Hey guys, I need some advice on whether or not I'm looking at a dead MAF sensor. I've been having erratic idle and stalling problems for the last 2 months and Today I have tried to record my problem via Conzult to show what my sensors are reading to help give me a clue as to whats wrong with my Z.

 

In the last few days my Z has been stalling constantly when at low revs. It also has a hard time starting in the mornings when the engine is cold. I took this initial video of the cars start up routine so you can see what I'm talking about.

 

 

Now with Conzult, I needed to press on the accelerator to stop the car from stalling a few times.

 

 

My currently thinking is I either have a fuel starvation problem or an air starvation problem. I did some diggin on the net last night and I found a video of another 300zx owner who was having almost the same problem I am having and he solved it by replacing his MAF.

 

So today my first point of call is to check whether my MAF sensor is dirty and if so clean it with some contact cleaner.

 

After removing the nose panel I pulled the MAF harness connector and it looked like this;

 

 

The MAF connector looked like so;

 

 

So far the connectors look good, no corrosion that I can see and no need for cleaning.

 

So I took the Air filter box out completely and then removed the MAF sensor and checked it.

 

 

 

I'm pretty sure the sensor looks perfectly fine and doesn't appear to be dirty in any way.

 

I gave the unit a wipe down but I didn't want to spray the sensor as it didn't look like it needed it.

 

 

 

Before I put the air filter box back onto the car I first needed to clean the inside of the air filter box as it appears more of the air filter oil has gather in the lower sections of the air box:(.

 

 

I thoroughly wiped the area down making sure there was not a speck of oil left and I'm considering going back to the OEM dry paper type of air filter now considering the amount of oil that is leaking from these K&N filters.

 

 

I reinstalled the air filter box back on the car and I decided I would try and see if the Z starts without the MAF sensor connected. To my amazement it did and guess what it was holding idle and my 02 sensors were reading for a change.

 

 

I then tested what would happen if I suddenly connected the MAF sensor in while the car was running. This is what happened

 

 

I again tested the car with the MAF sensor disconnected but I used ECUtalk this time and from what I can see the car is in limp mode and wont rev above 1600 rpm in park.

 

 

I took the Z for a short drive around my block and the car wont rev above 2500 rpm, but it was driving alot more smoothly and there was no shuttering or drops in idle when coasting.

 

From the information I've shown does it appear my MAF is dead??

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Yes definitely the maf is dead, with the maf disconnected you would not be able to go above 2500 revs either

Yes definitely the maf is dead, with the maf disconnected you would not be able to go above 2500 revs either

 

Thanks groover, very much appreciated. All my data points to a dead MAF sensor. Ill look into getting another MAF and hopefully that solve my erratic idle problem for good. Yes I'm aware that being in limp mode means I wont be able to go above 2500 rpm but luckily for me my job is only 5 minutes down the road. I can always reconnect the MAF sensor and just drive it with the erratic idle as well.

I had a similar problem a while back with my maf, when you get a replacement, also re check your TPS and idle air ratio, you wont get any realistic adjustment on the idle air with a knackered maf, so dont mess it with it till youve changed it lol, the reason for the erratic idle is the idle air control is trying to compensate and failing miserably :biggrin:

I had a similar problem a while back with my maf, when you get a replacement, also re check your TPS and idle air ratio, you wont get any realistic adjustment on the idle air with a knackered maf, so dont mess it with it till youve changed it lol, the reason for the erratic idle is the idle air control is trying to compensate and failing miserably :biggrin:

 

You sir are a legend. Thanks for the tip on the idle adjustment. Ill make sure to readjust the idle when i install the new maf. You have helped me alot with ur afldvice on this.

Before you do buy another open up the top and check the solder on the board and the pins. Like anything else they can get dry joints. I fixed my old maf doing this.

No problem bud, thats what we are here for :thumbup1: when you do get sorted and go to set the idle, get the engine up to temp, plug in the consult and you are looking for around 15% on the iacv at idle.

If you haven`t fixed this yet try the fuel pump ecu. Turns out mine had a dry joint or two which was causing mine not to idle until hot..which was problematic to say the least. Mine also ran ok with no maf so my guess is the main ecu bypassed my problem with no air meter reading. A kind of limp, cure all, get you home at least mode.

If you haven`t fixed this yet try the fuel pump ecu. Turns out mine had a dry joint or two which was causing mine not to idle until hot..which was problematic to say the least. Mine also ran ok with no maf so my guess is the main ecu bypassed my problem with no air meter reading. A kind of limp, cure all, get you home at least mode.

 

thanks santa, I replaced my fuel pump module in 2012 with a 95 model module just for the hell of it. I still have my old module so I will try and replace it and see if it changes anything. Currently I have purchased a brand new maf sensor from Z1 motorsports but they haven't sent it to me yet and its been a week:(.

No worries. I bought myself a new maf from them too in the black friday sale. I can reassure you they work perfectly so if you do still have trouble it`s unlikely to be the maf.

So guys my idle/poor running problems have been fixed and it is all thanks to a brand new OEM air flow sensor:).

 

So to further help prove reference material to the community for assistance to another Z owner who may come across this problem, here are my results before and after the install of the new AFM.

 

First thing i did was data log my Z's current sensor values from Conzult with my original AFM still installed on the car.

 

 

As you can see my idle/shuttering problems hasn't changed much since this whole thing began.

 

With my base data now recorded, I removed the old AFM sensor from the Z and took some comparison photos of the old and new AFM sensors.

 

 

 

 

I then installed the new AFM sensor onto the car and now the moment of truth.

 

 

Success, straight away the car felt more stable and the idle was constant and steady. I checked for error codes but found none which was good and let the car idle for a few minutes

 

 

My 02 sensors were reading fluctuating volts again which was another good sign and the shuttering had all but disappeared.

 

I checked the main signals screen to noticed no massive drops in base idle when switching to the main signals which previously it would drop 100 rpm instantly.

 

 

And finally when the car had reached the optimal temperature setting to test the 02 sensors they began oscillating as per normal when revving the car to 2000 rpm.

 

As you can imagine I was wrapped to see these results and as I had been told by the UK forums I have to now reset my base idle and I did just that. I reset my base idle to dead center at 850 rpm and the car is now purring like a kitten again:D.

 

I have done a few test drives and did a big 40 min highway drive to my parents in laws place and the Z didn't miss a beat.:zlove:

 

I would like to thank everyone who offered advice and spare parts to help me solve my idle problem. This community is a great place with a great bunch of people.:zlove:

So guys my idle/poor running problems have been fixed and it is all thanks to a brand new OEM air flow sensor:).

 

So to further help prove reference material to the community for assistance to another Z owner who may come across this problem, here are my results before and after the install of the new AFM.

 

First thing i did was data log my Z's current sensor values from Conzult with my original AFM still installed on the car.

 

 

As you can see my idle/shuttering problems hasn't changed much since this whole thing began.

 

With my base data now recorded, I removed the old AFM sensor from the Z and took some comparison photos of the old and new AFM sensors.

 

 

 

 

I then installed the new AFM sensor onto the car and now the moment of truth.

 

 

Success, straight away the car felt more stable and the idle was constant and steady. I checked for error codes but found none which was good and let the car idle for a few minutes

 

 

My 02 sensors were reading fluctuating volts again which was another good sign and the shuttering had all but disappeared.

 

I checked the main signals screen to noticed no massive drops in base idle when switching to the main signals which previously it would drop 100 rpm instantly.

 

 

And finally when the car had reached the optimal temperature setting to test the 02 sensors they began oscillating as per normal when revving the car to 2000 rpm.

 

As you can imagine I was wrapped to see these results and as I had been told by the UK forums I have to now reset my base idle and I did just that. I reset my base idle to dead center at 850 rpm and the car is now purring like a kitten again:D.

 

I have done a few test drives and did a big 40 min highway drive to my parents in laws place and the Z didn't miss a beat.:zlove:

 

I would like to thank everyone who offered advice and spare parts to help me solve my idle problem. This community is a great place with a great bunch of people.:zlove:

Happy days, thanks for the feedback, no doubt this post will help a fellow zedder in the future when troubleshooting a similar issue :)

I notice that the new MAF has only 4 connections and the old one looks to have 5.

Do we know why this is and will it make any difference?

I notice that the new MAF has only 4 connections and the old one looks to have 5.

Do we know why this is and will it make any difference?

 

I've asked this as I own both and have fit both, and nobody it seems knows :laugh:.

Great news! Glad you got it sussed.