EFI running rough while driving

[MADAZZ]

Hi all I have recently bought a 93GQ 4.2 pet with efi that started to run rough while driving and its graduly getting worse its more of a chugging misfire now like its short 2 cylenders I recently replaced leads,plugs and fuel filter , should I replace dizzy cap and button to eliminate that from the list of things to check

[Robo]

Read this, will give you alot to chew over.
http://www.nissanpatrol.com.au/forums/showthread.php?22876-Tb-42e-lumpy-under-accleration

[MADAZZ]

checked all that and just replaced dizzy cap and button and no change

[threedogs]

Check leads in the dark for shorting, do you think its electrical?
Also inspect all vacuum hoses

[MADAZZ]

all electrics are new inc coil it sounds like a vacuum leak but I cant find it even spraying start ya bastard around manifold while running and no change ,I did have a wet spark plug from fuel so got new leads could my dizzy be stuffed and not sure how to check it, there isn't a lot of vac hoses on it ,someone that had no respect for a patrol owned it b4 me and its only done 180 000 km

[Bloodyaussie]

Is it using water????

[MADAZZ]

no its not loosing water and oil is fine it is an automatic is there any vacuum lines to the gear box ?

[MADAZZ]

just emptied my new fuel filter and its full of rusty dust so injector clean might help I hope

[threedogs]

Seems like it needs a full service, start by changing all filters, then oils
that way you'll have a starting point for future services, vacuum line is cheap.
But a wet plug would tell me dizzy cap or that lead is U/S, There is a rotor button conversion I think too

[MADAZZ]

Still got me stumped ,I have replaced all electrics from coil to plugs fuel system cleaned from tank to injectors ,compression test no help ,plug 4 is wet or not burning fuel but lead has spark ,injector plug power is good ,timing is spot on ,not using water , F it still chugs like a steam train, cylinder 4 plug is like new but wet with fuel or oil. I was only dragging the kids around the beach a week ago on a sand board now IM F_____KED for ideas im sure someone has had this problem I hope, all cracked vac lines have been replaced, I can degrease engine running and it doesn't stop or get worse

[MADAZZ]

and no sparks in the dark

[Robo]

Have you done a compression test.
where are you.
maybe a very dirty injector

[NP99]

Have you done a compression test.
where are you.
maybe a very dirty injector

Some injector cleaner and 98 RON fuel???? Injectors don't last forever, so may need replacing/cleaning at a shop.

[MADAZZ]

injectors only cleaned Friday ,compresion test done sunday only 1 cylinder was a bit off the others but not too bad im in Bunbury wa I haven't given it to a mechanic yet ,I think its time to, have tried to save some $$ I think I have done well for a car detailer

[Parksy]

Vacuum leaks aren't the easiest things to find, even when you do use flammable liquids to try and find leaks. When I bought my patrol, it had lots of vacuum leaks, and every hose I replaced improved the performance slightly. But the biggest leak I had was either the manifold to head gasket or the gasket between the manifold halves. Replaced both and the engine ran like new. Mind you I installed new injectors, new ignition components and a new fuel pump. All of these were suffering in some way and caused an improvement when replaced.
Check your fuel rail pressure, should be 40 psi and rise up pretty quickly.

[Parksy]

Also take the distributor cap and rotor off and remove the plate underneath. There will be a disk with hundreds of little notches. There is an optical pickup sensor which reads these notches, any water or dirt that has managed to get in will need cleaning.

[MADAZZ]

checked dizzy its clean fuel pump is a bit sad when I cleaned it sock on the end was sucked in and covered in crap ,manifold to head not sure of

[Parksy]

If you can buy a cheap inline gauge, and install it after the fuel filter, that will give you an indication on what your pumps health is like. Mine put out 32 psi and rose to this very slowly. When I replaced it, as soon as i turned the key it jumped to 40 psi instantly. Made a big improvement to the performance also.

[MADAZZ]

just put a new fuel pump in to squash that problem and still misfiring but a lot more responsive when I give it gas, it is going to a mechanic in the morning hope he finds something simple I missed

[MADAZZ]

owning a 4WD is like owning a boat , B ring O ut A nother T housand

[Parksy]

There's a few members that are having similar issues that they can't get to the bottom of. I wonder if a dirty tps will give the occasional miss? Apparently drilling a small hole into the casing and filling it with some sort of electrical cleaner works wonders. Maybe give this a shot?

[NP99]

owning a 4WD is like owning a boat , B ring O ut A nother T housand

I'd rather be stranded in a 4B than my boat :)

[Clunk]

I'm guessing you're not running gas as well?

[MADAZZ]

halafuknluya problem found and fixed after a week of a mechanic didn't wanna look at it I gave it to another he did every check he could then said take it to wreckers to try another computer on it and 15 mins later after he climbed all over engine bay he said you have a broken earth wire somewere so sure enough I found it in harness behind alt ,that earth wire was for injector 4 so it had 24v and no earth so it was stuck open flooding plug ,almost thought it was a burnt vaulve im so friggin happy, THANK YOU BEST WRECK BUNBURY and buy the way the wire was joind cheaply with a little metal join that had corroded over time and broke.

[NP99]

Great outcome and thanks for finishing the story so that other may learn.

[MADAZZ]

I have a new problem my car is smoking bad until warm ,everything is ok except small sensor on the inlet manifold has no power to it ,I have tried to follow the wires 1 is earth the other disapeares near battery,i was told those 2 sensors might be dirty so I cleaned them and found 1 has no power

[MADAZZ]

problem solved valve stem seals were totally F#@ked to the point of I got it towed to mechanic they are still settling in weeks later but smoking less and less

[NP99]

Another good outcome. Did the $ sting much?

[MADAZZ]

$370 ish no need to remove head he took all plugs out and used air compressor to hold valves up still gotta let her warm up a bit but it doesn't choke out entire street anymore LOL

[threedogs]

Great out come on the broken earth wire, seems the Patrols have heaps of earth straps,
Might be worth checking others you can find ,re do them or run a few new ones.
Take it to the tip RLMFAO again great out come

[threedogs]

@ MADAZZ found this on another thread , may help without the need to reco head
http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_1005.html?Opendocument&land=GB&voilalang=e&voiladb=web.nsf