its a 99 civic ex with a jdm b20 swap in it, the swap has a 99 si engine harness on it from when i had my old b16a swap. i am having some issues with my car.... two that are bugging me and i cant figure them out exactly. number one i cant get my tach on my gauge cluster to work, it worked properly before my car had shut off on me for no reason at a stop light. i replaced the ignition switch since my old one was fried. ever since my car shut off on me my taach doesnt work and i know it works properly. i have taken your previous advice stated in one of my posts about changing the ignitor in the distrbutor actually i changed it out with a new dizzy and yet still nothing from the tach. so im ready to buy a new gauge cluster but i dont really want to unless its a must.
Number 2 problem is that my car has had this rfeally wacky idle ever since i put in the jdm b20 swap. i have an obd-1 p75 ecu unchipped with the proper conversion harness for it. ive replaced the map sensor and tps and they are both new items so i know they are good to go. im thinking it might be my IACV since it is old but then again i could be totally wrong which is why im asking you for your input on these two issues. oh my car will start up and idle at 1400rpm then once it warms up it goes to 800rpm and then when i press on the gas and let off it, the car goes to 200-400rpm and then sumtimes dies on me so i have no idead what it could be causing the engine to be idleing so horribly. ive checked all my grounds that i have on the car everything is there and tightened down. please help me if at all possible any advicce you have would be greatly appreciated since i am almost at my whitts end with this car. im really just thinking its my IACV that needs to be replaced.

 

What intake manifold are you using?

IAVC can be cleaned in 10 mins of work. have you tried to clean it?

Did u re-wire the distrib correctly for the B20?

Have you calibrated the new TPS?

 

Unlike 96-98 Civics, the tach signal for 99-00 Civics and their OBD2b wire harnesses comes from the CKP sensor via the ECU. However, the OBD1 P75 ECU does not have a terminal to output a tach signal to the cluster. That's your problem. Therefore, to get a tach signal to the cluster, you must run a wire from the igniter unit in the distributor to the cluster. I am assuming this missing blue wire is not already built into your conversion harness.

Start by cleaning the IACV as mentioned, and also the TB.
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Also, please create informative thread titles that reflect your tech question. Title edited.

 

i have calibrated my TPS and have also cleaned out my IACV two times and yet the idle issue still persists. i need to try and get another iacv and go from there. as for my tach issue is there any obd2b ecu i can use for my car to get it going without doing the wire from my ignitor? im stumped though when i first started my car with the obd-1 p75 my tach worked for a week, so im lost on how it just lost signal randomly, also could it be my conversion for my ecu? should i try and get a new one?

 

Is there a blue wire attached to the ICM? If so, check this wire for continuity and a short between the ICM and cluster.

There's also a tach plug near the clutch reservoir. Check whether it has continuity from there to the cluster. If so, you could run the ICM blue wire to the tach connector to get the tach working.

Idle problem -- start by thoroughly cleaning the TB and make sure the throttle cable is not adjusted too tightly. It needs to have some slack in it.

 

i dnt know bout the blue wire being connected the ICM i will have to take apart my dizzy today and see if it is there. the plug near the clutch reservoir i checked that yesterday and there is a blue that i saw that you speak of, i will check continuity, actually on second note how would i check that with a multimeter?
the idle issue i have cleand my TB many times infact before i threw my new b20 in, i cleaned it ill try cleaning it out once more and see if it helps. also my throttle cable is loose enough to have plenty of slack in it, so im good to go there

 

For the idle speed, you may just need to adjust the idle speed as detailed in the B20 service manual.

Continuity test:
You can ground one end of the blue wire and check for continuity to body ground at the other end. Set the multimeter to a low Ohm range like 20 or 200, or to continuity, for this test. Continuity generally means a measurement of less than 100 Ohms.

 

hmm i dont have a b20 service manual so i wouldnt know how to adjust the idle speed...and i will definatley try out the coninuity test as you have stated aboved. as for grounding the blue wire how would i go about doing that...sorry im a newbie on muiltimeters and wiring so i am a bit slow i appologize about that?

 

Disconnect it from the igniter unit and splice/twist a wire to it so that it can reach the black battery ground (-) terminal. Attach/ground it there.

 

ok i will disconnect the blue wire from the ignitor and test it from there with the steps you have provided. so all im looking for is an OHMS reading of less than 100 for this wire?

 

just remebered that i have an obd1 IACV it has the smaller hole on it, i was wondering if putting an obd2 iacv on would help my chances of getting my car to idle properly or does it even matter at all?

 

went to my shop this morning and put on another iacv and my car idles better its just low and my idle speed screw is almost all the way out

 

tried this and everything else that has been suggested about my idle....nothing is working i dont have any vaccum leaks and my car wont idle high enough to stay on its still in the low 400rpm range my throttle cable has bout an inch of slack in it since i havent messed with it since i stretched it putting in the b20 swap. so im thinking ill just have to adjust the calbe at 1/2" and go from there...if anyone has anything to say or advise me on this idle problem please do speak up please.....

 

nevermind...fixed my issues....tach wasnt workin due to a bad ecu conversion harness, got a new one now it works flawlessly, and i fixed my idle with a new IACV, the other one i thought was good but it was actually an old one that was off a customers car which ended up having a bad valve.

 

alright back on here to get some good input...i put my iacv on yesterday and noticed i do have the 99 si throttle body. i dnt have an fitv. im having trouble with my idle still. i try to do the idle speed adjust and my car shuts of right away as soon as i unplug the iacv and evap purge plugs. i try and start it back up and it either wont start or wont stay at idle after holding the gas pedal downat 1000rpm. need help im almost ready to sel this car its making me that mad. oh and i just replaced the o2 sensor. idk if tht helps anyone...but i need some help guys asap! thanks

 

bump need help asap....

 

okay so i think i might have a bad intake manifold gasket...cuz i just remebered that i reused my old one from my old b20 setup, not the best idea to do. and the gasket itself was in okay condition not brand new. im thinking i should replace this. also i did the idle speed adjustment today for the 4th time and my car dies after i unplug the iacv and evap purge solenoid. i can start my engine up after it dies but it wont idle at all it just dies. so what does this mean exactly? anybody please help i want this problem fixed. the iacv i have is my 3rd one in a week i know its a good one it came from a friends perfectly running car.

 

bump anybody please help...

 

did you ever figure out what was wrong with the car?