Newby Questions

[EurasiaN!]

Hey guys so I just bought my first Skyline a 1998 R34 GT-T. But overall im no expert or mechanic so I have a few questions (could be stupid) that im pretty clueless about.

Any info is greatly appreciated though.

So here goes...

1) I've noticed when I hit 5000rpm the engine cuts out, was wondering is due to a rev limiter on the car or has it got something to do with the ECU mapping?

(- Noticed in 1st gear im able to go past 5000rpm but have noticed a cut out in 2nd and 3rd)

2) Quite often the car back fires when shifting upwards. This has happened from all gears from 1st through to 5th. Sometimes loud enough to rattle the car a little.

I've read the fix could be coil packs, was wondering could this be due to other reasons?

And what coil packs should I be looking at and rough $$$,

3) I currently have a Greddy Profec Spec 2 boost controller installed, but it always sits at 0, -1 or -2. I thought this is only meant to happend when the car is idling.

So am I right to think the boost controller isnt connected and just currently running stock boost?

Sorry about the lack of knowledge, but just want to get a few issues sorted with my car.

[Shazza24]

Congrats.

1. Rev limiter is at red line unless it has been changed in a aftermarket ECU or BeeR* Rev limiter. It is probably running a safe mode map.

2. Not sure

3. even if the boost controller is connected it may not be working correctly. Normally when idling it should be -18 or something like that depending on what the unit of measurement is. Although the std. vacuum gauges are crap i take it that it reads well into the negative unlike the boost controller?

Are you running std. ECU?

So it literally cannot go above 5k rpm in second and above?

Is the car idling ok?

Edited March 28, 2011 by Shazza24

[EurasiaN!]

Congrats.

1. Rev limiter is at red line unless it has been changed in a aftermarket ECU or BeeR* Rev limiter. It is probably running a safe mode map.

2. Not sure

3. even if the boost controller is connected it may not be working correctly. Normally when idling it should be -18 or something like that depending on what the unit of measurement is. Although the std. vacuum gauges are crap i take it that it reads well into the negative unlike the boost controller?

Are you running std. ECU?

So it literally cannot go above 5k rpm in second and above?

Is the car idling ok?

Thanks for the reply,

Car idles not a problem.

1) Not sure what ECU is running, not good with all that jazz, might just take a pic under the hood tomorrow, probably be more helpful.

3) Well problem is the my standard gauge has a loose connection, so it works 1/7 days of the work so dont even know what im boosting.

And the boost controller sits at -1,-2 so thats no help either.. but never has it reached -18

[DVS JEZ]

Is it a missfire at 5000rpm?

If it is go to supercheap and get some bkr6es ngk-r spark plugs and put them in.

Hopefully running this spark plug which has a smaller gap will help stop the missfire. Otherwise u will need new coilpacks

[Messiah]

First things first we need to know about any and all mods.

Let's assume it's just thee boost controller, I'd say the cut there is the factory over boost protection. The lack of boost on your guage would suggest otherwise, however your not registering a proper vacuum either.

So, with that in mind check the lines for the boost controller and se if ones split.

Also your ecu is normally in the passenger kick panel by their left foot.

Check you have a factory blow off valve, it should be on the intake about a foot or two to the right of the trireme body. The factory bov should be plumbed back into the intake via a rubber hose.

[Messiah]

I mean throttle body, damn IPhone.

[The Dan]

Is it an Auto?

[Messiah]

i would assume not by his description of the problem not happening in some gears, but that is an assumption not a educated judgement.

[The Dan]

Ahh true, I didn't see where he wrote 5th. Thanks

[Hanaldo]

First things first we need to know about any and all mods.

Let's assume it's just thee boost controller, I'd say the cut there is the factory over boost protection. The lack of boost on your guage would suggest otherwise, however your not registering a proper vacuum either.

So, with that in mind check the lines for the boost controller and se if ones split.

Also your ecu is normally in the passenger kick panel by their left foot.

Check you have a factory blow off valve, it should be on the intake about a foot or two to the right of the trireme body. The factory bov should be plumbed back into the intake via a rubber hose.

+1

Given that neither your boost gauge or your boost controller are working correctly, you could have a vacuum leak. Would explain cutting out at 5000rpm and the backfiring.

[EurasiaN!]

Here's a few pictures of the engine bay and other things. As I said im no wizz with this kind of stuff so half this stuff I wouldnt know what it does

But hope it helps in some way at least..

stock coilpacks?

Is it a missfire at 5000rpm?

If it is go to supercheap and get some bkr6es ngk-r spark plugs and put them in.

Hopefully running this spark plug which has a smaller gap will help stop the missfire. Otherwise u will need new coilpacks

Thanks for the tip mate. Will look into it along with coil-packs.

Not sure if missfire and backfire are the same terms . But at 5000rpm it feels as if the engine has been turned off then power back on, which is one problem.

The backfire is the other problem when shifting upwards, regardless of rev range when shifting ie. 2000-4000rpm still backfires 5/10 times.

First things first we need to know about any and all mods.

Let's assume it's just thee boost controller, I'd say the cut there is the factory over boost protection. The lack of boost on your guage would suggest otherwise, however your not registering a proper vacuum either.

So, with that in mind check the lines for the boost controller and se if ones split.

Also your ecu is normally in the passenger kick panel by their left foot.

Check you have a factory blow off valve, it should be on the intake about a foot or two to the right of the trireme body. The factory bov should be plumbed back into the intake via a rubber hose.

I think its just a boost controller and after market bov.

Will have a look for the ECU soon. How do I know if its after market or stock?

Is it an Auto?

Its manual sorry forgot to include.

+1

Given that neither your boost gauge or your boost controller are working correctly, you could have a vacuum leak. Would explain cutting out at 5000rpm and the backfiring.

Boost gauge works from time to time, like this morning was showing boost fine for about 20 minutes, hence why I believe its a loose connection, but the boost controller is always at 0, -1, -2 so I think its just not connected? Uneducated assumption though

Thanks all for the contribution, just wondering how bad/damage is it to be driving this with the constant backfire though. As everytime it happens I feel im hurting the car just that little bit more . The 5000rpm isnt a real problem as I dont rarely ever hit those rpms but still would like to know the answer.

[Messiah]

is it just me, or is nothing connected to that boost solenoid...

Also, the aftermarket blow off you have there will cause crap in the log run... bin it and return to stock... AF Bovs are only good for defects and fueling problems.

[Messiah]

ps i rekon the backfire is due to the bov.

[JonnoHR31]

what boost are you running according to your boost gauge? (when it works...)

[Finchy33]

I had a problem where I thought the rev limiter was stuffed in the powerFC.

Turns out the intake pipe was sucking closed and it was like hitting a brick wall! Actually way worse than limiter as there was no momentum what so ever.

It happened at exactly the same revs, everytime. Only time it didn't happen was when I used half throttle and limited boost.

Edited March 29, 2011 by Finchy33

[KEBAB_DRIFTER]

connect your boost controller to your actuator PLZ

[Messiah]

Eurasian... You have a number of problems here. The main one, and please don't take this as an insult/attack, is that you have nfi about the car your bought and it's configuration. This could end badly if not sorted out.

Ok, first of all it appears to have a mixed bag of mods that don't appear to be well chosen or properly set up. Chiefly,your boost solenoid ( the greddy thing with wires). Is meant to be connected to the intake system but isn't . This means it won't control jack. Second what is connected to the boost controller isnt giving a reliable reading, so it's also possible that your boost is out of control with no way for you to see it.

Next up, you have an aftermarket return flow front mount. And a atmospheric blow off valve. This would suggest the the previous owner had done some solid work to it including a tunable ecu. Factory blow off valves plumb back into the intake, this means that air meaured going into the engine at the air flow meter eventually makes it into the engine. An atmo bov doesnt and instead spits it back out of the engine. This is bad as the engine has added fuel to mix with the air but the bov sneezed the air out before it could be mixed with the fuel. So now you have a rich spot an unburnt fuel... And probably the backfire. All atmo bovs are good for is making a stupid noise and getting you defected.

So the atmo bov and buggered up boost controller suggest the prior owner has left it in a right state for you. And pushing the car hard in its current state is il advised.

My advice. Take it to a reputable work shop. Have them return the bov to stock and fix the boost controller boost controller and gauge. Get them to check the ecu and tune while there. If it's stock, get them to lower the boost to 8 psi to stop the ecu from panicing. If not stock, get it dynod and the tune checked for safety.

If you don't do this your really risk arseing up your car. Get to know what state the car is in now and what it's safe to ask of it, the go from there.

[Galois]

Messiah is damned right there Eurasian, take it to an experienced workshop. You have too many problems and seemingly not enough know-how to solve all these problems (no offence, we all started learning somewhere). Make sure you get the issues Messiah mentioned checked and fixed.

Also you have an unshielded pod, meaning that your engine is sucking in hot air on hot days under a hot bonnet, which can cause you further issues, so it might be worth getting a heat shield box made up, or just replacing it with a normal airbox (not really much flow difference, esp with an aftermarket panel).

Go to the NSW section, search for workshops, look who has good and bad references. Don't bother actually asking as the thread will just be closed by a mod. There are a lot of good places in Sydney, so have a search and give some a call.

Good luck mate, let us know how you go.

[EurasiaN!]

Cheers Messiah for your advice and everybody else who's had an input

I think i'll be looking into booking my car in and hopefully getting some issues resolved!