94 Q45 Ecu Pinout

[vududoc]

I was troubleshooting an Idle problem to find no voltage to the IACV. Does anyone have the ECU pinout for a 94 Q45?

[Q45tech]

The ignition fuse supplies +12 volts to IAC and other 4 engine solenoids..[plus O2 heaters].........ecu grounds the solenoids [treminal #111]

[vududoc]

some one just sent me a fax of the power routing for the QIts a bad print out though. ill try to spiff it up and post.

P.S. I have no ecu pinout guide at all.....need point of reference for terminal 111.

[Q45tech]

You are missing the point the IAC electronic portion is not absolutely necessary for a low rpm idle..........clean TB and screw the IAC bypass screw out 2.5 turns from all the way in ...........you should then have a 550-600 rpm idle.

Apply 12 volts DIRECTLY to IAC solenoid terminals, the rpms should go to 1200-1500 rpm.

Not having +12 volts on one of the IAC connector harness terminals means the fuse is blown.

Don't worry about ecu till you've gone thru the above proceedures!

Never seen an ECU fail by not supplying ground to IAC.

[vududoc]

Ok point taken, yet bad initial post.I am totally flying blind on this vehicle.....kinda like saying hang 3 rights and look for a pink wire in a corner. A test lead grounded out killing the iac. there was no idication of an inline fuse nor any reference material for me to go off. Your second post however was alot more helpful than the first. what i didnt feel like doing is running back and forth to the board.

I had to receive power routing and ECU pinout for orientation and reference......with those and your input i can get through the whole car. Thanks for your help.

[vududoc]

It was a fuse(thx again)Car idles......... extremely low and bucks then attempts to stall....... ah well win some lose some.

[Q45tech]

Now study what the fuse feeds besides the IAC: EGR, evap control, VVT solenoids, both O2 heaters. [hicas if you have it].......what caused the fuse to blow?

Remove the IAC and clean it completely, probably gummed up and sticky!

[vududoc]

I caused it....grounded the test lead. the reason for testing was an erratic idle and bucking along with occasional stall.

Along with cleaning it out i have these instructions for all else to read. The IAC cost over 350....and i have wholesale accounts! so here is a great way to save some bucks.http://www.gt-skyline.net/main....htmlBelieve me i have been down this road one too many times with all my nissans and this is a weak point for nissan.

[Q45tech]

The Q IAC is a better more robust design, but needs periodic removal, gasket replacement and cleaning [most caused by failure to replace air filters in a timely manner!

After all it sources ]clean?] air from the large hose between MAF and TB.

The worst problems are usually associated with oiled cotton type cone or drop in filters.

Had a 96 Q yesterday with classic symptoms [funky idle - bypass screw all the way out- by a previous dealer tech who didn't understand]..............MAF replaced, induction cleaned..........unable to do power balance without stalling..........

Plus another 95 [198k] with melted knock sensors-----bad radiator cap.

[vududoc]

This design is similar the to RB. I had noticed on mine(rb) the sludge build up cleaned it out, reset the Brass insert,Etc. yet noticed slack in the spring. I started optesting it and have to drill out the adhesive and reset the spring to resync the plunger.

The motors are extremely close by PN though the unit off the Q does look a bit beefier(same plug type).....possibly upgrade maybe for the RB? Back to the lab.