My idle on my engine has started bobing up and down a bit. Ive seen this digussed before but worse than mine so i thought id get an opinion before i look at replacing the tps.

At idle it bobs between 900 and abot 500 rpm although tonight it has got a little lower 300rpm. If i put the air con on it goes as low as 200 and has even stallled once.

The next bit is more noticable in first or second gear. If i drive along at about 1600-2500 rpm as if i was just pottering along in traffic, keeping it at constant revs it sort of bounces as if i have kangarro juice in the tank. It tries to accelerate slow down accelerate etc. When i put my foot down no problems and no problems in any other areas really.

Does this sound like my tps to you? any answers from anyone in the know would be appreciated

Thanks Jon

 

Nope, sounds like your Idle air bypass and your throttle adjust screw are outta wack.

Disconnect your Idle air bypass and block off the hose to the IAB

Block off the hose connection to the stock elbow.

The engine is now forced to idle of just wait air sneaks past the TB. Play with the idle adjust screw until the idle is 800 RPM and steady.

Then turn on EVERY electrical accessory you've got. AC, Lights, brights, fogs, stereo, etc..etc.... again, play with the idle adjuster screw on the TB untill the idle is stable at 800 RPM.

Turn off accessories, turn off car. Re-connect hoses. That should solve your idle problems.

If the off throttle surging still continues after this, let us know.

 

Hey Jon - Do you have a blow off valve installed? If so is it a recirculating type or does it just vent to the atmosphere?

Thanks... I'm just curious... as I too have the surging problem and while Random's technique has made my car very drivable it still shows the exact same symptoms you describe.

Later...

Oh and my recirculating blow off valve looks really nice sitting in my garage - wink



[ October 30, 2002, 03:30 PM: Message edited by: iTiburon ]

 

Jon is MAP based.
He shouldn't have any problems using a recirculating, or non-recirculating BOV.

You only need the Re-circulating BOV if you have a MAF based engine.

 

Er.. ummm yeah.... I knew that... rolleyes.gif rolleyes.gif



Damn... UK'ers.... wink

 

Thanks Random ill try that after work today and let you know.

[ October 31, 2002, 08:24 AM: Message edited by: Jon ]

 

No did that and its still the same. It appeared to idle better for about 30 seconds then went back the same. When i took the pipe of it went like mad but even when i clamped the pipe and blocked off the elbow it went onto it still did it. I take it it was just that one pipe i had to take off and then block that and the elbow off.

 

If it still does it, after you blocked off the pipe to the IAB...then chances are, either your IAB or TPS are bad.

One easy way to tell, is to disconnect them. You Will more than likely get a CEL light from having the IAB disconnected, or the TPS disconnected, but it should narrow it down for you.

Warm the car up, let it idle, then disconnect the IAB. If the car's idle stays erratic, then the problem is TPS. More than likely, your idle will shoots up to a high RPM.

If you disconnect the IAB and there is no change, try reconnecting the IAB, and then disconnect the TPS. If it settles down, you know it is the TPS.

 

What i have alredy done is disconnected the IAB, i take it its that black rubber hose going to the elbow on the inlet, and the revs went up and down like mad. I also disconnected the plug to the TPS and the only change i noticed was if i bliped the throttle it didnt come back down the revs properly. But as for the idle before i blipped the throttle it didnt change it still bobbed about the same.

I can see the pipe but which bit is the IAB is it just the pipe on the front of the manifold or is there more to it?

 

Sorry, I meant the electrical connection to the IAB, not the hose to the IAB.

Ditto for the TPS. I was refering to the Electrical connection