I just switched my ecu's in my 93 del sol with a b16 swap. I had a chipped p28 but switched to a usdm p30. the knock sensor is wired up. The idle surges even after sitting for a little while with no headlights/ac/anything on. I don't think its a vacuum leak because it never did it before, and it has absolutely no CELs... just trying to see what else someone might think it is... Thanks

 

my sol does the same thing and i dont think it is a vac leak either....im getting it on the road thursday and im gonna bring it to get checked out!

 

EDIT: Nevermind, I'm retarded.

 

It happened right after you switched the ECU? Start with the IACV and fast idle.

 

if we plug the chipped p28 back in everything is fine... so wouldnt that rule out the iacv and fiv?

the ecu surges like its an auto ecu, but is not. socket R17 has no resistor and it looks like it never did, the ecu looks like its never been tampered with.

The surge is a consistent 1000rpm to 1500rpm.

Something else thats a little iffy on the wiring of the car is the IAT sensor. Its just plugged in and hanging there. It has always been this way, before the p30 install so I dont think it would be causing this.

 

I had a problem similar to this, and it was getting to me getting to me because it would work fine on a P13, but on a p28, it would surge. I traced it to a bad wire on the IACV (not saying this is your problem).

The idle surge is at any engine temp?

BTW, I have ran auto p06s on a manual with no surging.

 

any other ideas?

 

idle only seems to surge once the car warms up.

I unplugged the IACV plug and the surging goes away. However, for driveability issues we need the IACV hooked up.

 

I swapped my stock ecu and vafc for a chipped p28 running uberdata and ran into the same problem. I adjusted my idle and it helped a bit, but once I had it tuned, it went away considerably. Are you running any software? I know this isn't much of a help

 

My sol did the same things when i went i used a chipped p30 it would be fine but if i cut j1 and ran it un chipped it would surge but would calm down if i turned on the headlight..huh never figured it out though cuz now im running uberdata

 

So strange ........ask the seller if he had any issues

 

Why did u swap ecu's Amy?...If I may ask

 

switchd because usdm p30 is the RIGHT ecu for the motor, nothing beats oem ().

It did seem to react when I switch the headlights on as well, but not all the time.

I just don't understand what could be different between the p28 and the p30. Next step is to try the ecu on another obd1 5sp car and see if it does the same thing... if it does then the ecu must be bad...

The knock sensor was wired in for this ecu that wasnt used previously but I dont think a knock sensor has absolutely anything to do with idling...


Modified by dunkd at 1:58 PM 6/1/2005

 

Yeah mines idles a bit too not too bad its a b16a with a p05 converted to p28 chipped...im gonna clean out the IACV see if that helps.
Its funny cause when I had my EF swapped z6 with a p28 it also idled changed the IACV and FITV and still did it.
Arggggggggggh cars are a pain at times

 

Take off the intake tube and plug the bottom hole in the throttle body. If the car idles normally then it is the cold air idle bypass on the bottom of the throttle body. What I always do is just take the three 10mm bolts out that hold the cold air idle bypass on and just cut out a piece of gasket to block off both of the vacuum holes. You only need this bypass in very cold (less than 30 degrees) weather. Make sure you cut a hole in the gasket for the coolant to pass through. Then you should be good to go.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tizom57 &raquo;</TD></TR><TR><TD CLASS="quote">Take off the intake tube and plug the bottom hole in the throttle body. If the car idles normally then it is the cold air idle bypass on the bottom of the throttle body. What I always do is just take the three 10mm bolts out that hold the cold air idle bypass on and just cut out a piece of gasket to block off both of the vacuum holes. You only need this bypass in very cold (less than 30 degrees) weather. Make sure you cut a hole in the gasket for the coolant to pass through. Then you should be good to go.</TD></TR></TABLE>
oh yeah i forgot you could give that a shot but Idk why it wont do it b4 with the other ecu

 

ttt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by japspecjohn &raquo;</TD></TR><TR><TD CLASS="quote">oh yeah i forgot you could give that a shot but Idk why it wont do it b4 with the other ecu</TD></TR></TABLE>

yea really

 

try my p30 at marcus!! if my car makes it that far....hopefully its fixed tomorrow