Jump to content
SAU Community

Limp Mode

Barras

By Barras,
in Four Door Family & Wagoneers

 Share

Recommended Posts

bigkevracer Grand Master

bigkevracer

Posted
Posted

I seem to be having the same problem, except more intermittent.

Car threw a code on the dyno for TPS, without completely killing the throttle.

I didn't have great throttle response afterwards, but the throttle _always_ worked.

We cleared the code, throttle response was better.

Now twice in the last few days it has suddenly lost all throttle response, just idles. This wasn't on WOT or taking off, just normal street/highway driving. I pull up ASAP, turn the car off, turn it immediately back on, and throttle is fine.

No code clearing, no mucking about: Goes bad, turn off, turn back on, goes good.

I think it could be one of four things:

  1. TPS sensor - most sensible thing given that's the code it threw
  2. Cruise control, which has a T piece in the throttle - both times it's happened so far I've had the cruise control on and I've either been using cruise or just turned it off
  3. F-con throttle map
  4. Throttle wire on the ECU, where I had to splice in the wiring for the EVC

None make sense to me given the weird behaviour. I'm thinking of disconnecting the throttle T-piece for the cruise and seeing how it goes. If it continues, replace the TPS sensor.

Anyone else noticed anything similar?

scotty nm35 Grand Master

scotty nm35

Posted
Posted

I had to disconnect a cruise the other day for the same fault, I have also seen the throttle assembly being the issue. (tps)

Mine did the same thing with the pivot throttle controller plugged in, any resistance difference between the two throttle signals will trigger limp mode.

Try disconnecting the cruise for a while, it may well be the answer.

Daleo Grand Master

Daleo

Posted
Posted

I seem to be having the same problem, except more intermittent.

Car threw a code on the dyno for TPS, without completely killing the throttle.

I didn't have great throttle response afterwards, but the throttle _always_ worked.

We cleared the code, throttle response was better.

Now twice in the last few days it has suddenly lost all throttle response, just idles. This wasn't on WOT or taking off, just normal street/highway driving. I pull up ASAP, turn the car off, turn it immediately back on, and throttle is fine.

No code clearing, no mucking about: Goes bad, turn off, turn back on, goes good.

I think it could be one of four things:

  1. TPS sensor - most sensible thing given that's the code it threw
  2. Cruise control, which has a T piece in the throttle - both times it's happened so far I've had the cruise control on and I've either been using cruise or just turned it off
  3. F-con throttle map
  4. Throttle wire on the ECU, where I had to splice in the wiring for the EVC

None make sense to me given the weird behaviour. I'm thinking of disconnecting the throttle T-piece for the cruise and seeing how it goes. If it continues, replace the TPS sensor.

Anyone else noticed anything similar?

I have just had this happen on mine too, throttle hasn't failed, but response is really lazy below 3000 rpm, with basically no boost.

I actually thought it might've been a camshaft position sensor.

Reset once, was fine for a couple of days, then lazy again. Reset, but noted the code, which was 1705; throttle body.

I'm running cruise control also, but I have been for well over a year now with no issue. I don't think that's the issue.

Going to have a poke around tomorrow, check plug & pins are clean & plugged in; but I would think the next step is a spare known tb to see whether it returns.

I'd be interested to hear what you come up with Ryan.

bigkevracer Grand Master

bigkevracer

Posted
Posted

Cheers guys.

I'm with you Dale, don't think it is cruise control. Doesn't make sense after a year of fault free running.

On the other hand it is the easiest thing to test, and of Scotty thinks it could be a signal problem I'll give it a try.

Just weird the problem didn't appear until the fcon went in...

Daleo Grand Master

Daleo

Posted
Posted

After another look at the fault code listing, mine is actually; P1705 Throttle Position Sensor Circuit A/T

This could also explain why mine didn't want to kick down, or unlock the converter with a small throttle input.

I might be looking elsewhere...

bigkevracer Grand Master

bigkevracer

Posted
Posted

After another look at the fault code listing, mine is actually; P1705 Throttle Position Sensor Circuit A/T

This could also explain why mine didn't want to kick down, or unlock the converter with a small throttle input.

I might be looking elsewhere...

Easiest thing is to replace the sensor though, or that's what my thought was...

Commsman Veteran

Commsman

Posted
Posted

You've had some stuff going on with your car lately, hey Ryan.

I also don't think it's the cruise as mine hasn't given me that problem either (although I don't drive it much ;) ), but like you say - it's easy to rule out as it only takes a minute to unplug the throttle harness.

If the fault appears semi-regularly now, it shouldn't be long before you know. Hopefully it's not the F-Con but a TPS as that's means the F-Con is OK (as the last 'electrical' mod you've done it has to be high on the list of possibilities). It could also be the cruise control interacting badly with the F-Con, but I don't know anything about how they wire in so just throwing it out there...

The timing of the fault is a bit of a coincidence with the F-Con going in though, & I have a hard time believing coincidences, so good luck with the fault finding.

bigkevracer Grand Master

bigkevracer

Posted
Posted

I have Leon, although most are my own doing so can't entirely blame Mr Nissan.

I find it hard to believe it would be the F-con, but like you said it is one of the last electrical mods. Scotty has been running the F-con with the cruise for a while now without issue, and I also find it hard to believe it'd be the mapping for the throttle in the F-con if the throttle completely dies.

They wire in by plugging in between the ECU plug and the ECU, entirely piggy back, except for a MAP and IAT sensor harness in my case.

Daleo Grand Master

Daleo

Posted
Posted

dale, I have a spare TB and pedal sensor if you want to try them on your car for a few weeks

Thanks Iain! I'm going to see if it comes back this week, and I'll be in touch.

I still have to get the name of the shade sail place for you too.

Cheers, Dale.

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
      Starting again

      By GTSBoy · Posted

      This is the GTR fuel pump. Yellow shows 12V, orange shows earth. The ECU provides the earth to activate the fuel pump relay. The ECU side of teh relay will pull low when the ECU activates. This is the RB20 fuel pump. Almost the same, but a little simpler. You can see I indicated (above) where the 12V line goes down to the RB20 diagram on the overall diagram, whch shows both RB26 and RB20. This is where I show it coming in on the RB20 diagram below. You can see that the dropping resistor is handled differently. When the fuel pump control is not providing earth to the pump, the pump earths through the dropping resistor and thus runs at lower voltage (some is wasted over the resistor) and runs slower. I showed that "not 12V and not quite earth" portion of the wiring in a paler orange. The rest of the wiring that I did not colour on that little section below the pump would be orange when the fuel pump coontroller is providing earth. This drop is handled inside the fuel pump controller in the GTR. Regardless, you can see where 12V is supposed to be, where earth is supposed to be. The key on prime is via the ECU providing the pump for only a few seconds the switching off. You should be able to see that happen.
    • Duncan
      Starting again

      By Duncan · Posted

      Yeah so when you turn key to IGN the fuel pump should run for a few seconds. If you find the fuel pump relay (and have a multimeter, and a second person) to can check the relay inputs.  One trigger pin should be either fully earthed  The other trigger pin should get 12v from the ECU for say 3 seconds when you turn key to IGN, and at all times that key is at START (note, I said this from memory, it may be the other way around, ie one pin always has IGN 12v and the earth has continuity to earth when you turn the key) One Pin should have a good battery voltage The last pin goes to the fuel pump + Also note that if the power to the relay is good, and the relay is working, it is worth checking the pump has a good earth too. There is a computer in the standard system that increases the earth resistance to slow down the pump when not required, pretty old school and it may have failed
    • Ozdavroz
      Starting again

      By Ozdavroz · Posted

      All this talk about fuel and fancy ECUs, meanwhile my poor old R32 has neither.... When the ignition is turned on, should there be power running o the fuel pump constantly or just for the few seconds it usually takes to prime the pump? About to go have another look at it, have watched some YouTube vids on how to use a  multimeter and looked at some wiring diagrams but really have NFI what I'm looking for because electricity is invisible  
    • GTSBoy
      R32 Nostalgia

      By GTSBoy · Posted

      Yuh....but weren't all the supertourers, except maybe the Audis, FWD? I don't recall any of the others being AWD.
    • Duncan
      R32 Nostalgia

      By Duncan · Posted

      They ran them in Oz Super Tourers too https://www.supertouringregister.com/register/vehicle/212/ (I'm so old I remember racing with Matthew Fox) They ran them in Oz Super Tourers too https://www.supertouringregister.com/register/vehicle/212/ (I'm so old I remember racing with Matthew Fox)
×
×
  • Create New...