Nismo98

iTrader: (7)

This is going to be second thread since I would like to start out fresh in explaining my problem. So approximately 2 weeks ago I replaced the IAC valve on my 2001 & right after the start my RPMs jumped to 3K. From what I now understand, I should have left the car running for a little while in order to get some warm antifreeze flow hit the valve. Although I turned the car off and double checked all of my work. Same thing happen the second time I cracked the car, RPMs stayed at 3K for about a minute until I shot it off. Next morning the car did not start at all. So today I had a buddy/mechanic come out and take a look at it. None of the new codes came up on the scanner besides the old 0505 which I already knew about. This theory is that I damaged the MAF during the install, or my knock sensor went out because it's now sending a - signal. Could somebody please help me out with this issue, thank you very much in advance for any help what so ever.

Andrei

michaelnyden

iTrader: (15)

well, your not pulling a code for the maf, so it's not that...to confirm you could test it with a multimeter...plus if your maf was bad, your car wouldn't have revved to 3k...it would have been restricted to 2.5K max...

as far as the not starting issues...it shouldn't be related to your car not starting...does it crank? or what does it do? start then stall?

knock sensor going out wouldn't stop the car from starting either....recheck all your work...if it is starting and stalling, then check for proper vacuum or a vacuum leak from one of the hoses...check the iacv continuity at the ecu harness terminal if possible...

but if it is not cranking then standard starting troubleshooting should apply, check battery voltage, cps, starter, clutch interlock switch, fuses, etc. it might be a coincidence then with something else going bad when you were doing the work...

Nismo98

iTrader: (7)

The car did start the same night as I replaced the IAC valve, although next morning it would crank and that's about all it does. Someone correct me if I am wrong, but it's now necessarily to have a code for bad MAF. Today all of the connections where check, and it all boils down to a bad knock or MAF sensor.

Andrei

michaelnyden

iTrader: (15)

check all silicone couplings between maf, air filter, and tb, etc...all clamps are tight on hoses and couplings...no vacuum leaks...doubt it's a bad knock sensor...

P. Samson

I think I asked you before if you can hear the IACV operate, when you turn the ignition switch from OFF to ON and back to OFF, waiting a few seconds in between? If you can't hear it operate, there is a fuse and a relay in the IACV circuit here. Check the fuse labelled ENG CONT 1 in the fuse box that is between the battery and the fender. I doubt that you damaged the MAF (it's not THAT delicate, especially when there is no power to it), and anyway, it should not prevent the engine starting. And the knock sensor has ABSOLUTELY nothing to do with this issue.

Nismo98

iTrader: (7)

Waiting for my uncle to get back home, I'll work with him on figuring out if the IAC is giving out sound when the ignition is being turned ON/OFF. Also I check the ENG CONT 1 & 2 fuses, both of them were NOT blown. Is there anything else that I can look into since this uncertainty is driving me crazy!

Andrei

Nismo98

iTrader: (7)

BTW
Mr. P. Samson, thank you very much for all of your help on trying to figure out and working with me on this problem.

Andrei

michaelnyden

iTrader: (15)

if you have a multimeter you should check the iacv terminal on your ecu harness if possible...in the fsm...they give you the proper readings it should be putting out under different conditions...but don't even look at the knock sensor or maf...shouldn't be those at all...if the iacv makes some funny buzzing sounds for a few seconds with the key in the on position it is most likely okay...like mr samson is saying...

Nismo98

iTrader: (7)

Thank you very much, I didn't really think that MAF or knock sensor were the issue. Although since my buddy pointed out that those two could be the problem, it got my attention. So far no new on the IACV buzzing sound since I didn't get a chance to catch my uncle in time.

Andrei

P. Samson

If you are sure the connections are good and you still don't have battery voltage (Ign. ON) at pins 2 and 5 of the IACV connector, I would check the ECM relay. Give it a good tap or swap it/replace it and check it's connector pins in the fuse/relay box for corrosion etc. This relay puts battery voltage to pins 2 and 5 of the IACV, as well as other components.

RIC4044

P. Samson gave me the same advice. I have a thread going for an 00max that won't stay started. It cranks, will stay on as long as you're giving it a little gas. Had it towed to the dealership and was told that it was the iacv and a maf. I had the car towed back home cause the dealership wanted over 900 bucks to fix. I'll buy a meter and check the voltage on the iacv. Will also look into the ecm relay.. thanks for the advice... but if your car has the same symptoms as mine, it might not be my iacv after all. Good thing i haven't purchased it yet... and they're correct.. a maf sensor wont keep it from cranking..

P. Samson

When the ignition switch is turned to ON or START the ECM relay is supposed to put battery voltage directly to the six coils and the IACV through one set of contacts, and to the ECM, the MAF, the crankshaft position sensor (POS) and the TPS (closed position sw.) through another set of contacts. This relay is a critical little sucker.

RIC4044

how often do these relays go bad... is it common for 00 maximas or for all the 5th gens

P. Samson

Relays can develop problems such as burnt, corroded or pitted contacts that can affect current flow, and they can develop actuating/operating problems, or have corroded/damaged external terminals/pins or that of the relay receptacle or harness connector/s. Relays can just outright fail, or they can be the cause of intermittent electrical problems. This ECM relay in particular does a lot on our cars (both Gens. 5 and 5.5) and has to operate properly. It is controlled by the driver (the ignition sw....energized in START and ON) via the ECM. There are several other similar relays as well.

nismo_star

iTrader: (8)

possible ecu cookage, common when a iacv goes bad. check EGI relay, swap relay as necessary to check, also, check to see if the red indicator lamp for security is on, if not you may have a problem with the IMMU key ring which recognizes the chipped key.
Good Luck.

michaelnyden

iTrader: (15)

ah...good suggestion...but did he replace his iacv with a brand new iacv and then the problems started? but definitely check the egi relay...

I usually find a bad relay by the fact that they are very hot as compared to good relays which are just room temp and they also smell burnt when you take them out...

Nismo98

iTrader: (7)

I should be for not catching this mistake earlier. Although the TPS wasn't installed properly. The little metal **** on the spring was turned the wrong way, and it was catching one of two little pins on the throttle body itself. Once everything was placed back and double checked for 100th time, car cranked up right away. Although my RPM still stayed @ around 3K. Please correct me if I am wrong, by my next step should be idle air volume learning procedure in addition to throttle position sensor adjustment. I was out of time to read up on these two subjects, so it should occur later on tonight. Could someone give me some heads up on what to look out for during those two procedures, and thank you very much to everyone for all of their help which they've provided.

Andrei

monty31

iTrader: (1)

I've had similar symptoms as you and am in the process of replacing my ECU. You are still getting the CEL P0505 which indicates that your ECM thinks there is still a problem with your IACV. If you are in my case, and have replaced the IACV with a brand new unit, yet are still having idle problems and an existing CEL, then your ECU is most likely toast. I've also tried idle relearn many times with no success. If you search "IACV and P0505" you will find a few threads where I have been dealing with a similar problem.

michaelnyden

iTrader: (15)

well not necessarily...don't jump to that conclusion yet...if you are doing the idle air volume learn without the consult II...there is a good chance that you are actually not incurring the learn process...it is a very touchy procedure to induce without the consult II...the best way to do it is use the consult II at a dealership if possible as that way you can make sure it is initiating the procedure....

also, I have to think there is some kind of fuse so the ecu wouldn't fry in between...as if the ecu was fried, wouldn't everything else not work...car wouldn't run/drive, etc. and why would a brand new iacv fry the ecu anyway?

P. Samson

Nismo98......Unfortunately the TPS being disturbed is a complication. It will have to be adjusted and reset etc., but the trouble being that you have to get this car running and idling under about a 1000 rpm first, and fully warmed up to do just the basic required procedures (excluding the TPS closed sw. adj.). The Throttle Pos. Switch Closed Position adjustment first, then the Throttle Pos. Sensor Idle Position Memory reset, and the Idle Air Volume Learning all will have to be done. The first thing is still to confirm that the IACV is at least operating/moving in response to the Ign. switch, as discussed earlier. As someone mentioned this could turn out to be the ECM, but lets first deal with the IACV/circuit....... assuming you're still going to carry on at home. I believe these procedures are all in the "How tos". Now that you have the TPS sorted out, don't have the TPS located all the way counterclockwise.....rotate it clockwise so the screws are about centered in the slots, and as a suggestion, try leaving the TPS attach screws just loose enough to be able to rotate the TPS (clockwise, in the direction of the opening throttle) and see if you get a reaction in the idle (slower), if you get it started again. The TPS (closed sw.) will still have to be adjusted.

Nismo98

iTrader: (7)

Once again thank you so much for all of the helpfully information which you've provided. Your are right about me getting the car to run under 1000 RPMs since the lowest that I've seen it in the past couple of days was 2300. As for the following procedures:
1. TPS closed position adjustment
2. TPS idle position memory reset
3. IACV air volume learning
I will try on figuring out on how to accomplish this step by step, although just out of curiosity I was quoted $98 by my local Nissan dealership earlier today to get all of those things done. I checked the How-Tos, and only saw the TPS reset for 2002-2003. I guess I will have to stick to my .pdf files which I find to be pretty helpful.

Andrei

michaelnyden

iTrader: (15)

if you can get to a tech at nissan and slip him some cash on the side, he could do all 3 in 10/15 mins...with the consult...whereas a lot of the time, self inducing those procedures without the consult are nearly impossible in start since there is an entire timing procedure you must follow...and I believe the only one you can do without the consult is the iacv learn

P. Samson

Nismo98.........When you adjust the TPS ensure that the throttle drum is on the normal TB stop, not on the "start stop". Hold the start stop/actuator out of the way if you have it. Not sure if your '01 has it. My '00 Fed. has this start stop....no mention of it in the FSM.

michaelnyden

iTrader: (15)

ah yes...the vacuum actuated throttle opener--it's a brass diaphram with a hose attached to it that goes to the top of the TB and it has a brass pushrod coming out of it that keeps the butterfly plate slightly open so the car can start...when the car is running and vacuum is applied, it retracts and the throttle cam can rest on the normal throttle stop...good catch! I forgot this myself about two weeks ago when adjusting my tps...remember that now

P. Samson

Nismo98.......I think that once you get the TPS adjusted you will find that the idle will be in the ball park, remembering of course the elevated idle on a cold start and warmup. You will then be able to warm up the car and carry on with the other basic resets/relearns. The TPS not being installed correctly/maladjusted was in fact probably why you had the engine racing at 3000 rpm etc. The ECM was "seeing" a partially open throttle, as well as also commanding the IACV fully closed in a futile attempt to control the idle speed.

Nismo98

iTrader: (7)

I should have mentioned this right after I re-installed the TPS the right way. I guess that first night when the car was running on 3000 RPMs, my uncle tried to adjust the position of the TPS. With no luck of it happening, he accidentally placed it back in the position the wrong way where the car did not start at all the following morning. From what I am seeing here, I guess my best bet would be to talk to one of the mechanics with an CONSULT-II & reset/relearn everything that way. Please let me know if you think I should go ahead and try to resold the rest of this problem myself, thank you once again.

Andrei

P. Samson

What's happening now? Has it been running? So are you now sure that the TPS "rotor" is indexed correctly with the throttle shaft so it is being rotated with the throttle shaft from idle to wide open? It sounded as if you had the tools etc. and FSM info. Do you understand/are comfortable doing the TPS closed switch adjustment etc.? It is somewhat ambiguous. Once that's done, and everything is working (i.e. the IACV) then the rest should be relatively easy by following the FSM. The throttle stop is as the original? Other than that I don't know what to suggest other than if this is beyond your comfort level then I guess you will have to head to a dealer.

Nismo98

iTrader: (7)

Yes, the car is up & running since I re-installed the TPS because it put in the wrong way. I am getting same symptoms as the first time I started the car after the IACV has been replaced, it idles @ 3000 RPMs. At that time, the TPS has not been removed from the throttle body. It was only after my uncle tried to do some adjustments that first night, when he accidentally installed it back the wrong way. I took a car for a ride around the block, and everything seems to be fine accept the throttle shaft is way too open. In addition to that I do have all of the tools which are necessary for the job as well as the FSM. I am always up for a challenge and feel pretty comfortable finishing this project. Although I need to be clear on the order of my next couple of steps which I will have to perform. IACV adjustment, TPS adjustment & air volume relearn process is what I need to read up on.

Andrei

P. Samson

"The throttle shaft is way too open"? How much? When the engine is not running (no vacuum) the throttle drum will be on the "start stop", but that only opens the throttle a small amount. Once the engine starts (or you manually retract the start stop) the throttle drum MUST be on the main TB stop, which should mean that the throttle plate is "almost" seated in it's bore. You might just see a hairline gap there. Is the throttle plate fully closed "at idle"? Both the throttle cable and the cruise control cable should have slack when the throttle is at idle. That's OK?

Nismo98

iTrader: (7)

From my understanding the throttle shaft is way too open during idling. If you could please let me know how would I be able to set the shaft to the correct position so I would be somewhere in the ball park for the RPM range in order to proceed to the next step. In addition to that, please share your wisdom on the proper numbering of steps which I should take.

Andrei

P. Samson

Are the CarDomain pics actually of your car?

Nismo98

iTrader: (7)

Yes, those are some up close pictures to show the slack of the throttle cable and the cruise control cable. Maybe they are pointless, although I thought I should snap a couple. Please help me out on figuring out my next couple steps without going to the dealership.

Andrei

michaelnyden

iTrader: (15)

where's your throttle opener...? should be a brass piece with a hose and pushrod on top there mounted in those two holes...

also, if your idling too, you can turn the throttle stop screw a little (it's composed of a nut and tiny phillps head) have to loosen the nut first than turn the screw out, then remember to retighten the nut when your done...that should close your butterfly plate some when throttle off...

P. Samson

First thing, which is interesting is that you don't have the start stop. Must be a Canadian car thing or it was deleted after '00. Because of the lack of Torque-seal (the red witness paint) on the throttle stop, and the screw looks turned further in than mine, and the appearance of what looks like extra slack in the throttle cable then it does look like the throttle is open too far. This throttle stop is absolutely the No. 1 basic adjustment on these cars. It is either adjusted and sealed after the factory initial Idle Air Volume Learning using the ECM IACV Steps or Counts on Consult ll, or by the TB factory assemblers using an air flow rig or known basic setting. The correct idle throttle position will allow the ECM at the target idle RPM to position the IACV roughly in the center of it's travel range (the Idle Air Volume Learning) so that the idle speed can always be controlled to the target rpm no matter what loads/changes in loads on the engine at idle. I want to enjoy New Years tonight but tomorrow I will take a dimension between the edge of the throttle drum bracket at the stop to the TB casting. That may give you a starting point. If a dealer noticed the stop adjusment red witness missing he could really give you "the gears".

michaelnyden

iTrader: (15)

the 01 TB I bought from some guy to have bored out had the throttle stop on it...so maybe it's a canadian thing...

P. Samson

Nismo98.........on mine with the throttle drum bracket on the idle stop there is only about a .075" (just under 5/64") gap between the bracket edge and the TB lug face. In other words the screw protrudes out of the lug on the TB only about that much. There are also about 7 screw threads protruding beyond the locknut. I suggest you loosen the locknut, back the screw right out until you have some gap between the screw and the throttle bracket (don't touch the throttle, just let the return spring "seat" the throttle plate in it's bore), then turn the screw in until it just contacts the bracket, then count the number of turns of the screw it takes to give you about what I've given you with mine. I would like to know the number of turns for future reference. Don't forget to snug the locknut. My only concern is that because you don't have the start stop/actuator, did Nissan change this basic setting on your's? But, I think this will give you a starting point. After this you can do the TPS Closed Throttle Pos. Sw. adjustment or just for now to see if it will start, then just locate the TPS so that the attach screws are about centered in the slots. One thing for sure is that right now your throttle is open way too much like you had already surmized.

Nismo98

iTrader: (7)

Is it possible that I have a difective IACV? I did adjust the screw, and had plenty of clearance in between the throttle bracket. It did not take long at all of the spring to settle, but it did not play any role on the position of the throttle since I didn't see any drop in the RPMs.

Andrei

michaelnyden

iTrader: (15)

it should drop the rpms with as far sticking out the back as you had it...have you readjusted the tps to 0.500v with the throttle fully closed (resting against that screw stop) after messing with the screw?

Nismo98

iTrader: (7)

That's exactly what I thought should happen, although the RPMs did not drop even though I had the throttle bracket turned all the way clockwise. I need a little input on readjusting the TPS 0.500v.

Andrei

P. Samson

For this engine to be running there is air getting by the TB either past the throttle or the IACV and we don't want much going past the throttle at idle. For now take the TPS, loosen the attach screws enough and rotate it clockwise within the limits of the slots (just for now) and snug them up. This is all done with the Ign. OFF. IF you don't get the ACTUAL throttle plate in the ball park correct position in the TB bore, this is not going to work. It is the starting point of this whole process. I want the damn TPS out of the "loop" here, thus turn it fully clockwise just for now. Did you back the throttle stop screw out so the throttle actually closed completely and there was clearance (any gap at all?) between the end of the screw and the contact point on the edge of the bracket? This should gently "seat" the throttle plate in it's bore of the TB. Then I wanted you to turn the screw in until the tip of the screw just contacted the throttle bracket and then turn it (and it probably won't be very much) in until you had the 5/64" gap dimension that I gave you, between the TB casting (where the screw "tip" protrudes out of the TB) and the edge of the throttle bracket. This means that there should be about 7 threads of the screw sticking out past the locknut after you've snugged the locknut. Before, looking at your photo, it looks like you had only a couple. NOW, disconnect the battery for now and remove both electrical harness connectors from the TPS. Now you "adjust" the TPS by doing "Adjust Throttle Position Switch Closed Position" per steps 10 and 11, pages EC 117 & 118 of the FSM. Do you understand how to do that? Reconnect the battery and the TPS connectors. NOW start the car. The idle is still going to be about 1300 RPM plus because of the warmup, but hopefully it will NOW be more reasonable and this sucker will run and idle well enough to drive it and warm it up. THEN you accomplish step 12, the Reset Throttle Position Sensor Idle Pos. Memory on p. EC 118 and then the Idle Air Volume Learning on page EC 68.