SR20det Deceleration problem, **VIDEO INCLUDED** <-- CLICK

[venom369]

Besides from my SR not engaging in "warm up mode" (higher idle)on cold starts,

This is the next and only problem I am facing:

When deceleration the engine hangs around 2k rpm for a second or two.

I know this isn't normal therefore it is annoying /frustrating, as we all strive to have a flawlessly running vehicle lol,

Tps is at 4.5v, (reset the ecu after I adjusted it) and the engine has a perfect idle.

http://www.youtube.com/watch?v=y8J_eoe5gtE

If anyone you has come across this and has figured this out hanging problem out. please share your wisdom here!

[compactfean]

I would remove the iacv and take it apart and clean it...careful not to loose the small spring. Also make sure to clean out the coolant ports and everything in that area too. Also clean out the throttle body.

[venom369]

Thanks man , that is next on my trouble shooting list,

however

I have also heard of a bad tps causing that similar hanging issue I am having.

Has anyone had this issue with a bad tps.
& What would the effects of a faulty OR improperly adjusted tps?

[compactfean]

Come to think of it you say your tps is .45 closed or 4.5 v closed?

[venom369]

my mistake, its .45 volts =]

whats different from being at.45 rather than .55 volts.
less is leaner? higher is richer?

[compactfean]

Kind of....the majority of afr is adusted by the maf but if the tps is not adjusted correctly it will not allow ecu to go into idle mode or open loop. If you had a consult cable and monitored "open" or "closed" throttle ive seen some cars not register that the throttle was closed until .38 v. According to the fsm anywhere between .3 and .5 is ok....because of nissans habit of running rich I set mine at .35 to .38. I still run rich though. Lol

[venom369]

lol veryy good info here man thanks!, this is very useful.

Tomorrow I will reset the tps to around .4 (and go lower if necessary), and report back with the results!

[compactfean]

Dont forget that when you adjust tps you have to readjust timing as well.

[kingtal0n]

For the rpm to stick like that, extra air has to be flowing into the engine. If the throttle body is closed, air cannot enter that way, so it must be entering through your IACV motor. If you block the IACV tube off (clamp the rubber hose with a vice grip) the problem should dissipate (to confirm diagnosis)

At which point, you need to figure out why. most likely the computer feels that the 2,000rpm hang is necessary, or the IACV is bad/worn/dirty.

If it turns out to be related to the computer, it may have to do with input from a sensor (tps/maf/coolant/knock/etc) or something in the computer. I noticed the engine seems to dip very low in RPM and idle rough, this is an indication that either you have some aftermarket cams (hopefully) or the maf/computer is reading incorrectly, perhaps there is a vacuum leak or a stick value in a sensor.
Start out by figuring out if you have the right computer first. If its an OEM redtop, it should be a #62. If you have a #63 for instance, that is automatic transmission, and the engine may hang like that due to deceleration expectancy from the VSS or something weird like that.

[venom369]

Yes its the right ecu, # 62 (just checked)
Nope, stock cams

I checked the ecu for codes and it showed 34, which is the knock sensor.
I just rewired the connections, they were very loose inside the clip.

I will be checking the timing tomorrow and resetting the tps voltage.
Which order should this be done in?

Also. quick question regarding the iacv:
What is the "standard/normal" position of the adjustment screw.

All the way in? a couple turns out? whatever it takes to work? lol . just curious

Thanks for any more info!!