VTEC-E question, help!

[benfrogg]

Wouldn't getting into actual lean burn lower torque and raise MPG's?
That suggests that my extra torque had to have been coming from some other source. So, we are back to a couple possibilities:
Clogged cat
FPR
Other Sensors that have not been tested
?
B

[GasSavers_Erik]

You may be able to test the FPR by just disconnecting the vacuum line and see if the engine idle speed changes (when you do this fuel pressure will increase so technically it should richen the mix).

The FPR would explain the paradox (higher mpg AND more power). If the fuel pressure went up suddenly, the injector pulse width would remain the same (so the computer would calculate the same mpg) but the mix would be richer so you would feel more power and may need to let off the gas pedal a bit. At this point, the ECU would put you in lean burn mode (but you are really running rich because of the overly high fuel pressure).

So you would feel more power and see high mpg on the display because the injector pulses would be pretty narrow. If it was the FPR- you would also see a big difference when you fill up because the fuel used on the scangauge would not match the fuel you actually burned.

[pgfpro]

Originally Posted by *************

You can't use chrome on these ECUs and considering that the P07 ecu is far more complex than the other ECUs, I would say there is good reason for it. I don't believe it's a good idea to run the car lean just because the car is at a certain load and temperature, everything should be working and other factors we're not considering need to be considered which is what the stock ECU does and so you'll never be able to program the other ECUs to do what the stock ECU does since it's so complex. But what do I know, neither I nor anybody else has really dug into these ECUs. Something about "partial truths" and whatnot apply to the P07. I have to wonder if the HX's Lean-burn ECU is a refined version of this ECU or if they went back to a more basic version...

Btw, where did you get that chip burning equipment? I've got an older computer that I need to reflash the bios manually since I misflashed it but I need a "chip burner" I'd suppose in order to do this.

My Bad. I haven't had my hands on a FED VX PO7 just the Cali-Spec PO7 which is like the P28 (11FO or 1720 board) The internal wideband would be a problem on the FED VX board. Sorry to the OP for high jacking the thread.

[benfrogg]

Thanks for the ECU info. It's at least good to know that it isn't possible/feasable.

Is there any other way to test the FPR without a gauge? My book has only info on testing it with a pressure gauge.
I pulled the vacuum line, rpms increased but when I plugged the vacuum leak they went back down to normal. I put a manual suction on the FPR while blocking the vacuum hose coming from the IM. THis did nothing to change rpms or anything.
Unfortunately, neither or my parts motors came with the FPR. I think they are like $75 to replace, so I don't want to replace it unless I know for sure it is bad.
Maybe a fuel pressure gauge would be cheaper....
B

[theholycow]

I don't know if it would work with that engine but the $20 high-pressure fuel system tester (just a pressure gauge) works great on my GM V8.
http://www.harborfreight.com/fuel-in...ter-92699.html

[imzjustplayin]

There is one more (or two) sensors you may not have considered and especially in this way.. The O2 sensor... It's possible that before you get this better fuel economy and more power, you're stuck in open loop mode, for what ever reason. So here is what I want you to do. I want you to first inspect your exhaust manifold/catalytic converter, see if there is any rust. Then take off your exhaust up to the point of the last o2 sensor. Then remove the O2 sensors and inspect where they screw in. If you can, take pictures of all the rust you see, the bolts that go into the block, the holes the O2 sensors screw in and maybe other stuff. Then get a stiff brush and remove all the rust you see in the threads where the O2 sensor screws in, the rust where the bolts go through the manifold and then into the block, the bolts themselves etc.

Why am I suggesting this almost unheard of suggestion? You might not be aware but the body of the O2 sensor, the part that screws into the manifold itself is actually used with the O2 sensor for getting signal, and or providing ground power. When I've had to test O2 sensors, I specifically had to hook up a probe to the body of the o2 sensor and to one of the wires to get any signal (at least with a 4 wire). So it's still conceivable to me that this still applies. Anyway my point is, because of the rust, this could be affecting the way the O2 sensor either heats up or sends signal to the ECU. So my solution is to ensure there is a good path of continuity from the O2 sensor all the way to ground. This means removing rust from where the O2 sensor screws in, on the part of the manifold where the bolts go through into the block and the bolts themselves. Since you live in Maine, it's very unlikely for you to NOT have rust which is why I make this suggestion.

[benfrogg]

Yes, indeed, the whole maniverter where the 02 sensor is housed is rusty. It's cast, so it's not going to rust off or anything, but it has a lot of surface rust. I will pull it tonight and clean it/where the manifold hooks to the block and the like. Additionally, I may try to find a way to ground the sensor body itself... not sure how just yet, but I'll put my mind to the grindstone.
I didn't know that even the 5 wire sensor uses the manifold as ground.
Thanks for the tip.
B

[imzjustplayin]

Originally Posted by benfrogg

Yes, indeed, the whole maniverter where the 02 sensor is housed is rusty. It's cast, so it's not going to rust off or anything, but it has a lot of surface rust. I will pull it tonight and clean it/where the manifold hooks to the block and the like. Additionally, I may try to find a way to ground the sensor body itself... not sure how just yet, but I'll put my mind to the grindstone.
I didn't know that even the 5 wire sensor uses the manifold as ground.
Thanks for the tip.
B

I can't confirm this with the 5 wire and or even any other O2 sensor, but when I've done O2 sensor testing, I had to use the body of the sensor itself in order to get a reading. I don't own any 5 wire o2 sensors nor do I own a VX lean-burn civic but I have spent plenty of time researching this vehicle as I was planning on doing a swap with its engine into a 4 door 92-95 civic but instead choose to go the HX route and swap that into my '98 4 door civic. Be sure to take some pics before you hook the manifold back up.

One easy tip for getting rid of rust on stuff like Steel/Iron is to submerge it in CLR and clean it with a tooth brush. I had a stove in my house that was rusting and arcing due to the lack of grounds (chassis was rusted), so I took the stove apart and submerged the parts in CLR for a few hours, scrubbed with a tooth brush and ONLY the rust came off! Don't use CLR on aluminum, I think CLR is muriatic acid and muriatic acid will have a violent reaction with aluminum IIRC. Also I wouldn't use the CLR where it could get in contact with the catalyst/catalytic converter since I have no idea what kind of reaction it will have.

[benfrogg]

Well, I did clean the maniverter hole with a wire brush drill attachment. I also attached a ground lead to a manifold bolt.
Here's a photo:

And here's where all the grounds meet the battery:


For grins, I replaced the fuel filter. It's only been about 20k (or less) miles since the last one, but I did do a fuel tank replacement a while back. It was rusty on the outside enough to be leaking.

The initial road test seems promising. The car does appear to have a little less hesitation and get up and go when it is warmed up. (probably mostly in my head) I'll know more tomorrow during a 65 mile trip I have to make including some highway. I'll give an update.
It seems either the 02 grounding issue or the fuel filter might be the issue.

B

[imzjustplayin]

Originally Posted by benfrogg

Well, I did clean the maniverter hole with a wire brush drill attachment. I also attached a ground lead to a manifold bolt.
Here's a photo:

And here's where all the grounds meet the battery:


For grins, I replaced the fuel filter. It's only been about 20k (or less) miles since the last one, but I did do a fuel tank replacement a while back. It was rusty on the outside enough to be leaking.

The initial road test seems promising. The car does appear to have a little less hesitation and get up and go when it is warmed up. (probably mostly in my head) I'll know more tomorrow during a 65 mile trip I have to make including some highway. I'll give an update.
It seems either the 02 grounding issue or the fuel filter might be the issue.

B

If this solves your problem or at least helps a lot, do you promise to do a better job of getting rid of the rust? All the points where the O2 meets with the manifold, the bolts that go into the block, the part of the manifold where the bolts are pressed against in order to attach to the manifold, and I guess the other side of the manifold which meets with the engine itself. Maybe you could soak like the top half of the manifold in some CLR, wait like a few hours, scrub with tooth brush until the rust is gone, all the while making sure the catalyst doesn't get wet (upright), then dry it all out and while it may end up black, it'll be rust free!