rb swap and cannot get to run right...help

[rb 90 240]

I posted this up in a different forum but this is the right area I think:

I recently purchased the car already swapped and trying to troubleshoot. This car has a rb25 and once the car starts to rev it has power. Then shortly after maybe 3-3500rpm the power just stays about the same and just builds rpm. The car starts up great and runs smooth as hell. I just cannot find out what might be the issue. It has the stock side mount intercooler and stock piping. Has the stock downpipe and high flow cat with 3" catback. I believe its the stock maf and throttle body but I dont see any way how either of those could be an issue. It has an adjustable fuel pressure reg on the car, anyone know the correct fuel pressure? Its running 7 # of boost currently. The car pulls just up to the time the turbo is spooling and then just doesnt make anymore power after that.

Anyone that might have anything to help me out with let me know. Im clueless at this point. It reminds me of how motorcycles that are not jetted right and make power but then just stop once you start building rpm.

[FriedEGs]

do you have an accurate boost gauge in teh car? Aftermarket fuel pump that works? does the car feel like it's missing or sputtering at teh higher range? (similar to carbs that won't rev) How many miles on the motor?

If you have a fuel pressure gauge under the hood, it should idle around 35 lbs. of pressure...

btw, what part of Ohio are you from?

[matafied]

i would check your timing first, and then your maf

[rb 90 240]

I am from columbus as well, north end. Car has 255 pump

Ill have to get a fuel gauge hooked up to see if the guy before me adjusted it correctly. Im wondering if he just threw on the pressure regulator and never correctly adjusted the fuel pressure.

Car itself is a very solid body but just need of paint which we are going to do:

[mello88]

Hey man

Check these things, I bet one of them solves your problem:

#1 Bad/failing coilpack. I think you're experiencing the power loss because of a bad coilpack, your symptoms sound identical to my friends RB25 s13.. Does your engine miss at idle? If it does... Unplug each pack individually at idle to see if the RPMs drop.

#2 Boost leak. You might have a boost or vacuum leak, since it sounds like it runs OK up until you start to boost. Build, buy or steal an intake pressure tester.. Basically a cap with a tire stem that you can clam onto your hotpipe... Make sure the PCV, BOV, brake booster and other aux vacuum systems are capped off. Pressurize your piping + intake to 15psi, then listen for leaks. Could be a leaky BOV or loose T-Clamp, etc..

#3 Timing. As mentioned before you should check your base ignition timing to make sure it's right on.

#4 Fuel pressure. You should have 43.5psi (3 Bar) of fuel pressure in the rail with the FPR vac hose disconnected. If you're too rich you'll loose power and have a hard time starting the engine. Worth double checking yourself just to make sure it was done right by the prev owner

PS, do yourself a huge favor and download the engine field service manual. You'll find a link in my signature, get either the R32 or the R33 manual. Don't forget to post a reply to your thread if you get it solved.. GL!
Modified by mello88 at 10:51 AM 9/10/2007

[FriedEGs]

Alright, another RB in Columbus!

Yea, dl the FSM, it will help you out a lot. Espcially for timing procedures.. (4th mark)

And whomever installed the FPR should've bought a fuel pressure gauge in order to set teh fuel pressure. He/she may have used one to se it than took it out, but if not, then it's prolly not set right. Go to your local Jegs and get a B&M fuel pressure gauge which costs around $25 bux, and plumb it in right after your fuel filter and before the fpr. Use NPT fittings to match the hose and use fuel line clamps. While you're at it, spend 6 bux and replace that fuel filter with one for a Z32 300ZX.

Good luck!

[rb 90 240]

The local shop told me its prob a boost leak from what I have described. Although I talked to the owner who installed the motor and never hooked up a pressure gauge when installing the FPR. So I know the fuel pressure has to be out of wack for sure. He said it was some weird metric thread and couldnt get a gauge to work!?!? It is pig rich at idle and when running, very strong raw fuel smell for sure. I dont think its a coil pack, fires directly up and idles smooth as glass.

Ill get the FMIC plumbed in and while doing that Ill try and check all vacuum and other hoses. Thanks for the tips, hopefully I can get this figured out, its driving me nuts.

I have a greddy copy intake and g45 throttle body that came with the car. I wanted to get it running first before I did anything. Will those be alright or will it be overkill for a fairly stock motor?

[FriedEGs]

I'd be a little wary about the intake manifold that you have... Find out who makes it and see how well it flows air evenly across teh cylinders..

Get that fuel pressure gauge!!! Make that your very next priority! You don't need anything special to plumb it in. You can use sae threads on the npt fittings to reduce the size to fit the stock hoses. Use Fuel line clamps.

Also, coilpacks most likely won't give any problems at idle until they are really bad, but they will cuase problems under load.

[nuffboost]

Hi. I just wanted to add that I'm having the same problem with my S14 with a SII RB25det. The engine make about 190hp @3000-3500rpm and then just stays there all through the rpm range.Here is my current setup.AEM-30-1621Greddy Intake ManifoldQ45 Throttle bodySard Fuel Pressure Reg. @43lbs off vacFull 3" exhaustGreddy SpecII Boost ControllerFMICNGK Iridium PlugsGM Map SensorGM IAT Sensor

[rb 90 240]

Hi. I just wanted to add that I'm having the same problem with my S14 with a SII RB25det. The engine make about 190hp @3000-3500rpm and then just stays there all through the rpm range.Here is my current setup.AEM-30-1621Greddy Intake ManifoldQ45 Throttle bodySard Fuel Pressure Reg. @43lbs off vacFull 3" exhaustGreddy SpecII Boost ControllerFMICNGK Iridium PlugsGM Map SensorGM IAT Sensor

I have been busy as hell and not much time to even mess with the car but this weekend Ill start. If I figure anything out I will let you know and if you find out what is causing your issues, let me know. You describe my exact situation as well.

[nuffboost]

I found this post. Check this out.Not sure about the neutral saftey switch thing as it relates to the timing, but its sure worth to look into. Can anyone confirm this is the case?

zerothread?id=177365

[FriedEGs]

I found this post. Check this out.Not sure about the neutral saftey switch thing as it relates to the timing, but its sure worth to look into. Can anyone confirm this is the case?

zerothread?id=177365

I don't think this guy in here has an automatic ecu, though.. it's irrelevant

[nuffboost]

So I took of my front covers to make sure my timing belt was setup correctly. Right on the money. So as a test I advanced the CAS just a little than what I had it set at which was about 15 degrees. Didn't have a timing light to check but I figured its around 20 now. Wow what a difference in the power. Today I'm going to check to see what its set to. So I'm leaning towards timing being the problem or the VCT but its a sealed unit and not sure how I would check to see if its working correctly.
Modified by nuffboost at 6:39 AM 9/13/2007

[240z4u]

My car ran just as you describe when I first did my swap (before setting up timing).

I think your on the right track.

Evan

[Abdo]

I took my covers off and messed with my CAS a few months ago, I hope my swap doesn't have these types of issues!

[dipstickinva]

PS, do yourself a huge favor and download the engine field service manual. You'll find a link in my signature, get either the R32 or the R33 manual. Don't forget to post a reply to your thread if you get it solved.. GL!

Modified by mello88 at 10:51 AM 9/10/2007

sorry this is off topic but just letting you know that the file for the Nissan skyline RB20 Engine Manual is not downloading or working. i tried getting the manual my self. anyway you can get it working?

[FriedEGs]

go to the "links" section.. or "files".. (one of the two) on http://www.racebread.com

btw, rb 90 240 .. Did you get your motor running properly?

[rb 90 240]

go to the "links" section.. or "files".. (one of the two) on http://www.racebread.com

btw, rb 90 240 .. Did you get your motor running properly?

Nope, no luck at all, I was up at Quaker Steak last week talking to a few people in the columbus area about the issues. There were 2 dudes up there, one with a rb25 s14 and one rb26 swap. Tried to find out their thoughts and ask if they woudl work on it but didnt seem to be interested. I will pay anyone but i just want the car to run right, sucks I am just clueless

[eh?]

Who installed/dynoed/tuned your car??

Seems like user error to me. They did not set up the aem correctly. You do not have to touch the CAS. Base timing is 20 not 15.

[FriedEGs]

Nope, no luck at all, I was up at Quaker Steak last week talking to a few people in the columbus area about the issues. There were 2 dudes up there, one with a rb25 s14 and one rb26 swap. Tried to find out their thoughts and ask if they woudl work on it but didnt seem to be interested. I will pay anyone but i just want the car to run right, sucks I am just clueless

lol.. I was the guy in the black S14..(25) What car did you drive out there? Did I meet you?

There's gonna be another big turnout tonight.. If you're there, just look for me.. we can try to work something out..


Modified by FriedEGs at 6:51 AM 9/28/2007

[rb 90 240]

lol.. I was the guy in the black S14..(25) What car did you drive out there? Did I meet you?

There's gonna be another big turnout tonight.. If you're there, just look for me.. we can try to work something out..

Modified by FriedEGs at 6:51 AM 9/28/2007

I dont think I talked with you, I talked to the dude witht eh 26 swap about fuel pressure and he was showing me I believe now it was your car how to run that inline pressure gauge to start there. I was in the green supercharged 99 cobra last week, left around 1230(had a few races lined up) and came back around 2am. I was there last night as well in it but didnt see your car there, I didnt get there till around 1130 though.

As for the swap eh?, I bought the car already completed. It was someone elses project car and Im working the bugs now. I think he was close but just didnt know everything. The motor is about 100% stock, there isnt aem standalone on the car. I would think the stock computer is more than capable to run the car the way it is.

We did find out a few issues. I found one port on the very back side of the intake wasnt pluged. Fixed the slightly high idle and as soon as that happened the plugs were fouled out and didnt get to drive it. Check the fuel pressure with the inline gauge and was getting around 55lbs! Pulled the plugs and they were black as ****. So now im going to head down and try and get an adjustable pressure regulator and new plugs to see if we are getting close.

[rb 90 240]

dont really know what the boost controller had to do with it, I took it off just process of elimination and that is part of the cure. had a leak off the back of the intake manifold, boost controller, corrected fuel pressure and a few other small things. finally Im able to get it to rev to around 5500 or so before breaking up. So we are getting close, just not all the way there, damn its a ***** to buy someone elses project half *** finished

[eh?]

Sorry my post was directed towards nuffboost.

[DriftX]

Timing issue?

[rb 90 240]

Im going to try and search the forums for how to time this motor and check. I have a timing light just dont know how to do it on the rb motors. If anyone has any link to doing this, let me know as well

Thanks

[nuffboost]

I believe it was my fault seeing I changed the timing belt and did not mark the CAS. Also we were unsure of the base timing on the car we set it to 15. But its all been adjusted correctly at 20 and she runs great.

[mello88]

Did you ever get your car running nicely?

To time the RB it's pretty simple, there is a wire "loop" in the back of the engine near cylinder #6 coilpack. Attach the Inductive pickup to that for the gun, then adjust the CAS as needed. I can't remember if you need to unhook the TPS first like you do on the KA? Read the FSM.... It explains it all.

Speaking of that did you ever get a copy of the FSM? You should be able to find a good link on here, or at Racebread or even on google. It's called something like R32 engine manual.pdf

BTW the guy who did the swap -- who the hell installs an adjustable FPR and doesn't adjust it? They don't come pre-set...

GL