APV gear itself spins freely. Although it's more in the 2:30 position when full CW.
Cleaned MAF
Only codes are 37 and 410
Cleaned ESS
20 pedal stomp as well as battery disconect
Last edited by tgaffner; 09-02-2017 at 12:19 PM.
Reason: More intel
Yeap I definitely did not do that and now it's all apart haha. After some thought, I've probably had the BHR ignition for about 5k miles. I just pulled the plugs and honestly I have no idea how to read them. Here they are, 1 with and without camera flash.
Plugs look OK. They are all firing . If you look at the tip of the electrode they are silver looking and not black like they would be if they weren't firing
The insulators look clean and a nice light brown....so that is good too.
Not even a lot of crud as far as rotary plug go
Does it free rev past that? if you are stopped? In neutral?
I did try doing a few braps in neutral and yes it did seem to go over the 5800 mark. BUT, I only did it for a second each time and barely touched 7 because I knew something was wrong and didn't want to hurt anything.
I guess my throttle seems to be working. I mean it's never like worked intermittently. I push on the pedal and the motor spins faster.... I'll search to see if there are any tests I can do to give you a better answer than that.
So I took it out today for a spin, after not finding any problems anywhere. It did the same thing again which in a way is good because if it was fixed, I wouldn't have known what it was.
I put 4 new plugs in it because I found cracked porcelain on one. The thing is I don't remember dropping it or it experiencing a sharp jolt of some sort. It may have been cracked when I took it out and just didn't notice, who knows. All I could do was replace them and move on.
The only OBD data I have is from a cheapo Bluetooth one. AFR was 13-14 the entire time, even when experiencing the pause at 5.8k. It gave me a P0302 misfire code. Without a CAT or Air Pump, I always have the light on, but after a fresh battery reset those won't turn on right away. When I first hit the 5.8 mark the CEl flashed on, then dissapeared. I don't know if I just got lucky to catch the 0302 at the exact time because I was driving while looking at the OBD reader, because this is the first time I have ever read that code on this car.
Same gas and premix I have been using for 2 years.
Is that 5800 rpm indicated on the tach or via OBD? Because the tach is slightly behind and at 6300 is when the APV opens. Can you get above 5800 indicated with partial throttle? I lt's been a while since I messed with the APV but, if you're saying it's not fully clockwise at rest, can you get it to be morr clockwise? It could be jammed.
58 from the tach and the APV Gear rotates smoothly. When fully clockwise it actually rotates a touch farther than most of the threads on here say. Most say 1:00 and mines closer to 2:30.
It wont go over 5.8 with wot or partial throttle. Neither will do it
It opens at 6500 RPM unless the ecu programming was changed.
You might check the water temperature sensor reading. The engine has a cold fail safe that prevents revving past 6000 rpm or so when the engine temp is too low. That would probably show on the coolant temp gauge, but based on your description that sort of sounds like what it's doing though.
Dude I had that idea in the back of my head but I didn't really give it a chance. I recently re did my whole cooling system.
Ron Davis radiator
FAL 420 Fans
Mazmart thermostat
Petit Alm. Overflow Tank
Evans Waterless
Fully ducted with Ings bumper, ain't NO air getting around radiator.
I think my fans have turned on once haha. Usually operating temp is 174-6 on OBD reader. When going down a long hill out of gear it'll drop to 168. Did I make it way too good???
I think it's much lower than that,but if you have an adjustment for the fans you might consider letting the temp come up higher and see. Pretty sure I've run WOT much lower than that without issue. I know the APV won't open below a 68*F ECT temp, but the engine should still rev past 6000 without the APV opening up. Seems like it must be a limiter, which your description sort of supports.
I don't have an adjustment (still using stock setup) and the only time I noticed the fans come on is when I first put it together and purposely made them by sitting still for a long time.
Besides those rev limiters work on fuel cut, right? Meaning it would be abrupt and noticeable?? Mines smooth and doesn't feel harsh
The max rev limiter is very smooth like a soft limiter, not so sure about the other but I wouldn't think it be any different.
Also, with the drive by wire throttle just because the pedal is floored doesn't mean the throttle blade is fully open. I doubt that be it fully, but it might becan indicator for other things if you can verify visually or better would be by OBD2 data diring the actual condition.
Low oil pressure might also result in a limiter I think.
I first hit the 5.8 mark the CEl flashed on, then dissapeared. I don't know if I just got lucky to catch the 0302 at the exact time because I was driving while looking at the OBD reader, because this is the first time I have ever read that code on this car.
You may already know this but the ONLY time you get a flashing CEL is when you have a misfire at that point in time.
If I were you I would take a look at your fuel pump resistor. It is supposed to kick into FUEL mode when the secondary fuel injectors are enabled.
Follow this below to check the resistor. Its the funny looking silver box located under the air pump.
Resistance Inspection
1. Disconnect the negative battery cable. (See BATTERY REMOVAL/INSTALLATION.)
2. Remove the fuel pump resister. (See FUEL PUMP RESISTOR REMOVAL/INSTALLATION.)
3. Verify that the continuity between the fuel pump resister terminal A and B is within the specification.
• If not within the specification, replace the fuel resistor.
Fuel pump resistor continuity
0.304-0.336 ohms (20 °C {68 °F})
Due to rain I haven't been able to take it for a spin yet but I did make these vids in the garage quick.
There is a good amount of noise from the TB when it is powered, but I don't know anyone around me that has an 8 so I don't have anything to compare it to. Also, I have never actually watched the throttle plate move before in relation to pedal position so I also don't have a reference point. When the car is running though, nothing feels different in the throttle pedal to engine response department.
Like I said before, this is a cheapo OBD reader and this is everything that pertains to the throttle. The first few moments are without even touching the pedal.
09-02-2017, 12:13 PM
