MSefi.com read only forum (Jan.15,2018)

i swear i had a membership here a long time ago... ha ha ha... back to newbie.

i havnt played with my civic for 5 years. but i recently put it back together.

1983 civic, EL1 motor, ported head, custom cam, venolia pistons, turbocharged, multiport efi, edis

ms2, 3.0 board, 2.88 code

my car is running but i am having an awful problem with the engine surging... at idle and cruising... when i first noticed the problem was electrical, it was because i was tuning with the alternator not running. i had left the field wire off. then when i connected the field wire again to charge the battery i noticed it ran worse. (long story why i tune with alternator off, laptop battery useless and my crappy tire inverter fails when the car is charging)... however the car charges nicely and keeps a constant voltage.

soooo, i put a toggle switch on the alternator and played with it some. it definitely made a difference. so tonight i redid all my grounds and checked everything over. while doing so i did another test. with the car NOT running, i cranked my sterio and every bass hit from the woofer the tps would blip. only 1-2% but this is narrowing the problem with my erratic running. so i tried different grounding scenarios and could only make it worse, not better than 1-2% blipp. without running engine. when looking at the accell meter it is obvious it accells every bass note hit.

sooooo, something is wrong with my grounding im sure. but i cant track it.

-my WBo2 sensor ground wires are all soldered together and bolted to the firewall
-relay board batt + to battery itself
-relay board - to old distributor adjust bolt on cylinder head
-relay switched power from key (also powers EDIS and WBo2 sensor)
-tps ground to relay board
-air temp ground to relay board
-coolant is a single wire GM unit grounded to the block. the relay board coolant return is grounded to the firewall

thats my story for today... ha ha ha.... boost is fun, moore boost is more fun!!! but i cant play with that till i get this noise sorted out....

shnitz

just a little update... i had a spare alternator here, so i tried it. same irratic rpm cycling going on with it. as soon as i turn off the alternator it runs much better. sterio can still disturb the TPS. and when i rev it i also see the coolant bliping slightly....

my grounds are pretty awesome... i dont THINK thats the problem... but in the end, maybe it is.....

shnitz

I don't use a relay board, but my MS grounds all go to the same point on the engine block. All the sensor grounds are connected together just outside the DB37, and then one wire from them to pin 19. I can't see why you'd ground to the firewall. The idea is all grounds go the the MS so there can't be any differential current flow.

ill play with that some today then. ill rework my O2 sensor wires to the engine head, and ill send the coolant temp grounds there too. i wish i had a 2wire coolant sensor. but a am seeing the blips in TPS too, so i dont think my single wire sensor is the only problem...

keep ya posted.

well, thank you trakkies....... i hated that relay board from square 1.. could'nt ever figure out how to wire it right, the grounds and all..... and for a while ive been wanting to do this. sooooo, i cut into my cable from the MS to the relay board, slaughtered all the grounds and wired them how they were supposed to be from square 1... now sure enough all my electrical noise is gone.

ive read this time and time again, and still, needed to be told myself. so thanx for being patient.. ha ha ha...

running good and back to tuning. or no, a beer for celebration!!! tuning again tomorrow.

i found my old stuff, its over on the msruns site. cause the car did run. but i bet its goona be much better without all that noise!

however, now anyone searching for sterio noise will find this thread...... maybe benefit to some.

all 5 ms grounds to block, o2 sensor wires to block. and all other sensor returns to the MS return line. much better. still might buy that other 2 wire coolant sensor though.

thanx,

shnitz

old msruns link:

http://www.msruns.com/viewtopic.php?f=94&t=22420

My car already had EFI, so had the two relays needed. I merely modified the original loom for MS. However, the relay board does make provision for all the sensor grounds including the TPS so won't introduce ground loops. What I've not seen is an external wiring diagram for it - like the one for the MS. But then I've not really searched for one.