Intermittent misfire

[GTO]

My 2700i started misfiring intermittently on Friday.
I checked the plugs and leads out on Saturday + changed the fuel filter.
Test drove all seemed to okay(I specificly checked it under load), I drove it on Sunday all fine.
Sunday afternoon I was pulling it into the garage and it started misfiring again.It went on for a minute or so and then cleared up.I then changed the plug leads, but when I started it up I noticed when it was idling it stumbled slightly for a second and then cleared up.I test drove it again and it was fine.
So Monday I had it in at my mechanic, they said they found some moisture under the plugs that connect onto the ignition coils, otherwise everything was okay.(It didnt register any codes either)

My wife phoned me today to say it was doing it again, just for a minute or so and then it was fine.
Any ideas?

[zepplin]

Loose nut behind the wheel????

[Mr_B]

Intermittent miss can have many origins... fouled/burnt/cracked spark plugs... faulty ign leads... faulty/clogged/dirty injector(s)... loose injector plug... bad earth on the fuel pump... bad engine earth... burnt fuse(saw this recently, not blown, just burnt on the legs)... dirty fuel filter... misbehaving fuel pressure regulator... faulty coil(s)... faulty EMU... dirty/clogged idle control valve... etc.

I know... intermittent misfires can be a real pain to solve!

[GTO]

Intermittent miss can have many origins... fouled/burnt/cracked spark plugs... faulty ign leads... faulty/clogged/dirty injector(s)... loose injector plug... bad earth on the fuel pump... bad engine earth... burnt fuse(saw this recently, not blown, just burnt on the legs)... dirty fuel filter... misbehaving fuel pressure regulator... faulty coil(s)... faulty EMU... dirty/clogged idle control valve... etc.

I know... intermittent misfires can be a real pain to solve!

And I want to go camping in the Cederberg this weekend! :evil:

[CasKru]

Intermittent miss can have many origins... fouled/burnt/cracked spark plugs... faulty ign leads... faulty/clogged/dirty injector(s)... loose injector plug... bad earth on the fuel pump... bad engine earth... burnt fuse(saw this recently, not blown, just burnt on the legs)... dirty fuel filter... misbehaving fuel pressure regulator... faulty coil(s)... faulty EMU... dirty/clogged idle control valve... etc.

I know... intermittent misfires can be a real pain to solve!

What he said

[george]

Hi Stephen.

Have a read over hear
http://www.hilux4x4.co.za/3rz-misfire/index.php

[GTO]

Hi Stephen.

Have a read over hear
http://www.hilux4x4.co.za/3rz-misfire/index.php

I replaced my plug leads and it didnt help.

As I said its intermittent also it doesnt happen at any specific rpm.

On the weekend i must have done 50km between misfires.

[Mud Dog]

It could even be a 'sticky' valve (try some "Valve Eeze" to see if it makes a difference), but it really sounds more like the problem is electrical and Bretton has pointed out all the obvious possibilities. Hope you get to the bottom of it!

[Mr_B]

Can you use valve easy on a fuel injected engine? IIRC it's not recommended... I think there's a formula specifically for injection systems... ?? May be wrong though...

I don't think the 3RZ has a distributor... but another misfire origin can be a crack distributor cap or burnt/worn rotor...

[pietpetoors]

Take the plug leads out at the coil end and spray both the lead and inside of the coil with spookpis. If they found water there, perhaps there are more. Those coils sit on the most stupid place, right above the fan belt. So when you drive through water the fanbelt sprays all the water on the coils.

Mine was doing the same but on;y at low PM and in the end it was the plug leads.

I think you still have water on the coils.

[kfxnando]

just couz the plugs are new does not mean that they are right!!

recently replaced plugs on the V6 couz, couz was getting a miss!!

after the new plugs, still had a miss!!
after much searching found one of the new pugs (NGK) where the ceramic insulator was actually loose!!
yes on a brand new plug!!!

replaced that plug with one of the old ones, and miss was gone, and gone ever since!!

so just couz the plugs and plug wires are new does not mean that one could not have a new faulty part!! sad!! :evil: :evil:

good luck!!

[GTO]

Isn't contact cleaner the better thing to use rather than penetrating oil like Q20?(mechanics used contact cleaner to clean the plugs on the coils )
Also they changed the plugs but I see they put in Champion RC9YC plugs in but when I cross reference them on the net they seem to a colder grade than the std NGK plug which is a BKR5EY?

I have plan a camping trip for this weekend in the Cederberg, now I am not sure if I should go?

I wash my engine bay out every few months but it must be at least 6 weeks since I last washed it so I don't understand how water could have got in and then taken so long before it caused a misfire(if it water causing the misfire)

My other worry is my fuel pump packed up 18 months ago and is this not the start of a repeat pump failure?

[Stef]

Isn't contact cleaner the better thing to use rather than penetrating oil like Q20?(mechanics used contact cleaner to clean the plugs on the coils )
Also they changed the plugs but I see they put in Champion RC9YC plugs in but when I cross reference them on the net they seem to a colder grade than the std NGK plug which is a BKR5EY?

I have plan a camping trip for this weekend in the Cederberg, now I am not sure if I should go?

I wash my engine bay out every few months but it must be at least 6 weeks since I last washed it so I don't understand how water could have got in and then taken so long before it caused a misfire(if it water causing the misfire)

My other worry is my fuel pump packed up 18 months ago and is this not the start of a repeat pump failure?

Was about to suggest the fuel pump...my CTi did the same thing years ago. Contact cleaner cleans contacts as the name suggests, but does not really displace moisture, blow the suspect areas with compressed air & then use Q20 or CRC or similar. And go back to the std plugs or at least the same grade. Hope that helps...

[GTO]

I was speaking to a family friend who also had random misfiring on a Mazda Etude, his problem was the contacts on the plugs that connect to the coils. He cleaned them with a small file and bent them slightly and it solved his problem.
My thinking is if there was a moisture in there and seems it has been in there maybe for a while it may have corroded the contacts slightly?
So I will give it a try tonight.
I just phoned my wife, no problems today and she has driven 60km or so today.

[Mud Dog]

Let's hope that poor contacts is all it was!

[GTO]

I had connectors on the coils off last night, but it is too difficult to get in there to clean the contacts with a file or sand paper etc(they look good?).So I sprayed some contact cleaner in the contacts, then Q20 and then I smeared some silicone grease around the outside of the plugs to keep any water out and plugged them back on.
So I am holding thumbs that this will help!

[GTO]

Update:
I decided to go to the Cederberg as the bakkie was behaving itself.
On the way up I had to stop at the Stop/Go roadworks on the N7 near Mooresburg,I switched off but when I restarted it started misfiring again and it misfired all the way to the farm where I camp.It was fine again the next day so it seems to only happen whern it is hot.
On the way back it was fine until Malmesbury where it began to misfire on and off, then all the time from the Engen 1 Stop.
Anyway I got it back to the mechanics, it was misfiring on No 2 cylinder, they have just let me know that they swopped No 1 and 2 injectors around, it ran fine for a while and then started to misfire on No 1.
So its either a faulty or dirty injector!

[george]

Glad they could find the problem Hope it is just a dirty injector

[pietpetoors]

Can one clean the injectors or do you have to replace them?

[GTO]

Can one clean the injectors or do you have to replace them?

I have been doing some research, it seems to be a common problem:

http://www.aa1car.com/library/2003/ic30336.htm" onclick="window.open(this.href);return false;

http://autos.yahoo.com/maintain/repairq ... 076_4.html" onclick="window.open(this.href);return false;

Take note what they say about no's 2 & 3 cylinders injectors being more prone to clogging!

[GTO]

Steves Auto clinic link on injector sevicing:

http://www.steves.co.za/Service_Injector_How.html" onclick="window.open(this.href);return false;

[GTO]

I found a place nearby that does injector cleaning:

http://capetown.gumtree.co.za/c-Cars-Ve ... Z157733323" onclick="window.open(this.href);return false;

[GTO]

I got the injectors through to KC Auto this morning, they tested them and said the flow rate was below spec for all 4 but they reckon other than that there is nothing wrong with the injectors.So I had them cleaned anyway at R 450 in total it was worth it seeing that they are out any way.So the flow rate is now in spec.
Mechanics refitted them test drove the bakkie and had it at Market Toyota on there Diagnosis scanner, everything checks out okay.
So now I will have to wait and see if the misfire returns?

[pietpetoors]

How long does it take them to test and clean?

I think my bakkie is starting to do the same. I thought it was the plug leads but it keeps on doing it. Mine is not that frequent yet, like once every 2 weeks.

[GTO]

How long does it take them to test and clean?

I think my bakkie is starting to do the same. I thought it was the plug leads but it keeps on doing it. Mine is not that frequent yet, like once every 2 weeks.

I dropped them off at 11am and had them back by 1pm.
The test takes about an hour.Cleaning another hour.

[Family_Dog]

Don't yet rule out the plug leads. I still had this with Hound Dog too, but the new plug leads cured the problem, that was over 6 months ago.


-F_D

[pietpetoors]

Eric, the problem is very wierd. I cleaned the plug leads as I described in my article mentioned earlier. Then it goes well. Then all of the sudden one day it starts again (about 2 weeks later) I then cleaned the leads again, it was fine again but two weeks later it happened again.

I then figured that perhaps there might be a lead broken and each time I clean it, the broken piece make contact again and that is why it is fine each time after I cleaned it. After the 6th time I got fed-up and bought a new set of Bougie Cords. It was running perfectly, starts easier and runs smoother on the open road and the engine purrs hapily on the open road.

Today I was carrying a heavy load from CPT and was driving at about 100km/h all the way. I guess the Green one is not used to such behavior. It was running smoothly but each time when I entered a town and pulled away at a stop street it had this very slight miss fire.

I think it definitely is better after the new leads, but there is still something wrong. After today's symptoms I also suspect something like a dirty or dripping injector. It does have 392,000km on the clock after all and according to the service istory the injectors has not been touched yet. So perhaps a good clean won't hurt.

[3RZ]

Stephen just for interest sake what was the measured flow rate for the injectors, the specs should be as below:

Injector pressure 265-304kpa 2.65-3.04Bar
resistance 13.4-14.2 ohm
injector volume 72-86cc/15 sec or 288 - 344 cc/min

Any idea what the OEM Denso injectors cost at Toyota ?

[pietpetoors]

Willem, sit you or stand you?

New injector for a 1999 Hilux 2.7 is ONLY................................

R 3027.16 EACH according to spares at Market Toyota in Athlone

[3RZ]

Jislaaik

You can replace the injectors with RCEngineering injectors SL9-0310 http://www.rceng.com/Saturated-Injector ... P36C6.aspx you just have to buy these converters as well http://www.rceng.com/Denso-Clip-Connector-P48C9.aspx to be able to connect the Denso connectors to the RC connectors or change the connectors on the current cables. The injectors are approximately R665 each and the cable converters about R130 each, just keep vat and import duties in mind, I had to pay R830 vat and import duty on the four 440cc injectors I bought for my supercharger project. If it was mine I would also prefer having a Unichip installed to fine tune the fuel delivery and timing and to be able to compensate for any changes as these injectors may be running a bit lean.

[GTO]

Willem, sit you or stand you?

New injector for a 1999 Hilux 2.7 is ONLY................................

R 3027.16 EACH according to spares at Market Toyota in Athlone

Scary!

I got my bakkie back this morning seemed to go fine, but when restarted it after 15min there was a slight misfire and then it was gone.
Could the injector thats was messing around test okay off the bakkie but break down under heat?

[GTO]

Stephen just for interest sake what was the measured flow rate for the injectors, the specs should be as below:

Injector pressure 265-304kpa 2.65-3.04Bar
resistance 13.4-14.2 ohm
injector volume 72-86cc/15 sec or 288 - 344 cc/min

Any idea what the OEM Denso injectors cost at Toyota ?

Willem the flow was in 60's(before cleaning) I can't remember exactly what the figures were?

[GTO]

I have just measured the resistance of 1, 2 and 3 injectors(4 is too difficult to get too)

The manual says 12 - 16 ohms at 20C(68F)

No 1 reads 15.9 ohms and so does 3.

No 2 I can't get a steady reading.

I get 28 then 36 then a 50 ohm reading.

So that injector must be faulty?

[GTO]

I did 2 more readings again last night.
1st reading:
1&3 15.7 ohms
2 16.3

2nd reading:
1&3 15.4
2 16.8

This morning(engine completely cold):
1&3 14.6
2 no reading(I can't seem to get a reading)

[pietpetoors]

Willem, any idea why there are two different injectors listed for the 3RZ?
Does anybody has the OEM or Bosch part number?

I am trying to source them abroad but have to make sure I get the correct ones.

[pietpetoors]

OK, sorry for asking before Googling, seems like the one is pre-facelift and the other post-facelift
Found on an Yank site (remember they came out there long before by us):
1995-Sept 2000 - 23250-75050
Oct 2000 - 2004 - 23250-75080

[pietpetoors]

Stephen, did you sort out your problems yet?

[GTO]

Yes I changed the faulty injector with a new one on Saturday, now all my injectors measure +/- the same resistance.
So hopefully my problem is solved!
Pieter the facelift has a different injector to the prefacelift hence the different part no.
I found a used parts dealer in Kuilsriver that had used prefacelift injectors for R 175 each, but when I looked at them they were way different from my face lifts injectors.

[pietpetoors]

How do you measure it?

[GTO]

Here is a link to the Tacoma 3rz manual for on vehicle inspection:

http://www.ncttora.com/fsm/2003/Repair_ ... je/ovi.pdf" onclick="window.open(this.href);return false;

Also removal instructions:

http://www.ncttora.com/fsm/2003/Repair_ ... e/remo.pdf" onclick="window.open(this.href);return false;

Installation:

http://www.ncttora.com/fsm/2003/Repair_ ... e/inst.pdf" onclick="window.open(this.href);return false;

[pietpetoors]

I was already looking at importing new injectors when i got this brain wave a week ago (it sometimes happens)

I replaced the fuel filter and air filter and so far for this week it never misfired again.

[Flubber82]

Good Afternoon Gents,

I see this is a very old topic, but, I have a 2003 S/C Toyota Hilux 2X4, and I had a crank pulley replaced some time ago, and the guy washed the engine, when I went to pick up my Toyota, it had a miss in it, I returned to the workshop and they used a compressor to blow the spark plugs, and everything was great again, after that the it returned some week or so later, and again I went back to them. They had the LDV for some time and checked for fault codes and everything but could not find something. The miss was gone, and for another month or so nothing, but it returned again intermittently, and now it is permanently missing, what can I have a look at?

I have never had an issue until the engine was washed. Now I sit with only 3 cylinders running, I believe it is Cylinder nr. 2, that is misfiring, because if I have the engine running and I take out the resister on the spark plug the engine doesn't make any change in idling, any other one makes the engine splutter when I take out the resistor lead.

What might be my problem? Do I need to replace the spark plugs and leads?

Thanks guys.

Johan Human

[pietpetoors]

Start with the cheepest item, replace the spark plugs. If still there replace the plug leads, if still there let somebody check out the injectors.

[Mud Dog]

Agree with Pieter.

[Family_Dog]

I had the same with a 2700i after someone got over-ambitious with a hi-pressure pump. Only thing that solved it was a replacement plug harness from Toyota. Guess some water got inside the cabling and leaked to earth, although I could not see any sparks at night when I checked.


-F_D