Iv put New plugs, rotor cap, Tried other leads off another car the same, Cleaned air flow sensor. Anyone have any ideas what I should try next? Missing under load at low revs, Its fine above 3000rpm
morrisman1,
Apr 26, 3:29pm
Check Fuel pressure, try unplug the o2 sensor. Knock sensors occasionally give up too, they are located just under the intake manifold. You cannot leave those disconnected though cos it will go into limp.
dasfi,
Apr 26, 3:55pm
Also forgot to add its intermittent fine sometimes, otherwise not
poppy62,
Apr 26, 4:31pm
It's more than likely a crook plug and yes even new plugs can be a problem. Otherwise check the rotor.
dasfi,
Apr 26, 4:57pm
Any way to check the rotor? Or just replace it?
intrade,
Apr 26, 6:01pm
slip slop and slap on some sunscreen , that will fix it just like swaping parts randomly. or wont it. a fact that its not fuel pressure is that it pulls right at high rpm low fuel pressure shows up as starvation under heavy load where the injectors run out of fuel to supply . poster 4 is correct i seen a lot of faulty new plugs correct testing is required on a scope you would see if a cilinder is not firing right.
mechnificent,
Apr 26, 7:10pm
Inspected the vacuum hoses ?
Poor spark or lean mix are the likely things. or a combination of the two. When it does it, is it very throttle dependent. if you back off just a little does it go away, or, once it starts missing do you have to back off a lot to get it to stop ? How intermittent ?Once it starts, does it do it on every hill for the rest of the day/week, or just till it stops at the top of the hill, and then on again on the next hill. if you see what I mean. Intermittently every few minutes, or every few days ?
dasfi,
Apr 26, 8:13pm
I would say throttle dependant, low revs, ie driving around 50ks ish, just happens for maybe a second or two, then will go away, may do it again within a couple of minutes or may not do it until another day, But no problem what so ever if your stomping it, took it for a good hot run and kept revs up a bit.
mechnificent,
Apr 26, 8:23pm
Electric. Is the plug gap right ? Are they the right heat and running clean ?
As Intrade says. A scope shows up irregular spark. small gap etc. If you haven't got one but.
I'd suggest closing the plug gap a bit and trying it, and/or opening it a bit if the closing did nothing. (it's cheap and simple)
A NEW set of plugs leads would be nice to try. Sometimes the spark gets through the lead ok, but it tries to jump to the head and get lost. It could be that your mates one were a bit "leaky" but his head was clean and didn't have rust/arc stain like your one. Your head might have rust/arc stains that cause a spark leak to the head easily.
mechnificent,
Apr 26, 8:31pm
In general. If you have got a good spark to the plugs. the plugs will fire reliably for way higher mileages, and way dirtier, and bigger gapped, than they are mean to. The guess would be that you haven't got a good spark getting to the plugs.
The rotor. Leave it on the shaft and with the cap out of the way you hold the HT lead from the coil about six mills from the rotors conductor while you cause a spark. If the rotor is good no spark should jump. If it's a bit humid or there is a surface conduction from dust and stuff you might get a thin weak spark you can hardly see. If it's rooted, there will be a definite spark. You could look for a weak spark getting lost through the rotor and into the shaft.
dasfi,
Apr 26, 8:37pm
Head is very clean, Am I going to get zapped trying this lol, I also have to add sometimes the miss feels quite deep, ie maybe more than 1 cylinder dropping out for a split second, has also died at idle twice but not very often
snoopy221,
Apr 26, 8:59pm
IGNITION-ALWAYS Consists of a Primary AND A Secondary. Points need cleaning BRA- Or your electronic transistor (Hermeticaly Sealed) might be suffering from age and mileage.
mechnificent,
Apr 26, 9:08pm
Ok Dasfi. Good description. several misses in a row.
As Snoopy says, the electronics could be getting dodgy.
Did you check the plug gaps when you got them. they often aren't correct.
Have you gone over the engine wiring loom making sure all the plugs seem tight ?
Have you get the trouble codes out of the computer ?
dasfi,
Apr 26, 9:12pm
Wiring loom is all fine and everything is plugged in and clean terminals, Nope I have never checked plug gaps on anything before, (never bothered) Have not tried to get fault codes, I have access to be able to do so if needed, although I wasn't sure if anything would show up as check engine light has not come up
snoopy221,
Apr 26, 9:22pm
Have not tried to get fault codes, I have access to be able to do so if needed, although I wasn't sure if anything would show up as check engine light has not come up
Depending on trans actually think crank/cam sensor correlation can drop em Code it- K
dasfi,
Apr 26, 9:32pm
You lost me there snoopy?
mechnificent,
Apr 27, 5:13am
He's saying there is a cam sensor and a cramk sensor and if the cam chain gets stretch in it the two readings get out of time and syuff things up. It generally sets a trouble code though as far as aI know. It's possivle though that if it isn't actually something that will cause a pollution problem, it may not make the light come on, even though it has set a code. The lights come on if there is something that can cause pollution. Cam/crcank timing varience may not be a direct cause of pollution. even though a missfire is. New cars detect misfire, some of the older ones didn't.
they dont have crank angle sensors, just cam angle sensors. Also are not prone to chain stretch.
dasfi,
Apr 27, 5:35pm
Been driving it around most the day today. Doing it very often while idling and driving around 50ks ish
intrade,
Apr 27, 7:11pm
i think i told you more then 1 time to buy the nissan consult plug and software for your nissan. http://www.nissandatascan.com/ this is the cheapest way you can learn and repair your car correctly Fuel trim data in closed loop is what every professional on this planet uses to start off with a drivabilty problem, on a unmodified! car.
poppy62,
Apr 27, 7:13pm
Son # 3 was driven mad (nearly) about 10 days ago. His 750i V12 was running like a proverbial sos, this after replacing plugs, leads dist/caps and rotors. After exploring every avenue he rang son #4 (Auto Sparky) who suggested replacing the new rotor with the original one (Bosche) and . Voila. Problem gone. New rotor was the problem.
dasfi,
Apr 27, 7:27pm
You sure did, was just giving more info, will be getting onto that this week
bigfatmat1,
Apr 28, 7:44am
the crank and cam sensor is inside dizzy all in one. Driven off cam so does has have it but could not get a correlation code as both driven from cam
rlr29,
Feb 20, 8:40pm
Not really, It sounds like it's still parking up your driveway.
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