4age misfiring and running rich

[Sprinter Freak]

Car - 4age ke70
motor / part in question - 4AGE bigport
problem - misfiring and running rich.
occurs/started when (if applicable)- when going for a drive last night


Hey guys

so was driving the car last night and it started missfiring hard on the way home. aAll that night it was stuttering the tiniest bit at low revs, was barely noticeable but could tell it wasn't 100%. the fuel pump had been a bit dickie that night as well, sometimes it wouldn't turn off when the car was turned off. On the way home i could hear fuel pump didn't sound healthy so pulled over to have a look sounded like it was on its way out but there wasn't much i could do so decided to keep driving and monitor it and see how it went.

after driving for another couple of minutes it started missing a bit in low revs but cleared up when you got the revs up. Eventually it got worse and worse, till it was missing pretty bad, pulled over. cracked off the intake pipe on the fuel rail and it had pressure, went to take the plugs out and there was a pool of oil in the rear spark plug gulley, cleaned that out then pulled all the plugs out and cleaned them with a rag(didnt have sand paper), they seemed ok not black or anything. The leads were pretty soaked with oil cleaned them as best i could and put them on, started it up and it sounded alright, reving ok still missing a little tho. Then after about 10 seconds of starting up it started missing bad again.

Another thing, its seems to be running rich for some reason. theres always black soot marks on the back of the car and you can smell it as well.

i've checked most things
- map sensor connected and no leak/split in hose
- tps adjusted correctly
- Vaccum leak(sprayed the throttle body with wd40 and couldn't hear the idle change)

Only thing i haven't checked is ignition timing, which shouldn't have changed unless my adjustable cam gears have come loose.

What do you guys reckon it could be? its got a 2 week old set of plugs in it, new spark lug leads(were replaced when i put the new engine in) and it seems to be getting fuel. I have a feeling the dizzy might be the culprit, that or a bad batch of fuel.

any help is much appreciated guys

cheers

Ryan

[slide86]

to test which cylinder is dropping out:

run the engine upto 2000-3000rpm so you can clearly see its misfiring, then remove one injector plug at a time. if the engine starts running worse then you know the cylinder is operating ok, if there is no change to the way the engine is running when you remove the plug off the injector then you know that cylinder is the one causing the problem.

from here you can start narrowing down things to look at, seeings as you have new leads and plugs in it. i would recommend looking at the injectors.

the only other thing that sounds concerning is the condition of your fuel pump, you state that there was fuel in the rail........but pressure and flow are two different things. you might find that there isnt actually ENOUGH pressure/flow to feed the engine when its running. I would try clamping the return line and see if the problem goes away. By doing this you are suppling MAX pressure and flow to the injectors at all times, this will tell you if the pump is no good.

hope one of these things fixes your problem

[Matt]

did you do anything with your fuel pressure reg? You're running a fairly large walbro right?

[Sprinter Freak]

Ok so I tried the things you said and neither seems to be the problem. I tried taking each injector plug off,on every injector, at 3000rpm and it started to die when I unplugged each one. I then tried kinking the return line so there was no fuel being returned to the tank, and it didnt change anything another thing, i I think it could just be flooding/running rich, it only stutters and plays up at low revs, and seems to run better at 2500-3000+ rpm. I also tested for spark and it's getting spark and the alternator is charging the battery.

Could it be my fuel pressure regulator?

Also found what looks to be sand in my fuel filter:
could this be causing some of the problems?

Nah just the standard fuel pressure regulator, and yea I'm running a walbo, which is the equivalent of a bosch 044.

Is there anyone who Specialises in 4ages/ke70/sprinters in Sydney?

[Sprinter Freak]

ok so i think i might have found the problem, there was sand in most of my filters which cloged them so it wasn't getting fuel through. And also there was a tear in the rubber pipe connecting my lift pump to the in tank pipes.





Will try fixing these issues and see how i go.

[Futo_gt86]

Sand? Sabotage?

[dying3k]

also, someone above said about clamping the return line, to see if your pump is dieing, this is also used to see if injectors are fucking out(full of shit), and clamping the return line jacks up the fuel pressure thus pushing more fuel through the injector(conpinsating for blockedge), either uncloging it or if problem still occurs after unclamping return line, injectors are removed and sonic cleaned and flow tested, i often use this, and as my boss calls it "lebo injector service" clamp return line and take it for a thrash around the block

[dying3k]

get some gates EFI fuel hose for that pump, and yes get GATES, im running that from pump to my fuel rail and its perfect still, got some other efi hose and its already cracking(less then a year old) and if its all full of sand, someone doesnt like you, pull your tank out and flush it out

[Sprinter Freak]

dont think so, just got some shit house fuel never going to caltex ever again!

yea i think it is the tear in my pickup hose that was causing it to run crap, the surge tank ran empty. so the engine wasn't getting any fuel, also the fuel filters getting clogged wouldn't have helped. Will fix both those problems, hopefully this will fix it. Am also going to get my injectors cleaned and flowed, and get a bracket made up that holds the in tank pump in place.

The rubber pipe that was holding the pump on is the right type of hose, tried using efi hose and it just deteriorated, just need to get another piece of pipe. where do you get gates efi hose? and is it expensive? yea am going to flush my surge, fuel tank and all the fuel lines to make sure there isn't any shit in there.

[dying3k]

repco sells gate products, just ring or go into a local parts store and jsut ask for fuel hose and say you ONLY want Gates, 4 metres was like 75 bucks(not retail), man use a big hose clamp and clamp the pump to that return line running next to it