Stumbling-stall at idle + long crack to start + timing off – no DTC (FIXED)

[dglywasky]

After a long battle I have fixed this issue, posting this to help someone else along. I looked at countless posts, videos, service manual procedures, google searches – some helpful some not. Of course I had multiple issues at one time so it complicated the matter. Below I give the short answer but also all that went into it. Changed order so keep as clear as I could.

 

I have a 96 Pathfinder V6 3.3L VGEE 284k Miles

 

Had rough idle when stopped at lights, stop signs etc and long crank to start. This issue got progressively worse (see below details if you wish). Short story is I fixed a leak in fuel line + fixed vacuum leak from lower intake manifold (although I don’t think this did much for idle issue – see below if you wish) and replaced cam-shaft position sensor (part of distributor assembly). Now car idles correctly, idle at correct rpm, runs good (so far).

 

 

The ordeal/Details (not in exact order):

NOTE: at no time did DTC codes give me any indication to the issue.

 

Found a leak in fuel line – replaced section of fuel line – resolved the long crack time, still had rough idle.

Replaced fuel filter, air filter, 5 of 6 spark plugs (#1 is stuck) verify spark cables ok - no help.

 

Checked MAF sensor – the voltage readings ok with IGN “On” and idle and linearly increased when open throttle – BUT Serv. Manual says should go to approximately 4.0 V, mine to 2.3V. Checked another sensor and had same results. SO manual not correct? My issue is not MAF.

 

Checked Throttle Position Sensor (TPS) – all resistance readings were reverse of service manual (values at completely open were low 0.9 kohm and got to 3.3 kohm full open). Seemed a reversal is likely not possible and car ok at higher speeds (I just have idle issue). So manual not correct? My issue is not TPS.

 

Suspected vacuum leak – performed smoke test with cigarette blew into tube (see youtube videos) – found large leak coming from lower intake manifold. Pulled upper & lower intake off – replaced with new gaskets – no more smoke coming out. BUT rough idle remained (no change, I guess my car didn’t care about what appeared as a large leak!).

 

By now idle issue getting worse (put in Neutral at lights etc)

 

Timing was way off – had to move distributor a great deal to get timing marks to align but the marks were also jumping around (using timinig light). Checked TDC and alignment of timing belt, cams pulley marks etc all looked good.

 

Suspected Idle Air Control Value (IACV) – replaced with substitute from junkyard. Didn’t have a direct replacement so used on from a Xterra (part numbers differ by 1 digit). Solenoids checked ok and I adjust screw in similar location as existing. Reassembled and figured needed to tune it as not exact same IACV.

 

Started Design of Experiment – adjusting distributor position vs IACV screw vs TPS position. Was able to tune and get a good match although idle was higher than spec – ran great for a few days. Successfully went on 100 mile each way adventure… great until it wasn’t.

Idle issue all of sudden much worse, car would stall instead of being rough. Car actually died while driving (I was in parking lot) got started back and able to get home.

 

Suspected Cam-Shaft Position Sensor – replaced distributor with substitute from junkyard. Adjust distributor rotation and got timing 15deg BTC with Timing gun check (marks steady now).

 

Performed Service Procedure to set timing & idle (see Serv Manual combined procedures from EC 27 & 60). Got timing just right, brought idle rpm down but had to adjust IACV screw (fully clock-wise ie all the way in). Runs great – not sure I like the IACV screw fully in but I did use a slight different one. Runs fine, will drive for a few weeks, summer is coming and I need to get my AC fixed so if I need some more flow, I can adjust that screw pretty easy (move EGR BPT valve out of way and its right there).

 

HOPE this helps someone else out.

[Citron]

When you say service manual, do you mean a factory service manual or Chilton's? If Chilton's, then yes it is probably wrong. The best thing to do with a Chilton's is use it to hold the pages of the FSM open.

[ChemExposure]

Thanks, these are some pretty good tips.
I found to keep mine from stalling when idling I just have to pump the brake pedal. It's a pain in the ass to keep doing it but it's been getting me through the past six months. I'm definitely looking to figure out what's causing that though, pumping the brakes at drive throughs, ATM windows and long lights gets real annoying after a while.