CyborgGT : 1993 Accord EX wagon

[UnicornHondaSE]

If the plugs are wet, putting in new ones probably won't help since he hasn't solved the wet issue.

Wet plugs sounds like too much fuel, which is due to the fat tune to compensate for the vac leak, IMO.

Or possibly a deficiency with your ignition system.

Leak down test is to check for damage in the head. Compression test is to check integrity of the rings. For the life of me I cannot at the moment remember how to perform a leak down test. Lol like how to hook it up, even though I have a nice Jegs or Russell tool here in the cabinet.

Sounds like he found the vacuum leak, or one of them. Cars as old as ours should have all vac lines replaced by now unless it's a low mileage garage queen and even then rubber doesn't last forever.

Love that throttle body, looks beefy for a na four cylinder.

[Grumpys93]

Damn dude wish I could help on this matter. I fear emissions as I know I would fail in a heart beat. One thing that stuck out to me was you said you ran rich when you decelerated. Do you mean like engine breaking and coming to a stop? If so It should be the opposite and go lean not rich. I have no idea how emissions works, but if your smelling fuel coming out of your intake then that is pretty rich IMO and very well could be the culprit. How many tests are you allowed to have?

Curious on your Compression test. Have you pulled your plugs to see if they are wet or foul? Would putting in fresh plugs prior to the test help at all?

[CyborgGT]

Vacuum leak was the brake booster hose being dried out and cracked on the inside, so a fairly significant piece to have fail. But with the tune left as-is, fixing it only dropped my CO by 20 points. I never noticed any unusual brake pressure issues with the car, though.

And yeah, these cams are pretty popular, so maybe I was too confident with them not giving me problems.

[SSMAccord]

Yeah, I think leaning this out will likely yield results that positively impact your HC/CO numbers. I wouldn’t discount the EGR helping either as it helps to burn fuel that vapors that weren’t combusted on the first pass through the engine. Where was your vacuum leak? At the intake manifold gasket?

I think you are likely ok on your V2V clearance, a bit on the tight side at less than .030 given the specs of the Pro2 cam specs, but likely still in a safe range.

[CyborgGT]

From what I was reading about EGR, though, that system increases HC and CO a bit, if it affects them at all. EGR is only there to combat NOx, which my car is well under limits on (but that could change with a leaned-out tune). I did find this graph below... which, if taken in the sole context of air/fuel mix, does agree with that. It'll be interesting to see if, after some maintenance on my end (fixing that vacuum leak did make a noticeable improvement in idle quality on its own) and a re-tune to lean the mixture back out, if my HC and CO go down, but then NOx spikes. At that point I would definitely do the fuel rail conversion to get the EGR back on. And yes, I have a brand new California-rated cat, along with a brand new AEM wideband O2 sensor.


https://mechanics.stackexchange.com/...in-a-smog-test


An interesting post in the thread I found that graph in:

"Rich" and "lean" become too confusing because both can happen at the same time. When the injectors are dirty, they do not atomize fuel effectively. Micro-globs of gas pass through the combustion chambers unburned -- effectively creating a lean condition in the chambers -- so that the O2 sensors add more fuel to the mix, which in turn produces a rich mixture in the exhaust and uneven flame in the chambers. The cars EEC attempts to compensate by vacillating between more and less fuel every few seconds, which will also confuse the values on a scanner.

While I was fixing the vacuum leak and otherwise looking around my engine after that first test, I removed my intake pipe and noticed that with the throttle body open I could smell fuel in the intake manifold. I asked my tuner if he could test my injectors for a leak, but he said not to worry about it for now, that it should just be from his rich tune to get the car to idle with that vacuum leak we didn't know about. So apparently it's pretty rich. Wether it's rich enough to cause such a drastic failure in CO/HC, I guess I won't know until test #3. I'm obviously learning as I go here, but in a way I'm kinda glad my car did fail emissions, because I'm finding this information really interesting.

[Raf99]

I agree on the leak down test. but.... hold on. This is just a H22 running at 14.7. Everything is still sealed up (cams, valves, exhaust) just more aggressive for WOT response. This is no different than a normal prelude failing. Same engine, fuel, etc.
I like this post - https://community.cartalk.com/t/1991...and-co/33335/2

So you don't use an EGR but you do use a CAT? A bad EGR is the #1 cause of your symptoms (high CO / HC) on a normal car. Back in the day for Honda to meet regulations they came up with the EGR / CAT combo plus other items while keeping a 14.7 ratio. Assuming you obviously have the same ration (maybe not on WOT) you are going to fail IMO. You're going to have to implement some of the OEM smog features to meet standards. Not sure if a tripple CAT would help here too. Timing can cause rich conditions but not to the affect you are seeing on your readings...

(IMO / I'm no pro in emissions ...)

[CyborgGT]

Yeah, from what I was reading in one Honda-Tech thread, some people were saying there should be a greater difference between the two cam degrees... but again, everyone's engine is slightly different. My engine only has about 60k miles on it, so I'd imagine the head didn't need much machining. The block, on the other hand, was re-sleeved, and I wasn't told how much might have been taken off during that process.

I did not do V2V measurements, I'd have to look up how to do that if it comes to disassembly. I just stuck some play-dough on the pistons to check for contact there. But "not emissions legal" just means they didn't get them CARB approved like with the Tuner cams that leave the small lobes stock, it doesn't necessarily mean that they can't pass emissions. As far as checking for leaks, I was thinking a compression test will at least tell me if a problem exists if the pressure leaves the cylinders too quickly, and then from there I could do a leak-down to narrow down the source of the leak. I'd have to borrow a friend's air compressor for that one though. I do at least already have the gauges for both tests.

[SSMAccord]

Interesting on the intake cam degree. Did you do a V2V measurement when you degreed the cams? To see if there is a sealing issue, you’ll have to do a leak down test to see if there is any damage. Also the cam sheet for the Pro 2s indicates that they are not emissions legal (whatever that means). Hmmmmmmm…need to do some thinking.

[CyborgGT]

SSM, my intake cam is at +0.5 degrees. No adjustments were made to either on the dyno. I'll talk to the tuner about that when I revisit.

Raf, at this point with the vacuum leak fixed, I'm thinking the rich tune that was mapped to fight it is causing most of the high CO/HC. But given my inexperience with all of this, it's that huge difference between my actual numbers and the accepted limit that makes me nervous about how much the tune can affect things. It makes me feel like either I made some other massive oversight, or these cams just can't pass emissions. All that said, at least I believe the vacuum leak is fixed, but I'm thinking of ditching the thermal manifold gasket just in case because I don't trust its ability to seal. Or maybe it would work properly sandwiched between two OEM gaskets? I'll have to see if testing the coolant temp sensors is possible, because I'd want OEM for reliability and those things are $80 a pop. I also read that a bad TPS can throw things off, so I'll make sure mine's calibrated right. I'll go through the engine again as much as I can think to without pulling it from the car for now, and then go back in for the re-tune to lean it out. Since the dyno, I haven't been full throttle with the car. On the drive to emissions, the only worrying thing I really noticed in regards to a/f was it getting super rich (low 10s) when decelerating to a stop.

[Raf99]

Soo any car can have high CO / HC and fail, there's tons online. Same end result which is too much fuel or bad CAT, the easy things. A bad ECT sensor or O2 can cause issues as well but you would see all of this on the A/F gauge to my knowledge.
On WOT are you in the 12's or steady 14.7 across the board?

[SSMAccord]

I forgot you have the Rosko fuel rail that puts the banjo there! The link you shared would allow you to run a normal fuel rail and the RDX injectors and restore the normal EGR location. In theory, all of this should work…I have been too busy/lazy to do a 2023 update but I am currently running the setup you described: Euro R manifold, stock fuel rail, RDX injectors and CNC adapters and CB7 EGR valve and a Hondata S300 and it seems to work as intended. I have a Rosko fuel rail but couldn’t get over the banjo bolt location so I didn’t end up using it.

The stock CB7 EGR bolts into that location on the Euro R manifold like stock and should work as intended as near as I can tell.

Yeah, degreeing the cams is unique to each set up. If your exhaust cam is at 1 degree what is the intake cam set to?

[CyborgGT]

Hmmmm…how would the degree process influence your current situation? I think you did a pretty meticulous job when you did that process. Unblocking the EGR might actually help for your emissions test given what that system does with the exhaust gases.

If you need a set of blue top H22 cams, I have a set that I took out of a head over the winter. You can have them (free) as I don't have a need for them and they might do you some good.

If I degreed them wrong, the intake/exhaust overlap could be off, which from what I'm reading could affect emissions, or worst case there could have been valve-to-valve contact without me realizing. In my searching, multiple other people were saying they had to put something like 3 or 4 degrees of advance on their exhaust cam (in a thread about Pro 2s in H22s), where mine only seemed to need 1 degree. But everyone's block and head surfaces are going to be machined slightly differently. I'll have to do a compression test to see if the cylinders are holding pressure, which should at least tell me if a valve is bent and not sealing properly.

The problem with me simply throwing EGR back on is my whole intake manifold and fuel arrangement (Euro R, RDX injectors, and a fuel rail designed specifically to get the two to work together). Because of the aftermarket fuel rail, the banjo fitting now hangs directly into the space that the EGR needs to occupy (see photo below; my block-off plate still has tape masking it off from when I was polishing the manifold). So I don't know how much I would have to change up just to get the EGR to physically fit again... and that's assuming the Euro R manifold can use a normal H22 EGR and doesn't require a unique one that's hard to get ahold of. Worst case, I'm tracking down a new stock manifold and different injectors to work with the stock fuel rail just so I can relocate that banjo. Although I did find these adapters that look like they allow the RDX injectors to fit to "all '90-'00+" Honda fuel rails: https://jackspaniaracing.shop/produc...f7849148&_ss=r




If it comes to me having to switch back to stock cams, even if it's just to pass emissions, I'll let you know. I really appreciate the offer.

[SSMAccord]

Hmmmm…how would the degree process influence your current situation? I think you did a pretty meticulous job when you did that process. Unblocking the EGR might actually help for your emissions test given what that system does with the exhaust gases.

If you need a set of blue top H22 cams, I have a set that I took out of a head over the winter. You can have them (free) as I don’t have a need for them and they might do you some good.

[CyborgGT]

Yeah, EGR is blocked off with a plate. I don't think EVAP will really do anything for tailpipe emissions, it's more evaporative, but the responsible adult in me kinda wants it on there anyway. And I'm not interested in ethanol because of the inconsistencies, spotty availability around the country, and fuel economy.

I'm really hating the internet right now, lol. Trying to research my issue is depressing and making me second-guess my work leading up to this point. Like if I degreed the cams properly (and the damage that could have caused), and if it's even possible to pass emissions on these cams. My stock cams are chipped, they can't go back in. It's making me want to pull the engine to double-check everything, which could easily turn into an expensive venture if changes need to be made. Not to mention stretch this project well into yet another year. But for now I've got a couple small parts coming and I'll keep tinkering and doing what I can at home without pulling the engine, then go back in for a re-tune and see what comes of it. Hopefully it's just down to the rich tune he needed to get it idling on a vacuum leak. No idea what that timeline looks like though. If it still fails, I don't know what I'll do at that point. Ditching the headaches for a later time and getting a stock H22 just so I can finally drive my wagon is awfully tempting right now.

[UnicornHondaSE]

Well, congrats on finally getting it tuned even if it is not perfect.

Isn't EVAP system for the unburned fuel / vapors recirculating back into the manifold? I know some engines the EVAP or EGR system is a hole cast in the intake manifold, to which us gearheads machine a block off plate and remove the entire system.

Is that the same as what you have done?

You may gain power with Ethanol but I'm pretty sure your won't gain gas mileage as it takes 15% more fuel to achieve the same result, or something like that, at least with turbo applications, something to keep in mind.

There are various levels of Ethanol too, like petro gas has 87, 89, 91, 93, respectively (kind of lol). So you may find E70 or E85 or E whatever depending on the time of year and station. Some aftermarket performance companies sell a Ethanol test kit, it's a test tube with some other stuff I forgot about cause it's been so long since I have run that stuff, but you can test to see exactly your Ethanol rating for better tuning.

Nice job on the wagon so far.