Jump to content
SAU Community

Recommended Posts

First post in here but I've read quite a few. Had 2 Skylines, 4 x C34 Stageas and just current M35 last 2 years. Missus still has a C34.

This one, VQ25DET, started missing about a year ago and a new set of plugs fixed it, completely.

Recently it has started missing when I get right up it - like passing with my foot down when the revs get over 5 grand.

That made me think about the fuel filter, if it was restricting flow when everything is sucking full thirsty.

Did another run that I do, bout 900 km round trip, and just a few km from home it suddenly started missing like a bastard on idle. Then it started missing under throttle and was ugly but didn't get any worse. I nursed it home in 3rd, spinning her over with light throttle to minimise the uneven-ness. Anyway, situation now is, it starts and runs fine - from cold - for about as long as it takes warm up the exhaust.

In about as long as it takes for the exhaust to cool off, it will start and run even again, but for less time.

Ran it for about 10 minutes as I parked it up on a ramp to get under it. After running longer, it would start and miss straight away 20 minutes later. Put my hand up its skirt - turbo was still nice and warm.

So it seems heat related and I don't know if it could be the oxygen sensor, a coil breaking down from running with huge plug gaps, the fuel filter - mmmm nahhh. Gave the air mass sensor a few whacks - that didn't fix it.

Any ideas or "try this to see if"s ?

  • 2 weeks later...

I've got a code reader thing you plug in under the dash - there are no fault codes.

I'm thinking it's the oxygen sensor because it plays up after getting warm. Could be the MAF too I guess.

It's the MAF. Here's some info that might be handy.

While searching for info I read about a guy who had a MAF problem where the engine would run reasonably well without the MAF plugged in but ran like shit when he did plug it in.

The guy advising him said that although the engine will die if you unplug it when it's running, the system defaults to an "acceptable" mixture setting when started without the MAF plugged in. The purpose being to make it driveable to get home or to repair.

So I unplugged my MAF, started it and the engine idled smoothly on all pots.

Plugged it back in, started it and it ran like it had a rag in the intake again.

I know not all MAF faults affect the idle but it's a simple and sure fire test to see if it is the MAF when a rough idle is part of the symptoms.

  • 2 weeks later...

Well it wasn't the MAF sensor - put in a new one. And it isn't the oxygen sensor - got a new one from Kudos and put it in.

If I unplug the MAF sensor and start it, it runs on all pots but is in limp mode - limited to 2K revs.

Plug the MAF in and it misses.

Any ideas?

Checked continuity from mouth of plug back about 20cm on each wire individually, no loss of contact on any of the wires while flexing the wires around where they are bent into the plug.

I'm looking at the ECU unless I can find a big air leak has suddenly opened up somewhere.

My Mrs sez I'm plenty clumsy. I better check them. Where are they?

Eta. Found it. Nothing going on there. Will try replacing it.

Edited by TurboHicas
  • 1 year later...

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

    • LOL, when one "money pit" is never enough Noice, and excellent work mate
    • I have more than enough digging, laying blocks, moving gravel, airrating, feeding and top soiling the grass, and setting up the veggie gardens growing some seedlings,  and then removing all the unused rock to keep me busy for the next few months at least,  hopefully the rain stops soon so I can get a few hours in this arvo, but, before that Sunday is washing day, is every body happy, you bet your life we are Nice country road day drives are a day off whenever I'm muscle sore from all the landscaping at the moment, but, more epic multiple day drives will start once the majority of the big jobs outside are completed
    • I hear that would involve some nice country road drives into the hills for Mark...
    • I thought I'd come back and add something I JUST learned. A Toyota LandCruiser with a 1HZ, mates perfectly with a bottle of Nulon brake fluid. As in, it perfectly screws in. Great make shift funnel when you cut the bottom of it off. This may work for your Corolla.   Unfortunately, tipping a 10L drum is much harder than a 4 to 6L bottle, and they no longer include the easy pour tap which was just perfection to use previously.  
    • Guys since i bought r33 gts25t coupe 1994 automatic a/t(manual swap 350z gearbox)  all i got is problems, always problems. Lets start with that when i turn key into ignition(ON) fuel pump doesnt always works. Sometimes i have to turn key twice Off/on/off/on until it primes. Its new, dw300 - 340lph. My gearbox broke so i did gearbox swap, install different intake manifold, injectors and i take pipes. Car was sitting in garage for more than half a year. I did assembly all not that long ago and when i turn ignition cant hear prime. All of sudden it stopped working. Theres many videos on YouTube how to make relay mod on r33 straight from battery so i did and it doesnt work! 😰 30 - battery positive  87 - positive from fuel pump to relay 85, 86 - one of two wires from original fuel pump wires(light blue, grey) and it didn’t work. so I check on ignition and took original BLUE relays wires from trunk, next to fuses. (I believe it’s IGN+ and ECU pin 18. it didn’t work…  tried connecting (IGN+ from og relay) and (ECU 104 from 1of4 FPCM wires) to my new relay 85/86 and it didn’t work.  I unplug FPCM. Didn’t work. im thinking what’s wrong   fuel pump is working, if I leave IGN+ on 85 and 86 straight to ground it works but it’s just nonstop. Since it getting constant 12v after key in ON. light blue wire gives me 6-8v.  so how this should be connected? What causing ECU not giving — on pin? Or I did sth wrong and that’s why it doesn’t work? I need negative signal on ECU that control fuel pump. What this should be?
×
×
  • Create New...