bet you cant figure this out

[smilz]

1991 honda civic dx 1.5 16 valve
Idle surges up and down, up and down....
changes with ac on, up...and down... up ... and down...

codes .....code 5 ...m.a.p. code
code 5 is usually a mechanical problem rather than the map sensor itself, usually caused by bad vacume lines. Can also be caused by timing, valve timing, valve adjustment, and more

ok so... idle problem with map code 5.....
compresion was good and even amung cylinders
vacume lines were all good and in the right place (checked with vacume gauge and pump)
intake manifold gasket was good. Also was replaced 3 times just to make sure
exaust has no restrictions
map sensor is good, been replaced and checked with known good map sensor
throtlebody and intake are clean and free of carbon
egr valve is good
iat sensor good
valve timeing good... checked and rechecked
ignition timing good... checked and rechecked....
distributer cap roter wires plugs are all good...
intake man holds vacume even with it idling the way it does
probally more i checked that i dont remember...

drives ok but less power than i would think it should have
has brand new, rebuilt motor ....this problem started imiediatly after instal of new motor, wasnt there before
was short block moter, so valve timeing had to be reset and intake gasket was replaced, everthing else was untouched (everything on the throttle body includeing all the sensors and vacume lines)
dies on ocasion
has the 2 injector system with the two injectors one underneieth the other.. one main and one secondary whatever
when you disconect the vacume line to the map sensor it smooths out usually

ok thats about all i can think of, ask questions if you like, someone please tell me why my car is idling this way, and has that code

[honda_luvr_2000]

my 88 CRX dx was doing the same thing only on occasion and for a little bit, then it would go back to normal operation. pretty sure it's the IACV (Idle Air Control Valve) I never bothered to fix mine because shortly after the problem arose i got my 90 CRX so i could get my 88 CRX project underway.
92 hp doesn't feel like a lot, so it very well could be pulling the most it will.
check to make sure the plug for the IACV is plugged in. it also could be that the idle is adjusted too high. since the motor is rebuilt it will have less compression leak, and the idle may have been previously adjusted to compensate for a motor w/ significantly more blow-by problems. reason i mention idle set too high, is after my swap i was playing w/ my idle, after i got it up to a point it would surge like u'r describing. when i backed it back down, it smoothed out.

[superbluecivicsi]

with the cel 5. if you replaced it with a known good map sensor and passed the voltage test, then it can only be left in the ecu. swap out the ecu with a known good one.

the erratic idle may be caused by iacv, tps, and vacuum leaks (but you already tested the vacuum so that should be fine). solve the cel 5 first, then, see if that solves the erratic idle.

if the cel 5 is not in the hose, map, or ecu, then, i dont know what else to say. cel 5 is limited to the mechanical operation of the map sensor.

[civickiller]

did you reset the ecu through all of this ?

[bestcrx1]

did you ever bleed the coolant ofter the install you could have air in the head causing the sensor to read somethings wrong then it will tell the ecu to run a certien way that could be your problum.

[smilz]

yes ecu was reset, yes the coolant was bleed...also pulled of the coolant lines to make sure coolant was getting into the iacv. coolant is there. Havent changed out the ecu yet, although i think the idle problem is what is causing the map 5 code..during the surging a sudden loss of vacume would trigger the code... I will check the idle today.. i cant remember if i checked that already ..but it is worth a try. The old mottor had bad rings and at the point when it was changed had two burned valves. will let you guys know

[Hybrid1990crx]

ok i know this is gonna sound dumb, but check your sparkplug gap, having incorrect gap can cause your vacuum to be varied sometimes.

when the idle is surging next time try to pull up on the gas pedal, my 89 had this problem, i think it had something to do with a dirty throttle body.

[smilz]

checked the idle adjustment..is good .. on pulling up on the peddle i read that somewhere so already tried that. spark plug gap is correct

[smilz]

I have read tons of threads on idle problems so most this stuff i have tried already. I believe that it is something mechanical, something like valve adjustment, that is causing my problem. Has anyone else had a similer problem being caused by a mechanical problem such as valve adjustment or cam timing ..... any more ideas before i swap out the ecu ?

[civickiller]

have you tried taking off the iacv and cleaning the little screen ?

[smilz]

yes cleaned the iacv

[superbluecivicsi]

try a different ecu.

[91CRXTC]

i swapped in a JUN chipped pr4 to run my zc and since then ive had the same problem. i have adjusted the idle screw and it would serge more when i had the screw turned ccw to open the port, but with it closed all the way it still does it just not as much or as often. Didnt have that problem with pm7 ecu.

[superbluecivicsi]

if you did all what you said in the first post, only thing left is to swap your ecu.

also, if the ecu you are using is not intended for your motor. dont use it unless the fuel and timing maps have been changed to meet your motors needs.

i swapped in a JUN chipped pr4 to run my zc and since then ive had the same problem. i have adjusted the idle screw and it would serge more when i had the screw turned ccw to open the port, but with it closed all the way it still does it just not as much or as often. Didnt have that problem with pm7 ecu.

smilz is the same person as 91CRXTC?

out of curiousity, why are you using a b18a ecu on a zc?

[91CRXTC]

no we are different people, i am using a chipped pr4 that was suggested to me by the guy i bought a set of cams from. I got a code 9 (#1 valve) on my ecu when i swapped the cams, he said to swap my pm7 with the chipped pr4 so i got a 'JUN' chipped pr4 from ebay, may not have been the best thing to buy an ecu off ebay cuz id probably have these problems, but i wasnt sure if its actually the ecu or the chip program. But when i asked a guy about chipping my pm7 he said it doesnt matter what ecu you use to chip, it just matters on what the curves are. So ive been playin with my idle screw to see if i can get it to balance out but it just wont. WTF