Amave

So i was having an oil leak from the rear valve cover and i decided to tackle the job this morning at 10 am, all went well , removed the vacuum hoses without a hitch, found and removed the hidden bracket bolts on the rear by the firewall, and when i was going to put everything back together i saw my lower intake manifold gunked to hell so i decided to take some seafoam and them some brake clean and spray the runners and clean the gunk off with a cloth .


I also sprayed the hell out of the EGR tube that goes into the UIM because it too looked sooty and dirty.

I go to put everything back together and all went without a hitch.

I started it up and of course it starts and runs rough due to the seafoam and brake clean , i see the smoke billowing out and then it calmed down and no more smoke....BUT it is misfiring ...

I ran the ECU for codes and found p1420, p1335 p1336 p 1320....

the p1320 and 1336 have always been there since i owned the car, i cleared the codes and only 1335 and 1336 come back , but it has no misfire codes !


it chugs like it is running on 3 cylinders , when i go to remove the coils while running i can hear clicking on all coils , but when i disconnect them, the engine doesn't respond the way it does when i disconnect the 3 front coils.


Is it possible i reduced the compressions on the rear cylinders due to too much spraying and cleaning ?


Is it possible i unclogged the EGR tube and the gunk is stuck in the tube causing what seems to be a misfire?


Here is the tube i cam talking about



here is what under my valve cover looks like ...kiinda dirty but it ran fine ( up until i replaced the upper intake manifold )

carsnwomen91

uhh you're not done...you didn't clean it properly. take it OFF the car and spray it and clean it out. what you could've done by 'cleaining' it that way is just force all the carbon deposit and the bottom of that tube and perhaps clogging the tube opening or something else.

here's a link to how to do it. disregard all the 4th gen info until you get to the picture with the bolt hacking, thats what you need to do.

http://forums.maxima.org/4th-generat...ing-p0400.html

your thread title grabbed my attention lol pretty tough to kill these engines.

Amave

very cool, thanks!


gona read up on it, and yeah i did not remove the tube or anything else , it was raining out and i had to act fast before the rain go into the enigne bay so i just soaked the tube opening and that was it ...gonna completely remove the tube and clean it out per the link ...


my guess was the gunk got stuck in the egr tube and now it is causing back pressure

SandyMax96

iTrader: (12)

If you're chugging along, and have that p1320 code, most likely your coilpacks are done and you need to replace them. Also, if you seafoamed, you might as well replace your spark plugs since the seafoam fouls them up during the process, even if it cleans up the valves.

carsnwomen91

also, what do you mean by the idle bahaviour when you remove the coils? if you're checking if your coil is working what you need to do is turn on the car and unclip each coil at the connector and listen for a change in idle. if the idle stays the same after removing a coil then that one needs replacing. if you remove each one and none of them are changing the idle quality then they're still fine.

spark plugs could be fouled up too after the seafoam... if they're still originals or old ones the the seafoam could've loosed up enough carbon build up to foul them up but you could just take them out and clean them and see how it runs then.

finish the egr first and then try those to make sure you're getting spark. report back

Amave

yeah im leaning towards the egr being clogged...i literally just walked in from removing the UIM , egr valve, egr tube from intake manifold , and i sprayed the hell out of it, and i saw some crud spill out when i unbolted the egr valve.

the tube that runs from behind the engine on the exhaust manifold closest to the firewall is a ****** ****** to move around.

I unbolted the flare nut that holds the tube into the egr valve side and had to literally take a pry bar and pry the hell out of it so i can remove the tube that holds the egr sensor .


i will finish up the installation sunday , and i will take more pics, i can't take any now because it started to rain harder as i was finishing up .


fingers crossed it's the EGR and not the pistons....my last theory is i killed pistons #1,3,5 due to the seafoam ....possibly it took out the rings and now there is low compression so therefore it doesn't ignite.

just for the hell of it i will do a compression test once i get to work to get my compression tester .



i mean at idle when i remove the rear coil packs one by one, the engine doesn't respond, when i take the coil pack out with it still connected i can hear clicking from the coil pack grounding onto the engine

maxed_out_99

by any chance did you forget to plug something in?
the first lower intake gasket i did on one of these engines i forgot to plug in the rear coil connector it did the exact same thing your describing its located near the driver side shock tower on the manifold

check it out

Amave

hhhmmm im pretty sure i plugged everything back in....i will take another look once i go to install it

Kuhn_man

iTrader: (8)

i once threw metal shavings down my engine and ran it off diesel and it still runs like new true story yo

a clogged egr wouldnt do that, it really wouldnt do anything other than not work..if it was stuck open thats more than possible, once you cleaned all the **** out of it the seal probly isnt working because it was clogged up with soot and once that soot is gone its now stuck open ya know?

Amave

anyone have a picture of the rear coil connector ?


the wiring harness off of the UIM only has about 6 connectors
2 under the throttle body, the IACV, the coil plug connectors , the blue connector on the device with the vacuum hoses attached to it ...


i'll go take a quick pic and upload

blue connector bunched with the ignition connectors

sorry about the lighting






egr tube and valve missing ( already cleaned them out )







ignition coil connector located next to the high pressure p/s hose





egr tube removed and cleaned waiting to reinstall

hopefully thats all that is wrong with this thing

Scottwax

iTrader: (8)

Wouldn't be surprised if Seafoam wiped out the plugs or has so much crap on them they won't fire. Assuming all your connections are good, I'd pull the plugs and inspect them. Start with the easy stuff.

Amave

Yeah i'm going to swap plugs from right to left bank and see if the misfire follows...i got the egr valve and tube cleaned out and there was some grimy stuff that fell out , dirt and soot along with the brake clean...i also found my VIAS is broken at the usual place..so i wanna fix that before i put the UIM back on ...

gotta do a search for that now

update:


found out i had left the blue connector on the pass. side loose, i went back and retraced my steps and found the connector was plugged in but wasn't clicked

i clicked it in and it runs great now !
thanks to all @ the ORG

user name001

out of curiousity, what is that peice with the blue connector and 2 vac. hoses? MAP sensor? the first pic. from the OP in the last post?

Kuhn_man

iTrader: (8)

glad its fixed...

Amave

not exactly sure what it is.

maybe someone can chime in or else it may be found in the FSM

http://www.nicoclub.com/FSM/maxima/2000/



i rode tested it earlier and it feels sooooo much smoother ....im guessing the intake runner cleaning got all of the carbon off, and i also cleaned the EGR valve and tube squeaky clean ....

user name001

hmm.. ill take a look. glad you got your issue resolved!