Jump to content
SAU Community

Recommended Posts

Hi All

This abit of a long story, sorry. :)

Ok this is the history behind the problem. I decided that it would be a good idea to pull out the engine so I can replace the clutch and in the mean time I replaced the oil pump (N1 item), water pump (standard) and timing belt (standard). I also replaced all the seals on the intake and exhaust side of the engine. Injectors where ultrasonically cleaned. I have put on aftermarket dumps and front pipe. I also cleaned out the idle control unit (pulled it apart and cleaned), throttle bodies (I pulled out the butterflies to clean them), intercooler and piping including bypass valves, painted and cleaned the intake plenum. I have not touched the computer or the tuning.

So when I put the engine back in the car started to idle high (around 1200) and rough (sounds like it is back firing). So I searched thought the forum and searched everything from rough idle to how to adjust idle, I have tired the following to no avail:

- Cleaning AFM’s

- Replaced spark plugs (to iridium tip NGK ones)

- Checked timing belt marking so they match up twice

- Did a computer diagnosis check which came up with a faulty TPS.

- Have done idle adjust procedure according to manual and FAQ guide

- Screwed the idle screw in completely.

- Checked vacuum lines (but I don’t have proper vacuum line diagram so I don’t know if they are connected in the right way)

- Pulled apart TPS and checked it too but it seemed fine.

I think that’s it.

I am trying to avoid pulling off the plenum.

So if anyone has any ideas, I am all ears. I am getting sick of the car not running.

I may have missed some details so I wrote this at work and I keep getting interrupted.

Link to comment
https://www.sau.com.au/forums/topic/183491-rb26dett-high-idle-and-miss-firing/
Share on other sites

i had problems with a high idle a while ago the hose which comes off the intake manifold had a crack in it , this made my car run rough as well so i would be double check all the air hoses , im not sure what a broken TPS causes

Ok update, I brought a new TPS and installed it, the car idles abit better but still high and rough. Checked the computer and now says TPS and knock sensor error.

Whats a stepper motor? is that the distributor?

When i put the butterflies back in they didnt seems to sit properly. and yeah there was light coming through.

Are you serious about not cleaning the butterflies?

I had a slight missfire was due to the seals between the turbo intake manifold @ the plenum, also the ones between plenum and motor being buggered, new seals stopped the misfire might pay to check yours

Another update, I took off the intake plenum and the butterflies have a very slight gap on the top and bottom, does anyone know how to get the butterflies to close properly? do i just pull them out and try to find the throttle body that they fit into correctly?

Ok update, I brought a new TPS and installed it, the car idles abit better but still high and rough. Checked the computer and now says TPS and knock sensor error.

Whats a stepper motor? is that the distributor?

When i put the butterflies back in they didnt seems to sit properly. and yeah there was light coming through.

Are you serious about not cleaning the butterflies?

I need a new TPS for my RB20. Mine idles really high aswell, but not rough. Where did you get ur TPS and where can I get one for an RB20?

I need a new TPS for my RB20. Mine idles really high aswell, but not rough. Where did you get ur TPS and where can I get one for an RB20?
Morgan, your problem is possibly an out-of-alignment TPS not sending a "throttle closed" signal to the ECU. Does the engine tend to maintain revs on gear changes?

The fix has been covered - search.

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

    • How's your first born doing? 😛 As for now what? Time to forget about it for 12 to 18 months while your go down a totally unrelated rabbit hole... 😛
    • Fuse taps are perfectly fine to use, especially when you're adding stuff for your own car, and so long as you're being smart about it. IE, don't throw a 30amp circuit, onto a circuit that is only a small circuit. It's best to add a small circuit, to one that is already quite large. Oh, and make sure you're not going to blow the fuses that are further upstream too! I dislike their use in other applications, such as alarms, telematics/tracking devices etc, as it's far too easy for someone to unplug them and render a system useless. Those sorts of devices I go for wiring in quite secretively.
    • Fob is all cleaned up and it’s working well!! The amount of Vegemite looking sh*t that was in there is mind blowing 
    • Given it is temporary, I bought a  cheapy gauge mount (which has become enflattened) which I will screw into the existing phone mount Also a first for me; given this is a temporary install I could not think of any reason not to use one of those "add a fuse" thingies to source the battery and IGN power. I had always figured they were pretty dodgy but having a good look at them I think they are a valid option for sourcing power from an existing source without cutting 
    • Finally for now, a bit more work on the transmission temp gauge. I was wondering how Raceworks do a gauge for $100 that autometer want $500 for. No idea about the accuracy of course, but they have cut a few corners that made things hard.  First one I mentioned above, the sender is physically difficult to fit and doesn't work with their own adapters (the extra fittings I used to get the sender into a hose cost more than the whole gauge, lucky I had stuff in the shed) Second, the temp sender wires are way too short. They are shown as 2.7m on the box and I know my routing was long from navigator headlight to driver's firewall back to centre console, but I had to lengthen them by about 2m total - 2 joins in each wire. Also, same with the supplied power loom, they needed about an extra 1m to get the fuse box where I sourced power. Another join in each wire since one end wasn't supplied terminated. I know they could argue that the wires might be long enough depending on situation, but when you consider parts and particularly labour, it would be a very expensive cheap gauge if you can't do the work yourself. And, only a small issue....but it would have been nice if they remembered to tap a tread onto *both* spacers they supplied for the bracket....I haven't had to use the M4 tap often!
×
×
  • Create New...