I'm having a weird problem that I've never ran into in the past 10+ years of owning Honda's and I'm absolutely stuck.

The car is bogging down on anything past around 60% throttle, no matter the speed or RPM. Just feels like it won't go and kind of misfiring it feels like. I've been replacing parts left and right and I'm still got nothing. Also it whistles at around 50% throttle, sounds like the air intake (AEM). I don't know if that means anything. Every now and again the CEL will come on, and it's the TPS sensor.

List of parts I've replaced:
-Dizzy (rotor & cap too)
-Fuel Pump
-Fuel Filter
-Spark Plugs
-Wires
-TPS Sensor (reading .49 idle, 4.48 full reads all the way to the ECU)
-MAP Sensor
-O2 Sensor
-ECU

Checked & Cleaned:
-Timing right on (just replaced the belt, tens, & water pump less than a year ago)
-Cleaned the IACV & FITV
-Two fuel cleaners (Lucas standard & full treatment)

After all of this, I don't know where else to go. Anyone got an ideas?

 

I wish I could say I have a solid understanding of the ECU systems but I do not.

Going off the the TPS code it throws once in awhile I would also check that the tps runs smoothly through the voltages from closed to open.

But in all honesty, I am willing to bet you have a sizable hole in your air intake somewhere. I was told I was out of my mind but I got a throttle plate code thrown at me for awhile while there was a gaping hole in my CAI on my 07 Si. Once I patched the hole, I have never received the code again.

With the whistling you have as well as TPS code I tend to think the MAP (in my case MAF) sensor gets air readings beyond it's expected ranges and it then thinks there is something off with the throttle plate as they don't match the range it should be seeing with the throttle plate position it sees (in your case the TPS reading). See if you can find any holes in the intake system that is sucking unfiltered air into your engine.

 

Check tps wiring.

 

There are no holes in the intake, it's only a short ram. TPS wiring is good all the way to the ECU, no burns or tears in the wires. I get consistent readings all the way to the ECU, smooth with no jumping or anything. I've already replaced the MAP with a new one from Honda.

But I forgot to mention, it does something else stupid as well. When driving on the interstate, from time to time, just coasting at like 75-80, it will completely lose power it feels like. Feels like it just starts missing badly, and to keep it at speed, you have to full throttle it. And I know it's the bad thing to do, but the only way to fix it while driving, is to cut the car off, and back on. It just feels like after driving a while, a switch flips somewhere and starts running bad.

 

Kind of a weird thought, but could it be a vacuum problem? Everything mechanically is sound from everything I've checked and electronically replaced almost everything to do with the ignition & fuel other than the FPR (which showed to be in check with the right specs).

 

Update: So now I'm have a new and worse problems. The last thing I changed was the Dizzy, about 4 days ago, and yesterday afternoon has been the worse the car has ran since replacing stuff. While driving home on the interstate, my RPM gauge was fluctuating at my cruise speed of like 75. It normally runs about 3700ish RPM, and it was running that but the RPM gauge was dancing from 3500-3900, and every time it dropped to 3500 it felt like a big misfire. Like it just choked and didn't fire at all. And it's not running correctly at all anymore. At idle, I can here some small pops from the exhaust, and if I smash the throttle hard it misfires erratically and then catches. I'm gonna check all my grounds today, and check the timing again. Something feels way off right now.

 

Can you pop the cover off the ECU? The capacitors are known to go bad and leak. I am beginning to wonder if your ECU is the culprit.

 

Yeah, I'm not sure. I have replaced it though. I'll check it out. Can a stopped up cat converter make it act this way?

 

I always thought a clogged cat would be a consistent issue, not a sporadic one that comes and goes.

All this work, have you checked compression, done a leak down test etc?

 

Yeah, I've done a compression test, it's what my step thought it might be. But it was really consistent across the board, 181 in cyl 1, 2, & 4 and 182 in cyl 3.

My thought with the cat though, the longer I drive the worse it acts. And if I drive say 45 mins, and then stop for 5 mins, and then get back in it, it's garbage. So my thought here is the heat build up kind of screws stuff up in a way. I don't though, I'm so far out of my head.

 

Easy way to check is pull your cat off and shine a light through. Maybe it's partially blocked?

 

We'll see. I'm going to take it all apart tomorrow, and go over everything. Check the timing again, check the cat conv, and redo all the readings again. I've missed something somewhere, and I'm gonna get down to the bottom of it. Or I'm just gonna take it and drive it off a cliff. Who knows.

 

If your taking the cat off get some bleach and distilled water. Seal off one end and fill the thing with the bleach, let that sit overnight or two nights if your patient. Come back and rinse with that distilled water and prepare for the nasty to flow. Once you have it all rinsed i suggest baking it on the oven (there made to get hot) to prevent it rusting from the inside. Even if its not "clogged" this will help it flow much better and shouldn't hurt the catalyst. Theirs a good DIY thread for it somewhere.

 

Humm lots of good ideas. But the things you are listing sound alot like what my wife d16z6 did. An It was a bad valve. Yea I know weird but it's true. While running it almost felt like the power was ok till I tried to get on it but then it flutter an no more power.

 

Well I've took everything apart and down again. Check timing, compression, read all the electronic readings, everything is in spec. Valves are seating nicely, fuel pressure is good, timing is dead on. All the sensors are reading what they're supposed to. I'm so lost at everything. My grandad spent about fours going over everything and we've both came to the conclusion of some sort of fuel problem. It's starving at low rpms full throttle, and the flooding at higher rpms with a big puff of black smoke out the tail pipe. Something some where is not reading right with fuel delivery. Don't know if it injectors or something else. I'm bitting the bullet and taking it to my local Honda dealership tomorrow. Gonna pay out the butt just for a diag check and test, but at least I'll get an answer to whatever my problem is. I'll post an update tomorrow of what they find.

 

Oh and the cat conv was pretty much clear. Little sut in there and black, but nothing blocked. Overall pretty clear straight through

 

Did you ever check your fuel pressure? Tested the FPR? Checked the injectors?

If you believe it's fuel related, those I think are the basic checks.

 

Yeah, we check them all yesterday. All the injectors dropped the idle RPM when unplugged which means they're all working like they should. The FPR showed to be alright. The fuel pressure was 36 with the vacuum hose on, and 44 with the hose off. Everything checked out there. I still have a feeling it's something electrical sending the wrong signal or something.

 

 

tach dancing around= bad ICM= shitty parts store distributor= change it out.

 

Just got off the phone with master technician over at my local Honda dealership. By everything I told him and y'all (you guys for the yankees), he believes it's the Coolant Temp Sensor. He said when those go bad most of the time, it continually reads the engine as cold and dumps too much fuel and will make the car feel like it's almost choking. He said it can cause misfires, rough idle and normal running problems. So I'm gonna drop by a local part store and pick one up, and try it. If all else fails, he told me to bring it by if it doesn't fix it, because he hasn't worked on an older model Honda in a while, lol.

 

Update:

Just got home with my car from the local Honda dealership, and the findings are, well, crazy. The tech like the car cool down, and then began to fool with it. At cool temperatures he noticed it misfiring slightly and adjusted the dizzy and the idle screw. The full throttle mishaps went away, that was until the car warmed up. After the car warmed up, it started behaving just like I've described to you. So he hooked it up to his diagnostics tool to get all the readings. What he found neither one of us liked. All the sensors where erratic in the readings at times. TPS, MAP, O2, ect. were under volting and over volting at random times. He asked if I've replaced the ECU, and I told him I had and also had the old one with me. He hooked the old ECU up, and same thing. He came to the conclusion it has to be in the wiring somewhere. So he goes over the car, and after about 20 mins he finds the problem. In the harness from the ECU there is a section of the harness close to the firewall that is burnt up around 15 wires. So long story short, I've gotta find a harness.

 

Good to hear you found the problem. All that just to find it was the harness smh smh.