Jump to content
SAU Community

Recommended Posts

For a while now my 32 gtr has been carrying on a bit first thing in the morning. On light throttle it sort of misfires and I can hear the air going chew-chew-chew (while I've still got the power down). On more throttle I can hear this loud sucking noise, but it is way down on power.

But then as the temperature gauge gets to half way, it’s like a switch has been flicked and the car becomes totally normal, full power and full boost available. All good.

This is something that’s been getting gradually worse, but today (coldish day) the switch didn’t flick when it warmed up and it carried on like this for ages. Got out looked for loose hoses or anything like that, but all appeared normal. I turned it off, waited a minute, turned it on again and everything was sweet. WTF?

I’m thinking it might be a dodgy air flow meter screwing with the computer as it fixes itself so quickly. Does that sound right?

Things I can rule out:

- Turbos – because they are the best part of a week old and it was doing this before

- Oxygen sensors – brand new

- The plugs were recently checked out and gapped

Ps. Running stock computer

  • Replies 46
  • Created
  • Last Reply

Top Posters In This Topic

you really want to check the coolant temp sensor. this sensor is used for fuel enrichment when the engine is cold.

chances are its stuck at a hot value (resistance) and the car is running real lean when its cold.

can measure the resistance of the sensor with an ohm meter with it disconnected or use a volt meter with it connected to see if its in spec, but either way from your description this sounds the culprit.

Hey, I'll be interested in what you find is wrong. I have a 33 GTR with the exact problem. However i have not replaced the oxygen sensors. But i did check the coolant temp sensor last night, i got a reading of 2.4k ohms which is a little below the spec of 2.6k at 20 degrees.

Jazza.

Jazza,

not sure if I can add value to this issue, but I wouldn't expect the diference in resistance between 2.6k ohms standard vs 2.4K ohms measured will be an issue - that difference is within 10% - so I suspect you have another gremlin somewhere.

Typical electronics specs for resistors (non automotive) is +/- 10%. Automotive won't be very different.

Mike

The battey has been in the car since i have owned it (about 8 months) it sometimes sounds like it's lacking cranking power if havn't driven the car for a few days.

Whats interesting is if i rev the engine (below 3k) it has the missfire and chutter, then if i unplug the O2 sensors it revs freely. Makes me think there giving the ecu wrong readings.

I've checked alot of other things i thought it may have been like trying another good set of coils, changing igniter, changing plugs & gaps, cleaned air flow meters & check voltages, throttle voltage, fuel pressure, coolant temp sensor, timing, there are no ECU error codes are coming up. So it's got me pretty buggered at the moment.

Thanks for your help.

The fact that it ran OK after you stopped and re-started suggests the battery is on its way out. You don't know how old the battery was before you got the car, so it could well be the source of the problem.

If you are not prepared to replace the battery immediately, get hold of a mate's that you know is relatively new and see if that cures the problem.

Sorry, i wasn't that clear. The car only runs like crap when it's cold. When i unplug the O2 sensors while it's running like crap and rev it, it clears up and revs smoothly. That gives an indication of a faulty sensor or incorrect reading maybe.

It runs fine when it warms up, and like the post above, it's almost like a switch gets flicked because the car goes from running very poorly, e.g. hesitating and chattering out the air filters to absolutely fine and normal in half a second.

Thanks for you help, i will replace the battery soon to something with more grunt.

Yeah well as I said in my original post my o2 sensors are brand new as they were changed with the turbo/dumps a week ago - so rules them out in my case.

I'm going to see how much a new coolant temperature sensor is tomorrow, and also see about my air flow meters. I have heaps of oil and crap in my intake pipes (bigger issue) so that's why I suspect afms.

I'll keep you posted.

I have a sim Issue but it happens sometimes even when the car is warm going to take it to hyperdrive tomorrow let you know what they think and maybe it might give you a direction

any updates on price of coolant sensor?

Yeah rang up today about the coolant sensor. The guy sounded a little confused... he concluded there is a sensor right near where the top radiator hose goes into the block that sends messages to the computer. It's $93.40 retail price and the part number is 2263001U00 (if I can read my shite hand writing correctly).

I'm going to hold off on it until I can rule out my afms. I cleaned them today with electrical spray, but obviously can't see if it's made any difference until the morning when it's fully cold. I'll let you know.

The AFMs wont be the culprit because the cold issues disappear instantly every time once the temperature reaches a certain level. (like flicking the light switch on) Ive got the same thing when i run my standard computer. When i run a non-tuned PFC, then the problem isnt there.

I reckon rb30-POWER is onto the problem...it has to be temperature related

Well this morning, after cleaning the afms and resetting the computer - it didn't do it!

But I'm not going to claim victory yet - I bet the twisted bastard of a car is just playing games.

So yeah anyway RB30, that would be tops if you could give us a run down on testing the coolant temp sensor. Firstly, where is it? I'm told it's near the top radiator hose - but there seems to be a few different sensor looking things around there.

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

    • Yeah, plenty of air flow, there is a dedicated path that feeds the air in to the OEM intake tube behind the bumper As for a "tangible effect", maybe, but getting the pod/intake air out of the hot engine bay is worth it psychologically to me, even if it gives no performance difference, so the tangible effect in my Lizard brain saysss yessss  In the end, to me a tangible effect isn't always about performance, sometimes it a sound or a look, or even a...... feeling  Ooga-Chaka Ooga-Ooga Ooga-Chaka Ooga-Ooga Ooga-Chaka Ooga-Ooga Ooga-Chaka Ooga-Ooga
    • yeah first and reverse is where you will find clutch release issues (whether hydraulic or mechanical) because the difference in revs required is the highest there; particularly changing down from 2nd to 1st when still moving. To be clearer though, it is possible that the clutch release bearing is the wrong height. This is less likely than a hydraulic issue but it is not unheard of when you are mixing and matching
    • Quite right, if you make it to that pension you deserve every cent
    • Hi all, Restoring r33 series 1 rb25det. All the heater hoses were on their way out, have replaced them and put it all back together. After testing I noticed a small leak from behind the head on the actual metal water line to the turbo when cars warm. I tried running a longer hose over it but it kept leaking...   I am about to take the (stock) manifold off again😔 to change the water line does any one have any lines they recommend? I was looking at Aeroflow Turbo Oil & Water Line Set but not sure what everyone else recommends. Car is completely stock but want to upgrade turbo eventually. it looks like ill have to disconnect a lot just to replace these lines so if there's anything else recommended to do please let me know. Thank you in advance!
    • From memory, on the R33 GTSt at least, while everyone says "It's not adjustable", I found when I changed clutches in mine, it just needed a small adjustment on the rod length. But be very wary here, as you could end up trying to push the pushrod in the master too far, or blowing out the slave.   Most likely though, if the master/slave isn't bypassing internally or leaking out, then the throw out is the wrong height compared to the fingers on the clutch, so when it moves to disengage the clutch, it isn't 100% disengaged. You can check part of this out too by jacking the car up, having the engine running, put your foot on the clutch and try to engage 1st gear. If it goes in pretty easy (Compared to the ground) and/or the wheels start turning a fair bit and it takes a bit too much brake pedal to bring them back to a stop, this is likely the issue.  I'm not sure if you can adjust the height of the forks etc in these though, it's been that long since I've touched any RB gearbox.
×
×
  • Create New...