RB25 running rough now, was running fine for months

[jbballa9876]

Hello zilvians, would greatly appreciate any advise or suggestions.

I have a rb25 swapped s13, mainly stock- stock turbo, fmic, greddy intake manifold. Did swap myself, set timing etc.

Ive been driving the car for almost 8 months now without a single problem, idles great at about 600 rpm, pulls strong etc.

Driving down the highway the other day and started to lose power so i pulled over, and couldnt get it to run smooth so got it towed home.

Now after doing a few checks: alternator checked out good, checked for spark on all six coilpacks/spark plugs. Checked vacuum leaks, nothing. I thought it was a bad maf so i replaced that and no change.

It runs like the timing is bad, no power stalls out idling after let off the gas. Also when i start the car the starter will only crank for a second before stopping, and then i have to try to crank again.

Could a failing CAS cause this?

I tried to be as clear as possible explaining my situation, I would greatly appreciate any input. Thanks, Jeff.

[jbballa9876]

gonna get battery tested, battery drains over night regularly. But when i jump start the car the battery still puts out 14.5 volts so confused. I will update soon
'

[sexcii-zenki]

check timing, check plugs, and do a comp test...see if that helps

[jbballa9876]

battery was good. plugs dont look too good but i dont know how the car could have gone from running great to running so bad

[greenwood]

just because the coils are getting spark doesn't mean that they are giving good spark at all rpms. I personally have spare coils that I know are good. when I encounter an issue, i swap coil by coil.

How is your ignitor?

where did it not run smooth? How is your fuel pressure?

Easier said than done, check out your wiring, look for bad grounds. My starter wasnt grounding right and that was causing my battery to drain overnight too. Have you always had the problem of your battery draining overnight?

[jbballa9876]

No im trying to remember what happened but the battery started draining like 3 months ago, and ive been unhooking it everynight. Fuel pressure is about 38 psi at idle with vacuum attached at 1000 rpms.

I have series 2 with built in igniters in the coilpacks. It runs like the timing is really off, im about to get a timing light and have a check, and maybe unhook the fuel rail to check the injecters.

Ill probobly end up going through the wiring this weekend to check for shorts or bad grounds too

[greenwood]

does it run like shit at all rpm?

[jbballa9876]

Yea its pretty rough altogether, I didnt want to rev it past 3 to cause any more damage. It will try to go back to idle at around 500, then almost stall then jump to 1000 and keep doing that. Thanks for everyones input so far.

[chris300zr]

Check each of your injectors- with the car running pull each connector one at a time and see if your idle changes. If you pull a connector, and the idle doesn't change you have a bad injector. Good rule of thumb on coilpacks, is you have sporadic misfiring around 3000-5500rpm you may have a cracked coilpack(I had this issue, bought some fresh ones from a friend and wrapped them in high-temp electricians tape to be safe). As far as the starter, sounds like a charging issue. Double check to make sure all your grounds are tight and you don't have any loose wires (Battery, fusebox, etc.)

GL man.

[N3cronomicon]

how is your afr's?

[jbballa9876]

i tried unplugging the injectors one by one with the car on and seems like they were all working. Ill try replacing the spark plugs, but it seems like a lot of power is gone for just spark plugs to be the culprit? but need to do this anyway while resetting the timing

oh and i dont currently i have an afr gauge, just running the stock ecu (series 2)

couldnt see any vacuum leaks anywhere, unless intercooler is damaged

Is there a cheap way to check the ecu for codes?

[sexcii-zenki]

im not sure on that jdm engine too much but most older nissans have a self diag on the ecu there should b a knob with 2led lights nex 2it...turn the knob to the 1 side and perform selfdiagnostic counting the flashing leds red and green or the check eng light should flash indicating a code...if i remeber right the red will b the 1st digit and the green is the 2nd...example red flash once and green flash twice meaning code 12...or the oposite...if it wasnt ripped off a sticker on the ecu will tell u how 2do it

by like i said im not sure if the rb ecu has that... gl

[jbballa9876]

unfortunately the rb uses a cable of some kind, not the blinking light. Gotta see about gettin the cable, just dont know if i want to continue investing in this motor cause its not the most streetable power combared to say a v8, but still makes you feel good nonetheless.

tomorrow i will be getting spark plugs and update some more, and try to narrow down possible problems.

i saw this about checking the codes but doubting it will work on s13? :

http://www.skylinesaustralia.com/forums/topic/266512-reading-nissan-fault-codes-ecu-fault-codes-how-read-them/

[Fredward]

did you check the timing yet? If it feels like the timing is off then that would be the first thing id check

[jbballa9876]

So i just did a few further tests and i will do a recap of my problem.

Car is running really rough and acts like it doesnt have any power. I took off the fuel rail to see if the injectors were working and all of them were good.

I also took out each spark plug with their coilpacks and each of them fired, and i just got new spark plugs to rule out bad spark plugs.

Fuel pressure is good, a little under 40 at around 1000 rpms.

I also got another MAF to see if that could be the problem, but still acts the same.

Could a bad coolant temp sensor, CAS or TPS cause the car to runs so bad, or partially working coilpacks??

No boost leaks either. Im running out of ideas now, when the car started running like this it didnt gradually happen, it happened all of a sudden, the first time I broke down. And also there is a bad parasitic drain somewhere, the alternator and battery both test good. I plan on taking the wire harness out to make sure theres nothing wrong.

Before this happened the car had been running smoothly, and when i broke down i wasnt doing anything crazy, just cruising down the highway.

[fliprayzin240sx]

Just to make sure, you had the battery tested to make sure its good right? You didnt just hooked a multimeter to it to check the voltage?

Google search on how to check for parasitic power drain...basically you'd have to get a test light, spool of wire to get from your battery down towards your fuse panel to troubleshoot which circuit is staying on when the power is turned off.

[jbballa9876]

Yea i had the battery tested at autozone, im pretty sure it would only read volts. But yea i unhook the battery and it wont die

[jbballa9876]

It would really be great if someone knows how to check codes for rb25 in s13. I had a ka24e originally. The ecu doesnt have the leds, and I cant find out how its done

[jbballa9876]

it looks like im going to end up trying to hook up a consult plug, and buy the cable and software...

[greenwood]

Sorry if this was posted already. Have you done a compression check and made sure that you are running good vacuum etc. I would t buy that just yet. I bet it's expensive.

[jbballa9876]

I have a boost gauge so i could check my vacuum when i start it again. i havent checked compression, I rebuilt the motor recently and when it broke down i was only cruising, so not thinking its compression and i dont have the tester.

I know i should check timing also, but i set it a few months ago and it shouldnt have changed at all.

[greenwood]

I hear you. Compression check is cheaper than software. Can u post a vid and more specific details of its running shittiness? My friends RB was running garbage status, turned out to be Nast vacuum leaks and a bad TPS sensor along with a dirty maf. Cleaned all that up and she began puttering smooth again

[jbballa9876]

yea def thanks for the input, i will give the compression test a shot. Made great progress in finding the parastic drain, which turned out to be one of the fuel pump wires closest to the pump. I recharged the battery earlier, around 2 or 3 and is still at 12.3 volts.

So now just gotta find out why shes running crappy. Something broke all of a sudden for this to happen.

Also the consult wire isnt too expensive, found it for less than 40 on ebay, but i dont know which one is the right one for rb25 series 2. This is my only car, which is my "daily", but i always have the option of taking the train to class and walking to work.

^^ I will take a video tomorrow if i get a chance. It seems like its running rich though and not smooth, when i drove it around the block had all its power sapped...

[ch1873857]

you said you cant rev past 3k?

sounds like safe most

try unplugging maf . wont rev past 2 but may clear up your idle.

[jbballa9876]

no it will rev all the way up just rough the whole time. i thought it was a bad maf, tried replacing that but no change

[Croustibat]

How old is your fuel pump ?

[jbballa9876]

fuel pump is less than a year old, its a walbro. I seem to be getting pretty steady fuel pressure

[monstersisson4466]

Fuel PRESSURE doesnt actually rule out the pump, it just shows that the pump can flow enough fuel to get to the restriction in the fuel system... being the regulator. If the pump doesnt have enough FLOW then it would actually run extremely lean. We use a COTA. It tests fuel presure and the ENTIRE systems flow rate. On the vaccum at idle, does it stay at a steady hg? (EX. contant 14in Hg) or does it fludder around? fluddering around would indicate that it did indead jump timing or something like that..... Im rather new to RB's but its pretty generic engine performance diagnostics

[chris300zr]

FYI: static/base fuel pressure on an RB should be 43 PSI/3 Bar. If you DO have an adjustable FPR, try and set it to 43 PSI to see if anything changes....

[monstersisson4466]

sweet man ill keep that in mind for my RB. Much appreciation :)

[jbballa9876]

hmm i think i see what you mean with the fuel pump, i did run out of gas not too long ago

when i rev it in idle the fuel pressure barely changes, although its not supposed to

when i drive slow in second it feels as if it were in 5th gear, and it takes a bit of cranking to get it started also

Ill get a inline fuel pressure gauge and test later, see if this is the issue. I got a feeling this walbro is a dud

[EDT007]

Would it be possible for you to get a hold of a spare ecu to test out? Not sure how Nissan ecu's are but I know in my DSM (Mitsu) days the 1g ecu had leaky capacitors that would cause some funky stuff. Not to mention you've been disconnecting it every night for months, can't be the best for the ecu pins. Just a random shot. Good luck. Hope you find your issue.

[jbballa9876]

thanks for the input. No i have no backup ecu, no back up coilpacks, or backup anything, kind of why i wanted to hook up consult since the series 2 ecu doesnt give led error codes.

[sexcii-zenki]

Have u checked the timing yet? Even if the belt is new possibility tensioner was left loose...

[jbballa9876]

i torqued all timing belt tensioners properly according to the r33 fsm when i put the motor together last year

[sexcii-zenki]

It won't cost u anything to check timing and at least rule timing out as a possibility, if u don't have a timing gun take off the timing cover and recheck, I've seen it hapen lots of times where cars come in and belt jumped..the most it will cost u is time...gl

[welts12786]

Man I am having similar issues. Seems to have a good idle and drives normals even at WOT. Other times It doesnt want to stay idle and dies out or idles hops and wont rev past 4k. I just ordered all my sensors since the motor was bought off of some high school kid. I did not order a TPS. Any suggestions?

[jbballa9876]

I just replaced the fuel pump thinking i wasnt getting enough pressure. Well, that didnt fix it, but now i have a beefy q45 pump compared to my walbro- not a bad upgrade for $20.

But i looked at the coilpacks, i dont know how you would go about testing them because they have built in ignitors. However, one of the coilpacks looked especially crappy.

I took the rubber plug off all the coilpacks. One of them had white powder crap built up in it and on the spring. This leads me to believe it could be the problem? Now i need to either order an extra set of coils or pickup some ls2 coils from the junkyard.

[ch1873857]

i have a set of splitfires for neo for sale..

[jbballa9876]

^^^ literely too poor for those, unless maybe you can sell 1 or 2

[kouki-gymkhana]

Try cleaning the coil packs. Google it for the instructions.

[sexcii-zenki]

post up a few vids of the runnin condtion

[greenwood]

^yes please

[jbballa9876]

Thanks for everybodys suggestions so far. I would have posted a video but don't have a video camera of any kind but ill try to ask a friend for one soon.

I just ordered consult, that should be here in like 2 days. Also am going to put in some new coils before the weekend.

[sexcii-zenki]

Thanks for everybodys suggestions so far. I would have posted a video but don't have a video camera of any kind but ill try to ask a friend for one soon.

I just ordered consult, that should be here in like 2 days. Also am going to put in some new coils before the weekend.

not to sound like a douche, but ur fone dont have video? also did u rule out timing yet before u started ordering parts?

[jbballa9876]

No im gonna check timing soon along with compression, and my blackberry curve doesn't have video (college has made me very poor, but not for long).

So far ive only wasted $40 on a maf, and $40 on the consult program I just ordered though.

And the coilpacks im upgrading to GM which are only $70 and I planned on doing a check on timing when I put those in. One of my coilpacks had extremely bad corrosion, and a few others didn't look too good. If that's not it and I don't come up with any codes with consult I will check compression, the timing belt and go from there.

[greenwood]

Get a friend with an iPhone to upload video. C'mon man. Ur in college use ur noggin'

[jbballa9876]

Alright I installed new coilpacks and the same thing, but I almost finished wiring up the consult plug (had to pin in those wire to the ecu plug because they weren't there). Well I found the IGN pin #45 with a extremely bad looking connection upstream could have been shorting. There was bare wire hanging out with green crap around it. Ill fix that in the morning, and hopefully have consult running and report back.

The program im using for the consult plug is called ECUTalk by the way. I plan on taking apart the engine harness to check for any more bad wires that may have been contributing to this bad running problem/ battery drain issue.


Also after looking at the r33 wiring scheme in the fsm I found this IGN wire leads to a starter wire, maybe the reason why my starter seems to be struggling.

The IGN wire also leads to ignition coil, and maybe the fuel pump relay which I currently have jumped.

As long as I don't have mechanical engine damage Ill be extremely happy.

[greenwood]

Sounds good man. I hope that fixes it. One of these days I need to also go back through my wiring and clean it up

[jbballa9876]

Damn so I checked the codes with consult and got 55 (no error codes). Took off the top timing cover and guess what. It appears the belt is off a tooth. If I line up the intake cam gear on the left, the exhaust cam gear doesn't line up, its about a whole tooth away.

Also the timing belt had a crack, not front to back but in the middle.


Tomorrow I will line it back up, do a comp test...

[greenwood]

One tooth off shouldn't hurt compression, get a new belt on there don't run that cracked one and change ur oil

[jbballa9876]

^ thanks for all you input greenwood and everyone else. I would fix it today but gotta go to work. This seems like the problem to me but ill find out tomorrow, I hope your right about the compression

[jbballa9876]

Alright the timing belt is back on correctly, I rotated it about 10 times and made sure the marks lined up each time. Turns out there was shrapnel in the timing belt area, that little key that is on the crank collar, an extra one was just hanging out in there...

Im gonna get a timing light on it tomorrow, and check compression and see if my baby is fixed. If not ill be lookin for another head

[ZenkiCam]

i'm sure your head is fine. i had a 510 with an l20 and my camshaft snapped after the first set of lobes (cyl 2-4 valves werent moving *YIKES*) and fortunately when i took the head off all the valves were in the closed position and the head was still in perfect condition minus a camshaft, did a leakdown test and everything. just telling you that to ease your mind about your head being bad. goodluck with your compression test. look for consistency not high numbers.

[jbballa9876]

So I think the rb25 is all fixed and runs great now. Pretty hard to believe but this whole mess was caused by the woodruff key that either came out of the crank timing gear or was never on in the first place, scary! So I played it safe got a new timing gear and key and she seems fine now.