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Discussion Starter #1
Car won't start.

Looked in this forum for a don't ask, read this directions to other threads but didn't find it.

So, I was getting a 34 knock sensor code. Found a leak under the EGR pedestal at the gasket and fixed. And came up with an 0204 code, IAC/ACC, before it was fixed. Reasonable, air leak effecting the vacuum. But it won't clear and the car won't start.

I bought a Zurich ZR4 code reader. This is a 1995 Altima 2.4L, autotransmission, but a 1996 engine. It has an OBDII socket which works fine with the ZR4.

The reader shows code P0505, same thing IAC/ACC. The code won't clear. But the reader shows other stuff with the 8 leds in the top row and 7 in the bottom. Those that light in the top are the first 4 - 3 green and 1 red. MIS,FUE,CCM all green then CAT red. Lower row show two lit red, AIR & HTR.

The code P0505 won't clear. I understand some codes won't clear until the problem is resolved.

All new silicon vacuum hoses. EGR and EGR pedestal cleaned well, remounted with the high temperature copper spray gasket sealer on the gaskets.

I try to start the engine and it fires once and then no more. I open the intake and spray in ether and go to start. It revs up then stops and no more.

How it's getting those codes without running is beyond me unless saved from running with the leak.

Suggestions please.

billj
 

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Discussion Starter #2
What I'll try next is try to find what the four wires to the idle air control are and if they can be accessed from the computer plug to test continuity. There's a chance that I may have interrupted continuity at the 4 wire plug aft of the intake manifold passenger side somehow. I have an old idle air control that's likely no longer functional I can check for comparison. Unless there's a better suggestion. Also the car is outside on a hill not under a canopy where I usually do work. The weather might not hold.
 

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09 Altima 3.5SE 6MT Sedan
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Any chance you just have a fuel low/clog/pressure problem? Maybe made worse by the hill? Seems like you have fire, and air is hard to avoid...so if it won't run...most likely a fuel prob.
 

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Discussion Starter #4
Possible but I turn the ignition on, wait as the fuel pump runs and turns off then I try.

Brought in the old idle air control valve to check what resistances I should expect and noticed the idle air adjust plastic threaded plug and was just going to run out and check it's in place only to find that it's started raining. So, tomorrow then. I see the IAC yellow is always hot then goes to pin 101 corner pin on the ECM plug. Easy to check 12v there. Knock sensor goes to pin 54, can check that resistance. I replaced the oil pressure sensor wire but can't find what it goes to on the ECM or perhaps it doesn't but to a relay.
 

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Discussion Starter #5
I'd like to check the continuity of the oil pressure switch wire. I could picture the fuel pump running with no oil pressure to get the engine started but shut down if no oil pressure registers. Just not seeing where the wire goes.
 

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Discussion Starter #6
I was having a rough time getting at the knock sensor and put pressure on that nearby pipe. Perhaps an end opened in such a way to allow a leak.
 

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Discussion Starter #7
I'd like to check the continuity of the oil pressure switch wire. I could picture the fuel pump running with no oil pressure to get the engine started but shut down if no oil pressure registers. Just not seeing where the wire goes.
Probably not related to the oil pressure switch as I see posts saying to check oil pressure put a gauge in place of the switch.
 

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Discussion Starter #8
Brought in the old idle air control valve to check what resistances I should expect and noticed the idle air adjust plastic threaded plug and was just going to run out and check it's in place only to find that it's started raining.
If there had been a long term leak under the EGR pedestal perhaps I found it ran better with the idle air control valve bypass screw all the way turned in. When I look tomorrow, although forecast calls for 100% chance of rain, I'll back that screw out and give it a try.
 

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OP, you are a classic case of getting so wrapped up in your own bullsh-t the car will never run again or if it does it'll be by accident rather than skills.

If the car ran to rev up for a second with ether then pursue fuel pump issue like said. Once you mess with that bypass screw enough you'll have it where it will never start again. That screw if car was running fine should have never been touched.
 

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Discussion Starter #10 (Edited)
OP, you are a classic case of getting so wrapped up in your own bullsh-t the car will never run again or if it does it'll be by accident rather than skills.

If the car ran to rev up for a second with ether then pursue fuel pump issue like said. Once you mess with that bypass screw enough you'll have it where it will never start again. That screw if car was running fine should have never been touched.
Ray of sunshine on a rainy morning, troll. A suggestion: the-writers-control-of-tone-readings-with-analysis-for-thinking-and-writing-about-personal-experience_edward-m-white

That said, fuel stopping is likely. If the main relay closes after there's oil pressure, e.g. relay coil low to the oil pressure switch then my replacement of the oil pressure switch lug failed.
 

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Discussion Starter #11
That said, fuel stopping is likely. If the main relay closes after there's oil pressure, e.g. relay coil low to the oil pressure switch then my replacement of the oil pressure switch lug failed.
The harness is 24 years old. I was sure my lug is good as I soldered it onto good wire then twisted to the parted wire. Upwards of the twisted wires were previous splices under heat shrink tubing. One felt iffy as if the connection may have parted inside. So, I soldered my wire to that just after the harness bundle. With high hopes I gave it a try and again, one detonation then dead cranking. Wasn't it. Am considering jumping the fuel pump relay to allow it to run and give it a try. I should mention I let the car roll back and turned 90° so the trunk is now higher than the engine.
 

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Discussion Starter #12
Is anything known to break or go bad when the fuel pump relay is jumped such that the fuel pump continues to run and a car start test is conducted? I see that the computer is looking for a signal that the distributor has moved 180° before allowing the pump to be held on. I'll try resetting the distributor plug before jumping the fuel pump.
 

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Discussion Starter #13
That was it. I unplugged then reset the distributor plug, facing forward on this year unlike later years where they move it to face the rear with less exposure to exhaust heat deteriorating the plug plastic. Before touching the fuel relay I started the car. I should note that the IAC bypass screw was almost closed when I checked it earlier but then remembered the original setting, which may or may not have been the original setting, was 2½ screwdriver blade faces. :)
 

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Discussion Starter #14
After letting the engine warm up I shut it down and checked the codes. P0505 and P0325 knock sensor. Used the code erase function on the ZR4. Didn't remove the P0505 but did remove the P0325. Ran it again. No check engine light. But the P0505 won't clear. Haven't driven it yet.
 

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Discussion Starter #15
Will drive it tomorrow and see if things change. If not, I may stop at a junkyard and buy/cut both ends of the IAC connector then splice to make a test jumper as the room beneath the manifold is tight.
 

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Discussion Starter #16
Looking at the old IACV that had been sitting in weather for years. Not really understanding it. I see the Yellow wire from the battery to the motor coil and a black to the ECM. I don't see how the motor can be reversed. Took the motor out, took a hammer. Might be a gear motor. Appears to have a piston inside a brass hat having air slots. Piston can move to block air flow and if it could be reversed I would understand. Perhaps the ECM has a 24v voltage pump to provide reverse, no then it would need pump the current back into the battery. Or maybe the gearmotor has an internal cam that when the engine is shut down the motor drives the cam bringing the piston back. Motor measures 10 ohms. It takes a 10 amp fuse. Put it on a supply but it wouldn't turn. Spritzed it with some WD40 and might try again. That corner pin, 101, will tell me if the fuse is blown or if a lead or the motor is open. Should always be hot. A pair of connectors from a junk yard would allow me to see if in the case of an open, if it's in the motor. Never had the 0205 (P0505) before this repair.
 

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Discussion Starter #17
It was running last night and starting at will. This morning it didn't. Checked spark, it's okay. Checked vacuum and it's not okay. Unplugging the vacuum line to the fuel regulator and putting on a vacuum gauge it barely nudges the needle.

I'm avoiding an actual fuel pressure test because one time on the road in an old motor home, new to me, having fuel problems I worked on it in a parking lot. 4 barrel progressive Rochester I believe is how the carb is referred to. Disconnected the fuel line and went to work. Only the first 2 ports would open and the other two remained closed no matter what. By the way, I had the flu and I don't mean the sniffles. The linkage was wrong. I thought I might have gotten it right and turned over the engine - with the fuel line disconnected and it sprayed gas all over, then caught fire. The superstore Kiddie fire extinguisher completely failed. Got my dogs out but nothing else. Afterwards a few things were left. Very bad experience. So, I avoid checking fuel pressure tho I have a tester.

When it was running yesterday I went around with carb cleaner. There was just a bit of RPM increase when I selectively sprayed behind the EGR valve but it was not repeatable. Don't think it's the EGR or pedestal gaskets as I used the copper sealant well and almost polished the surfaces with a Dremel first and torqued the pedestal bolts.

Will try adjusting the IACV idle adjust screw all the way in. While running I had adjusted for 800 RPM. This memory of mine at 71 isn't great and I see it should have been set for 750. The engine was hot.
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So, I turned the screw all the way in and it almost started and the vacuum needle jumped. I backed the plastic screw out just a little and the engine started. The vacuum is steady just below the green but in the red. The engine is cold. RPM is 920. Won't adjust down. Will wait until the engine is hot, turn it off, disconnect the IACV harness, start it up and adjust for 750.
 

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Discussion Starter #18
Seems okay. Warm running had RPM at 620 and vacuum well in the green and steady. Adjusted the idle to 750 and reconnected the IACV. My inexpensive tach seems to show the idle more stable when the IACV harness is connected but the code won't clear. Will grab my cellphone and AAA card for a trip around the block.
 

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Discussion Starter #19
Disconnecting the IACV harness without disconnecting the battery may have been a bad idea. Didn't do the 10 miles it takes to get around the block but turned around early because the speedometer and temperature gauges weren't working. Idle seemed worrisomely low. Since the temp wire is near where I need to squeeze my hand and arm to get to the IACV harness connectors, I checked that first thing when I got home and it's properly connected. Three codes, P0505, P0325, P0125. IACV, knock sensor, no temp readings to control fuel supply. Nothing relating to speedometer.
 

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Discussion Starter #20
With battery ground connected there's 12.8v at pin 101 of the ECM plug. Disconnecting the battery ground, I measure 4.5k through pin 54 to the knock sensor to the block. This doesn't say that the IACV can't be bad but it does rule out an open wire anywhere in the circuit back to the battery. The 4.5k from pin 54 to the engine block rules out any open and appears to be the correct resistance for the new knock sensor. I suspect that a test of the thermostat wire will also be okay. No explaining the dead speedometer. I'm going to take out the ECM and remove my push button with an ad hoc debounce connected to the ECM screwdriver code reader pot.
 
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