Hard Start, no power, Check eng lite:J30

[tiggermarty]

Oh one other thing - the buddy I mentioned replaced a leaking fuel line (2 hoses over the center-rear of the engine block) just before I took it in to this guy. I also recall that before this all got started I could hear a slight whining belt-like noise at idle which increased in pitch (not volume) when accelerating - so in neutral I could hear it whine in correlation to the rpm's but when driving it was drowned out by the slight road noise that J's give off).

[tiggermarty]

Also - you mentioned running daigs - I am in an apparent wasteland - the nearest dealer is over 100 miles away and no one I have called has a Consult. The mech I have it in with said it's not necessary to find the problem. He said in his analysis that #6 is not firing but that he was able to divert signal from the source side (the ECU - I'm guessing another cylinder but I don't see how that would work) to get it to fire so he says the coil and wiring are good. He told me that he had problems getting the codes from the ECU and that it is 'flaky' at best. Does any of this sound logical? I checked and he doesn't have any complaints from the BBB but I wonder if that tells the whole story...

[tiggermarty]

He also said in his diag that in its current state he sees voltage but no ground going to that cylinder and so he thinks that the ECM (sorry was saying ECU) is not providing a ground signal? I told him that since I asked him to get the part I would at least pay for the shipping to have it sent back from whence it came. He tells me he will check w/the people he got it from and let me know by noon today (I am not holding my breath but I have a feeling he's going to tell my I own the part - is that right?).

[VimyJ]

Nissan dealers will have a consult to read the ECU for a VG30DE.

[tiggermarty]

Ok so he just called me and said he tried the replacement and it works - the car is running smoothly again. However after I picked it up I noticed the droning noise is fairly loud and it gives off occasional puffs of white smoke (but hey it's winter and *really* cold outside?). So in a way I think I'm back to square one but at least it's running. Any thoughts on the engine noise? The check engine light is not on now. One more bit of useless trivia (I hope) - we took the car to Florida a few months ago - the droning started about a week after we got back.

[tiggermarty]

Also regarding the work I got my old part back so I'm thinking of testing it w/ohmmeter - believe I saw instructions in the service manual on that - to see if the pin for cyl #6 is really faulty...

[Q45tech]

Very common [corrosion] and heat damage to rubber boot on connectors. My 300zx techs say as a matter of course they change the injector and KS/coolant temp harness then check every plug in connector in engine bay for corrosion!

The ecu does provide the ground for all injectors [& spark coils]......they get +12 in common from a relay then fused.

Easy with a current probe or an inline 0.1 ohm resistor and cheapo oscilloscope] [substituted for the fuse] to look at injector waveforms [or spark coil waveforms].

I get very upset when people use mechanics as very few life threatening things are mechanical......bolts may shear and bridges collapse. Chain guides, vibrations, etc.

Unless the engine has been oil abused [or is just worn out] 95% of problems will be electrical in nature prior to 250,000 miles.

When they say they don't have or need a Consult and lots of other expensive diagnosis equipment ------------run away fast!

[tiggermarty]

Well after taking the ecu home and taking it apart - there was serious corrosion all along the lower edge of the circuit board. It's amazing it was running up to that point. Strange thing though, is that it still sounds really rough (wonder if I may have overdone it trying to run the heated O2 test while the car was only operating in 1st gear). Sigh - at least it's on the road again.