Jump to content
SAU Community

Recommended Posts

hey guys,

recently i had problems with my coil packs as it seems to pop/fart/missfire when i hit +3k rpm then found that my 3 of my coil packs had hairline cracks so i epoxy-ed it and changed my plugs since the oppurtunity was there. problem solved able to hit +4k rpm no problem but today I had the itch to launch but noticed that when i 80% full throttle it boost then cuts off/jerks hard then boost again at around 5k rpm....is this a coil pack problem? fuel starve? or voltage starve? or u what? no problem when i accelerate normally n hit boost but full throttle it does that.

Link to comment
https://www.sau.com.au/forums/topic/301724-need-serious-help-here/
Share on other sites

+1 for asking what boost you are running.

i'm guessing you still have the stock ecu and your boost is up around 13psi, yes? if so, you are hitting the ecu boost protection. basically when the AFM sees too much airflow for a given point in the load/rpm scale it backs off

hey guys,

recently i had problems with my coil packs as it seems to pop/fart/missfire when i hit +3k rpm then found that my 3 of my coil packs had hairline cracks so i epoxy-ed it and changed my plugs since the oppurtunity was there. problem solved able to hit +4k rpm no problem but today I had the itch to launch but noticed that when i 80% full throttle it boost then cuts off/jerks hard then boost again at around 5k rpm....is this a coil pack problem? fuel starve? or voltage starve? or u what? no problem when i accelerate normally n hit boost but full throttle it does that.

supporting mods i have is FMIC, exhaust system, Turbosmart boost tee controller set at 7clicks (apparently suppose to be equivalant to 7psi not sure), stock ecu, stock turbo.....

today took a better look at my boost gauge n it hits 1.3 bar which is strange when i set my controller at 7...hmm then watched the stock boost gauge(dash gauge) noticed that it hits +7 then cuts so now the problem is defined....i reduced the boost to 4 clicks but still does the same thing...turned it off completely and still hitting +7 .,,,its as if the turbo is boosting by it self or somethin....any ideas?

lol wow - dude, stop touching you car. You are lucky you have not blown it up, and i am not saying that in a joking sense, im deadly serious.

7 "clicks" will be 7-10psi above the BASE pressure. Factory you run 7psi, so +7-10PSI more and you are talking 16-17 through the factory turbo and then some... no surprise you are hitting 1.3 bar (absurd pressure)

1. You are hitting Rich & Retard

2. You are basically putting the turbo in to absolute danger zone running that much boost - it will disintergrate. Anymore than 11-12psi is a no-no.

3. +7 is the MAX the factory gauge shows, this is roughly 14psi

4. If the turbo fails, it CAN kill a motor. Especially @ that level of boost, and compressor speeds etc, bad bad bad shit can happen.

Take it to a professional for gods sake - seriously.

You also make no mention of a fuel pump, this is also ridiculously dangerous.

I'd be highly surprised if some form of damage has already been done.

hey guys,

recently i had problems with my coil packs as it seems to pop/fart/missfire when i hit +3k rpm then found that my 3 of my coil packs had hairline cracks so i epoxy-ed it and changed my plugs since the oppurtunity was there. problem solved able to hit +4k rpm no problem but today I had the itch to launch but noticed that when i 80% full throttle it boost then cuts off/jerks hard then boost again at around 5k rpm....is this a coil pack problem? fuel starve? or voltage starve? or u what? no problem when i accelerate normally n hit boost but full throttle it does that.

lol,sorry for laughing but i know a guy like you who decided to fiddle with his boost when you have no idea what your doing.he decided he wanted to run his car on 20psi on a pretty much stock r33 and blew it up.

i bet your car is damaged from this and if it aint showing now it will soon.

As long as Nissans little EGT (exhaust gas temperature) sensor is doing its job the engine shouldnt have taken to much internal damage, the turbo though can easily been heavily damaged.

I see you've got a aftermarket exhaust system, have you still got the EGT connected? It looks like a small lambda sensor, placed right before the cat.

What factory EGT sensor?

The only sensor there is after the turbo is the O2 sensor, and the Cat temp warning sensor. The cat temp sensor being plugged into the cat itself.

Is it NOT a EGT sensor in the true sense as it does not have anything to do with the ECU.

All it does it flash up a dash warning light for CAT overheat.

just to add to this thread,

my problem is similar... although i only get it in 2nd gear on full throttle... hits about 3500rpm, miss fires then full boost again... any other gear on full throttle there is no missfire.. running stock boost

(mods 3" exhaust, turbosmart boost tee, greddy oil cooler)

What factory EGT sensor?

The only sensor there is after the turbo is the O2 sensor, and the Cat temp warning sensor. The cat temp sensor being plugged into the cat itself.

Is it NOT a EGT sensor in the true sense as it does not have anything to do with the ECU.

All it does it flash up a dash warning light for CAT overheat.

I could be wrong i guess but as i've been told earlier the ecu change the timing if it runs to lean, this 'cause of the cat temp sensor and knock sonsors giving a to high value.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Great work! Give it a clean up with some Emery paper, and I'd run a thread die over the threads too to clean them up. It will make reinstall much easier, and also life easier for the next time it needs to come out.
    • I'm not a fan of high humidity, it's one reason I don't mind being further inland out Ipswich, except the last 3 odd years, the drought broke, and it won't stop raining, which is making the humidity nearly unbearable when the rains are in during summer! For me, my body hates the cold, once the cold sets into my body, I'm totally screwed. I end up with severe muscle spasm in my back/shoulder muscles, and it feels like someone is trying to tear the muscles out. I have no issues with it getting stupid hot, so long as the humidity goes away. So the last 3 years as above, have been woeful! Ha ha. However, June 1st, and I'm only just converting from shorts and a tee, to long pants and a t shirt. And that's mainly as it's a bit wet and miserable and I wanted to work on a car.
    • I much prefer colder weather to hot weather, and especially prefer cold to hot and humid, Goulburn does gets pretty warm in the hotter months, but, I've found the humidity there is not as painful as even Sydney, the humidity up north is to oppressing for this old rooster  In saying this, it does get rather "nippy" in Goulburn for early morning, late in the evening walks, but nothing that a layer or two, some thermal gloves, and a beanie doesn't fix to make it an enjoyable experience, which is much more bearable to me than the oppression of heat and humidity,  especially at night when your trying to sleep If I recall correctly, a "wise man" once said that the "Southern Tablelands" was gods country, and I will not argue that point with him for the fear of a "permaban" LOL In car part related news: My intake is currently in Botany getting processed for the last leg of its shipping journey to my door   
    • Had a go at the stuck crush tube this afternoon. Tried things like grips and a chain wrench first but wouldn't just twist straight off. So got to work with a drill. Started small and kept a depth stop on to make sure I didn't drill into the bolt. Made a line of drill holes all the way up and enlarged them. Then a combination of chisel and Dremel to split it all the way up. Levered the split to get oil in there and eventually it gave a bit while levering. Worked it back and forth with loads more oil till it was spinning freely, then with grips I could work it downwards and off. And no significant damage to the bolt (not by me anyway - just the 27 years of rust)
    • Well, I'm tired. I'm tired because about 4PM yesterday, before today's appointment someone immediately bought my bumper. They couldn't get it any other day as they're on the way back to NSW. So I had to do that big GTR conversion I had been planning. Unfortunately, the information on SAU about what you need and how this is done is incomplete. So what should be a simple bolt on affair, yeah, it's not. Did you know if you use all GTR items the bonnet won't close? This little manuever sent me into about 1am the night before trying to dodge a way to get it closed. I will have to revisit this in the next few days  - or maybe not, I may let a body shop figure it out. It all needs to come up and my motivation to pull the bumper off is low. It also seems to hit things in the bay where the GTT bonnet didn't. Yes I used 100% new OEM GTR items. Today, I had the joy of driving to the dyno looking like this: Given I had roughed in the fuel and given sensible but pretty conservative timing, I didn't really bet on having the car drive out any real difference than when it drove in. Sadly due to a miscommunication and laptop fun and games (and almost bricking the dongle, prayers and firmware updates indeed), I ended up using HP Tuner credits to licence the car that was already licenced. So in the end my laptop was used. It turns out my butt dyno is still well calibrated after all this time. The 325kw was on 74% Ethanol, the 313kw line was on 98. The other line is the 'before' line which was 281kw. While the numbers are pretty low, they're pretty in line with what you'd expect. Even if US dynos bump the whole result up about 50KW, gaining 10-15% is similar gains.  The curve of the cam is pretty much spot on with what was discussed as well. All this said, it still feels bad to not see the number you secretly want to see. Even if the car drove great beforehand, and I knew pretty confidently the car would drive out much the same way it drove in due to the nature of a wellish dialled in LS1 not gaining much if anything at all from being tuned from where it was. As expected, the car isn't particularly sensitive to running it at anywhere between 12.0 and 13.0 - And the initial timing at 20deg and 12.0 made 308KW. So 3 degrees of timing, and leaning it out to 12.7 for 5kw, anything above stopped giving any benefit until E85 (which has an additional 2 deg as before). Car itself behaved entirely fine. I found out that 100C = 1.15V! IAT at about 7pm was 19C. I might mess with the bonnet mounting.. but given the REO NEEDS TO BE CHOPPED TO FIT A GTR BAR this is possibly something I may leave gathering (more) dust until it returns to paint jail.
×
×
  • Create New...