Seriously about to give up on this engine!

[HotRB240]

I bought my 240 with RB25DET in it about 2 months ago. The car ran, but barely. I've since spent $800 to have engine management put in and have it tuned. The 6th cylinder coil pack was replaced at $60. Another 600+ dollars were spent between two garages: Speed Theory in Fairfield New Jersey, and Import Intelligence in West Chester, PA. The car still runs like crap. Please give me ideas because I truly am losing hope in this car. At this point I'd really just love to be able to enjoy it for one week and then I am selling it.

The car starts and idles fine. At low RPM, if you expect very little out of it, I suppose you could say it runs fine too. It also runs fine if you are screaming the living hell out of it. However, at mid RPM if you hit the gas hard it just sits there-does nothing. It may go for a second, and then it sucks back, then goes, then sucks back.

Please give me some ideas to take back to the mechanics who have worked on this car-I really can't afford to replace everything on it to figure out what the problem is.

Thanks in advance,

Truly frustrated!

[Coolwhip]

What fuel management as well as relivent mods do you have done?

Might be a tune problem.

Do you have gauges and what are they doing at that point of fustration?

[Darius]

When you got it tuned did they tune the entire map or just for idle and high load pulls? For a good tune, they should do the entire map. Especially for the money you shelled out.

[Coolwhip]

yea the intermidate map/transition map sounds wacked.

Considering you had some tunable Fuel Management put in I am assuming you have upgraded injectors and turbo?

[StricNyne]

i feel your pain man, i honestly do... but dont give up, i wanted too sooooo many times, after sooooo much money, heh, if u need help i kinda live close to you, i got a set of coilpacks you could test with and yadda let me kno [email protected]

[HotRB240]

I'm not POSITIVE, but I can be reasonably certain that the problem is mechanical and not a tuning issue. I cannot tell you which fuel maps specifically because to me none of that means anything. However, the guy who tuned it is the in-house tuner for Import Intelligence. Mine will have been about the 30th RB25 he has done in the last year...Both the mechanic and the tuner rode around in the car together and are baffled. They pretty much agreed together though, after tuning to the absolute limits of the software, that the problem is mechanical. I know it's pretty much a stock map. Everything other than BOV and fuel pump are pretty much stock. I don't even expect that much out of the car-just want it to run properly...

[HotRB240]

No, I have neither upgraded injectors or turbo. The reason for engine management was to crank boost from 7psi to about 14psi. Later found that it wouldn't hold more than 7 anyhow, so it seems at this point that it was a total waste of money.

Seems everyone wants to think it is a tuning problem. He's done so many of them and spent so many hours in mine that I just really don't think that is it. What's really sad is that if that is the problem, then ALL of my money was a waste.

[Darius]

Have you checked for boost leaks in your piping or at the intake manifold?

[HotRB240]

Now here is where we might have something; although, please everyone else don't think that I don't appreciate your input. I will try anything at this point! But...The guy who worked on my car...well that's pretty much all they do is RBs-they even have a shop one that is in a nissan truck.

The last thing he said to me is that it might be the coilpacks because the RB25 is notorious for having bad ones, and that the next time I'm down there we can swap mine out with the ones on the truck to try to eliminate that as a problem. I'm truly hoping that doesn't eliminate that as a problem but rather that it IS the problem. I don't mind paying for new coilpacks if that is it.

See, the polarity on the fan was backwards for a while and it was overheating a lot, which was surmised was the reason the 6th cylinder coilpack went bad.

Could it be coilpacks still even if it idles so smooth and pulls good at high RPM?

Where you live StricNyne?

You know, I WANT to give up, but can't yet cuz something inside is telling me this is going to be a really fun car IF I ever get it figured out.

[HotRB240]

Have you checked for boost leaks in your piping or at the intake manifold?

Yes, he did check for that. That was one of the things he thought it might be before I took it down there. I will say this: The piping is very inefficient. There is a lot of it. But it's all tight, no bolt missing on turbo either...

[HotRB240]

What fuel management as well as relivent mods do you have done?

Might be a tune problem.

Do you have gauges and what are they doing at that point of fustration?

I have 3 guages: Boost, Oil Pressure, Water Temp.

Only one that works is the Oil Pressure gauge.

Checked boost manually during tuning process, and it is at 7, so I guess it's running stock off wastegate.

[Darius]

Don't give up. Many of us have had issues and some longer than others (NRRBA members). It forces you to learn more about what makes your motor tick and you appreciate it more when it runs right. I waited for almost two years to get my swap/rebuild done.

[jrd450r]

You check the fuel pressure? My car had similar symptoms and the cause was the fuel pressure being to high. Also like everyone else said, boost leaks. Make a tester and test it for sure, it will take 20 mins and give you a thumbs up or down on weather its all tight.

[StricNyne]

i live in perth amboy, nj like an hour from you, so if u wanna come by, just let me kno in advance, i actually just set my coil packs asside to wire up my haltech so i got them all ready !! i got fsm also i think it tells u how to cheeck for bad coil pack with a multimeter checking for resistance

[HotRB240]

Don't give up. Many of us have had issues and some longer than others (NRRBA members). It forces you to learn more about what makes your motor tick and you appreciate it more when it runs right. I waited for almost two years to get my swap/rebuild done.

Thanks for the encouragement. I guess I am kind of an impatient person. Within two weeks of first hearing about swapping the RB engine into a 240 I bought one with the swap already done.

I guess I could try to be more patient about it if I had another car. Unfortunately I turned in my totally reliable leased '06 Audi A4, which by the way was faster than this car, and bought this for $10,250.

At the time I thought it was a good deal.

Anyhow, the problem for me is that it is my only car, and I have to drive 65 miles each direction to and from work every day, and it is killing me in gas $ the way I have to drive it to get it to move.

Just hope I can get it figured out before I run completely out of money!

[StricNyne]

wow, that sucks man, but let me kno, u bring pizza i will supply beer and we can git r dun plus i can show u my l33t motor

[HotRB240]

wow, that sucks man, but let me kno, u bring pizza i will supply beer and we can git r dun plus i can show u my l33t motor

Sounds good. I sent an email to the email address you gave in your last post. Write back when you have a chance and we can coordinate something. And thank you!

[Sil240]

As president of the NRRBA.You can't quit!!!I haven't driven my car for years!!! (literally)3,4 or close to 5 years.It's been so long.

Keep with it bro.This board is really good.You need to do a lot of Searching, and you'll find any and everything you need.

[Coolwhip]

The longer the battle the sweeter the victory!

[mello88]

Go back to the basics.. Check your compression, re-test for boost/vac leaks, check base ignition timing, check fuel pressure, check fuel pump and fuel filter, check spark plugs, check your wiring, if possible pull codes from the ecu. You could have some bad wiring somewhere thats shorting under load. Can you replace the tuned ECU with your stocker for testing purposes? It doesn't sound like you've done anything to require the tuned ECU just yet... Do you have a wide band o2 setup, can you check your AFR when it's giving you problems? Have you taken the car to a dyno lately?

GL

[s14_sport]

Yes, its ALOT of cash...and YES, its alot of time and patience. But, guaranteed if you stick to a plan, take ur time and check out all the basics like mello said above. You will weed it all out and get to the root of your problem. I've been thru alot with my RB and finally got it running right, but, that was only with persistence.

Don't give up! You'll regret it!!!

[Eikon]

I'm confused by a couple things..

Why did you go to a stand alone engine management system? If you have stock turbo and stock injectors, go back to a stock ECU. Whoever told you to buy a stand alone was retarded.. The stock internal wastegate is set for 7 psi on a stock rb25 turbo. You can swap over the Rb20 turbo spring to get to 10 psi. Or you can get a boost controller and push it higher.. at the risk of blowing your crappy old rb25 turbo.

I'm assuming your management system is tuned to keep adding fuel as your turbo builds from 7psi up to 14 psi.. but when your gate hits at 7psi, your turbo quits.. so the result is that you keep getting more fuel, but not any more air to use that fuel.. so your running super rich... and basically falling on its face.

Here's what you need to do.. GO VISIT StrNyne. He's made a very generous offer, and you need to take him up on it. He's way more of an expert than I am.. but I'll offer this advice.. go back to the stock ECU and start from scratch. Get it running properly in stock form (since your turbo and injectors are still stock). Diagnose for boost leaks, etc.. If everything checks out with the stock ECU, then you can start to work on upping boost with a boost controller and a simple air fuel device.

I'd save that engine management system for down the road. Until you decide to upgrade the turbo and injectors and really start making some power.. you don't need it. I'm not saying it's wasted money.. because you'll use it eventually.. But it's not helping you right now.

[Darius]

You know...Eikon brings up a good point. You're running a stock turbo, stock injectors and stock boost since you do not have a boost controller (that I heard of anyways). You do not need an upgraded ECU at this point, but it shouldn't make any difference when tuning. You can tune a completely stock motor for 7 psi and it should run like a champ.

With or without a stand alone ECU, this is where a boost controller comes in to play. Without it, you are NOT going to boost higher than the 7 psi of the stock wastegate spring. I was really confused when you said you were trying to run 14psi, but didn't have a boost controller and were running the stock gate and wondered why it got up to 7 psi and stopped. You are correct, that is the stock spring rate and will only allow you to run up to 7 psi. I would think your tuners would know this too.

Lucky7, cdorhout, and I have all run the motor tuned on stock injectors, stock turbo, and PFC with boost controller kit and the injectors do not max out on a reasonable tune. MAF is good to go too. I think lucky7 actually dyno'd his at 306whp on the stock setup with just a FMIC. So you are far from the tuning limits of the stock setup.

[Yellow4g63]

If you go visit sycn try and swap out your CAS with his and set the timing and see how the car drives. My friends RB25 ran like horse shyt, he got smoked by a 99 integra GSR lol. We later found out his CAS was fubared. Changed the CAS the car ran like a champ no hesitation or anything.

[HotRB240]

You know...Eikon brings up a good point. You're running a stock turbo, stock injectors and stock boost since you do not have a boost controller (that I heard of anyways). You do not need an upgraded ECU at this point, but it shouldn't make any difference when tuning. You can tune a completely stock motor for 7 psi and it should run like a champ.

With or without a stand alone ECU, this is where a boost controller comes in to play. Without it, you are NOT going to boost higher than the 7 psi of the stock wastegate spring. I was really confused when you said you were trying to run 14psi, but didn't have a boost controller and were running the stock gate and wondered why it got up to 7 psi and stopped. You are correct, that is the stock spring rate and will only allow you to run up to 7 psi. I would think your tuners would know this too.

Lucky7, cdorhout, and I have all run the motor tuned on stock injectors, stock turbo, and PFC with boost controller kit and the injectors do not max out on a reasonable tune. MAF is good to go too. I think lucky7 actually dyno'd his at 306whp on the stock setup with just a FMIC. So you are far from the tuning limits of the stock setup.

OK, I'll try to answer some questions here since everyone, and rightly so, seems confused.

I bought the car in August for $10,250. Many things are still stock, but some mods have been made. The problem is that I can't be POSITIVE that the mods the guy said he made were actually done.

Anyhow, the car wasn't running properly. When I hit the gas hard the turbo would go in pulses instead of one steady boost.

I also wanted to run more than the stock 7PSI of boost to get more HP out of the motor until I do an eventual turbo upgrade, and I was told the way to do this was thru tuning.

The tuner later told me that my system wouldn't maintain more than 7PSI of boost pressure. He told me that if I'm going to do anything else to the car I'll need engine management, so not to think it was a waste of $800

The car does have an APEXI Dual SBC boost controller, but I'm not sure if it is working correctly.

It has Walbro 255lph pump, TurboXS type H blowoff, and was bored to 2.7l and fitted with Wiseco forged pistons...

I'll be happy to answer any other questions, but that is all I can recall that is relavent.

[HotRB240]

If you go visit sycn try and swap out your CAS with his and set the timing and see how the car drives. My friends RB25 ran like horse shyt, he got smoked by a 99 integra GSR lol. We later found out his CAS was fubared. Changed the CAS the car ran like a champ no hesitation or anything.

Pardon my ignorance here, but what is a CAS?

[Coolwhip]

CAS = Cam Angle Sensor on the Exhuast side cam pulley.

[Coolwhip]

It has Walbro 255lph pump, TurboXS type H blowoff, and was bored to 2.7l and fitted with Wiseco forged pistons...

There might lay your problem. That TurboXS blow off valve might very well be leaking boost as it builds.

Anyways:

1. For a fact you do not need any tuning what so ever to up the boost (within sensable limits). This can be done by a simple $5 Manual boost controller.

Question: What Fuel management unit are you using? Didn't have a chance to look over the thread again.

2. You might be able to measure the stroke if by dropping a long stick (slim metal pole) down a sparkplug hole and slowly turn the engine from TDC to BDC and see how far the pool travel down into the cylinder well.

Suggestion: Why would you want to up the boost if you had a rough running motor to begin with? Thats like wanting to buy ligher running shoes when your legs are broken.

So like the people above had said: Pull all that extra crap off (boost controller, fuel computer, etc) and replace with factory parts. Check out the basics, and solve from there.

9 times out 10 its going to be something simple and stupid that was easily overlooked.

Good luck

[USMCgetsome]

ok killer. I read all the posts but havent read any of your wrench time. No compression test results. No multimeter voltage posts an def no timing posts. This is where u get off your duff get a multimeter compression tester and a fuel pressure gauge and get knee deep with your investment. I had a very similar if not exact issue like yours. My fuel pump was slowly fading. No real way to test that unless your under the hood while driving. Also my timing was off. Took me 2years to trouble shoot that. I had to learn how the mechanics of the motor and electrical system worked.

My suggestion. Get a 12 pack some buddies that like and know nissans and get to work. Post your findings and we'll help out as well!

[HotRB240]

There might lay your problem. That TurboXS blow off valve might very well be leaking boost as it builds.

Anyways:

1. For a fact you do not need any tuning what so ever to up the boost (within sensable limits). This can be done by a simple $5 Manual boost controller.

Question: What Fuel management unit are you using? Didn't have a chance to look over the thread again.

2. You might be able to measure the stroke if by dropping a long stick (slim metal pole) down a sparkplug hole and slowly turn the engine from TDC to BDC and see how far the pool travel down into the cylinder well.

Suggestion: Why would you want to up the boost if you had a rough running motor to begin with? Thats like wanting to buy ligher running shoes when your legs are broken.

So like the people above had said: Pull all that extra crap off (boost controller, fuel computer, etc) and replace with factory parts. Check out the basics, and solve from there.

9 times out 10 its going to be something simple and stupid that was easily overlooked.

Good luck

I would want to up the boost if I had a rough running motor to begin with IF I was told by the garage where I was taking it that the reason it was likely running rough was a tuning issue, and I was assuming, after tuning, it would be running well again and could benefit by boost increase.

Think of it as a doctor who was about to fix my broken legs also having a side business of selling lighter running shoes ;-) He fixes my broken legs and then offers me a great deal on some lighter shoes to run in.

I can't account for if the information they gave me was wrong. I don't profess to know anything about cars, I just like driving them. Rather than me trying to work on the car with no tools and even less knowledge, which I think would demonstrate the very height of ignorance, I took the car to two different garages that supposedly specialized in this sort of thing.

I value the ideas and help you people offer, but I'd be lying if I said I was going to be doing the work myself because I really don't know how to do that. I was just looking for ideas to give the mechanics where I have been taking it since they can't seem to figure it out on their own. I print these responses and take them to them. I'm sure some of you will probably be outraged to hear that I do not work on the car myself. I know what I am good at, and at least as of yet it isn't working on cars. I'd rather pay someone who knows what they are doing. The same goes for if I ever have children who are deathly ill-I'll likely not try to work on them myself; I'll probably care about them too much.