Popping on engine

GlenJ

GlenJ

hey all

As the title says, after some work on the head and putting back together it seems fine on idle for a few mins then sputters and i now have a popping sound i would say around 3-4k or when put the accelerator down quickly its seems to lag then rev up. Spoke to the guy who i was gonna book a dyno test with and he will look at it first but at a cost obviously :) (thought it might be in the tweaks they do)

What would you guys be checking before send it off to rolling road?
 
dizzy timing retarded too much so combustion is still burning/popping during exhaust stroke.
synchronise the ecu timing to the crank pulley timing with a strobe.
 
Yeah thought you guys might say timing, reckon i will let them deal with that make sure its set up properly i wouldn't be to sure the steps you take for that and even so they will be tweaking in that area anyways so hopefully it won't be to much trouble for them to sort.
 
They're only cheap. About £30. Used to use it all the time years ago but just sits in the garage now as most cars don't require one. Also that popping and laggy pickup can be a lean mixture. You don't have an air leak do you?
 
cheers for the reply bud, I'm gonna check as much as i can over the weekend, been to a garage today and they want £40 hr they reckon i could be a tooth out on the chain. So if the cheap timing lights are ok to use i will have a go myself me thinks (if it ends up being that)
 
Ah I see. Didn't read your first post about the head work. Can you not remove the top chain cover and check. You don't need a light for that. Just set the crank pull to tdc and check the top chain markings.
 
when put back together all seemed fine, turned by hand a few times and all lined up. My grasser rebuildish shows the pics

Cheers
 
*grasser rebuildish blog sorry. Will have a play around and see, will try get a vid of it popping but don't really wanna keep running it incase anything damages
 
changed plugs ( bosch 4) and a general check around, just want to eliminate these two things

Pipe is off back of TB- i thought it went under air box/breather but not to sure now
Green and white wire, think i have asked this before with a reply from frank but cannot find the post, asking again to eliminate but it is also same colour as the left hand side injector wire and is live when ignition is on

Cheers
 
Skinner_87 said:
I never had much luck with the Bosch 4 plugs. Went back to NGK and been well since , yours pics won't load for me for some reason mate
Click to expand...
Hmmm don't know why they not coming through, I'm clutching at straws i think with the spark plugs, tried bosch 4 and NGK iridium
 
ok got myself a timing light and had a little play and think i know what i am doing:eek: what i can't figure out tho is the dial at the back when i move it to say 20 it doesn't seem to do anything, but when the light is on it it does looks like it was quite retarded, managed to get it on idle around 16/17 degrees it seems to idle quite high then drops a bit and back up when taking up the revs the popping sound in the engine bay seems to have gone but the rasp out of the exhaust is something i have not heard before, just started p**** down will get a vid of it when stops. I have not looked at what the timing does when take up the revs yet
 
when using the strobe to sync the ignition timing with the ECU timing, the idle speed must be 600-650 rpm and the ECU timing at that rpm must be locked to 15deg, otherwise it'll be pointless trying to set the crank pulley at 15deg while the actual ECU timing is all over the place.

first check ur idle control valve at the TB front is clean and working smoothly and the fast idle waxstat mechanism at the back TB ain't seized solid (so the TB ain't just stuck in fast idle mode),
warm up the engine to 82c,
unplug the throttle position sensor at the side of the TB to make the ECU goto 15deg at idle,
adjust the idle bleed screw at the back of the TB till the tacho says its idling at 600-650 rpm,
check the crank pulley timing is at 15deg BTDC (markings left to right are 5 ATDC, 0 TDC, 5, 10, 15, 20deg BTDC)
reconnect TPS,
readjust warm idle speed to 650rpm
 
cheers for that polly, this is were I'm struggling a little with no tacho just doing it by sound and never really messed with timing before. Will get stuck in to what you advised above (when the rain moves on) get it to where I'm happy then take it to dyno next week, just didn't want to take it and him mess with it for hours

Again cheers
 
without a tacho you could either:
fit a micra tacho dial,
fit an aftermarket tacho to the blue dizzy wire,
get a digital tachometer (from £4 online),
buy a consult cable and connect ur laptop to the ECU with free diagnostic prog,
buy a cheap standalone diagnostic tool.
 
cheers bud, the consult cable connecting up to laptop sounds good, way over my head but hey will give most things a try
 
Anybody know what the loose wire is in the pic above? still can't find the post

Anyways couple of vids after playing around again, I'm happy where it is see what dyno guy says saturday



Little smokey as always :mad: and a wee raspy

 
pollyp said:
when using the strobe to sync the ignition timing with the ECU timing, the idle speed must be 600-650 rpm and the ECU timing at that rpm must be locked to 15deg, otherwise it'll be pointless trying to set the crank pulley at 15deg while the actual ECU timing is all over the place.

first check ur idle control valve at the TB front is clean and working smoothly and the fast idle waxstat mechanism at the back TB ain't seized solid (so the TB ain't just stuck in fast idle mode),
warm up the engine to 82c,
unplug the throttle position sensor at the side of the TB to make the ECU goto 15deg at idle,
adjust the idle bleed screw at the back of the TB till the tacho says its idling at 600-650 rpm,
check the crank pulley timing is at 15deg BTDC (markings left to right are 5 ATDC, 0 TDC, 5, 10, 15, 20deg BTDC)
reconnect TPS,
readjust warm idle speed to 650rpm
Click to expand...
Polly you got a link to how you remove wax stat (working on a spare i have at the mo) and also how do i check icv is working smoothly
 
GlenJ said:
Anybody know what the loose wire is in the pic above?
Click to expand...

I'm guessing the head's been removed before.
That loom is supposed to be routed right underneath where the inlet manifold meets the head.
looks like the yellow loose wire is the oil pressure sensor connector
 
engine swap bud then head off :), this wire was loose all last year was just curious again (especially when its live on the ignition) will go have a look where can put it

Cheers
 
pollyp said:
when using the strobe to sync the ignition timing with the ECU timing, the idle speed must be 600-650 rpm and the ECU timing at that rpm must be locked to 15deg, otherwise it'll be pointless trying to set the crank pulley at 15deg while the actual ECU timing is all over the place.

first check ur idle control valve at the TB front is clean and working smoothly and the fast idle waxstat mechanism at the back TB ain't seized solid (so the TB ain't just stuck in fast idle mode),
warm up the engine to 82c,
unplug the throttle position sensor at the side of the TB to make the ECU goto 15deg at idle,
adjust the idle bleed screw at the back of the TB till the tacho says its idling at 600-650 rpm,
check the crank pulley timing is at 15deg BTDC (markings left to right are 5 ATDC, 0 TDC, 5, 10, 15, 20deg BTDC)
reconnect TPS,
readjust warm idle speed to 650rpm
Click to expand...

Hi Paul How do you lock the ignition timing to 15 degrees
 
haynes says just unplug the TPS but I just use nissan datascan to force the IGN to 15deg and adjust the idle speed to 750 to guarantee its at the 15deg.
 
Ok got the car back after being on the dyno it confirmed something wasn't right, was showing it was running lean and a lot worse when warm, after going through all of the above again swapping, soldering cleaning parts it ended up being a dodgy injector. Changed the rail and all seems fine (fingers crossed)

Cheers for the help all
 

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