R32 Gtr - Hesitates While Cruising

[ali-turko]

to tell u guys d a truth i think its the air flow meter coz my car was fine un till i replaced my broken afm wif a second hand one, im guna give that diy thread on fixing the afm ago..

will let u guys no what happens

[cowie165]

to tell u guys d a truth i think its the air flow meter coz my car was fine un till i replaced my broken afm wif a second hand one, im guna give that diy thread on fixing the afm ago..

will let u guys no what happens

I tend to agree however it should not be limited to cruise only in that case. Regardless, I had similar problems with my car.

The stuttering is most likely to be one of the AFMs with a dry solder joint. As the dry joint moves the resistance increases and as current is constant, this causes a voltage drop. The voltage drop confuses the car as one sensor is making sense and the other one is reporting very low airflow (for me it dropped to ~0.4V whereas the other AFM output was 3.0V(ish)(for comparison).

I'd have a go at Steve's DIY on AFM repair. You'll need an iron with a long tip. If you have a desoldering tool, even better.

Do you have a mate in Brisbane with a consult cable?

[Risking]

Okay my vehcile was giving me the shits today so I spent considerable time with consult and a multi meter diagnosing the problem instead of guessing.

This is what I have found and so far it HAS rectified my problem

The issue I was having was at cruise speeds the vehicle would feel like it was surging back and forth. There was no obscure turbo noises it would just surge as it cruised almost felt like a lean burn misfire.

Wideband showed I had reasonable cruise mixtures, 14.5:1 so its not a coil pack issue nor a MAF sensor problem which was confirmed by consult (genuine nissan consult) I had rock stead MAF sensor inputs and the A/F alpha feedback was sitting steady at 100%. Also my self learn and idle air learn was 100% indicating engine wise the thing is spot on.

If I flicked the vehicle into RWD the problem went away and it drove normally. This lead me to beleive I had some form of ATTESSA control issue.

On page CH-66 of the work shop manual (full manual not engine manual) there is a basic wiring scematic for the ATTESSA.

First thing was specific ground and power supply checks.

So on the ATTESSA control unit checked terminals 22,2,3 and 50 for continuity to ground. They all checked out okay.

Checked terminal 1 for power through the ignition.

Also terminal 39 for power from the motor relay.

Next easy to do checks are on the ABS unit under the bonnet.

The main ground for the ABS solonoid relay and the ABS motor relay is through terminal 21. CHECK THIS GROUND WELL.

This ground was the problem on my vehicle. I had a very poor ground here. As a quick check I simple spliced into the loom and ran a new ground to a 10mm bolt that was into the wheel arch. I re-checked the ground and had perfect continuity.

After a decent road test my hessitation and surging on cruise is fixed.

If you are going to do this Id suggest starting from the start and working your way through the diagrams and not nessisarily jumping straight to the ABS Ground. I found I had a bit of resistance on most of my grounds and its possible with a vehcile this old you may have a grounding issue anywhere so i suggest checking them all to avoid disapointment.

It may not fix your problem as there are many things that could cause the symptoms described in the thread but for the hour it takes to do a few basic wiring checks it may save you alot of money down the track.

Brad

[ali-turko]

well i just did the diy thread on the afm and it helped alot, i was crusing last night for bout 4 hours and was fine till i was bout 10mins from home.

usally starts stuffing up within 20 mins

[markimak]

fixed my AFm with the solder on sunday. so far not a miss. normally start missing after u flog it heaps. but she got a flog and nothing. also replaced my Panel filter while i was at it

[ali-turko]

good to hear mate im glad that plobles out of the way aswell!!