Jump to content
SAU Community

Recommended Posts

Hey pplz.. I guess this is the fun part about owning a car i was sposed to be going for a roadworth cert. last friday but now shes playin up :D okay..saturday last weekend i put all new plugs in my R31, that afternoon it worked perfectly...(quieter..no smoke) then the next morning i started it up, it idled fine, let it warm up then lightly put my foot down and the revs dropped? to about 500Rpm and nearly stalled, then once it got past that stage and revved it to around 2000rpm it started unevenly revving (1500 - 2500)... so any help would be greatly appreciated, changing the plugs is all i have touched under the bonnet since it started playing up..i am trying to avoid a mechanic atm as they'll no doubt charge more than i paid for the car :)Brady.

post-29588-1150186036.jpg

Edited by BradyJ_R31
Link to comment
https://www.sau.com.au/forums/topic/122109-weird-misfiring-at-2000rpm-rb30/
Share on other sites

Did you put the leads back on in the right order?

Have you re-checked that one of the leads hasn't come loose?

Did you buy the right plugs?

How did the old plugs look? (colour/condition)

Did you touch anything to do with the distributor?

You mentioned smoke prior to changing the plugs, what colour was the smoke?

Um the guy at supercheap auto picked out the plugs for me....they fit perfect and all but would surprise me if they are wrong, nah i checked all the leads and lead numbers, the old plugs had barely any soot on them but were very very old, i was going to try putting the old ones back on but i threw them all bar one : the smoke prior to the new plugs was like wispy blue smoke, evn after it had warmed up, i had a look in some other forums and some ppl said there AFM was gone....wats that lol...thnx brady

Everyone seems to jump to the AFM (Air Flow Meter) conclusion, but its rarely the cause.

If your car ran fine before you changed the plugs then there is really no reason to look at things like the AFM.

Start by looking at the plug leads - are they clean and tight fitting. Are they in the correct order?

Look at any inlet piping removed during the replacement - are any hoses loose or missing (some are under the inlet / plenum and can be hard to see).

Look at the electrical connectors - are any loose or disconnected?

Hope this helps! If not, let us know and we'll give you some other pointers!

Cheers,

J

Ahh ok, because i did have to take all the inlet piping off above the rocker cover, i did not know about too many hoses under the plenum lol, so i might have to check it out, how much (average) would all new spark plug leads cost? could be a wise investment, the old ones could be the cause aswell as they arent the best lookin ones ive seen :D

I have a set of standard leads on mine original from factory - still working perfectly.

Mate of mine had a set of after market 8mm leads on his GTS - ran like shit. Ended up putting my standard ones on the GTS...

Also, make sure your oil filler cap is tight and sealing properly. This will make a big difference if not right!

Geez i never realized how many things it could be lol but yeah this weekend i might just get in there and try it all out, maybe go back to supercheap and check the polug type, could it be anything fallin into a cylinder (dust,gunk) thats doing it? from when i took the plugs out,?..thanx a heap

Yeah it sstill starts 1st time everytime, and it idles fine (around1000rpm) but if you slightly put your foot down the revs will drop....then pick up again and at round 2000 it just fluctuates the revs, but nah i havent checked the gaps yet, thnx brady

make sure you have the right gap in the spark plugs as well this makes a big difference.

For 33's its 8mm's off head. Dont know about yours but should be similar

8mm thats a big gap!!! I think he means 0.8mm. And for a naturally aspired RB30 it should be about 1.1mm gap. Check that you didn't crack a plug when you installed them would be my advice.

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


  • Similar Content

  • Latest Posts

    • Well, that's kinda the point. The calipers might interfere with the inside of the barrels 16" rims are only about 14" inside the barrels, which is ~350mm, and 334mm rotors only leave about 8mm outboard for the caliper before you get to 350, And.... that;s not gunna be enough. If the rims have a larger ID than that, you might sneak it in. I'd be putting a measuring stick inside the wheel and eyeballing the extra required for the caliper outboard of the rotor before committing to bolting it all on.
    • OK, so again it has been a bit of a break but it was around researching what had been done since I didn't have access to Neil's records and not everything is obvious without pulling stuff apart. Happily the guy who assembled the engine had kept reasonable records, so we now know the final spec is: Bottom end: Standard block and crank Ross 86.5mm forgies, 9:1 compression Spool forged rods Standard main bolts Oil pump Spool billet gears in standard housing Aeroflow extended and baffled sump Head Freshly rebuilt standard head with new 80lb valve springs Mild porting/port match Head oil feed restrictor VCT disabled Tighe 805C reground cams (255 duration, 8.93 lift)  Adjustable cam gears on inlet/exhaust Standard head bolts, gasket not confirmed but assumed MLS External 555cc Nismo injectors Z32 AFM Bosch 023 Intank fuel pump Garret 2871 (factory housings and manifold) Hypertune FFP plenum with standard throttle   Time to book in a trip to Unigroup
    • I forgot about my shiny new plates!
    • Well, apparently they do fit, however this wont be a problem if not because the car will be stationary while i do the suspension work. I was just going to use the 16's to roll the old girl around if I needed to. I just need to get the E90 back on the road first. Yes! I'm a believer! 🙌 So, I contacted them because the site kinda sucks and I was really confused about what I'd need. They put together a package for me and because I was spraying all the seat surfaces and not doing spot fixes I decided not to send them a headrest to colour match, I just used their colour on file (and it was spot on).  I got some heavy duty cleaner, 1L of colour, a small bottle of dye hardener and a small bottle of the dye top coat. I also got a spray gun as I needed a larger nozzle than the gun I had and it was only $40 extra. From memory the total was ~$450 ish. Its not cheap but the result is awesome. They did add repair bits and pieces to the quote originally and the cost came down significantly when I said I didn't need any repair products. I did it over a weekend. The only issues I had were my own; I forgot to mix the hardener into the dye two coats but I had enough dye for 2 more coats with the hardener. I also just used up all the dye because why not and i rushed the last coat which gave me some runs. Thankfully the runs are under the headrests. The gun pattern wasn't great, very round and would have been better if it was a line. It made it a little tricky to get consistent coverage and I think having done the extra coats probably helped conceal any coverage issues. I contacted them again a few months later so I could get our X5 done (who the f**k thought white leather was a good idea for a family car?!) and they said they had some training to do in Sydney and I could get a reduced rate on the leather fix in the X5 if I let them demo their product on our car. So I agreed. When I took Bec in the E39 to pick it up, I showed them the job I'd done in my car and they were all (students included) really impressed. Note that they said the runs I created could be fixed easily at the time with a brush or an air compressor gun. So, now with the two cars done I can absolutely recommend Colourlock.  I'll take pics of both interiors and create a new thread.
    • 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.
×
×
  • Create New...