zeroptzero

Fuel injectors could be the next culprits, often causing misfire codes. Unfortunately you have to swap them out to really know for sure, some people swap the injectors around but that just wastes time and won't help in your case with 3 of the cylinders giving codes.

If you don't feel like swapping injectors right now run a full bottle of Redline fuel injector cleaner with Shell V-power fuel, it's a cheap experiment that might be worth trying.

It could also be a map sensor, quite often people will recommend a map "whack" , I never really thought that as being much of a maintenance routine, but some people think it works. I've got a spare map sensor if you wanted to try one.

cleenyc99

if you have multiple cly that started misfiring at the same time you should be looking for something they all have in common. the first thing I would check is fuel pressure looks like it could be low. if you push the pedal down WOT does it die or rev up and smooth out? borrow a gauge and check fuel pressure.

Slowcrash_101

To check fuel pressure, you remove the fuel pulsation damper and hook up the gauge where the damper used to be. First check the vacuum line from the fpr if it smells like gas that's your culprit right there. If it checks out block the return line and see if you're losing pressure. You can also use a volt meter to see if the injectors are opening the same. If your injectors are the culprit your plugs would be wet with gas, so I'm guessing it's pump related.

MR.T

I'm pretty sure you need a special widget from honda to test at the pulsation damper. I tried getting one awhile back and at the time they were unavailable.

Pulling off the fuel rail and tapping it would be the best way I think.

I may have missed it but...valve adjustment? Have you done one?

mattstryfe

Thanks for responding. I bought some cleaner but I have a full tank of gas. I have cleaned out the MAP sensor a few times when I was down in florida due to long history of heat bog issues I was running in to. I will clean it again and ensure it's making good contact. I don't have the actual zip tie kit on it but it was idling fine prior to Monday. You're right though. Swapping injectors won't really prove anything at this point.

I am going to try testing the fuel pressure to rule out my pump. If the pump is good the only real thing left to do is send the injectors off to be tested or simply buy 4 new ones.


I haven't gone WOT since it started running badly. Back in January it would hesitate/sputter until a certain RPM then it seemed to level off (or at least get a little better). At that time, I was only getting 2 cyl misfires; whereas now I am getting 3. This time, on the short drive back from work, the car seemed to have a lot more trouble compensating.


I am going to tap the spare fuel rail I have but I am curious about testing each injector with the volt meter. I will look up how to do this and try that first thing tomorrow. Thanks.

As far as wet plugs, they were dry in January and Monday.


Thanks for responding. Yea, we don't have a schrader valve so finding a kit which can test the fuel pressure at the rail is rare. I have a spare fuel rail and just needed to buy a gauge (it will be here tomorrow). I plan on tapping it and testing the pressure. For those who may need this later on, here is a very good thread regarding tapping the fuel rail. I wasn't able to find the gauge they used so I will be only using (with liquid/oil inside it), so this will be for spring/summer use only. My local parts store didn't have any gauges that read fuel/oil and went over 15psi so I found one on Amazon (Aeromotive 15633 0-100 psi Fuel Pressure Gauge). Hope it works out.

As far as the valve adjustment, I did one about ~30K miles ago. Also, it's one of the items I checked back in January when this problem came up the first time. Both the intake and exhaust gaps were fine.

MR.T

It sounds like you're barking up the right tree, at least with eliminating most likely issues, etc.

Wadzii is a member on this forum and has a machine for cleaning injectors. Fair price and quick service.

flyins2000

I had the exact same issue 2 months ago. Backfire and sputter up to 3k Rpms then it was flawless all the way to redline. I posted the issue online and people were saying I needed headwork, burnt valves, etc. To me, those solutions didn't make any sense it was running fine over 3k rpms.

I did everything in this order. Clean IAVC(nothing), Map(Nothing), Tried seafoam(Nothing), Checked/adjusted valves(Nothing) replaced injectors(nothing) replaced coil packs and it fixed my issue for good. Maybe see if you can borrow Injectors from a friend and see if that corrects the issue.

cleenyc99

if its still running like it was in that video I wouldn't be driving it. I hate to throw parts at something. I no if I looked at it I could help you out. any chance your from around my way?

mattstryfe

Yea, it's quite frustrating. I find a bit of solace in the fact that some of these part swaps and diagnostics are not bad to do anyways. What I am getting hung up on the most is that replacing the coil packs fixed the problem for 2 months. I am in the process of tapping a spare fuel rail to install a pressure gauge but I don't have the proper bit. If my pressure is good, it's the injectors. If the pressure is low, I need to look at the pump. I am not getting any gas smell from the vacuum line coming off the fpr which, I think, rules out faulty injectors (as Slow_crash mentioned).

I have a 1/8NPT-27 tap but based off what I read in this thread, the proper drill bit for it is a size Q (.332), which I don't have and can't really find anywhere.

I'm not. It's been resting since Monday. I agree with not throwing money at it. Both things it might be (injectors or fuel pump) are ~400 dollars, which is fine, but I want to be sure which one it is so I'm not spending 800 in the end.



Thanks for your help.

DeeKay

Don't overlook the obvious.If new coils fixed the problem for 8 weeks, and the vehicle started acting up in the same manner again, I would have immediately gotten new coil packs. Overlooking the dependent variable can be expensive both monetarily and chronologically. I'm not testifying this will fix your vehicle, however I'm simply stating my opinion based on observation of information and experience.

Short story: Once got gas, while running (weak battery), as soon as I left the pump I noticed the vehicle bogged down. Got home, would start and bog and die. I started checking connectors, found screw came out of fuel pulsation, contemplating low power to ecu, maybe fuel pump getting weak, fpr, contemplating all these components from advice. I used battery to wire fuel pump up directly, pumped all gas out (full tank), went and got fresh gas and fired it up after about three cranks. For over a week I jumped through hoops overlooking what I knew was the dependent variable. If coils fixed it, get new coils. Maybe something is causing the coils to go bad.