egine misfire

[timsx200]

can anyone help me,my sx200 1993 has developed a misfire between 2000 and 3000 rpm tha rest of the range is fine,when driven at this speed the misfire is greatly pernouced.also now the car does not tick over when you come to a stop.the car is still under warrenty and the garage i brought the car from have had it for 2 weeks and cannot solve the problem.i have had the car compression tested at another garage and the results were 160 160 130 100,could this be causing the problem,the garage where the car is at the moment say no,when the car did tick over it was very lumpy and caused the whole car to rock.i would be grateful of any help or instances of similar faults and how to fix it.

[goosegog]

Check the Lambda connections above the exhaust. Most S14s have melted insulation
I replaced my connector - I cut the wires then noticed 2 of the Lambda wires were white. I think I may have them mixed up as my car is now a little lumpy at idle and twitchy power at about 2-3000 and getting worse for some reason....

I'll investigate and keep you informed

Ferg

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[Daniel san]

Dunno where you are in England, but I'd suggest the following. Take the car away from whoever has it at the moment and get it to Abbey Motorsport 01883 732331, in Surrey. They will tell you what's wrong.

Personally, I think it sounds like it's running on 3 cylinders around that engine speed. Not quite sure why though, sorry.

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Dan
www.puresx.co.uk

'98 Saphire Blue S14 (manual of course)
Far too many mods to list here, it takes up far too much space and after being asked very nicely I've decided to shorten the sig (Is that a WOOHOO I hear??)
I, have NO SMELLY TREE, have no plans for a smelly tree and do not want a smelly tree, EVER!!!
Do not take offence to anything I say, even though I probably mean it. I am more than slightly mad, so just chill de feck oooot, ok!

[Stevecarter200]

If your car is a '93 then its an S13, not S14. Pop up headlights?

But anyway, it sounds like your valves are knackered. This is a known problem on the CA18DET engine where the valves/seats have worn allowing poor compression, dodgy tickover and poor off boost performance. Get your garage to check it again.



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Grampa Steve (aged 30 1/4)
Blue '89 S13, MANUAL, T28, HKS stuff, Pipercross.
280ish bhp, 13.77s @103mph Qutr http://www.300zx.co.uk/200sx/ubb/biggrin.gif
TC is for girlies http://www.300zx.co.uk/200sx/ubb/smile.gif
Poor as a church mouse thats had his stash of cheese stolen
Car disintegrating around me.
http://www.puresx.co.uk/smalls/fmic_4_small.jpg

[Mike_L60]

Some time ago I posted a topic asking if any one knew why my S14 seemed to have an occasional misfire at around 2200rpm. A few others reported similar symptoms but no explanations.

The misfire seemed to have been cured at a major service but it is becoming noticeable again. I've had a new lambada sensor (to cure poor petrol consumption), Spark plugs ie the obvious been done(?)

If the fuel mixture suddenly goes weak would that cause a misfire. Note. it only happens occasionally not continuously which make diagnosis dificult. I'm wondering if some component is worn/tired (air flow sensor, bleed valve/waste thingy(?),etc) and can't cope with conditions at this rev range. Seems to go okay otherwise.

A local garage/tuning specialist looked at it but could not find anything obviously wrong - I live with it now but would really like to cure it!

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Mike_L60
Red S14 95

[TomM]

Originally posted by Mike_L60:
I've had a new lambada sensor (to cure poor petrol consumption)


I take it this regulates the mixture... how does it all work? Is it possible to plumb a variable resistor or soemthing similar in, so you can adjust the mix and get kick-ass consumption for long hauls? Or would this just royally fcuk things up?!?

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Driving a Citroen AX 1.4D... mmm mmm!

[goosegog]

The Lambda sensor monitors exhaust gas and has an influence on fueling and possibly? ignition timing? It could in theory be tapped into to modify fueling but that's not the correct way to go about it and certainly should not be adjusted to the lean side to aid fuel economy as this can cause cylinder overheating and eventually engine damage!

I've just realised I haven't had my plugs out in a while! Everyone knows a mechainc's own car is badly maintained! I am religious about oil changes every 3000 mioles of course!

Ferg

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[Deano_s14]

My s14 has just started misfiring at about 2200rpm too. I had it on the rollers last weekend and it was fine at first but its just started like 'jumping' a bit around these revs. The guy who tuned it says it might need the timing adjusting again, I dont think he had the right equipment to do the timing ie. a big scary computer, cos he told me I could adjust it myself but I know for a fact I cant after reading the workshop manual. Going to take it to another garage who can do the timing and see if this cures it.
I'll post the results when I get chance to book it in to the garage hopefully soon.

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1995 S14, ND boost actuator, NGK cold plugs, K&N cone, Bailey DV26 Evo piston dump valve, CAI Boost gauge, 230bhp@15psi.

[TomM]

Originally posted by goosegog:
It could in theory be tapped into to modify fueling but that's not the correct way to go about it and certainly should not be adjusted to the lean side to aid fuel economy as this can cause cylinder overheating and eventually engine damage!


Right, so less fuel = overheating! http://300zx.co.uk/200sx/ubb/confused.gif

Why is this? Oh, and are there any rasonable ways to lower the fuel consumption of an s14?

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Driving a Citroen AX 1.4D... mmm mmm!

[goosegog]

I can't explain why a lean mixture burns hotter, sorry

I have found a great way to better fuel consumption - Move your seat back one notch or wear thinner soled shoes!

Ferg

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[geoff_s14]

Originally posted by goosegog:
I can't explain why a lean mixture burns hotter, sorry



Lean mixture burns hotter cause the intake charge itself makes a significant contrubution to the cooling of the combustion chamber, pistion crown and valves (which is one of the reasons why it is advantageous to cool the air/fuel mixture as much as possible before it enters the cylinder). The specific heat capacity of the mixture - the amount of heat energy it can 'absorb' per unit volume - is directly dependent on the proportion of fuel in the mixture. Basically, mixture with more fuel cools better than mixture with less fuel, cause it's wetter.

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Geoff
Emerald S14a

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

[Mike_L60]

Deano,

I will be very interested in the results. If it is the timing I'm interested to know how it can be out at 2200 and not through all the rev range. Unless the engine is more sensitive to conditions at 2200?

Do Nissan check the timing when they do a major service (I'm assuming it is a simple test for the plug-in diagnostic computers?)

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Mike_L60
Red S14 95

[Marcos]

Yeah thats why you see go-kart drivers putting their hand over the air intake at the end of a main straight, to keep the engine moist (oo-eh!) and cool it. otherwise it goes bang and you tend to end up with bits of crankcase in buried in your kidney!

[fireballjason]

I have just brought a s14 200sx i had a AA inspection the only fault was a missfire and lag at crusing speed.Nissan looked for the problem could not find the problem!!!.But happened to me twice this week.WE SHOULD ALL SEND EMAILS TO NISSAN OR LETTER`s SAME DAY ETC!!! AND GET THIS PROBLEM FIXED.Come on nissan how good are ha!!!

[Tom_S14]

Mine does this thing at 2200 revs too. Aint the timing, mine's spot bollock on. Can't see any anomolies in the fuelling either to be honest. I can hold it there, at 2200 revs and the mixture seems to be fine.
I've heard some people say to clean the AFM element, I tried this and it didn't do any good at all.
I'm beginning to wonder if it's a fault in the ECU map myself, it seems such a common problem.
hmmmm. spark plugs.. that reminds me http://300zx.co.uk/200sx/ubb/smile.gif

Tom

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1996 Blue/Green S14 (manual)
K&N cone filter
2.5" Tube-torque Cat Back Exhaust.
TechTom MDM-100
Race-Technology AP-22
http://tom.marshall.tripod.com

[Actual_Ben_Taylor]

Originally posted by timsx200:
can anyone help me,my sx200 1993 has developed a misfire between 2000 and 3000 rpm tha rest of the range is fine,when driven at this speed the misfire is greatly pernouced.also now the car does not tick over when you come to a stop.the car is still under warrenty and the garage i brought the car from have had it for 2 weeks and cannot solve the problem.i have had the car compression tested at another garage and the results were 160 160 130 100,could this be causing the problem,the garage where the car is at the moment say no,when the car did tick over it was very lumpy and caused the whole car to rock.i would be grateful of any help or instances of similar faults and how to fix it.

As already mentioned, it sounds like it could be the inlet valves. Supposed to be quite a common problem...

[Mike_L60]

The inlet valve problem has been identified on S13 models - does it look like the same problem is on the S14 engine. I have not noticed a rough tick-over, which is one of the symptoms.

I thought that the disk mapping might be wrong too - If you have your car chipped does this not alter the disk mapping? Have any chipped cars got this problem.

If it is the inlet valve what needs to be done to sort them out?

If it is the inlet valve it seems strange that it only shows at 2200 - unless performance is down over the entire rev range and I have not noticed.

Is there a way of asking Nissan technical questions (and getting a reply!)?



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Mike_L60
Red S14 95

[Tom_S14]

Am I right in saying everyone finds this problem worst in 5th gear off load ? Indicated speed about bang on 60mph ?
I drove my car last night, got it to do this misfire thing and went through all the parameters on my MDM100. Mixture was fine, the only thing was that the ignition is running at 43° at 2200 revs, but more like 36° at 2500 revs.
Could it be the ignition is just a bit too advanced on the map ?

Tom

[Mike_L60]

Tom,

Two things come to mind....(2 more than usual) http://300zx.co.uk/200sx/ubb/biggrin.gif

1)Can anything be done about this mapping?

2)This seems to be a feature that has developed as the engine puts on the miles (50K+).

So is some other factor(s) also playing a role here. ie inlet valves? Though my poor knowledge of engines struggles to find a relationship between valve wear and misfires.

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Mike_L60
Red S14 95

[Tom_S14]

My understanding isn't exactly rock solid either, but limitted as it is, I beleive the map is set to run about as advanced as they can get away with off load. I think the valve timing determines how advanced you can set the ignition timing... I think.
So it's possible that wear in the valve train, possibly the variable valve timing actuator or something might mean that 43° is just a bit too advanced if the valve timing goes out ?

Other thing I thought of, was it could be the camshaft position sensor. I've noticed that on idle, mine normally sits at 15° spot on, but sometimes it jumps around a bit, dropping to 10° and up to 17°.

I'm noticing increased amounts of misfire at low revs at the moment, I'm going to keep an eye on the timing readings so see if they get much worse. If so I might replace the camshaft position sensor I reckon. Only thing that troubles me is it's just a slotted disc with an IR led on one side and a photodiode on the other. Not much to wear out. Maybe the dodgy signals from the sensor are indicative of mechanical wear ?

Tom

[Darksurfer]

I am picking my 200 back up from Nissan in the morn after my alarm fault.

I too have a mis-fire but I just put that down to the plugs and was going to change them.
They have had my 200 on the diag machine and they have said
"it might be an ignition coil failing"
"we recommend you replace all four as they start to fail together"
295 + vat thank you...

I think this is cr http://300zx.co.uk/200sx/ubb/smile.gifp !!!

A) "It might be" I am sure the diag machine could be more specific, plugs, coil or signal from the CPU.
B) What is there to go wrong with an ignition coil?? its just wire wrapped around a magnet !

What do you guys think?

295+vat on a 'may be' from the Nissan experts?

[This message has been edited by Darksurfer (edited 25-10-2001).]

[Bean]

Originally posted by Deano_s14:
My s14 has just started misfiring at about 2200rpm too. I had it on the rollers last weekend and it was fine at first but its just started like 'jumping' a bit around these revs. The guy who tuned it says it might need the timing adjusting again, I dont think he had the right equipment to do the timing ie. a big scary computer, cos he told me I could adjust it myself but I know for a fact I cant after reading the workshop manual. Going to take it to another garage who can do the timing and see if this cures it.
I'll post the results when I get chance to book it in to the garage hopefully soon.




My car has always had a flat spot at 2200rpm but it didn't seem to effect it too badly.

However my car seems to be getting worse at 2000-3000rpm recently, it judders and feels very lumpy.

It's currently running like a sack of ****, just in time for the RR, typical!!! http://300zx.co.uk/200sx/ubb/frown.gif http://300zx.co.uk/200sx/ubb/frown.gif http://300zx.co.uk/200sx/ubb/frown.gif

At least I'll have new tyres and zorst fitted for the RR. http://300zx.co.uk/200sx/ubb/smile.gif


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95N/S14
(Blitz Nur-R in its box)
http://300zx.co.uk/200sx/rides/beans14/nissan3m_180_135.jpg

Linux/Solaris Trainee Guru

[Tom_S14]

HT Coils do go, I had one pack in on my last car, but I'm not convinced they break gradually ! I'd guess it would normally be due to overheating causing the coil to burn out at some point. Maybe you could measure the resistance of each primary winding to see if they're the same ?

Looking in the service manual, there are a number of things to check for "hunting" or eratic idle, although I'm not sure those descriptions fit ?

Check the EGR valve for sticking.
Do power balance test (disconnect each fuel injector in turn. Any cylinder which does not produce a momentary drop in engine speed could be dodgy ht coil/injector. But surely it would be obvious if the engine was running on 3 cylinders !?

I think I'll replace my spark plugs first http://300zx.co.uk/200sx/ubb/smile.gif

Tom

[David_S14]

Have a read through http://www.se-r.net/engine/troubleshooting_guide/tuneup.html and http://www.se-r.net/engine/troubleshooting_guide/info.html . I had a hesitation/lumpy running problem which went away after I cleaned out the EGR control system as per the guide.

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David
"Purplish Blue Pearl" 1995 S14
K&N,Mongoose,HKS Fuel pump, Blitz FATT-S,Racelogic Adj. Traction Control & Tree.

[Bean]

Originally posted by David_S14:
Have a read through http://www.se-r.net/engine/troubleshooting_guide/tuneup.html and http://www.se-r.net/engine/troubleshooting_guide/info.html . I had a hesitation/lumpy running problem which went away after I cleaned out the EGR control system as per the guide.



Excellent, I think I'll have a look at the EGR tomorrow. NO point turning up to the RR with a badly running engine, kind of defeats the point!!!!!



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95N/S14
(Blitz Nur-R in its box)
http://300zx.co.uk/200sx/rides/beans14/nissan3m_180_135.jpg

Linux/Solaris Trainee Guru

[Tom_S14]

Yep, Cheers David !
Sounds like quite an easy job to do http://300zx.co.uk/200sx/ubb/smile.gif

Tom