civicophy

Hey guys, first post ever.
1998 Civic ex coupe

I have the strangest problem and I cant figure it out. In any gear (even in neutral) when i press the gas pedal the RPMs bounces from 1000-2500 or so, depending on how far I press the pedal. It only stops bouncing once I get up to around 3-4000 RPMS, and then it drives steady. When its in gear this make the whole car lurch like crazy, and you cant even drive without riding the clutch hard or reving up to 4500 RPMs.
(Just to be clear, the engine is actually revving, it is not the instrument cluster)

Some History.
It only does this when the engine is warm, usually after about 15-20 mins of driving, give or take. when it first started doing it, it was very minor. At that point I thought it was the motor mounts, so I replaced all 5. I also cleaned the throttle body up to the throttle plate.
After cleaning the throttle body it got worse (would lurch until about 1600 RPMs). I replaced the TPS and took off the throttle body and gave it a thorough cleaning. After this the problem got EVEN WORSE, to the point where it is right now, lurching between 1000-3500 RPMs. It is undrivable when it starts doing this.
The problem is immediate. One second, It will be driving like a dream, and the next second its throwing its passengers into the dash. Its unbeleivable.
I unplugged the upstream o2 sensor and the problem went away, I even took a 3 hr trip this way with no problems. So I replaced that 02 sensor with a new bosch one, but then the problem came back, so I have been driving it unplugged since.


What the heck is going on? Why does the problem go away when I unplug the upstream o2 sensor? I can't figure it out.

grumblemarc

iTrader: (4)

Is it throwing any CELs? YOu should have at least one running without an O2 sensor.

civicophy

Yeah I went to autozone and they scanned it. The dude said it was nothing to worry about and didnt even give me a print out of the report. He did say it was throwing a code for low o2 sensor response, but i tested and replaced that after this.

I just ordered my own scanner because im sick of dealing w/ idiots who think they know about cars at autozone. It will be here tomorrow and ill scan and post an update

civicophy

Ok... 7 codes.
P0135. O2 sensor heater circuit malfunction bank 1 send 1
P0325. Knock sensor 1 circuit malfunction bank 1 sens 1
P0452. EVAP emission control system pres sensor low
P0505. Idle control system malfunction (definitely unrelated)
P1337.
P1457 P.
P0505 P.

crazyhouse2011

MAybe a fueling issue?

Former User

Moral of this story.

Question anything AutoZone employees say.

Start by resetting the ECU to see if any codes repeat.

civicophy

Ok, will do.

Also, I defined one of the codes incorrectly. P0452 is Fuel tank pressure sensor circuit low input.

civicophy

By the way, I found this thread, which seems to be describing the same problem. I'm starting to think I should replace the throttle body. When I cleaned mine (very thoroughly) the problem got much much worse, so I think I am having the same problem.
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/civic-hx-bucking-under-light-throttle-3065450/

Any recommendations for throttle bodies? I know I can get an $80 one on ebay that will match my air intake (metalic blue) but I am not sure this is a good idea for performance.

nub

Hold off on buying a throttle body, in fact hold off on buying anything.

As already suggested start by clearing the codes and see which ones repeat.

You need to troubleshoot and eliminate all of your trouble codes as a first step.

civicophy

I will, I dont want to just throw money away... Ill post the codes when I get home tonight

grumblemarc

iTrader: (4)

P1337 Crankshaft Position Sensor
P1457 Evap control system leak near canister
P0505 IAC (Idle Air Control) System Malfunction

tony_2018

Not really a throttlebody issue. If it were than all you would need to do is clean it.

tony_2018

Going by what Grumpy posted you might have a wiring issue.

civicophy

I drove the car yesterday and rescanned. 3 codes. Remember, the o2 sensor is still unplugged.

P0135 o2 sensor heater circuit malfunction
P0325 knock sensor circuit malfunction
P1337 CPS no signal

Should I try plugging the o2 in, clearing codes, and seeing what comes up?

Former User

Looks like there may have been a bad engine swap.

1) What engine and ECU are in your car?

2) Are the knock and CKF sensors connected?

tony_2018

Whats the engine code? Whats the ecu part #?

civicophy

D16Y8. Car has never had a swap to my knowledge. I dont know where to check for ECU number...?

Sensors are plugged in, to my knowlege. I cleared codes and plugged o2 sensor back in, got 2 codes instantly: Knock sensor and crank pos sensor, same 2 codes as before. I guess ill replace these next and see what happens.

Former User

Are you getting the engine information from the block and head codes?

Are you the original owner? How long have you owned the car?

The ECU is located behind the passenger kick panel.

Are you guessing or did you properly identify the connectors and check them?

crank pos sensor? Don't you mean CKF sensor?

Both sensor connectors are on the rear side of the block.

Shuka

when i had these problems with my d16y8 it turned out to be either a vacuum leak or wiring issue with my IACV. spray with brake cleaner for instance around your vacuum hoses and around your intake manifold as well with the car running and see if it begins to bog down when you spray a particular area. that would suggest something is receiving air which should not.

civicophy

I got the code from the block, right next to the transmission.


I have had it for 3 months

yeah, just guessing. I will try to locate the sensors later today if possible.


yeah that's what I mean.

civicophy

What was wrong with your IACV/What did you do to fix it? I find it ironic that I threw a code for IACV, and since I have cleared it I haven't thrown the code, but also haven't been able to replicate the symptoms, even while driving with the o2 sensor plugged in. I have a feeling this may be the problem!

tony_2018

I notice you said you replaced the TPS, did you adjust it properly?

civicophy

They don't come precalibrated? I just slapped it on the car...

grumblemarc

iTrader: (4)

Precalibrated? Hell no.

HondaPartsHero

Check to see if the CKF sensor is plugged in or the wiring is damaged aside from all the above: