Tb-42e lumpy under accleration

[Pezzer]

I have a slight miss whilst at tick over, when I checked the leads to the dizzy I had a weak spark at No 3 I cleaned the inside of the cap and the rotor tip now all have a strong spark. Plugs and leads are all good where should I look next? Timing is set to 10%.

[threedogs]

Is it dual fuel ???
Check under bonnet in a dark place it might look like Luna Park at night time ,sparks everywhere.
You should be able to hear them cracking as well

[Pezzer]

Yes it is dual fuel, would it be TPS I have no idea where it is located on a n Efi motor??

[taslucas]

I don't reckon a faulty TPS will give it a miss at idle. Id be looking at your leads first. Do as mentioned above; lift the bonnet and look at the leads at night (the darker the better) with the engine running. If you see any tiny sparks then it's an indication that the leads are braking down or the distributor cap is faulty

[Pezzer]

Okay I will get on it tonight, never had that suggested to me thought you were having a lend ,LOL.

[taslucas]

Lol, nah it's a good trick. I was suffering similar problems with mine so I looked at it at night and found sparks all along my leads. Leads are cheap to replace but often over looked

[Pezzer]

Okay just checked in the dark, not a random spark anywhere.

[Clunk]

lumpy on both fuels?

[Pezzer]

Slightly on gas but mainly on fuel.

[taslucas]

Does it clear out under acceleration? Ie: rev harder = misses less??

Have you got:
Good plugs?
Do the efi dissy have a rotor button? If so, is it good?
Is there any air leaks in either; between the carby and manifold, intake manifold to head, leaks in any vacuum hoses (including any lines to air con idle control etc).

[Pezzer]

Yes it clears under acceleration mainly bad between 1000/1500 rpm, rotor button is good, no air leaks as far as I am aware. I will check plugs today just awkward to get to with LPG fitted.

[threedogs]

Is your condenser freezing over at all ??
Also squirt some WD40 inside the dizzy and on top.
You may have condensation under the leads on the dizzy
You could remove one at a time to check, make sure they got back in correct position
and push them all the way in

[Pezzer]

Yes I checked this, I believe now possibly dirty injectors, I crimp the return fuel line and it rev'd which to me shows a lean running motor pressures seem good vacuum on fuel regulator strong with no signs of petrol seepage. crimped and blipped it a few times now lumpiness is a slight random miss. Idle is 900 as this seem the best for lpg and petrol to load up and pull away.

[Pezzer]

Just went for a quick run on the h/way and every time I accelerate it misses.

[threedogs]

You could/may still have cracks or splits in the vacuum side of things be it only little

[GQ TANK]

have you replaced the dizzy cap - could be arking

[threedogs]

How new is rotor button X 2 on the Dizzy cap

[Pezzer]

No I have not renewed either just a good clean up and I have a terrific spark so I thought that this was a good sign. No arcing at night visible.

[Parksy]

Could be your injectors. Have you tried an injector cleaner? I found fuel doctor actually works, bought at super
Cheap. Have you checked fuel rail pressure? Should be 40psi. When I bought my patrol it measured about 32 psi. Changed the fuel pump and it jumped back to 40psi and made a world of difference.

Edit: forgot to add, if you have a vacuum leak, an obvious sign is a "putt putt" sound at the exhaust.

[Pezzer]

No vacuum leaks, I will check fuel pressure and get some fuel doctor. THANKS FOR THE HELP EVERYONE.

[Robo]

I ran fuel doctor stuff, and after 4 attempts I threw it in the bin.
97 efi 1.8 ltr lancer normally getting 7.8 ltr per 100k.
put additive in tank as described that jumped to 10 lt per 100 each time.
that is while the stuff was in the tank, next tank returned to 7.8 as usual.
car wasn't suffering any problems I simply treat last tank before an oil change.
translated 4x treatments for 20 000klm.

I heard (mates Dad) of a cleaner product actually turning oil to clag clue in a diesel GU some yrs back.
but "Barry" actually put the stuff in each and every consecutive tank.
"not as described Barry".
It destroyed the mtr.

dual fuel is a real problem to tune.
electrical system needs to be 101% top condition.
cap rotor leads and plugs don't skimp on quality.

Recently replaced plugs with Y electrode as it was all I could get.
waste of time my system hates em, it missus as you describe in your problem.
I use morreys in petrol tank occasionally 3/4 strength and run it in dripper system full time for the gas/petrol.
find it helps keep system cleaner.

also check around injectors with a little light oil see if injector seals are leaking.
cleaners only really remove small amounts of garbage,that's been my experience.
removing em and proper clean and new seals if needed.
can be cleaned on car by special equipment but never done that personally.

but first get electrical system working 101% before you start looking at other systems.
x2 dark and looking for wayward sparks

[happygu]

I am not the expert on the Petrol 4.2, as my last Dual Fuel vehicle was the L28.... but

It could be a worn Distributor Advance Mechanism, Crank Angle Sensor, Ballast Resistor......

Give these three things a little look at.

Mic

[Pezzer]

ok will check these tomorrow.

[Bigrig]

Wow ... how many contradicting responses can you get ....

If I'm not deleted/banned by the time you read this, PM me and I'll tel you what the issue is ...

Other than that; search my old threads on dual fuel issues with TB42's ... you're problem is pretty easy to isolate with the right advice ... as opposed to what you've received so far ...

[davo94]

Ok guys the bloke is asking about an efi engine.. so no ballast resistor no carby no points.....

Please read before posting dribble about what your mate may have told you....

I would check fuel pressure, compression as a bare minimum to start with before anything.

Clearly someone saying it could be the tps is a stab in the dark and an uneducated one at that. Check your service manual for the correct resistance readings if your unsure. But KISS (keep it simple stupid) 1st.


Seems a lack of mechanical knowlage on this forum in regaurds to anything not diesel. That's my rant over.

[davo94]

Wow ... how many contradicting responses can you get ....

If I'm not deleted/banned by the time you read this, PM me and I'll tel you what the issue is ...

Other than that; search my old threads on dual fuel issues with TB42's ... you're problem is pretty easy to isolate with the right advice ... as opposed to what you've received so far ...

This is the only post so far with any idea how to fix this blokes problem. .

[Parksy]

This is the only post so far with any idea how to fix this blokes problem. .

Mate, you merely gave the same advice I did earlier on then claim that no one else is giving good enough advice? Ffs, what is wrong with people just having a go?

[Drewboyaus]

Mate, you merely gave the same advice I did earlier on then claim that no one else is giving good enough advice? Ffs, what is wrong with people just having a go?

Don't worry about it Parksy. The bloke is an egomaniac who seems to have some sort of chip on his shoulder at the moment.......



Tip tip tip......tap tap tap....

[davo94]

Don't worry about it Parksy. The bloke is an egomaniac who seems to have some sort of chip on his shoulder at the moment.......



Tip tip tip......tap tap tap....

I see your staying on topic and helping this bloke with his problem.

Id say this forum is mainly populated but the nerds that were picked on at school for been know it alls.. as for being an egomaniac is that all you have got to contribute to this post??? Clearly your not a mechanic and have f-all experance.

[davo94]

Could be your injectors. Have you tried an injector cleaner? I found fuel doctor actually works, bought at super
Cheap. Have you checked fuel rail pressure? Should be 40psi. When I bought my patrol it measured about 32 psi. Changed the fuel pump and it jumped back to 40psi and made a world of difference.

Edit: forgot to add, if you have a vacuum leak, an obvious sign is a "putt putt" sound at the exhaust.

No sing of a compression test here.. as for the put put out the exhaust you may be refering to a way people check valve clearance. Fuel doc yep that will fix its as its having the samw issue on gas and fuel...

[taslucas]

Ok guys the bloke is asking about an efi engine.. so no ballast resistor no carby no points.....

No one has mentioned any of those things?



Please read before posting dribble about what your mate may have told you....

I would check fuel pressure, compression as a bare minimum to start with before anything.

Ok, at least the last part of that was constructive, but it is missing on both lpg AND petrol. So as you said above: Please read before posting.....


Clearly someone saying it could be the tps is a stab in the dark and an uneducated one at that. Check your service manual for the correct resistance readings if your unsure. But KISS (keep it simple stupid) 1st.

It was the OP that mentioned the TPS and the only response to that was mine saying that it would not be the problem


Seems a lack of mechanical knowlage on this forum in regaurds to anything not diesel. That's my rant over.
Diesles are a straight forward engine. Petrols and more importantly dual fuels are more complicated. There are quite a lot of simple things that can be the cause of a slight miss and it is hard to diagnose straight away over the internet without asking a lot of questions.
I have had the same (or similar, its hard to tell without seeing the vehicle) problem twice with my dual fuel TB42 (carby). The first time it was leads, the second time it was a vacuum leak affecting the vacuum advance.

[taslucas]

Wow ... how many contradicting responses can you get ....

If I'm not deleted/banned by the time you read this, PM me and I'll tel you what the issue is ...

Other than that; search my old threads on dual fuel issues with TB42's ... you're problem is pretty easy to isolate with the right advice ... as opposed to what you've received so far ...

Hey scotty, firstly welcome back! One way to keep threads on track with the right advice would be to post it here instead of over PM? You know that those symptoms could be caused be a few different problems but if you already know exactly what it is then please post here for the benefit of others and also so that those of us that have know idea may learn a little more.
Contradicting responses are sometimes more like trial and error...... "have you checked this?" "yes its fine", "ok then, what about that?" "yes that seems good as well"........etc

[taslucas]

Lets please keep this thread back on topic, refrain from cr@p slinging and help our fellow patroller get his beast running the best it can:)

So if you definately know whats wrong then please post away and help this guy

[threedogs]

I've owned a dual fuel 4x4 for over 400,000k and long distance diagnostics is not my forte.
Agree with the electrics need to be 110% no question about it , with my BIL and son being Auto lects and sharing a factory with
a gas conversion mob. I used to see it all the time, That's why I push for the use of "Y" instead of "T" pieces on the water side of gas.
Could even have an air lock in the converter. again lots of questions need to be asked as its a process of elimination, that gas person
said that 99% of gas problems are electrical

[taslucas]

lumpy on both fuels?


Slightly on gas but mainly on fuel.


I've owned a dual fuel 4x4 for over 400,000k and long distance diagnostics is not my forte.
Agree with the electrics need to be 110% no question about it , with my BIL and son being Auto lects and sharing a factory with
a gas conversion mob. I used to see it all the time, That's why I push for the use of "Y" instead of "T" pieces on the water side of gas.
Could even have an air lock in the converter. again lots of questions need to be asked as its a process of elimination, that gas person
said that 99% of gas problems are electrical

Its missing on both petrol and lpg.

[threedogs]

That's my point whats common to both ,,,,,,,,electrics
Do we know where timing is set to ??

[Drewboyaus]

I see your staying on topic and helping this bloke with his problem.

Id say this forum is mainly populated but the nerds that were picked on at school for been know it alls.. as for being an egomaniac is that all you have got to contribute to this post??? Clearly your not a mechanic and have f-all experance.


Never said I was a mechanic chief. Just a curious observer and Patrol enthusiast answering a member who was clearly miffed by someone else's curmudgeonly attitude.

Must be a relation.........


Tip tip tip......tap tap tap....

[taslucas]

I have a slight miss whilst at tick over, when I checked the leads to the dizzy I had a weak spark at No 3 I cleaned the inside of the cap and the rotor tip now all have a strong spark. Plugs and leads are all good where should I look next? Timing is set to 10%.


That's my point whats common to both ,,,,,,,,electrics
Do we know where timing is set to ??

Lol, it's all there 3d

[davo94]

Ignition with overlooking the mechanical aspects of it?? It cold be down on compression. So do a comp test and a cylinder leakage test to confirm that it is not related to an internal fault.

[Pezzer]

Hey guys I really appreciate the help, that's one reason I joined this forum also to to add any experience that I can offer to assist other members, its how we keep our vehicles on the road without going to big brother all the time emptying our wallets.
The Maverick has gone back to the LPG workshop for a tune and he is going to check a few things, the miss is definitely more apparent on fuel than on Lpg but its there. Reading other threads spiral leads seem to be the go with a cooler plug, the head has had lots of work done to it and mechanically all compressions are spot on. When I checked the vacuum lines I did not detect any leaks and no stray arcing was seen or heard at night, the vacuum operated fuel regulator shows no signs of seepage either. It does take 3 turns of the key to fire up, system always selects fuel to starts on.

[Pezzer]

I concur always a Y not a T.

[davo94]

Hey guys I really appreciate the help, that's one reason I joined this forum also to to add any experience that I can offer to assist other members, its how we keep our vehicles on the road without going to big brother all the time emptying our wallets.
The Maverick has gone back to the LPG workshop for a tune and he is going to check a few things, the miss is definitely more apparent on fuel than on Lpg but its there. Reading other threads spiral leads seem to be the go with a cooler plug, the head has had lots of work done to it and mechanically all compressions are spot on. When I checked the vacuum lines I did not detect any leaks and no stray arcing was seen or heard at night, the vacuum operated fuel regulator shows no signs of seepage either. It does take 3 turns of the key to fire up, system always selects fuel to starts on.

1-Confirm fuel pressure
2-confirm fuel supply rate of flow

Does it start better if you prime the High pressure pump by cycling the reds on and off 3 or so times?

Does it start better when warm?

[Pezzer]

When warm no problem.

[taslucas]

1-Confirm fuel pressure
2-confirm fuel supply rate of flow

Does it start better if you prime the High pressure pump by cycling the reds on and off 3 or so times?

Does it start better when warm?

Pezzer said that the miss goes away with higher revs. Would a fuel supply or pressure issue do this or would it get worse the higher the revs?

How old are the plugs pezzer?

[Pezzer]

Not sure on the plugs, but we have done 3000kms on them, I reckon on around 5000kms

[davo94]

Pezzer said that the miss goes away with higher revs. Would a fuel supply or pressure issue do this or would it get worse the higher the revs?

How old are the plugs pezzer?

Depends if they run a dual speed fuel controler. You could also try and crimp the return line to run full line pressure and isolate the pressure reg (just for testing)

[taslucas]

Depends if they run a dual speed fuel controler. You could also try and crimp the return line to run full line pressure and isolate the pressure reg (just for testing)
Is this what pezzer has done below?


Yes I checked this, I believe now possibly dirty injectors, I crimp the return fuel line and it rev'd which to me shows a lean running motor pressures seem good vacuum on fuel regulator strong with no signs of petrol seepage. crimped and blipped it a few times now lumpiness is a slight random miss. Idle is 900 as this seem the best for lpg and petrol to load up and pull away.

[davo94]

Is this what pezzer has done below?

Seems he has.

Get a compression test to rule out the mechanical aspect then we can isolate it to the ignition system.

[Pezzer]

yes I crimped the return line and also removed the vacuum line to the regulator, no noticeable difference.

[Robo]

What brand of plugs and gap are you running.
Lpg likes a smaller gap around .2 less.
and more advance on the timing 12-15 deg not 10 as per petrol specs.
go to advanced and petrol runs out of puff at a much lower speed and ping/det becomes a problem.

My experience found NGK iridium plugs work better and last longer.
Design is a much finer electrode to concentrate the spark,
also helps expose the spark better to the mixture, m2c.
but 3 x times the price.

Have read some where, maybe this forum.
LPG = NGK plugs, more reliable.
quality or something
I'm sold on em.

[Pezzer]

Okay still with Gasman, so far changed all plugs, found a broken hose after the air flow sensor and replaced cleaned Maf sensor got a rise in revs straight away. So now we have an engine running rich that the computer believes is lean.

[Pezzer]

Latest update loose fitting injector plugs.

[Pezzer]

Injector plugs sorted still a dam miss on both LPG AND PETROL replacing leads, fingers crossed.

[Bob]

Okay still with Gasman, so far changed all plugs, found a broken hose after the air flow sensor and replaced cleaned Maf sensor got a rise in revs straight away. So now we have an engine running rich that the computer believes is lean.

Disconnect your Battery for an hour to reset your ECU

[Robo]

a stuffed O2 sensor can rich-en an engine.
humm dosent explain lpg does it !

[Pezzer]

the sensor was stuffed but replaced so all petrol probs have gone, just a miss on both fuels. To top that my Rodeo has done an alternator so I cannot go to the workshop to check whats going on.

[Robo]

So It must be electrical then.
And this problem is not unique to just efi either, carby can do the same.
so you may rule out dizzy but the cap still suspect! ,
read here only use gen caps, less troubles.

[Pezzer]

Okay took it for a run today hard to start first up, and was shuddering I then went onto the Hway and it started missing then started pinging (only drove on petrol). The Lpg guy has a concern that the oxygen sensor location in the extractors only collects from the front 3 exhausts and not all 6.

[Pezzer]

Sorry forgot to add, whilst on the highway when coming off the throttle and going back on it, the drive take up was quite aggressive.

[Parksy]

Pull the dissy cap off, pull the rotor off and there's a cover with a couple of screws on it. Underneath it is a thin disk with 360 notches in it. Make sure this disk is immaculate. If there's traces of dirt or water you might have to pull the entire contents out and clean the optical pickup sensor.

[Pezzer]

okay Parksy will check it out.

[Robo]

Feel for ya Bro,
there is nothing more frustrating, when this then that with little result.
and a truck load of $$.

seems it's not your problem , maybe worth a mention anyway, ya never know !.
My sons GQ tb ,also lpg, has a Genuine Nissan dizzy cap and it runs as smooth as a baby's bum,
people have commented how well it runs and starts.
tuned by me 12 mths ago, and I ask regularly how it's going, "still good" .
there maybe something to Gen product ver's aftermarket.

Ver's Mine has a slightest of miss,cant seem to tune out.
might talk him into swapping parts to compare.
will post up results afterwards.
Hope ya get it sorted soon.

[Pezzer]

Yes its a bitch as its stopping us from using the boat in this great weather.

[Robo]

Have had a set of the top dollar bosch lpg compatable ign leads fail within about a year.
running coil wound at the moment seem ok

[GQ TANK]

Just a thought - in let manifold gasket leak similar to this thread

TB42 running on 4 cylinders?

[Parksy]

Just a thought - in let manifold gasket leak similar to this thread

TB42 running on 4 cylinders?

I thought the same thing too but pezzer has only just recently swapped from a carby setup to an efi setup.

[Pezzer]

Yes definitely no leaks, still have original dizzy cap and rotor button.

[Robo]

Just a thought - in let manifold gasket leak similar to this thread

TB42 running on 4 cylinders?

also had same thought, I also have new gaskets, and a slight miss and guess/ruled it out.

[Bluecrab]

G,day, I gota 4.5 EFI petrol.
Had a miss at idle even after service, plugs, leads etc.
Got my tappets adjusted next major logbook service.
Rough idle/miss is gone?
Worked for mine, Maybe try that??
Daz

[Pezzer]

The coil is being checked over at the moment so hopefully waiting for a call.

[Pezzer]

I have pulled the Maverick from the Gas shop and am now having our mechanic check it over as now its quite bad missing across a few cylinders and stalled 2 times whilst pulling away on a hill.
No leaks
new leads
new plugs
new oxy sensor
cleaned Map sensor
cleaned in dizzy under plate
cleaned rotor button
cleaned dizzy cap
Timing set 10 degrees
Fuel injector plugs all checked and refitted securely.

[mudnut]

What was the compression reading on all cylinders? Another component that is common to both fuels is the changeover switch. Check that the wiring and connectors are crimped tight. You could bypass it to eliminate that the internal contacts aren't loose.

[Pezzer]

Ignition died found the coil to be the culprit, fitted new coil and started straight away still missing and hunting at idle on both fuels.

[Pezzer]

compressions all around 150. dual fuel switching all good.

[mudnut]

Clutching at straws now, but, next component common to both fuels is the carby. Running gas, can dry out the seals and such inside it and cause trouble can't it?

[Pezzer]

It is fuel injected.

[mudnut]

Yeah, I forgot. sorry. Haa ha. Its such a common problem with gas. Thinking cap back on... You've cleaned the dissy. Are to able to swap it with someone elses, just to eliminate it entirely? As years ago my falcon had an intermittent miss, and I found it had tracked a long some almost invisible fine cracks.

[Pezzer]

Done that no difference.

[mudnut]

I am out of Ideas, sorry, Pezzer. I have owned two efi vehicles, and they either ran really well, or not at all.

[Parksy]

Did you replace the collector gasket when you had it all apart? Ie split the big intake plenum apart and replace the gasket? Is it possible you've hooked the vacuum lines up incorrectly? Does the air regulator on the bottom of the plenum appear to have any leaks? Have you cleaned the aac valve assembly on the back of the plenum?

[Pezzer]

Everything was on the bench throughly cleaned or replaced, passed the miss it runs like a sports car it hammers along.

[Robo]

Everything was on the bench throughly cleaned or replaced, passed the miss it runs like a sports car it hammers along.

Good news at-last.
Nice to hear it's sorted.
So what was the cause you, he recons ????

[Pezzer]

It runs well once you pass the point of the missing, still runs like s@$# between 1800/2100 rpm.

[Parksy]

Have heard of the temp sensor under the thermostat causing engine running issues. Do you know when it was last replaced?

[Robo]

Everything was on the bench throughly cleaned or replaced, passed the miss it runs like a sports car it hammers along.

Ok so once the engine revs passed the miss it's good.
You sound like you have a very similar problem as I do.
First I replaced the standard type spark plugs with Iridium plugs 1 range colder of course.
that made a big difference to idle problem.
Mind you I've tuned sons car perfectly on std type plugs.
Don't think plugs are the real problem, but something that is wanting as an connected underlying issue.
Currently looking at coil feed voltage.
remember reading that can be an issue.
maybe see this, may give you some ideas.
voltage.http://www.nissanpatrol.com.au/forums/showthread.php?23147-Re-wire-tb42-coil-power

[Pezzer]

Well our regular mechanic took it for a run today and without hesitation he said its a lean mixture seems electric symptoms but definitely lean mixture so out with injectors tomorrow. Fitted a new coil yesterday made the starting a lot better 1st turn and vrrrooooom.

[Parksy]

Does it have a miss on LPG also? If it does then cleaning the injectors isn't going to fix your issue. Have you replaced the coolant temp sensor? Sounds insignificant, but when one of these gives up the ghost, it will wreak havoc on the electricals.

[Pezzer]

The lpg is lean but we know that and will be sorted Friday coolant sensor is good its been tested, although not sure of the thermostat.

[Robo]

Faulty o2 sensor maybe?.

[Pezzer]

Sensor is new, injectors being removed cleaned and checked.

[Robo]

Might just pay to go around all the chassie earth connections and clean em up.
possibly even add an extra earth strap back to battery from a good solid spot like starter motor Mt bolt.
not necessarily a fix, but a smoother engine is usually the result.

[Pezzer]

It appears there is corrosion in the fuel injectors, fuel injector expert tried a standard clean but too heavily contaminated, so he has taken them away for a more intense work over. Reason for this donor vehicle running old fuel from standing around.

[davo94]

Possibily cheeper to replace the injectors in the long run. After water ingress the fuel system will never be the same until you replace injectors and high pressure pump.

[Parksy]

Hey pezzer, check these out.
http://www.fuelinjector.citymaker.com/catalog/item/5426601/5376382.htm
Might be cheaper than getting them cleaned. I've bought off them before, highly recommended.

Edit, for your information, the tb42e injector part number is JS21-1. I think the oem number is 16600-86G00. If you search the Internet, you can come across some great deals. Don't bother buying new ones off eBay or from nissan. They are expensive!

[Pezzer]

Cheers Parksy, see what happens tomorrow.

[Robo]

Hey pezzer, check these out.
http://www.fuelinjector.citymaker.com/catalog/item/5426601/5376382.htm
Might be cheaper than getting them cleaned. I've bought off them before, highly recommended.

Edit, for your information, the tb42e injector part number is JS21-1. I think the oem number is 16600-86G00. If you search the Internet, you can come across some great deals. Don't bother buying new ones off eBay or from nissan. They are expensive!

Thanks Parsky,
They have alot of useful info on their site worth looking around it.

[Pezzer]

Miss fife now gone but running lean checked fuel pressure all good but delivery of fuel is low, new pump to be fitted.

[davo94]

Did you end up with new injectors?

[Pezzer]

No the specialist said apart from some stubborn crap they were not that old and that they were firing perfectly. However there was flow issue so on pulling the fuel pump out we found some debris had gone through a split in the strainer and damaged the pump.

[Pezzer]

Finally car all sorted all the above inclusive of a faulty MAF sensor, so much torque now it lifts the front wheels on take off. Hopefully a good weekend for putting the boat in the water.

[Parksy]

Happy days pezzer! Glad you got it sorted.

[taslucas]

Happy days pezzer! Glad you got it sorted.

Yeah x2 in that mate, happy days:-)