Cutting out when Warm

frank said:
this is where a narrowband a/f/r gauge is mega useful for diagnosis, using it to check the engine is coldsart enriching and closed looping properly and checking if it goes off the scale lean or rich when the judder occurs etc
Click to expand...

Narrowband does have some uses then frank, generally the opinion seems to be that narrowband is the devils work!! :p
 
MicrAde said:
Narrowband does have some uses then frank, generally the opinion seems to be that narrowband is the devils work!! :p
Click to expand...
they do seem to be reviled eh ade :confused: but the ecu uses those very same signals from the lambda to regulate the fueling for 90% of the time, and to pass emissions tests
 
frank said:
this is where a narrowband a/f/r gauge is mega useful for diagnosis, using it to check the engine is coldsart enriching and closed looping properly and checking if it goes off the scale lean or rich when the judder occurs etc
Click to expand...

Just remembered I've a multimeter in my glovebox!

Any simple quick checks I can do?
Might have to boot Windows and fire up AutoData
 
skymera said:
Just remembered I've a multimeter in my glovebox!

Any simple quick checks I can do?
Might have to boot Windows and fire up AutoData
Click to expand...
yes you can do a resistance check scott (it should read 2500 ohms when cold, and 300 ohms when hot), or else tap into the lambda signal eh
 
frank said:
yes you can do a resistance check scott (it should read 2500 ohms when cold, and 300 ohms when hot), or else tap into the lambda signal eh
Click to expand...
Shall do it later :)

Just driven to work (15miles) with the 2pin sensor unplugged.

Cold idle was good, around 1,500rpm which gradually dropped the further I drove.
Pulling in 1st is okay.
Pulling at low revs is a little boggy.
Warm idle was around 750, little splutters at some lights but never cut out.

Revs are still sticking to 1,000 for about 5 secs before dropping??
 
Just as a totally different angle of it... is your fuel pressure regulator ok?
I still believe its the coolant sensor at fault but could be worth a quick look? :)
Revs will stick for a few seconds because of it overfueling iirc
 
sounds to me like you,re getting mad leanouts scott, and running on constant coldstart (unplugged) is just masking the problem.
if the a/f/r goes leaner than 20:1 ish you get a sharp missfire/judder, like a sparkcut/dizzy problem.
or is the judder a soft missfire/judder, like its over-rich/8 stroking ?.
and its juddering on all 4 cylinders ?
 
frank said:
sounds to me like you,re getting mad leanouts scott, and running on constant coldstart (unplugged) is just masking the problem.
if the a/f/r goes leaner than 20:1 ish you get a sharp missfire/judder, like a sparkcut/dizzy problem.
or is the judder a soft missfire/judder, like its over-rich/8 stroking ?.
and its juddering on all 4 cylinders ?
Click to expand...
Bad injector? Fuel pump?

Couldn't tell you the type of misfire as I'm not an expert.
All I can say is it juddered more with the sensor plugged in.

I'll need to hunt for somewith with an AFR gauge :/
 
a duff injector will only affect 1 cyl eh mate, it might be the lamba ? if the ecu is,nt getting lambda signals it probably drifts into very lean conditions at certain throttle positions.
you can test the lambda signals with the multimeter on the dash like on some of my youtube vids eh :)
 
frank said:
a duff injector will only affect 1 cyl eh mate, it might be the lamba ? if the ecu is,nt getting lambda signals it probably drifts into very lean conditions at certain throttle positions.
you can test the lambda signals with the multimeter on the dash like on some of my youtube vids eh :)
Click to expand...
The lamda isn't too old, but it isn't a genuine Nissan/Bosch on either! Cheap eBay jobby..

I'll probe the signal wire when cold and warm and note the resistances/voltages
 
Good news. My throttle body should arrive at home today.

So I'll fit that if I have the time. I'll also fit the coolan sensor and I'll try unplugging the lambda. I've run without a lamda before (seemingly) without a problem.
 
Years ago I had a Honda prelude, that used to cut out when warm. The garage eventually found one of the fuses was separating when warm!!! don't know which one. they changed them and everything was fine for years...maybe ????
 
Well car has cut out just as I parked at home. Refuses to start. Going to get the top chain cover off to see wtf is going on.
 
Does this look right?:rolleyes:
7q3bGAz.jpeg
 
Timing tensioner fitted, engine starts and runs fine.

Plugged the coolant sensor back in bug the eml light and fan are still on?

And it's also idling between 1500-2000rpm?
 
Okay, tensioner fitted, coolant sensor properly connected :oops:

Here's how she sounds now. Still not perfect but a million times better to the previous video!

 
The chain bouncing about like that and no tension it could have very likely skipped a tooth. Or you have chain stretch
Not say timing is your issue but its does sound like it
 
h701micra said:
The chain bouncing about like that and no tension it could have very likely skipped a tooth. Or you have chain stretch
Not say timing is your issue but its does sound like it
Click to expand...
Yes! Thats what I meant. Curse my feeble brain.
 
Enuo said:
Could the timing have been set on a slack chain? Otherwise theres idle adjustment valve on the tb probably
Click to expand...

I can't remember if I dicked about with the throttle cable or wiggled the waxstat mec when I was trying to "diagose" my problem.

I could adjust the idle screw but that might just mask a problem? Though I've had no issues when driving to work other than a high idle

Revs to 2000 then drops to 1500. Cold start was 1500 bang on
 
Easy way to tell is leave it idling when the fan kicks in if it adjusts idle ok then its fine. If it has a bit of a fit then yea its poorly :)
 
frank said:
its easy to trap the O ring at the bottom of the i/c/v scott (package en route btw :) )
Click to expand...
Sweet.

I'll whip that off later and check.
I was tugging at the waxstat plunger, not sure if I could have moved it forcing idle open.
 
skymera said:
I can't remember if I dicked about with the throttle cable or wiggled the waxstat mec when I was trying to "diagose" my problem.

I could adjust the idle screw but that might just mask a problem? Though I've had no issues when driving to work other than a high idle

Revs to 2000 then drops to 1500. Cold start was 1500 bang on
Click to expand...
Hello bud. From your last line, that's exactly what mine was doing when I first got her, changed the TB and away I went....no more problems:)
 
davyboy said:
Hello bud. From your last line, that's exactly what mine was doing when I first got her, changed the TB and away I went....no more problems:)
Click to expand...
TB is coolant heated? I can just clamp the hoses with mole grips and simply unplug and swap over?
 

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