'96 Eunos V6 Idilling problems - Help Please!

[wizedkyle01]

Hey Guys

I have a '96 Eunos V6 1.8L, since around last week or so if i drive the car hard and i stop at a set of lights the car rpm dies while its idling generally i can rev the engine to sop it from stalling though this morning it did stall after i stopped reving it. The car normally revs at 700rpm sometimes drops to 600-500 but picks up really quick. So after about 5 mins or so of "easy" driving the car drives perfect and it idles fine when i stop. I thought it was a vacum hose but the car drives fine and the revs are fine when im driving.

So im a little stumped on what is going on any ideas would be good ?

cheers.

[Newfie_dan]

you will need the following denso part number for the obd2 mx-3; Denso # 234-3085, if rockauto does not have them then you can order them direct off the denso web site.

[wizedkyle01]

Cheers mate is that an o2 sensor or some sort of sensor?

[Newfie_dan]

that is the correct factory 02 sensor.

[wizedkyle01]

Before i go and spend money on o2 sensors i forgot to add this morning as i was in a hurry for a lecture, it only happens in traffic as soon as i take it on the highway it runs perfect not a thing wrong, the air filter is also extremely dirty so im replacing that tommorow and as soon as the auto choke turns off and its at optimal temp it starts to have the idle problem.

[Mooneggs]

yeah before you spend a ton of money on factory 02 sensors, check your TPS, IAC and check for cracks in the "accordian" looking plastic intake tube. Tiny cracks in that can cause a rough idle or stalling!

[davmac]

you will need the following denso part number for the obd2 mx-3; Denso # 234-3085, if rockauto does not have them then you can order them direct off the denso web site.

I think this is a response to another thread:
http://www.mx-3.com/phpBB3/viewtopic.php?f=15&t=73892" onclick="window.open(this.href);return false;

[umcamara]

Yeah... I think Dan accidentally posted in the wrong thread.

I have the same problem sometimes with brand new Bosch O2 sensors. Do NOT just go out and buy new O2 sensors.

[davmac]

Idle is controlled by engine computer output to idle air controller (IAC). The most important inputs are coolant temp sensor (green), throttle position sensor (TPS) and VAF (vane air flow meter). Your problem seems that when the car has been run hard and is hot the idle control gets confused. I’m going with temp related issue – the coolant temp sensor is bad or coolant level is low (or there is air in coolant). When running hard you push coolant around and temperature rises. You could be inducing air into coolant if there is a leak somewhere.
Check coolant level and test coolant temp sensor.
Bleed air from coolant
As others have suggested check air tube to throttle body for cracks allowing unmetered air to go into the engine.
For good measure check resistance of the IAC (black cylinder under the throttle body), check and set the TPS – with ohm meter and feeler gauge as described in the service manual.

[wizedkyle01]

I thought i would add some more detail. The car runs perfect at cold once its almost at optimal temp it doesnt hunt but falls to 500rpm and if left stalls once it gets past this little interim stage and gets to optimal temp in runs fine and idles fine.

[Newfie_dan]

davmac your a little off on your description of the coolant issue, when coolant is moving you can not induce air into the system, its a pressurized system meaning that if there was a leak then coolant would leak out and that gets replaced from outside air, so inuction is not exactly how it gets into the system. He would have a trace of a coolant leak if that were the issue. With that said if the coolant temp sensor is not totally immersed in coolant it does burn out causing issues with idle, check the coolant level as davmac had said then check the resistance with the engine at full operating temp it should be somewhere around 1.8k ohms. The idle will hunt if the coolant temp sensor is off, mine did this when the car warmed up to near operational temp, once I replaced it the idle was fixed. Also check for vac leaks like the other guys said as well as replace the pcv valve, a faulty one can cause the near stall condition you mentioned when stopped.

[wizedkyle01]

Found the problem on the air intake hose theres about a 5 cm crack along one of the "trenches" in the ripple part of the hose, taped with a bit of duck tap for the moment till i can get a replacement this week

[Mooneggs]

yeah it's a common problem - cracks hiding in the ripples... always check the easy simple stuff first! glad you got it sorted...

[SpatialTerror]

hey guys. i do believe he said its a 96.
any guesses on what that means?
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Its obd2. get a code reader

[wizedkyle01]

???