Jump to content
SAU Community

Rb25det Intermittent Power Loss

BlackLine33

By BlackLine33,
in Engines & Forced Induction

 Share

Recommended Posts

BlackLine33 Contributor

BlackLine33

Posted
Posted

Hi guys,

Have done some research on SAU and online but haven't come up with a definitive answer yet.

Car details: bog stock except turbo back exhaust, aftermarket bov, turbosmart boost tee @ 8 psi, brand new yellow jackets,

Milliseconds after hitting boost it feels like I've hit a brick wall (like foot is off the accelerator when it physically isn't). I'll try to accelerate again but instead it's an intermittent violent herky jerky motion as if I'm repeatedly on and off the accelerator. If I attempt to smoothly apply throttle without boost it may pick up again. Sometimes I will come to a stop and car will stall. While car is decelerating I can see the boost guage fluctuate according to the pressure I'm applying to the accelerator. Though not as pronounced, the engine sometimes will also cut out intermittently after a warm start on idle and stall...doesn't happen on a cold start. The other night also had trouble starting the engine from warm. It would crank fine but would only fire for a second then stall. Tried starting repeatedly and got it to idle fine after about half an hour of attempting.

Thought it could've been coilpacks so I got brand new ones along with plugs and dropped them in but same issue.

I've recently cleaned the AAC valve and AFM in the past month.

I've read that it could be the cam/crank angle sensor? Possible timing issue - RnR? Fuel cutting?

Any advice appreciated. Thanks.

Link to comment
https://www.sau.com.au/forums/topic/464480-rb25det-intermittent-power-loss/
Share on other sites
GTSBoy Grand Master

GTSBoy

Posted
Posted

Coils were the obvious choice. Next most obvious is a dodgy solder point on the AFM. You might be able to fix that yourself. Have a search for howtos.

Faling CAS is possible, but doesn't often give the symptoms you report. Failing fuel pump could.

It is not R&R unless someone has advanced your CAS all the way.

BlackLine33 Contributor

BlackLine33

Posted
  • Author
Posted

Thanks for the responses. Last time I cleaned the AFM I had a look at the soldering on the joints and it seemed fine. Maybe the actual measuring element is playing up.

Will be trying another AFM. Is the R34 AFM interchangable with the S2 ECR33? The part number for the S2 ECR33 AFM is 22680-31U05 and the website says it is compatible with R34 as well (http://www.rhdjapan.com/nissan-oem-maf-mass-air-flow.html). However I'm looking to buy an AFM with the part number 22680-31U00 since it is cheaper..I'm thinking this is the R34 GTT one. Can anyone confirm before I hit the buy button?

Sklyn Grand Master

Sklyn

Posted
Posted

just to be sure, when you say 8psi, that is on an aftermarket boost gauge right? and not the stock gauge. Stock one is not psi.

If you cant boost properly how do you know its set at 8?

Was it all working fine then suddenly one day this started? or Did it gradually get worse over time?

what was the last thing you did before this happened?

  • Like 1
BlackLine33 Contributor

BlackLine33

Posted
  • Author
Posted

Yep 8psi as seen on an aftermarket boost gauge. I've since had to remove it due to it being a defect but when I had it on it did read 8 at WOT.

Prior to the issue the car was running fine and it read 8 psi.

Just happened suddenly. I remember first time I experienced it.. I was at a red light and gave it a decent launch and the car got all herky jerky on me. Didn't know what it was but I cleaned the afm with CRC but didn't resolve the issue. It has since gotten worse over time. I don't remember doing anything major prior to the start of the problem.

BlackLine33 Contributor

BlackLine33

Posted
  • Author
Posted

Also, just as a precaution I checked the coil packs and plugs. I found one of the coil packs didn't have a spring in it as seen through the hole which sits on the plug. I thought this was the problem. Spark plugs didn't look to have any abnormal wear. So I bought brand new YJs but issue still persists.

Sklyn Grand Master

Sklyn

Posted
Posted

The reason I went with YJs is for the post sale support.

I have only ever heard bad things about their post sale support, but if thats what you want.... Would be nice if you can report back with positive feedback on the YJ's eventually though.

try replacing the afm ( borrow before buy :) ), double check all piping and connections, remove boost T and just run wastgeate actuator pressure.

Just starting with the basics and cheap options. hope you find the problem soon.

BlackLine33 Contributor

BlackLine33

Posted
  • Author
Posted

Not too sure how this turned into a flaming thread.. Didn't ask for anyone's opinion on the coil packs I bought.

Anyway I got a working afm and it has seemed to fix the problem. Thanks to the guys who provided feedback about my problem.

  • Like 1
Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

Hopefully when your coil packs die they're still in the warranty period so you get a brand new set (brand name clearly not mentioned, so vendors don't has a sads).

I had two coils die out of warranty, bought two new ones. Kept missing firing gave up, bought Splitfire coil packs and they're still running like a cut snake till this day, even with added dwell because I live life on the edge.

#keepdosing

  • Like 2
admS15 Grand Master

admS15

Posted
Posted

Hopefully when your coil packs die they're still in the warranty period so you get a brand new set (brand name clearly not mentioned, so vendors don't has a sads).

I had two coils die out of warranty, bought two new ones. Kept missing firing gave up, bought Splitfire coil packs and they're still running like a cut snake till this day, even with added dwell because I live life on the edge.

#keepdosing

Ffs u blokes r all missing the point here. Who gives a shit what brand coils he bought. A dose pipe will cure all misfire issues. That is my new recommendation for these type of threads. Should of bought a dose pipe.That is all.
Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

Ffs u blokes r all missing the point here. Who gives a shit what brand coils he bought. A dose pipe will cure all misfire issues. That is my new recommendation for these type of threads. Should of bought a dose pipe.That is all.

Ahh very true, excuse my ignorance and lack of knowledge.

Yes a dose pipe will fix the issue and introduce good backfires on deceleration like a bawse!

Suuuuuutututu pop flame brap lol

  • Like 1

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      R33 Fuel Pump & Brakes after alarm swap

      By GTSBoy · Posted

      Power is fed to the ECU when the ignition switch is switched to IGN, at terminal 58. That same wire also connects to the ECCS relay to provide both the coil power and the contact side. When the ECU sees power at 58 it switches 16 to earth, which pulls the ECCS relay on, which feeds main power into the ECU and also to a bunch of other things. None of this is directly involved in the fuel pump - it just has to happen first. The ECU will pull terminal 18 to earth when it wants the fuel pump to run. This allows the fuel pump relay to pull in, which switches power on into the rest of the fuel pump control equipment. The fuel pump control regulator is controlled from terminal 104 on the ECU and is switched high or low depending on whether the ECU thinks the pump needs to run high or low. (I don't know which way around that is, and it really doesn't matter right now). The fuel pump control reg is really just a resistor that controls how the power through the pump goes to earth. Either straight to earth, or via the resistor. This part doesn't matter much to us today. The power to the fuel pump relay comes from one of the switched wires from the IGN switch and fusebox that is not shown off to the left of this page. That power runs the fuel pump relay coil and a number of other engine peripherals. Those peripherals don't really matter. All that matters is that there should be power available at the relay when the key is in the right position. At least - I think it's switched. If it's not switched, then power will be there all the time. Either way, if you don't have power there when you need it (ie, key on) then it won't work. The input-output switching side of the relay gains its power from a line similar (but not the same as) the one that feeds the ECU. SO I presume that is switched. Again, if there is not power there when you need it, then you have to look upstream. And... the upshot of all that? There is no "ground" at the fuel pump relay. Where you say: and say that pin 1 Black/Pink is ground, that is not true. The ECU trigger is AF73, is black/pink, and is the "ground". When the ECU says it is. The Blue/White wire is the "constant" 12V to power the relay's coil. And when I say "constant", I mean it may well only be on when the key is on. As I said above. So, when the ECU says not to be running the pump (which is any time after about 3s of switching on, with no crank signal or engine speed yet), then you should see 12V at both 1 and 2. Because the 12V will be all the way up to the ECU terminal 18, waiting to be switched to ground. When the ECU switches the fuel pump on, then AF73 should go to ~0V, having been switched to ground and the voltage drop now occurring over the relay coil. 3 & 5 are easy. 5 is the other "constant" 12V, that may or may not be constant but will very much want to be there when the key is on. Same as above. 3 goes to the pump. There should never be 12V visible at 3 unless the relay is pulled in. As to where the immobiliser might have been spliced into all this.... It will either have to be on wire AF70 or AF71, whichever is most accessible near the alarm. Given that all those wires run from the engine bay fusebox or the ECU, via the driver's area to the rear of the car, it could really be either. AF70 will be the same colour from the appropriate fuse all the way to the pump. If it has been cut and is dangling, you should be able to see that  in that area somewhere. Same with AF71.   You really should be able to force the pump to run. Just jump 12V onto AF72 and it should go. That will prove that the pump itself is willing to go along with you when you sort out the upstream. You really should be able to force the fuel pump relay on. Just short AF73 to earth when the key is on. If the pump runs, then the relay is fine, and all the power up to both inputs on the relay is fine. If it doesn't run (and given that you checked the relay itself actually works) then one or both of AF70 and AF71 are not bringing power to the game.
    • Kinkstaah
      My BMW E39 528i touring

      By Kinkstaah · Posted

      @PranK can you elaborate further on the Colorlock Dye? The website has a lot of options. I'm sure you've done all the research. I have old genuine leather seats that I have bought various refurbing creams and such, but never a dye. Any info on how long it lasts? Does it wash out? Is it a hassle? What product do I actually need? Am I just buying this kit and following the steps the page advises or something else? https://www.colourlockaustralia.com.au/colourlock-leather-repair-kit-dye.html
    • GTSBoy
      My BMW E39 528i touring

      By GTSBoy · Posted

      These going to fit over the big brakes? I'd be reeeeeeeeaaaall hesitant to believe so.
    • PranK
      My BMW E39 528i touring

      By PranK · Posted

      The leather work properly stunned me. Again, I am thankful that the leather was in such good condition. I'm not sure what the indent is at the top of the passenger seat. Like somebody was sitting in it with a golf ball between their shoulders. The wheels are more grey than silver now and missing a lot of gloss.  Here's one with nice silver wheels.
    • soviet_merlin
      My BMW E39 528i touring

      By soviet_merlin · Posted

      It's amazing how well the works on the leather seats. Looks mint. Looking forward to see how you go with the wheels. They do suit the car! Gutter rash is easy to fix, but I'm curious about getting the colour done.
×
×
  • Create New...