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Discussion Starter #1
Like the title says, on my 2001 stock LX manual, getting beyond 6k or thereabouts causes the car to go into a low power mode of sorts.

It is not a limp mode, it does not put a throttle lock or speed lock on the car, but acts more like the car suddenly gained 1500 pounds.

Car SLOWLY goes, as if throttle is blocked halfway.

pulling over, shutting car off, and restarting it instantly fixes it.


Happened twice yesterday. Both times, car was already fully warmed up.

First time was on interstate onramp, just as I was hitting close to top of second gear, car hesitated, and when I went into 3rd gear thinking I simply hit a soft rev limit, speed was harder to achieve.


Second time it happened, I intentionally was hitting near redline on a backroad to see if I could re-create it. It took 4-5 times, but it acted up again.

Not sure what is happening.

Oil is pitch black and nasty, after only 1500 miles on it. Never had any of my cars, even teh sludgemonster accord, get oil this nasty this fast.


No smoke or pressure out of the valvecover breather.

No real oil loss

fuel mileage still good (38-44mpg, 80% interstate driving)

Never once have I ever seen coolant temps higher than just under half gauge.



Thoughts? Inputs? Similar experiences?

Lemme know.

Might just fix this by dropping in the D17A2 I have in teh garage once I have the AEM box and the d16y8 topend conversion done.
 

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Discussion Starter #2
Just a comment on the oil. Its not the color I am worried about. Nearly all cars that have high mileage tend to color the oil in as little as a couple miles or couple hundred.

The oil feels very thin.

I topped off with 10w40, car was half quart low. I had it at a little over the MIN mark last oil change, half a quart brought it to half between MIN and MAX marks. Roughly 1/4 quart loss in 1500 miles or so


No dripping leaks. Just oil wetness around valvecover.
 

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BATSLOMAN GIVES NO FUCKS.
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might not be relevant but the civic did that too, it would go into limp mode until it was restarted then acted like nothing happened.....the ecu got wet or was getting wet. replaced the ecu and never happened again
 

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Discussion Starter #6
alternator issue that ate the ecu is fixed.

Car has been running pretty damn good.

Just a new odd issue I guess.

Car has been running good so far, I am just going to avoid 5500 rpm or higher I think, even if the massive gap in 2nd and 3rd gear makes me super slow entering the interstate
 

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You said it's an 01 civic, so I'm assuming it's got the D17 in it. I'm curious if maybe the EGR valve is malfunctioning? The valve cracks a bit during WOT and close to WOT conditions, to keep in-cylinder temps down to prevent knock/detonation and lower overall NOx emissions, but if they get stuck wide open can cause low power concerns.

1. Those valves have a position sensor in them. I've had them where the position sensor malfunctions, and causes the ECU to try and open the valve more than normal to achieve commanded valve position.

2. Or the valve could be flat out faulty and not allowing the valve to return, due to electromechanical issues inside the valve or there could be a bunch of carbon on the valve stem causing it to bind when being pulled open.

3. Or you could have a carbon chunk interfering with the valve operation, where turning the engine off allows the carbon chunk to not be forced into the valve opening anymore due to no exhaust flow, letting the valve close fully again when you cycle the key.

I've taken those valves off before and literally had them full of carbon pebbles. The EGR passage design in those engines are not the greatest, and only work as intended when completely clean. The exhaust gas supply port to the valve travels from an exhaust manifold port through a bore hole in the head to the valve, then through the head some more, through the intake manifold, and into the intake stream. Lots of places for carbon to build up.

Easiest way to diagnose will be to pull the valve off, and have a helper start the car while you observe the valve flange area.

**NOTE - If you follow the below steps and DON'T have any flow through either the intake or exhaust ports at the EGR valve flange due to clogging, the EGR valve will not fix your lack of power problem.**

1. You should be able to hear a massive intake leak coming from the intake port side of the valve flange when the engine starts/attempts to start (it may or may not stay running). If you do, that means the ports to the intake are open and flowing. You should be able to place a finger/thumb to cover the hole, and feel strong suction and stop the leak. The engine should run normally at idle this way.

2. You should also feel a large amount of exhaust gas coming out of the exhaust port side of the valve flange, by placing your hand over the port opening. If you do, then you have flow from that port as well. You won't need to clean anything.

3. If you did not find carbon deposit evidence inside the valve that could be causing the valve to get stuck open, then take a pop/soda can and some scissors/tin snips. Cut the aluminum and make a flat gasket that blocks the EGR ports entirely and reinstall the valve. Drive the car as normal, and see if you can duplicate your low power concern.

- If the concern doesn't return, consider EGR valve replacement.

- If the low power concern is still there, you know for a fact it isn't EGR system related in any way. At least you now have a decent chunk of low power symptom diagnostics out of the way and can continue diagnosis.
 

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Discussion Starter #8
EGR was on my list to check.

The odd thing is, if it was stuck, an engine kill and instant restart would still show a reaction to it.

The car's reaction is immediately better upon restart.

Its not a limp mode. I went through limp mode when the previous ecu took a shit. That was a hard 2k or 2.5k rpm limit, and bouncing idle on initial start, which then settled to a high but smooth idle.


This feeling is as if you suddenly got an elephant to sit on the car. Engine felt dragged down, like you were trying to go up a steep hil in 5th gear and you are out of power.

This happened again today. Instead of pulling over, I hit neutral, killed motor, restarted with key, and she kept driving perfectly.

I am going to check the EGR anyways. I am thinking its worth a check regardless of its potential impact, as they are well known to get clogged and dirty on these d17 motors.
 

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You don't by any chance have a cheapo OBD2 laptop based data logger do you? You can pick up an ELM327 device for cheap (less than $20), and some of the best generic software out there isn't much more than $20. That will allow you to graph most of the important calculated values and input/feedback devices over time, giving you a better look at how the car is responding during the issue. Watching something like short and long term fuel trim responses before and during the event are very powerful in giving you ideas for places to look.
 

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Discussion Starter #10
Wanted to update this thread.

Ecu got killed.

high rpm shutoff/severe rpm limitor is early sign.


Fixed with an AEM 30-6030 and AEM wideband.

Waiting on a tune, going to install a new alternator that doesnt spike high voltage randomly at high rpms, and a fresh OEM ELD
 

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\/Your Mom Was Here\/
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My buddy wrecked the 05 EX I sold him, he might want to part some stuff out if you need it, like the ECU and motor parts, has a new JDM D17A in it, doubt he will pull the motor out of the car without selling the whole car but the ECU and interior stuff he might part with if you need anything. 05 EX sedan 5spd black with grey interior.
 

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Discussion Starter #14
Since I solved the ecu issue with an AEM 30-6030, probably not really interested in much.

Although it would never hurt to have a spare cylinder head, but I doubt he would want to yank only that.
 
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