ionpcs

Hi all, it's been a while since I've been driving my Maxima and with tax time I have finally come across a little money to get her running again. It was having trouble starting and I've fixed that (bad battery/warranty item) but it is also running fairly rough and has some issues with the suspension.

I will get the suspension fixed by a true mechanic however I am not sure it is worth the expense until I can figure out why the car is running so rough. The car behaves fairly normally when driving except a hesitation to shift up to the next gear from first gear but idles very rough. When in park I will be idling around 1,000 with strong vibration and when I drop the car into drive my RPM drops to about 450 and vibrates even stronger.

Here are the engine codes:
0701 Multiple Cylinder Misfire
0205 Idle Speed Control

Here is what I have done so far:

1. Cleaned (very well) the IACV - including taking off that circular brass-looking piece and making it shine inside & out.

2. Replaced spark plugs (it has been a while I am sure).

3. Cleaned Throttle Body while cleaning out the IACV.

4. Unplugged negative terminal on battery for 20 minutes to reset the ecu (? - i think?)

None of these repair steps have really smoothed out the idle. I realize there could definitely be more steps to take. Please help.

Just some background info:

1995 Nissan Maxima GLE
V6 Automatic
158k
Transmission rebuilt at 126k

pmohr

iTrader: (26)

The vibration issue is a misfire. Have you done any diagnostics, other than new plugs?

Narrow the misfire down to a single cylinder, then move on to the IACV once that's figured out.

snowboi1289

iTrader: (3)

Have you replaced you coil packs recently or ever?? Check all of them to see if any are bad. Clean all the connections to the spark plug, and from the harness to the coil packs, I had that problem, I easily cleaned all the connections, removed the code.

As far as IAVC, take the sensors apart, and clean them, dont soak them, just clean them with a damp rag. I just recently did that (just a copule minutes ago), and I'm waiting to see if its not throwing the IAVC code.

ionpcs

No, I haven't really gotten around to other diagnostics yet - what else would you suggest. The car's registration expired and I am trying to get it running pretty decently before I dump money into the new plates and insurance.

What would you suggest to determine which cylinder is the problem? Should I unplug the harness that plugs into the coil pack, one at a time, seeing where the problem doesn't worsen? Can I pull the wires while the car is running or should I turn it off while unplugging a particular cylinder.

Thanks a lot for your response.

ionpcs

I have not yet replaced a coil pack on this car. Is there a particular procedure you can use to test to see if your coil pack is bad? Has anybody had any luck finding them on the cheap? Also will you explain in more detail how you would clean the connections to the spark plugs and harness as well as which sensors in the IACV needed to be taken apart.

I'm a noob but I promise I won't be asking the same questions again later.

pmohr

iTrader: (26)

Yes, just unplug the coils one at a time to isolate the individual cylinder that's misfiring. After that, swap the coil to another cylinder, see if the misfire jumps. If it doesn't, ohm out the injector.

JtzMax

iTrader: (5)

Also, for your p0205, look for a vaccum leak, possibly a gasket for the TB or IACV. Did you get all the lines back on the TB? Had that happen before and it took me a minute to figure it out.

Plugs are cheap enough and easy enough to do, if the car has been setting for a while, not a bad idea to do them.

edit: oh ... to clear the ECU, just tape the pos / neg leads together (OFF THE BATTERY!) and so they don't touch the battery. Leave it for 15 mins or so ... clear.

ionpcs

Can I test the coils with an ohm meter to see if they're working properly? If not do I need to turn the car off before unplugging all the coil packs. Also you mentioned cleaning the coil packs - can you give me any more information on this procedure I would be happy to clean the heck out of them this evening.

I will look for a vacuum leak with some soapy water unless there is a better technique. Is there a method to test the IACV with a volt meter or something to make sure it is functioning properly?

I did replace the plugs yesterday with almost no improvement - maybe a little more pep on the drive around the block. Is there a picture of which wires you tape together on the ECU? I'm not familiar with this procedure - I was messing with the little OBDII connector next to the gas pedal with the little screw. Is resetting the ECU like this a necessary step to cleaning out the IACV?

THANKS for all your replies. This forum is great... I recently purchased a newer Honda and the forums available for that vehicle are so scattered with only a fraction of the knowledge that has accumulated on this website over the years. Thanks again.

pmohr

iTrader: (26)

You could test them with a multimeter, but it's not a very conclusive test. If they test bad, they're bad. If they test good, they may still be bad. You can unplug them while the engine's running, no problem.

Cleaning the coils?

Yes, there are diagnostic tests for the IACV. Look in the FSM, EC section under P0505 (IACV).

You don't tape anything together on the ECU itself. If you connect the positive/negative battery cables, it'll discharge any capacitors that may still be energized. Same thing as just pulling the battery for longer. Personally I never bother removing power to the ECU, I don't see it as worth it.

Product_Of_Korea

iTrader: (8)

this might relate or not but im hoping someone can clear this up. but would'nt a faulty knock sensor throw a misfire code as well??

pmohr

iTrader: (26)

No.

ionpcs

I just remembered that when I looked at the OBDII scanner at my mechanics it said "IACV" not "Idle Speed Control". I had taken it to a mechanic months ago and only just recently cleaned the IACV. Is it possible the Idle Speed Control is something other than the IACV unit - is it possible fixing the misfire will clean up the idle speed control issue?

pmohr

iTrader: (26)

Different code scanners display code definitions differently. P0505 is an IACV or wiring fault.

And the misfire fixing the IACV code, unlikely. Remotely possible, but very unlikely.

QNO_A32

iTrader: (7)

yeah wont throw a misfire code but will definatly feel like one. and ionpcs...start the car, unplug a coil. the idle should worsen. if it does that coil is good so move on to the next one. you looking for the one that makes no difference in idle when unplugged. hopr that makes sense

JtzMax

iTrader: (5)

KS will not throw a CEL / SES light. Nor will a bad KS make your car feel like it's missfiring. Mine has been bad for a LONG time and it really makes no difference, maybe a tad bit less power - or really a later power band (which in our stock IM's only allows power till ~4,200 rpm) then it's just noise - at least for me.

QNO_A32

iTrader: (7)

a bad KS makes a big difference. maybe yours isnt as bad as you think it is. gas mileage and performance suffer. also there will be a hard stumble/miss at anything past moderate throttle, due to retarded timing..

Product_Of_Korea

iTrader: (8)

k i just couldnt remeber. i thought there was something when having a ks code or something it also threw a misfire code as well but i stand corrected

JtzMax

iTrader: (5)

This has been covered so many times and I'm not going to hi-jack this thread and turn it into a KS disscusion, sorry. My codes read bad KS but I still get ~30 mph on the hwy. No real performance lose to speak of either ....

Product_Of_Korea

iTrader: (8)

^^^ wait wait a second. not trying to be arguementive or switch this over to a KS thread either but your saying a bad ks doesnt hurt your perfomance and gas????

i have had 3 bad KS in 3 diffrent max's and all 3 of them got 250-300 miles to a tank. and they ran like a stock civic

JtzMax

iTrader: (5)

I got the ghost code, but no 'problems' to speak of ....

Product_Of_Korea

iTrader: (8)

well it usually does come up as a ghost code. thats why i would suggest the the OP gets his car scanned.

but anyways back to the topic :P

any updates?

i would deffently have to agree with pmohr and isolate which cylinder is missing and go from there. IE coils plugs ect ect

Dont leave us in the dark man keep us updated.

Product_Of_Korea

iTrader: (8)

opps didnt read the entire thread i see that you had your mechanic scan it. any other codes that drew from the scanner besides what you pulled?

ionpcs

No the mechanic pulled the same codes as me.

Sorry, I'm not trying to keep you in the dark ... I just haven't had a chance to get to the car and start pulling the different plug wires. It's a little concerning though that these coil packs are running me 95 dollars + shipping to my local car quest. I haven't ordered them yet but I am wondering if there's a better way to get these parts. Is there a reliable online vendor?

Product_Of_Korea

iTrader: (8)

ok you can either go to the 4th gen classifieds or PM Maxima_Joe off this site. he can get you a used set for a fair price im sure. or depending on if you need rear one i could sell you some of my rear one that i just have laying around as well.

if your looking into a brand new one though try rockauto.com they have some starting at around 55 a piece


but paying 95 bucks for a coil is pretty high.

JtzMax

iTrader: (5)

And, the normal 'going' rate too. Make sure it's a coil pack before you buy one, nothing like being stuck with unwanted / unused parts.

ionpcs

-- U P D A T E -- "One Problem solved . . . sorta." - -

I was able to determine that one rear and one front coil were not firing properly using the provided advice. This didn't seem like the end of the world. I know someone else with a Maxima so I borrowed two of their coils, installed the coils, and started the Maxima.

For the first time in a while it sounded halfway decent. When driving the car has significantly greater power than before the coil swap. The car however is still idling about 50% as rough as it did before and refusing to shift from one gear to the next like it should. It's an automatic transmission that I had rebuilt around 120k (156k current).

The transmission is not covered under any sort of warranty anymore and the car has significant work to be done on the front-end suspension (lower control arm, inner tie rods, right strut mount . . per Big O). I am not sure if it's possible that a simple fix could be standing between me and a properly idling car but I am willing to try just about anything. Any suggestions?

(recap: I cleaned the IACV and Throttle Body, replaced the spark plugs, tried new coil packs)

After changing the coil packs I reset the Check Engine Light and ran a new diagnostic. I received two error codes, still:

Idle Speed Control &
0201
"Diagnostic Trouble Code 0201 indicates a problem with the ignition coil and power transistor. The ignition signal from the Engine Control Module is sent to and amplified by the power transistor. The power transistor turns on and off the ignition coil primary circuit. This on-off operation induces the proper high voltage in the coil secondary circuit.

The malfunction is detected when the ignition signal in the primary circuit is not entered during engine cranking or running.

The items to check include
- Harness or connectors (the ignition primary circuit is open or shorted.)
- Power transistor unit built into ignition coil
- Condenser
- Crankshaft Position Sensor (REF)
- Crankshaft Position Sensor (REF) circuit

A misfire on any individual cylinder should set a code, and a problem with the CPS should also set a code.

I would have expected to see DTC 0201 along with one of the following DTCs.
0407 - Crankshaft Position Sensor (REF)
0608 - Cylinder 1 misfire
0607 - Cylinder 2 misfire
0606 - Cylinder 3 misfire
0605 - Cylinder 4 misfire
0604 - Cylinder 5 misfire
0603 - Cylinder 6 misfire

You didn't get one of these "companion" DTCs, and that is puzzling. Maybe one of them will show up in the next few days."

I did not, however receive any of these "companion" DTCs and the car did not seem to be misfiring anymore. Any thoughts on this?

Also I am very curious if there are any possible fixes for the issue with the transmission. Spending another dime on the car seems like a really bad idea if the transmission is going to run me a second $1600 trip to Mr. Gooch (yes, that's his name - no, I wouldn't really go see Mr. Gooch if my transmission went out again for obvious reasons). The issue is best described as whenever it would be a great time for the car to shift to the next gear it delays and it is completely necessary to let off the gas to get the car to shift gears. Even if you floor the car it will go 0-45 or so, start to hit red on the tachometer and continue to hit red unless I back off the gas pedal significantly.

pmohr

iTrader: (26)

If you unplugged any coils while the engine's running, the 0201 code is normal.

As far as the P0505, have you tested the IACV yet?

ionpcs

Yes, I did unplug the coils while the engine was running - thank you for that information.

As for the 0205 code . . . I am still not sure where to look for information on testing the IACV unit. I went to the Fault Indicator Light *sticky* thing and was only able to find this information on fixing the idle problem:

http://forums.maxima.org/4th-generat...de-0205-a.html

I believe I have done everything suggested on that thread to fix the issue other than cleaning the electrical connections which don't seem to be corroded or anything. I might not understand what thread to which you guys were referring?


Found a junkyard locally that will get me the ignition coils for $25 a piece and guarantees they'll work. I figure I will pick those up later today and install, is there anything you suggest I do for the 0205 code while I'm with the car tonight?

Thanks again.

PS - I found the procedure for testing the Automatic Transmission for errors and I plan to run that test later tonight as well. I will let you guys know.

pmohr

iTrader: (26)

Test the harness for any continuity issues, proper power supply and ground, and test the IACV per the FSM.

ionpcs

What is the FSM? Thank you for the info.

pmohr

iTrader: (26)

Factory Service Manual, see my sig.

Diagnostics start on EC-123.

QNO_A32

iTrader: (7)

pmohr, care to school us on posts 14-20. thanks

pmohr

iTrader: (26)

What about them? I have a bad KS, and I get a consistent ~21mpg city, 28-30mpg highway, and don't notice any power loss.

Long story short, it's not as drastic of a difference as some believe.

Replace it, bypass it with a resistor, whatever.

QNO_A32

iTrader: (7)

oh thanks for your opinion. i guess it depends on how shot it is.

JtzMax

iTrader: (5)

I don't think works like that mate. I think it either works, or doesn't. From my understanding anyway. Please correct me if I am wrong. The ECU goes into a default mapping if it doesn't recieve the sig from the KS. You can have a good KS and use crummy gas and not have it detect too. It will 'retard' the timing to a degree, but I agree with Pmohr, it's not as drastic as some would be lead to think. Coming home from work getting on the hwy this morning, I was pulling 5,500 rpm in 3rd gettin on it for the hell of it and it felt strong. If you clean your IACV, TB, air filter, you'll notice a decent improvement, perhaps if you're having issues and you feel it might be your KS causing them, clean those and see if it helps.

Cheers!

QNO_A32

iTrader: (7)

i noticed an improvement after i changed my KS. trust, the car will hesitate hard once the KS goes completly dead from the reterded timing/safe mode. personal experience> "i think". guess were both right...kinda

Product_Of_Korea

iTrader: (8)

i belive this is how it works.

The ecu has two diffrent maps one for your normal operation and a safe map for when sensors and what not fail(IE ks) When it doesnt recive a signal from the ks it goes into the safe map(retard timing) to prevent knocking and detontion


pmohr im i kinda hitting it right or am i completly off??

ionpcs

You guys are pretty nutty about your knock sensors.

pmoh, I just found your sig (it doesn't display for me for some reason in google chrome) - thanks for the FSM download.

My sister's 95 gle's transmission mount broke and the transmission fell down onto the CV Axle and trashed the transmission. I might be able to get her car for parts. I will let you guys know how it goes.

pmohr

iTrader: (26)

That's odd, with only one mount failure the entire powertrain should stay in place. The other three mounts are more than enough to hold everything up.

JtzMax

iTrader: (5)

Did it crack the bell housing? If it fell onto the CV shaft, I'd say it had to have.