Hoping someone can help me here..
1999 Maxima

Had a coolant leak at the two small hoses near EGR behind UIM. Caused over heating.
took out battery, intake, unplugged connectors and took off UIM to get a new hose and better collar setting on. Got that done.

A couple days after, started idling at 1500rpm in Park and Neutral.

Read some threads here it could be:
-EGR needs cleaned or sensor
- IACV needs cleaned or sensor
-TB needs cleaned or TPS bad
-clean MAF and Air Filter
-bad IAT (after market aluminum tube grommet, part isn’t snug)

Also saw some people adjusted the screw on top of IACV.. but I won’t do that.

while setting the coolant hose,
-UIM gasket still fresh rubber from replacing 2yrs ago, didn’t replace, made sure mounted back in place at 17ft/lb torque
-cleaned IACV with carb cleaner.. might’ve got a bit of it on the solenoid.. could that be an issue?

then the 1500rpm idle.. so I,
-used MAF cleaner on MAF, let dry
-used K&N filter cleaner/oil kit to clean my eBay short Ram filter
-IACV took off to make sure it is clean ✅, the metal gasket is rare to find online w/o buying kit,. Gasket was bowed a little, I used a light coat of HighTemp gasket between the IACV and gasket, let it cure before tighten onto plenum and operation.
-after market Ram filter plastic mounting and rubber gasket bowed, used a light coat of gasket maker between the parts, let cure etc

Let everything dry and settle, put everything back in place.. drove to store, idled at 400-700rpm and lagged acceleration..

notice my TB Accelerator cable has about 1inch play..regardless of adjustment.

the next day, car cranked and won’t start.

what could I have done wrong or could it be?

thanks,
AM

 

I just checked fuses.. the ENG CONT 2 fuse bad, replaced, started and it turned over, new fuse popped…

help please

 

Is your car auto transmission? The rear mount is filled with a ferrous fluid that is infamous for eventually leaking and causing a short, I believe that fuse you see popping over and over is part of that circuit. Solution is to disconnect the rear motor mount permanently.

The coolant leak you described also doesnt bode well, these motors are infamous for having coolant leak onto the IACV and cause a short that can ultimately burn out your ECU. Lots of threads on the topic.

 

Yes it’s an Automatic Transmission.

im not sure what you mean about rear mount filled with ferrous fluid leaking into IACV?
the original leak was coolant from the tedious line in back of UIM by egr, that’s now fixed and there’s no leak.
I could see how the coolant leak could’ve landed on electrical down by transmission or under TB. But car ran after fluid leak fix, just had 1500rpm idle in park and neutral.. the threads here said to clean MAF and air filter, adjust the idle on IACV screw or adjust TB cables…

 

Separate issue, the rear motor mount can burst and leak onto the wiring that is connected to it, causing a short, this issue does not involve the IACV. Coolant leaking from the UIM could get on the IACV and short that. Two separate issues that both tend to yield the same host of problems, which is why they are related to eachother. Unplugging the rear motor mount and bypassing the stupid UIM coolant line is how you prevent them from happening in the future.

Either way, you 100% have a short somewhere, these are the usual suspects so you may want to start with them.

 

Slamrod, you're talking about 5th gen stuff. Not helpful on a 99.


Per the FSM ENG CONT 2, FUSE #57

MAIN
MAFS
POS
AAC/V
EGR
IGN/SG
EGVC/V
PGC/V
NATS

 

Yikes, woops my bad lol. Used to have 4th gens, got mixed up.

 

thanks for the FSM info..
will look into this and report back.

 

follow up:
turn key to accessory, no check engine light
code reader:
-p1320 manufacture control
-p0505 idle air control
-P0304 cylinder 4 misfire
-p0335 crank shaft position sensor A circuit

 

cleaned crankshaft sensor.. replaced CAM sensor with used part. Cleaned IACV for the third time and more diligently taking the actual solenoid out of its plenum.
made sure crankshaft sensor, cam sensor, and iacv are tightly bolted.

car still doesn’t run.. blowing out Eng Cont 2 10A fuse.

car will run on 15A fuse there.

need help. Do I really have to cut open the engine/ignition wire harness???

 

Update:

saw a YouTube of a guy swapping the “Inhibit / Clitch Inter Lock” fuse by the battery to fix the Blown 10A IGN CONT 2 fuse..
so I replaced it… and can now turn engine over using standard 10A fuse.

however..

most times I have to give it some gas to turn engine over…

The high idle is still present… but only between 1k-1300rpm… sometimes after driving, put in park, will idle between 700-1k rpm… hit/miss

There’s a weird pumping noise coming from near the egr-fire wall area… during idle
when accelerating on throttle there will be a weird hissing/squeal … does not happen in park when on gas

Any advice is appreciated

 

Vacuum leaks sometimes make noises and whistles. Try using an unlit propane torch near the noises and see if the idle increases. If it does, you found a leak that can screw up the whole intake balance.

In fact, probe every where you've worked on it that a leak can happen.