ok guys, its been a while since ive been this stumped and couldnt figure out an issue...anyhow here goes the story, a few months back i noticed when i get under a quarter of a tank the car would stumble when accelerating HARD...if i babied it or drove normally it would be fine,so i took it as nothing and kept driving it and didnt diagnose it then,well as of Friday the car does it almost constantly...figuring i needed to change rear valve cover gaskets i went ahead yesterday and changed them,the intake manifold gaskets,cleaned my egr guide tube,cleaned my iacv,throttle body and mass air flow,and changed plugs and coils...used coils i got from here which were tested before shipped...ok great i get it all together thinking shes gonna run like a champ...yea...not likely...its still doing the same thing, i had it scanned and the only new code that came up was po300...random multiple misfire... ok well went back checked all connections,looked for vacumm leaks...NOTHING.. so as she sits now she stumbles while idling...not constant though,shell run fine for a few minutes then stumble for a minute going back and forth...under normal driving (shifting at 2-3k) shes fine...but under heavy accelerating i can feel the skip in the power... where would i look for answers??? ive been told possibly a weak fuel pump,which i have noticed seems to be a bit louder,but my injectors do as well....ive also been told to check the fpr...any thoughts?? this is my project//daily for the time being and its been a money pit the last 3 months(alternator,maf,tires,brakes,exhaust work,bodywork) so any input would be appreciated....


On another note,and im unsure if its related or not,my mevi doesnt seem to be functioning as it should either,its set to activate at 5600 rpms,and i noticed today bringing it up to 6000 the actuator arm didnt move as it usually does....maybe flava or wizard could chime in here...or someone that knows about the mevi cause i checked the wiring to harland switch and its all good,and the vac lines all seem to be intact and running to proper locations...my line is T'd into my fpr vac line if it makes a difference and i have the oem vac canister that used to come with it... help me out here because right about now.....im pretty sure a civic running on 3 cylinders would whoop my a$$

 

Did you reset the opening point on the Harlan. I'm saying this because if you disconnected your battery you have to reset your Harlan's activation point.

My guess on the other problems is that all coils are bad. Do you have a volt meter to test them yourself??

 

+1. Harlan's need to be reset (both settings: coil per plug and the activation point) if the battery is disconnected. Do you know for a fact that your MEVI was activating before?

I'd say it's your coilpacks, especially since you're getting the code for it. When I went from NA to boost, I had the same problem as you when I would accelerate hard...sputter sputter sputter. Cruising my Max was fine. It was indeed my coilpacks (and we both have 99's). I'm afraid to say that the used coils you got may be no good after all; testing them is inconclusive and can not be trusted. Might be time to bite the bullet and buy new OEM ones. The whole quarter of a tank thing tells me your fuel pump is either going bad or the fuel pump filter is clogged and/or not aimed right....should be aimed towards the bottom of the tank to suck up the low level fuel. Start with the coilpacks first, then the fuel pump.

Also, when is the last time you replaced your fuel filter?

 

Got a z32 ff sitting in hallway.... when this was all done battery never got disconnected...dumb i know,but forgot to do it.... last time i opened the hood about a month ago mevi was activating fine .. what do i need to test coils?? Multimeter?? Also my fuel pump has a high whine to it which i dont remember hearing before....

 

Pull the stalks off the coil packs and look at the contact area where the spring meets the coil. If there is any corrosion, clean or replace that coil.

 

No matterwhich coil i pull doesnt seem to make a difference in engine idle... im almost to the point of sending it to the shop...i just started smellin what smells like burning electrical in the cabin....hopin ecu isnt fried

 

Testing coils is inconclusive. Bad coils often test good. If your pump is whining maybe you should start there

 

Yea the pump has been quiet up until now

 

sounds like the fuel pump is going bad. the one in my Z started to whistle and had a rough idle. i drove it like that for a few years until the thing finally died. that's probably what it is.

 

Write down all your codes before doing what I'm about to say;

Reset your ecu if you haven't done so already

 

That Z32 feul filter sitting in the hallway? Put it in, like now. Your feul pump is supposed to be silent.

Also, looking into adding TC-W3 to your tank. I've used it on my car. Check this thread out;

http://forums.maxima.org/general-max...troke-oil.html

It would be good to see if TC-W3 can bring your fuel pump back from the brink. Let us know.

DW

 

Yea imma do it...as soon as it stops raining... ill look into that stuff youre mentioning and see what it does... i can snag a 255lph fuel pump on the cheap so i may just swap it and put in new strainer etc etc

 

I might try the marine 2 stroke additive myself.

 

fuel filter, fuel filter for sure.

 

no one has mentioned this, but take the boots off the coils and inspect the spring for corrosion on broken points. Had this happen to me and fixed problem. Also check to make sure that none of the pins, are bent down going into the coil, where the connector hooks up. Very common problem.

 

What are the chances 2 diff sets of coils have that problem??

 

Possible but not likely.did you ever pull the boots off to check the coils for corrosion?

 

No, idk where youre at but im ib CT and working during the day lol.... chances are it may go to the shop tommorow afternoon... i dobt have time to be chasing issues...

 

First thing I would do is pull the pump and check the sock and hoses/tubes for cracks. Test the fuel pressure. Then check the coils as stated already.

 

yea agree with ASAND, you gotta check fuel pressure. See if thats within spec.

Random misfire usually means fuel issue or maf issue. Since u 99 def check the coils, but the codes should have pointed you to a specific coil.

 

Yes i have a 99... BUT. A 97 engine... coils are from a 97 as well... maf was unplugged while runnin and car almost died till i plugged it back in

 

I'm surprised I didn't mention this earlier. My car used to mysteriously misfire as well. Not from a low tank. Anytime. Especially if I suddenly floored it.

Solution? FPR. Problem solved.

DW

 

ive had those money troubles lately and have been running my tank down lower than id like to a lot more often. im praying i dont start having problems.

i mention because your problem seems fuel related since it happened below a quarter tank. idk why but when mines below a q tank i feel like ive got less throttle response.

 

Can a fpr still be bad even if its vac line isnt leaking fuel??

 

Sure can. Mine wasnt leaking, but it wasnt up to snuff, so to speak. Leaking fuel usually indicates that the FPR is failing catastrophically due to the diaphraghm breaking, or, there's fuel coming from somewhere else in your system.

 

Yea its definately not leaking... i checked that...my fuel pump has a nasty whine... i can hear it from like 30 feet away from my car... in the car its slightly muffled but can hear it when windows are up and radio isnt on...never used to be able too

 

Well, what's the verdict?

 

Not quite sure bro, had a garage look at it... they scanned it and it came back with cylinder 5 misfire and a camshaft sensor code, ended up changing my MAF to my other one. That eliminated most of the hesitation and i ordered a camshaft sensor which should be in today or tommorow. My idle isnt as bad now after running some seafoam through the gas tank. Maybe i had or have some crud in the tank cloggin up my strainer?? I know my 99 ecu on a fed emissions engine isnt helping either lol. Gotta look into my mevi issues still though, Manny sent me some pics of his setup and how its all ran and it looks NOTHING like mysetup... i have the oem canister mounted under my drivers side fuse box and it runs to the metal lines on the drivers side fender area to a check valve that returns into the other line going to canister... so theres no vacumm actually going to it... then theres another canister which appears to be running my mevi actuator arm and fpr but as of yesterday it wasnt engaging and there is plent of vacumm coming from the T on the fpr.... so im going to check wiring going to my harland and see if its getting power... if so ill be at a stand still scratching my head

 

The part I highlighted in bold has nothing to do with the MEVI, not sure why you even mentioned it. It's for the buttefly valves on the lower IM since you're a 99.

Are you sure the other vacuum canister has a built in check valve? W/o a check valve somewhere in the system (either in the canister, or inline), the canister is useless.

Draw me a picture of how your MEVI is getting vacuum and electrical, and I'll tell you if it's ok or not. Shoot some pics of your vacuum canister, vacuum solenoid etc too.

I installed Manny's MEVI, as that's how I typically do my MEVI installs. I later changed Manny's setup so that his VAFC activates his MEVI, not the Harlan.

 

........with a 97 motor, hence I call his car frankenstein

DW

 

I see. That stuff can either be ignored or removed then.

 

Lol so the canister under my fuse box is for swirl valves? That explains alot... LOL so off of my fpr is a T .. from the T is a vac line running to the solenoid and another from the solenoid to the canister and one outta rhe canister into the actuator arm! The check valve is connected to the canister for butterfly valved as you menioned... unless the check valve is inside my actual canister it doesnt have one...never has...Manny sent me pics of his setup but i assume the only difference between his and mine should be the wiring for vafc,correct?

 

And as far as my engine to ecu... either im going to repin the eiring needed or get a stepdown harness for plug n play....i guess i inherited the problem from someone that blew the original engine and tossed in a fed spec ....bugs bugs and bugs

 

Ill grab a short video going throuh the mevi setup tommorow and post it... its dark here already... no mevi cover installed....so dont hate on it lol i gave my mothers fiance my cover bracket so i can get one machined up for manny... free cnc parts....yessir....