I am going to have to wait and make the video tomorrow, but I am having a weird issue that I simply can't figure out.

Last spring I had a surging/missfire/engine bucking issue. The issue would happen at all rpms, and random. No missfire codes. The issue would only occur after the engine was warmed up. cap rotor all the way to plugs were replaced, the ecu was replaced (factory em1 ecu), and cleaned CAI along with throttle body and the IACV. After cleaning the IACV the problem went away. I had/have good compression. The timing belt was replaced 10,000 miles prior to this with water pump etc with no issue. The tps has been tested and is good. the barometer censer is good as well.

The problem started again yesterday. I cleaned the IACV, this did nothing. I replaced it today and took it for a test drive after a warm up. The issue still exists. All replacement parts used were OEM parts and oms were checked.

Please note this year does NOT have a fast idle valve nor an egr valve.

Any help would be great because I feel stuck.

 

Any CEL codes?

 

Just for *****, put your finger over the hole going to the IACV and see if the surging stops. Also check for a vacuum leak somewhere or maybe a bad gasket. And just to clarify, you noted multiple problems that HAD happened but now you're saying the problem(singular) has returned. Can I assume it's just the surging that is happening?

 

No cel

I replaced with oem parts, the ecu, the entire ignition system (dissy to plugs), the IACV. The ecu is also new oem.

I tested the primary 02, the compression is good (so no bad head gasket), and I did a leak down test. I also did check the injectors (by the sound test and by the unplug test).

I also just replaced the coolant temp- problem still exists after test drive.

The problem only exists after operating temp has been reached.

The problem is the engine bucks and bogs (almost as if it had an egr gone bad) at random rpms. This does this regardless of being under load or at idle. Also, When at idle and put into gear if you are not VERY slow at give it gas, it will kill.

Also, so you folk are aware, I have been on this site before. Its just been a long time and I don't remember the password for my old email or my old user name. I am not knew to this. However, this one has me stuck.

The only thing i can think of at this point is one of the following;

the knock sensor is bumping up the degrees of timing and the KS has gone bad.

The tps voltage could be off thought the oms are correct.

could be the primary o2 on the basis that the way I checked it was by unplugging it.

Could be an intake manifold gasket leak causing a vacuum leak after it expands from the heat. The same could be said for the throttle body gasket.

I don't think its pure timing on the basis (and this is key here) that it only happens after operating temp is reached.

Any other thoughts?

 

Elaborate on this^

 

I didn't check OMs on the 02 while laying on my back. I used unplugging method which is basically unplug it to see if make it worse or better. There was no worse or better.

 

Have you tested the FPR?

 

1. no i have not checked the fuel pressure regulator.

2. How would a bad fpr cause this issue ONLY when the vehicle reached operating temperature?

 

Just for the heck of it I just tested the fpr.

At idle it is at 38.

Revving at 5k it is at 42

Revving at 8k it is at 42

After removing the vacuum hose and holding it so the line is pinched to increase pressure it went to 46.

This tells me (because op range is 38 to 48) that the fpr is good.

 

any other ideas guys? otherwise this things going to the dealer Monday...

 

apparently this is a common issue. I found this link, which no one has replied to. His car does the same thing except his rpm issue is more specific than mine.

need help plz, 00 civic si b16a2 bogs on acceleration when only when hot what could i | HondaSwap

 

Well, the car is at the dealer. I will keep you folk updated.

 

I just got a call back. So far it was throwing a tps code and also they told me the VTEC was stuck on. They are going to check the timing over the next 2 hours. Again I will keep you folk updated.

I am documenting this for a couple reasons the biggest one is that all the threads that are about this problem for some reason end and die off with no answer. I will make sure to get an answer to everyone.

 

 

 

cel was burnt out. I am guessing its not the tps but the vtec valve causing the tps to throw a code.

 

Click the Codes link in my signature. You clearly were unaware that the CEL must work to conclude that no CEL codes are thrown.

^No. The TPS code is purely electrical.

What exactly did they say caused the VTEC malfunction and what do they suggest will fix it?

 

He is checking the timing. Will update soon.

 

They're checking the timing because they think it is causing VTEC to be stuck on?

 

That was what I got out of it. The service adviser told me that one, I didn't talk to the tech. I talked to the tech when I dropped it off. I will see if I can get a hold of the tech directly asap.