VX California to 49state Conversion help
 

Hello,

Yep, another California Honda Civic Vx, 1995, trying to convert to enable Lean Burn. I acquired the proper computer, 5-wire sensor, and an engine loom from a 49state car. Hooked it all up and got a flashing CEL and clicking ignition relay under the dash. Never heard the fuel pump start up, and didn't attempt a start. Any thoughts?

Scott

Use a Scangauge to find out what fault it's reporting.

Presumably, you've checked all the obvious things, like connections, state of battery, etc?

Can you cross the jumper and tell is what code it is throwing?

No, just check your grounds. The main fuel relay clicks uncontrollably when there is an intermittent ground circuit somewhere, usually the one that connects to the water neck housing (thermostat housing).

Check/clean/replace every ground you have, clean them all, then go do try to start it again. It's a pretty common problem, honestly.

Oh - you could also have a bad battery.

Update!! Success!!! Lean Burn!!!!!
 

Success!!! Much has happened since the first post.

I didn't make it clear that the flashing was not normal code flashing, it was a fast flashing, like something was very wrong, along with the clicking of the ignition relay. Turned out I had indeed missed the ground wire that goes from the engine loom to above the thermostat housing. Hooked that up, had a momentary panic when it tried to start, and revved rapidly. Close! I had switched two of the sensor connectors, the one to the IAC with the vacuum solenoid. Then it started and NO CEL!! Yeah!!!

For the road test and I was hoping that I'd have a Shift Indicator light. No light. And nothing really felt different. I did the paperclip in the engine diagonstic connector and the CEL didn't act right when turning on the ignition.

Fortunately I had another 49state P07 ECU. Hooked that one up, took it for a drive and lo and behold, the CEL passed the paperclip test and on the road, Leanburn!!! It's amazing that 14 years after the car is made, and over 220000 miles, the engine can now can do what it was supposed to do in 1995, staying true to it's design.

OK, back to the SIL. I took our "replacement" instrument cluster out. We had had a speedometer failure when we got the car, and the junk yard sold us a true 49state speedo cluster with the white box surrounding the SIL, unlike our old speedo. I pulled out speedo out and saw that there is a socket that had nothing to connect to. Reading the wiring diagram I see that there is a 5-pin connector that we are missing on the California-spec loom. I'm sure that I can run a wire from the light to the ECU and get the SIL to work, but I'm wondering, did the VX and CX have a separate wiring loom to the 5-pin connector that I'm missing? Or was there a 5-wire connector in the instrument cluster loom that they just left out. Amazing that a car designed for a single state would have a different dashboard loom AND engine loom from the 49state car.

Wrapping up, it seems that the 49-state engine loom will indeed mate with the california body and give you 5-wire a and leanburn. Very exciting! The rewiring of a secondary loom with junkyard connectors project just seemed too cumbersome for me.

Now that I'm experiencing leanburn for the first time, I'm detecting that it works in all gears when the car is warm? What are the parameters for it's operation? Fully warm cat? When driving around town I can be moving along with a light throttle and give it a slight bit more gas and feel a gentle increase in power. It's brilliant. Does anyone ever wire up a light to show you when leanburn is engaged?

That's about it for today. Haven't done any mileage checks yet because we just were driving around town.

Scott

I think the parameters are just a warm o2 and low load.

Good job getting it working :thumbup:

Monitor leanburn Vx
 

To monitor leadburn in the Vx I installed the Autospeed Voltage Monitor kit which is 10 LEDs that indicate AFR by measuring the voltage of pin D14 on the ecu. I guess a single light would work almost as well but I found it easier for me to just get the kit . And yes the leanburn seems to work in all gears even accelerating ( engine warm ) if you do it veeerrry slowly. Not sure yet if it is better to accelerate briskly and cruise in leanburn or acelerate very slowly in leanburn. I plan to test this as I also have the MPGuino Kit which gives instant feedback

First tank of gas
 

Thanks for the leanburn tips! Our first tank, combined city highway yielded 48.54 MPG. Learning how to drive with a totally brand new car!! Learning the ins and out of Leanburn. We have lots of road trips this week so we can get more data. It's amazing! That's about 10mpg higher for an average than we were doing with the California spec engine. Course that was one tank. Our mileage will vary :) I'm going to RadioShack tomorrow and shop for a green LED. If the new Insight can have fancy lights indicating an economy mode, so can I!!

Scott

oldertech: congrats on the early success. I'd highly recommend getting an MPGuino to fine tune your technique. The instant MPG screen is as good a lean burn indicator as anything!

turbothrush - thanks for posting that info. (Where are you in Canada? I looked for a VX briefly before settling on the Metro/Firefly - the few VX's I saw were either Swiss cheese with rust or stupidly expensive.)

ohoh, new trait I don't like
 

Today i ran into a new trait that I'm not happy about. The California setup was rock solid with it's driving habits. Never missed or stumbled at all. We now have a VERY occasional stumble at low rpms with the Fed setup, like today just after a shift with light throttle from first to second. Might be the only one that happens in a day of driving. Little "miss" of some sort. Is this setup just more sensitive and perhaps the higher-mileage engine makes it burp more easily?

Scott

If I'm not mistaken, that's the "lean burn stumble". If you have an MPGuino or a lean burn indicator, you'll see the correlation.

Learn to love it :) - that's why you're getting the good MPG now.

I've only spent limited time in a lean burn Honda (Ben's VX engined CRX), so I found it a bit hard to notice. But Ben could identify the hiccup and knew when he was in lean land without needing to confirm on the fuel economy display.

Aye, according to every Honda Technician I know, they all hated the lean burn setup for only one reason - it's not very "smooth" in transition... the Honda ECU doesn't slowly lower the AFR, it literally just drops the fuel ratio under the curve when the input is correct to enter lean mode.

So you might be cruising along, and lift your foot off the pedal slightly, and all of a sudden, you're in lean mode, and you feel a 'burp' in the otherwise smooth operation of your engine... what's actually happened is that while you were cruising along, you were probably maintaining an AFR close to 14-15:1... all of a sudden, the stars aligned with the moon, Saturn entered it's third phase, and Jupiter got rings, and your AFR dropped down to something closer to 17-20:1 (if I remember correctly).

So what actually happened? Ever get an air bubble in the carb bowl while tuning a carb'd car? When that happens, you get a 'burp' from the engine... one or two cylinders don't fire for a cycle. Bam - there's your explanation.

If you're absolutely bothered by it, you could try a few things, like softer motor mounts, or making sure that all of yours are perfect and that your engine is aligned correctly (there is some play in the mounts of most Hondas, which allows you to re-align the engine slightly.)

The softer your mounts are, the less feedback you get from the engine when it makes funny and does things you don't think it should be doing.

You are funny
 

Christ, you are a funny writer. I was at the gym when I read your post and laughed out loud about the planets aligning for the sake of a Honda VX.

I read that the EGR valve can contribute to a stumble so I took it off and cleaned it up, new gasket and off I drove tonight without any stumbles. I wouldn't change any engine mounts but I hear what you are saying. All along, when I have been researching the VX and wondering about it's operation in LeanBurn, I've figured that was some kind of tradeoff for the mileage, and apparently there is. Good to know that Honda mechanics hate it. So I'll keep my head under the hood and won't bother them with such an efficient machine subject to untimely burps.

I know the valves are a bit noisy. Would I benefit any MPG by adjusting them?

I was hypermiling back in the 80s with my MGB and a CalCustom MPG computer and I'm doing it with my Chevy Cobalt with mpg indicator. Those cars trained me what to do to get good mileage, but I do need to seriously look into this MPGuino gizmo.

The VX is such a perfect car for me to be driving. I've always liked older technology that performs in advanced ways to achieve things that other products, cars, etc., aren't doing. Often that means some exotic technology that was prone to "burps." But I like that once I understand them. Look at my website Oldertech.com Two of my other cars are old British cars with liquid suspension and front wheel drive. Wonder how they'd run with a VX Honda motor under their hoods????

Thanks for the posts and advise from MetroMPG on the "lean burn stumble." Just drove the car around town and to Kansas City and back, racked up 150 miles and the fuel gauge is just south of F. Oh happy day. I think the truckers hate me for staying in Leanburn on hills.

Scott

Congrats on the good news. Glad to hear about another VX owner actually enjoying the LeanBurn bump.

I can notice the bump in my VX but ever since I put the NGK Power Cables in, it seems to be even less noticeable. They are spendy plug wires but they help reduce any lean burn misfires.

Plug wires
 

We bought the Honda dealer plug wires, which were indeed pricey, so we don't have aftermarket there. The ones you have are even better?

Scott

The NGK Power Cable have far less resistance than the OEM ones. The OEM ones are great quality but are around 1.5K - 1.7K Ohms per wire. the NGK Power Cables are about 300 - 470 Ohms per wire as measured on a few sets I've had my hands on. The less resistance allows for a hotter temp spark which works well for lean burn conditions. And the way that NGK winds the wire it has no noticeable EM Interference. But the Power Cables are $80 the cheapest that I can get them for.

dealer plug wires
 

Dang. The dealer wires were about that price.

Scott

VX Vtec solenoid question
 

I agree with you all, it would be nice to add the mpg meter, but in the meanwhile, I just want to monitor the leanburn with a light.

Today I put a voltage meter on the wire leading to the vtec valve. In my mind, it would seem that there would be a change of state on that wire when it is told to alter the cam and open or shut the valves. I measure .02volts on the wire when the car is on and 0 when its off. When Leanburn is kicking in and out I see no change in voltage. What am I missing on this?


TomO, your signature has civicvx.com as a link, but it's a dead link. Did you used to have a page on the VX?

Scott

The wire that runs to the VTEC-E solenoid is grounded internally by the ECU when it engages VTEC-E. I use an LED with a switched 12+ and then the ground is connected to the VTEC-E wire, when VTEC-E engages (2500+ RPM and more than 50% TPS) then the LED will light up. VTEC-E operates independently of Lean Burn.

Yes, CivicVX.com used to be my website devotes solely to the VX, but due to a hosting disagreement, I only have the rights to the domain name now, and no longer have any content there.

vtec-e .... maybe I don't totally get it
 

Ok, now I'm a bit confused. The vtec solenoid doesn't operate at the same time as leanburn? I was under the impress that the engine had to go from 16 to 12 valves to let the condition be right for the leanburn. My thinking was that if I monitor the solenoid that I would know when leanburn was happening. But is there some other sequence that I'm missing?

I can feel leanburn kicking in and out, and when I'm in second gear to slow down for a toll gate, I put on the gas and it feels like afterburners kick in at 2500 rpm or so. Are these separate processes?

In the California version, does the vtec kick in and out at 2500 rpm?

Scott

You are correct that Lean Burn works when the motor is in 12Valve mode, which is when the VTEC-E is NOT engaged. at 2500RPM and above that certain throttle threshold, the ECU grounds the VTEC solenoid and then fully opens all 16 Valves, Lean burn does not happen when VTEC-E is engaged, mostly because the combustion dynamics turn to a tumble type system which doesn't support a lean mixture. When VTEC-E is not engaged, the vehicle is in 12 Valve mode where both exhaust valves are opening normally but only one of the intake valves are opening normally. The other intake valve is only opening enough to release any fuel that is sitting on top of it. This makes the fuel mixture swirl inside the combustion chamber. That makes it easier to ignite a lean mixture.

So, basically, Lean burn is dependent on throttle position, engine temp, and engine load below 2500RPM, but once VTEC-E engages, there is no Lean Burn.

SVOboy would be able to verify if Lean Burn is available above 2500RPM as he has had his motor in Lean Burn up to 70mph I believe. But the circumstances for that would be a light engine load and very small <10% throttle position. That is one way that you can go above 2500RPM and still have Lean Burn. VTEC-E will not engage until 3000RPM then as the driver is not demanding the full power of the motor.

Hope this clears some things up.

Led monitering
 

TomO,

Clears things up beautifully. Leanburn and vtec have a different relationship than I had first understood. So if one were to monitor the system to have a green "Eco" light, it would have to read injector pulse timings to activate the light. Right?

Glad that helped to clear things up.

To monitor Lean Burn on the VX, you can simply get the voltage monitor kit from Autospeed magazine and set it to the range of the OEM wideband to get a reading. You can even use just one of the LEDs from the readout so you would have an "Eco" light.

here's the how-to from Autospeed: Monitoring Factory Wideband