Can someone PLEASE clear this up for me!!!!!!

OK.....I am having the rough idle problem with my 2003 tacoma 2.4 L automatic. In the 2003 service manual located here: http://misc.mmdsi.net/tacoma/tacoma-manual/ on page SS-30 it tells me the spark plug gap should (.043), but on page IG-2 in the service manual it tells me to gap the plugs to (0.31). I know this has been hashed over in the past. When I recently replaced my plugs I gapped them to 0.43 and the idle got rougher! DOES ANYONE KNOW THE PROPER GAP! :) Thanks

Mike

http://sparkplugs.com/results_app.asp?productTypeID=1&AAIA=1418431

Different plug types/brands have different gaps. Move your cursor over the product name and check the descriptions. The Denso Double Platinum has a 0.032" gap. Most of the others (including the NGK Double Platinum) have a 0.044" gap. Maybe you bought a plug that needed a 0.032" gap and installed a 0.044" gap.

Thanks Brian, I bought a stock plug K16R–U11, the same one that was in the truck when I bought it brand new. Read this:

Recommended spark plug:
DENSO made K16R–U11
NGK made BKR5EYA–U
(e) Adjust the electrod gap.
Carefully bend the outer electrode to obtain the correct
electrode gap.
Correct electrode gap: 0.8 mm (0.031 in.)
(f) Using a 16 mm plug wrench, reinstall the 4 spark plug.

AND THIS:

SS–30
SERVICE SPECIFICATIONS – IGNITION (2RZ–FE, 3RZ–FE)
Author: Date: 198
2003 TOYOTA TACOMA (RM1002U)
IGNITION (2RZ–FE, 3RZ–FE)
SERVICE DATA
Spark plug Recommended spark plug DENSO made
Recommended spark plug NGK made
Correct electrode gap
K16R–U11
BKR5EYA–U
1.1 mm (0.043 in.)
Camshaft
position
sensor
Resistance at cold
at hot
835 – 1,400 W
1,060 – 1,645 W
Crankshaft
position
sensor
Resistance at cold NE+ – NE–
at hot NE+ – NE–
1,630 – 2,740 W
2,065 – 3,225 W


The above texts are both out of the 2003 service manual!


Mike

If the plugs you installed run bad at 0.043", I think it's obvious that they need to be gapped at the other specification. In reality, I don't adjust the gaps on my plugs. I just install them as obtained unless there is an obvious plug that is different from the others. Many times, the plugs have electrode configurations that are very difficult to gap correctly. Those are best left alone.

Mike, let us know what happens when you close the plug gaps. I remember your early discussion on the plug gaps and didn't realize at that time the gap depends on which plug is installed. I don't recall ever seeing gaps determined by the type plug installed, usually the gap is specified for the car/truck and is not dependent on the spark plug. I hope it solves your problem, but I wonder why the big difference? I'm out of ideas but the problem interests me because I have a 04 that has the same engine. I prefer NGK plugs over Denso and will choose the NGK when I can.

Clifton

Let me preface this with stating that I ALWAYS buy plugs from the dealership! I decided to purchase 4 new plugs again and check them right off the bat to see what the Denso plug for my truck is gapped to coming from the dealership. All 4 plugs were gapped to (0.037) right out of the box. Remember, both the gaps we are talking about in the maintenance manual are (0.031) and (0.043) so it seemed kind of odd that these plugs had a totally different gap setting. I decided to install them just as they are and see what kind of performance I will get. I will let you guys know after I drive the truck for a couple of days. :)

Mike

Let me preface this with stating that I ALWAYS buy plugs from the dealership! I decided to purchase 4 new plugs again and check them right off the bat to see what the Denso plug for my truck is gapped to coming from the dealership. All 4 plugs were gapped to (0.037) right out of the box. Remember, both the gaps we are talking about in the maintenance manual are (0.031) and (0.043) so it seemed kind of odd that these plugs had a totally different gap setting. I decided to install them just as they are and see what kind of performance I will get. I will let you guys know after I drive the truck for a couple of days. :)

Mike

Been driving with a (0.037) gap and the idle is bettter.......not great, but better. I am considering closing the gap even further to (0.031) and see what the results bring. I'm still puzzled about the different gap specs in the manual.

Mike

The larger the gap, the higher the potential needed to bridge the gap and produce a spark, and the shorter and stronger the spark will be. The ignition is designed to give you a spark after a specific potential (voltage) is reached, which is determined by the spark plug gap. If the gap is too large, you will not get normal sparking because the ignition will not reliably produce enough potential to jump the larger gap. Too small of a gap will give a longer cooler spark because the energy stored in your ignition (a fixed quantity) will be dissipated over a longer time. As soon as the energy released by your coil as its field collapses is enough to bridge the gap, the spark begins.

This means that in order to work with your ignition, the total gaps in both plugs must be the same. The difference in external gap in the electrodes can be explained by the presence of a larger internal gap in the insulator of the Denso plugs. The total gap (internal + external) in the two plugs should be the same for the same performance, but the external gaps are differerent because the internal gaps are different.

If you get a chance to take an x-ray of the Denso plugs, you should be able to see the internal gap. Also, because of the gap, I bet an ohmmeter will show there is no continuity between the center electrode and the spark plug wire connector at the top of the plug in the Denso.

This is a quote from my post above. "I remember your early discussion on the plug gaps and didn't realize at that time the gap depends on which plug is installed."
I have done some additional research in both volumes of my 2004 Tacoma shop manual. The gaps do not appear to be plug specific as I mentioned. In volume I page SS-30 the information is as Mike posted above. DENSO K16R-U11 or NGK BKR5EYA-U. The recommended plug gap is .043" for both plugs. In volume II in the ignition section for 2RZ-FE and 3RZ-FE engines on page IG-2 the same plugs are specified but the correct gap for both plugs is .031". Obviously one of these recommended gap settings is wrong. For the 5VZ-FE engine volume I on page SS-32 the recommended Plugs are DENSO K16TR11 or NGK BKR5EKB-11. In volume II page IG-3 the same plugs are recommended with gaps set at .043". I think the .031" gap is an error. Most vehicles have used plug gaps of around .043" for several years.

I have a 2002 Mazda Protege 5, recommended plugs are NGK BKR5E-11, DENSO K16PR-U11 or Champion RC10YC4. The gap for all plugs is .043".

FWIW, I made some ohm-meter measurements of a NGK, DENSO and Bosch resistor type plugs from the top lead connector to the center electrode, all showed infinity resistance.

Clifton

This is a quote from my post above. "I remember your early discussion on the plug gaps and didn't realize at that time the gap depends on which plug is installed."
I have done some additional research in both volumes of my 2004 Tacoma shop manual. The gaps do not appear to be plug specific as I mentioned. In volume I page SS-30 the information is as Mike posted above. DENSO K16R-U11 or NGK BKR5EYA-U. The recommended plug gap is .043" for both plugs. In volume II in the ignition section for 2RZ-FE and 3RZ-FE engines on page IG-2 the same plugs are specified but the correct gap for both plugs is .031". Obviously one of these recommended gap settings is wrong. For the 5VZ-FE engine volume I on page SS-32 the recommended Plugs are DENSO K16TR11 or NGK BKR5EKB-11. In volume II page IG-3 the same plugs are recommended with gaps set at .043". I think the .031" gap is an error. Most vehicles have used plug gaps of around .043" for several years.

I have a 2002 Mazda Protege 5, recommended plugs are NGK BKR5E-11, DENSO K16PR-U11 or Champion RC10YC4. The gap for all plugs is .043".

FWIW, I made some ohm-meter measurements of a NGK, DENSO and Bosch resistor type plugs from the top lead connector to the center electrode, all showed infinity resistance.

Clifton



The plugs I took out had a gap of about (0.047). I figured the gap spread a little over about 30,000 miles of time. I gapped the new set to (0.043) and the rough idle continued. I installed another new set of plugs from the dealership which all had a preset gap of (0.037) and the idle got a little better. I also believe that the gap should be (0.043). I have NEVER had an idiot light of any kind in this truck.

Brian, are you saying my ignition unit could be going bad?....getting weak? I dont believe that purposely reducing the plug gap to fix the idle is the correct maintenance procedure. There must be another problem somewhere!

Mike

If gapping the plugs at 0.031" fixes the problem, that's a cheap fix. I would leave well enough alone. The plugs you have may be designed to have that gap.

If gapping the plugs at 0.031" fixes the problem, that's a cheap fix. I would leave well enough alone. The plugs you have may be designed to have that gap.

I dont believe in perfornming maintenance that way. If I took my truck to a Toyota dealership for expert service and the technician told me he just gapped the plugs to "whatever" until the idle got better, I would be pissed!

W

If it saved you a couple hundred dollars? and if it might really be the problem?

This is not "whatever". Some plugs use this gap.

Denso K16R-U11 just bought 4 from my local Toyota spare parts department for my 2000 Avensis T22 1.6 110hp engine, to my surprise they all came gapped at 0.80mm. I have gapped them to the recommended 1.1mm but am now not sure if I shouldn't have left them at 0.80.

Pepe,
welcome to Automotive Forums..
whether you are in Spain, or the Yucatan; i hope it is warmer there than colorado..
you attached your chat to an older forum post about the gap of a Tacoma that just happens to use the same plug.. on your radiator support/shroud should be a placard with emissions notices and tune-up specs; which will include plug gap.
that being said, the toyota 1.5 and 1.6 engines usually have (you are correct) a 1.1mm; or .044" in america, plug gap.. they might be pre-gapped at .8mm in your area, if another (more popular) Toyota engine that sells more plugs (a V6 or 8cyl) might be gapped at the smaller .8mm (or .032").. hope this helps.