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1JZ - Why does my 1J like plugs gapped less than .020??
Can someone please tell me why my 1JZ only runs good on plugs gapped under .020? Everyone says between .026-.028
A little background:
1JZ, single 70mm, stealth 340 pump, NGK BKR6E-11 plugs.
So, I was doing some work on the car (fuel rail) and decided to put new plugs in. Figured I'd go top of the line and got some Iridium BKR7EIX. I gapped them to about .024 (then read that you shouldn't gap iridium or platinum because its easy to damage the electrode tip). With new fuel rail and plugs, car ran like crap. Choppy, and horrible. So, ended up putting stock rail with 440's back on. Car now runs good. Except in boost. Breaks up around 5-7psi.
So, I bought some V-power BKR7E and put those in. Gapped to .028. Still same boost breakup. And even got to the point where car would just die on me at idle and light throttle. I was luck enough to coast into a parking lot and let the car cool, then it started back up again.
So, I grab the old plugs, the BKR6E's and look at how they are gapped. The round gap tool goes as low as .020, and that doesn't even fit the gap! So, I am guessing that they are all gapped to around .016-.018.
So my question is, why does my car require a gap so small? Is that indicative of something?
not sure why but you can gap iridiums down, I do them all the time. the tip is alot stiffer so once you get it moving its easy to overshoot, you kind of have to go slow. I usually just put it on a block of wood and lean against it till it goes down some.
Thanks Ali, good to know. I was a bit worried that I might have ruined them.
I have been doing a little reading and I think it could be the coils maybe not giving a strong enough spark. But when I removed the coils to install the plugs, I looked over them really good and they looked like they were in good shape. Then, I shrink wrapped over them, so it's hard to believe that they would be the coils.
do you have an aftermarket regulator, you could be pushing too much fuel and the spark is having trouble keeping up. probably not but just a thought with the injector changes. yeah gapping Iridiums down is tricky but just go slowly if you go to far and have to open up the gap thats usually when the tip breaks.
when checking the coils did you remove the boot and look at the tip, that is usually where it cracks badly.
that is a weird issue though I haven;t heard of such low gaps being needed except with an aem ems v1.
seems like it would be the coils though are you on the stock ecu?
also you want the plugs without the -11 as those are .043
if you just get the bkr7EIX they should come .032
do you have an aftermarket regulator, you could be pushing too much fuel and the spark is having trouble keeping up. probably not but just a thought with the injector changes. yeah gapping Iridiums down is tricky but just go slowly if you go to far and have to open up the gap thats usually when the tip breaks.
when checking the coils did you remove the boot and look at the tip, that is usually where it cracks badly.
that is a weird issue though I haven;t heard of such low gaps being needed except with an aem ems v1.
seems like it would be the coils though are you on the stock ecu?
also you want the plugs without the -11 as those are .043
if you just get the bkr7EIX they should come .032
I do have an FPR and have it set to 45psi with vacuum connected, so about 35 without, which is about 3-5 psi more than stock I believe. That is thought that I actually had too, to bump it back down to stock psi, since I have a stealth 340 pump in now, I shouldn't need to compensate anymore with higher fuel pressure. But, I am able to just tune the fuel map down, so didn't bother with it.
I am running stock 1JZ ECU, with a MAP ECU3. The capacitors were good in the ECU last year when they were checked. When I checked the coils, I did not remove the boot, only looked at the body of them. They were pretty solid, no cracks. I will have a look at them again this weekend. Thanks for that info, I didn't realize that's where most of the damage occurs.
Thanks for the plug recommendation too. I think once I get this gap thing all sorted out, I'm going to put the BKR7E V powers back in.
I removed the shrink wrap that I put on and removed the boots and had a look at all coils. One had an obvious lengthy crack. The others I was hard pressed to find anything even under a magnifying glass light.
Can one bad coil cause the breakup issues that I am having?
I am assuming that whoever tuned it before me was having similar breakup issues and probably just gapped all plugs down the same amount, even though possibly 5 out of 6 didn't need to be. Either that, or they just didn't know to look for cracks to determine that only the one needed to be gapped so low to compensate.
In any case, to be safe and so that I know that all are in new shape, I picked up a set of 673-1200 Denso coils from RockAuto for $382 shipped. For those that may not know, 673-1200 Denso coils are the same as 90919-02205 Denso coils. AlibabaExpress has them, and I have been quoted as low as $136 shipped for all 6. There is an option to get "China new" or "refurbished". I don't trust either one, so spent the extra $ to get factory new.
When they come in, I will throw them in along with my V-Power's gapped correctly, and will update this thread.
I got the new coils in. Denso 673-1200 coils are the same EXACT coils as the Toyota branded Denso 90919-02205 coils. In the pics, you can see where the Toyota label and part # have been sanded off. A guy on SupraForums actually called a Denso rep and confirmed. So, these are a good, cheaper option. I didn't see anything on CL regarding these, so wanted to share with everyone:
Finkle is Einhorn, Einhorn is Finkle
This is what a cracked coil looks like under the boot
SO, after putting the new coils in along with the properly gapped V-power plugs, the car would not start. I put the old plugs back in, and still would not start. I got the laptop out, and turns out the MapEcu was configured for 4 coil on plug ignition setup. The MapEcu gets very buggy at times and sometimes some options don't show up in the software, and boxes check themselves, etc. Maybe its just a Vista thing, I don't know, but it does get frustrating. So, anyways, after making sure the config and maps were all good, it started and ran fine with the old plugs.
I took it for a ride and it drove mint while in open loop. Once it entered closed loop, it started acting funky again. Random jumpy idle, and dying out.
I checked the coolant temp sensor. It was plugged in, and checked the resistance with multimeter, and was reading properly. I tried to disconnect the coolant temp sensor while car was running, and nothing happened. Should something happen?
I also tried the same thing with the IACV. Unplugged the connector while running, and nothing happened. Should something happen?
I tried the same with the IAT and the wideband changed, so I know that is working correctly.
I tried to adjust the TPS while running, and the idle changed, so I know that is working. When I installed the fuel rail (before putting the stock one back in), I did remove the TPS to get access to the coolant line clamps. I hear that these can be a pain when out of adjustment and there is a fairly precise procedure to follow to dial it back in. I did have a picture of how it was fastened, and when I re-installed it, I fastened it back in that same position, so would think it is good.
Tomorrow I might try to gap the new plugs down a bit to see if it gets any better. But it doesn't make any sense that it drives mint until closed loop.
Anybody have any suggestions for other things to try?
As posted above, can somebody please help me to understand why nothing happens when I pull the IACV connector off while running? I would think that the idle should go wild? Instead it did absolutely nothing..
Also, same thing for the coolant sensor. I would think it would go back into open loop if I pulled the connector off?
Yesterday I removed the TB to calibrate the TPS. The lowest I could get the resistance down, even with the slightest, tiniest movement, was 34 ohms. I believe I am supposed to be able to get pretty darn close to zero? Does this mean that my TPS is bad? I ordered a new one anyway from Driftmotion, but just looking for some peace of mind until it comes in.
tha IACV has mainly a few positions. a start position where it opens alot, an idle position where its trying to idle. when you disconnect it, it just stays in the last place it was, so yeah nothings going to seem to happen when you disconnect it, it stays where it was, its not the best way to see if its working. if you were having trouble starting then maybe but if you are starting easy then its probably going back and forth alright.
when you say "I do have an FPR and have it set to 45psi with vacuum connected, so about 35 without", I don't think this is right.
when you have the vacuum connected you get less fuel, so without the vauum connected you would have about 8-9 psi more of fuel pressure, so without vacuum it would be over 50 psi if you really set it to 45 with the line connected. reset your fuel pressure the proper way follow the manual I think you may have set it wrong.
OK, thanks for the info on the IACV. I didn't realize that it functioned like that. You are right about the fuel pressure too. I had it backward. It is supposed to be adjusted to 42psi without vacuum connected, which is about 32 psi with it connected. So yeah, I am running a bit high. I will adjust it back down.
Can that cause breakup issues? I have the AFR's tuned pretty good. And it only seems to breakup and idle/run crappy after warm up and in closed loop. Hopefully my new TPS comes in within the next couple days and then I can calibrate and put it on, and bring the fuel pressure down a tad.
I have never adjusted one I just know how it works and the base fuel pressure is around 42 something psi. its going to be higher without vacuum than with the vacuum on it. what are the afr's before closed loop when you first start it, it should be around 11-12. once it warms up it should stay on 14. if the fuel pressure is too high the ecu can correct some so the afr's might look ok but its not going to boost well or respond to load well. just my thought I would double check it at least. the rest of it sounds alright to be honest.
when you get your tps you can do a check if you have it in the right position or not. put the jumper in the diganostic port on te1 and e1, and you should hear the engine change in sound, this is how you check the base timing. if you did not hear the motor change sound, then the tps is bad or in the wrong position, and you need to play with it till you can get it to change sound and show the lower base timing around 10 degrees.
I will try the jumper when I get it all back together. Regarding AFR's, with the MapECU, it was recommended to me to unplug the OEM O2 sensor to disable fuel trimming. I have always been a bit skeptical of this, but it has been running mint all summer until I started having fuel delivery issues which ended up being a lazy pump. However, in the midst of troubleshooting the fuel delivery problem, I changed other things such as fuel rail, plugs, etc. While changing fuel rail, I messed with a lot of things such as removing TPS and IACV, and removing wire trough, etc. So, unfortunately I disturbed quite a few things.
But to answer your question, I have two maps, one for cold start that includes OEM fuel enrichment, and one for when it kicks into closed loop (which I have no idea how it does since no O2 sensor..). The closed loop map is about 10% richer than cold start map to compensate for lack of OEM enrichment. My cold start map has AFR's at around high 11's, and eventually begins to taper off as OEM enrichment tapers off into closed loop. At which point, I flick my switch to select other map. This has been fine for me all summer until the above fueling issue.
thats a very odd way of doing it, I am not surprised it runs like that. the cold start should run richer then the warm stuff, not the other way around. closed loop shouldn't have more fuel enrichment generally speaking.
maybe someone wired the wideband to the map ecu that way you disable the stock one, if not then maybe try it with the stock one. I am not sure how your wideband is wired up. I used one of those before and do not remember having to use 2 maps, I think that may be part of the problem, 10% fuel enrichment is going to also affect the timing and especially add a bunch more fuel in boost. I would stick to getting 1 map correct the stock ecu should do cold start enrichment based off the coolant sensor, so not having an o2 sensor means it will just not be able to dial it in perfect but it still knows when its warmed up, you do not need 2 maps I bet thats also part of the problem.
alot of times when the tune is not perfect it shows up when the weather changes, a good tune that has the ability to fine tune itself via o2 sensors etc.. will work well year round. I would not be so quick to start disabling stuff and reverting to 2 maps. the only time you should have 2 maps is with nitrous or e85.
09-24-14, 07:46 PM
1JZ - Why does my 1J like plugs gapped less than .020??
