Single Turbo RX-7's Questions about all aspects of single turbo setups.

keep fouling new spark plugs..need advise please!!

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Old 10-14-09, 08:10 PM
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keep fouling new spark plugs..need advise please!!

ok so heres the thing. I keep fouling brand new spark plugs. I mean they only last like 2 days. I have gone threw about 100.00 in spark plugs this month and it is kinda getting expensive. I do the whole deflood procedure and it is definitely flooded. I try to clean them with a brush and brake/carb cleaner and they still dont work. But when I buy new plugs it fires right up. I am thinking I should adjust the cranking injector time from 52.0 down to 35 above 10+. Water temp is between 16-18 when cold. I am running 850 primarys with a stockport motor. Do I need to run a hotter plug or invest in a twinamp? I changed my wires from the ngk to the msd 8 mm 40ohm wires. My fuel pressure is 38-40 psi....and the plugs I am running are ngk 9's non platniums. My injectors are not leaking. They are brand new from the rx7.store. The tune is also from the rx7 store so I know my tune is good. Any thoughts???? It only seems to flood when it is cold but once its started I can turn the car off and turn back on with no problem. I even did a spark test to see if the coils are good and they are fine. I can get a spark from the supposed spark plug. I realize though when under compression the spark is weaker. my front rotor is a 120 psi and and rear is 118 so i know I have good compression.

Last edited by kru510; 10-14-09 at 08:13 PM.
Old 10-15-09, 10:53 AM
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what are the AFR's at idle?
Old 10-15-09, 11:44 AM
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Originally Posted by arghx
what are the AFR's at idle?
between 10.1-10.8
Old 10-15-09, 11:55 AM
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what's your ignition setup? you may not be able to burn all that fuel.
Old 10-15-09, 12:47 PM
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Originally Posted by hondahater
what's your ignition setup? you may not be able to burn all that fuel.
just stock coils and msd 8mm spark plug lines with ngk 9's.Also when I adjust the fuel pressure down to 20 psi it actually idles better...but at 35-40 the idle gets a little rough. I am thinking I do need to get a twin amp...btw this is an fd and go ron paul 2012!!
Old 10-15-09, 01:41 PM
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Why in the hell are you running 10.s AFRs at idle??????????
That is insane!!!!!!!!!!!
Should be around 12-13 AFR.
Idle should be as lean as possible with optimum timing to get best lean smoothness.


Which ecu are you running?
Old 10-15-09, 02:48 PM
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Uh, 20 psi fuel pressure? Keep your base pressure at 40.

Try and lean the power FC out in those cells in the inj menu. Use the map tracer to see what cells you're idling in (probably N2 and P7 or P8) and take out 10 to 15% of fuel, see how that works.

And I wouldn't blindly say that your tune is good, faulty logic like that with an FD will lead you to disaster down the road.
Old 10-15-09, 03:14 PM
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^^Agreed. I'd imagine the best thing to do is get someone from Cali to retune your car before the motor goes to be with the rotary gods.
Old 10-15-09, 03:25 PM
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Originally Posted by cewrx7r1
Why in the hell are you running 10.s AFRs at idle??????????
That is insane!!!!!!!!!!!
Should be around 12-13 AFR.
Idle should be as lean as possible with optimum timing to get best lean smoothness.


Which ecu are you running?
im running a power fc w/a datalogit...im just curious...would to much fuel in the oil cause it to run rich. I have flooded it a few times.
Old 10-15-09, 03:59 PM
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LOL these are obvious questions. but your learning. You don't have a tuner near by that can help you out. Besides why didn't you try to look at the datalogit website. they have default tunes for certain circumstances
Old 10-15-09, 05:27 PM
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You'll probably have to run negative lag to get the 850 primaries to run leaner. I agree with Chuck, 10.1 AFR'S is too rich for idle. It's too rich for anything actually. It's no wonder you're fouling them out so quick. At idle run no richer then 12:1 and try for 13-13.5:1 if you can. Make sure the air atomizing port is hooked up, it will help with getting it to idle leaner. And yes run 40 psi base pressure, low pressure just means a crappy spray pattern and inefficient burn. Under cruise get your afr's to 14.7 -15.5, under boost run 10.8-11.5 depending on how much boost and fuel quality. That should help dramatically in plug life.
Old 10-15-09, 05:57 PM
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Originally Posted by Dudemaaanownsanrx7
You'll probably have to run negative lag to get the 850 primaries to run leaner. .

That is his problem. Expect to retune the entire map after running negative lag...
Old 10-15-09, 06:08 PM
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If he's running that rich at idle i would expect the whole map needs to be tuned anyway. Thats the first thing tuned usually. Thats what i always start with
Old 10-15-09, 06:25 PM
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Your problem is quite simple. Your fouling your plugs because your running too rich. 10.1-10.8 is stupid rich for idle, you don't even run that rich under boost. As Chuck mentioned between 12 and 13 is where you want to be.

You also have another problem. With 850 primaries, its always going to run rich. Negative lag helps a little but but its always going to idle in the 11's. Also, negative lag affects some drivability which can't be fixed. Some people on the forum claim 850's run fine. Of course they do, you can learn to ignore the problems associated with running them but that doesn't mean they are fine. If your paying attention and know how it should run, you know there is a problem.

Get rid of the 850's and have it retuned by someone that knows what they are doing. Or a better option is since you have a datalogit, get Chucks (cewrx7r1) notes and start learning to do it yourself.

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Old 10-15-09, 08:19 PM
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Originally Posted by kru510
between 10.1-10.8
Thats one of your problems. Your a/f at idle should be in the 14's. Your tune is probably too rich as well.
Old 10-15-09, 09:42 PM
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ok so i got my idle afr running at about 11.5 and that is with the negative lag ...but the idle is not that smooth. I am kinda thinking if I should go back to the 550's and and run the base map on the pfc right now till i get tuned. My atmomizing port is hooked up to the turbo outlet. I think I am just learn how to tune on my own I guess off the base map. Wish me luck lol...
Old 10-15-09, 10:16 PM
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How did the RX7 store tune your PFC? Did they only send you a map or sell you a PFC with the map on it? Best would be to post on the PFC forum as that is your ecu. Do you have a Datalogit, if so download the map and post it along with your engine mods.

Since you do not know PFC tuning, find one locally before you ever get on boost.
Old 10-15-09, 10:27 PM
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The map he has we have used probably a hundered times on similar fuel setup with no issues. The car should start and run fine on that map. As I recall the idle map has fuel taken out and the injectors have been adjusted. The car should start and idle with no problems.
For those that dont tune or rarely tune you can add 850cc primary injectors, change the lag and % and the car should start and idle with no problems. That is with no adjustment to the fuel map.
Old 10-15-09, 10:29 PM
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Originally Posted by kru510
ok so i got my idle afr running at about 11.5 and that is with the negative lag ...but the idle is not that smooth. I am kinda thinking if I should go back to the 550's and and run the base map on the pfc right now till i get tuned. My atmomizing port is hooked up to the turbo outlet. I think I am just learn how to tune on my own I guess off the base map. Wish me luck lol...
To me it sounds like you have another issue other than the map. Are your primary injectors sealing correctly? Take some carb cleaner and spray under the manifold while the car is idling. If the motor bogs then you have a vacuum leak.

Last edited by Jason; 10-15-09 at 10:31 PM.
Old 10-15-09, 11:00 PM
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Originally Posted by kru510
ok so i got my idle afr running at about 11.5 and that is with the negative lag ...but the idle is not that smooth. I am kinda thinking if I should go back to the 550's and and run the base map on the pfc right now till i get tuned. My atmomizing port is hooked up to the turbo outlet. I think I am just learn how to tune on my own I guess off the base map. Wish me luck lol...
How much negative lag are you using? And how much fuel did you take from the base map. If you take too much fuel out of the base map it will run funny, you may need to put a little fuel back in the base map and then lower the lag. Is the fuel pressure at 40 where it should be?
Old 10-16-09, 10:06 PM
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Originally Posted by Dudemaaanownsanrx7
How much negative lag are you using? And how much fuel did you take from the base map. If you take too much fuel out of the base map it will run funny, you may need to put a little fuel back in the base map and then lower the lag. Is the fuel pressure at 40 where it should be?
yes the fuel pressure is at 40psi. I set the neg lag to -40. i will do a vacuum leak test to confirm.....the leak issue. I am gonna take some pix of my vacuum line setup. Oh and by btw...Not to get of subject but I got a killer deal on an ls7 engine w/23,000 miles on it. Guy totalled his vette and wants to part the car out. He wants 7000.00 for the engine and tranny. What do you guys think?
Old 10-16-09, 10:58 PM
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ok so i have another newb question. I am going over my whole vacuum line setup and took off the uim. I just realized I capped off all the nipples right after the tb I was looking at the diagram again a saw that it calls for only 1 vacuum cap right after the tb. Could this possibly cause less air into the intake causing a rich mixture?

Last edited by kru510; 10-16-09 at 11:03 PM.
Old 10-17-09, 02:03 AM
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oh snap!..so i found there is still a fat exhaust leak right between block and the turbo manifold. Would this also be considered a vacuum leak? And now that I think about it you can totally hear it. Could this cause a rich afr due to lack of air circulation?
Old 10-17-09, 02:53 AM
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No an exhaust leak is not the same as a vacuum leak. It can make it pop and such though.
Old 10-17-09, 04:13 PM
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ok so here are some pix i took of my setup..the there doesnt seem to be any leaks in the hoses visually. But I was wondering if I can get a second opinion on what needs to be capped and what doesnt..another option I was thinking is that maybe there could be a leak in the couplar. Would that cause a problem with the afr ...thx
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