Thread: D2 V8 non-starter

Greetings all.
Thought I'd throw this out there to gain a fresh perspective.
My D2 V8 manual (2001, no CDL, acquired ten years ago, named "Jill" to distinguish it from "Jenny" the D2 V8 autobox with CDL) is currently turning over quite happily but just won't quite start. She wants to - I can hear her go oh! so close, but no cigar. Real travelled mileage is about 339,000 kms, but a probable transient accident with the Nanocom seems to show in excess of 1.6 million these days - not that I care... something that conveys bragging rights, you see.

It had been gradually deteriorating over the previous couple of months, with the occasional low-level backfire when coasting down to idle (which has itself been getting lumpy with the occasional stall, but previously starting right back up again). Replaced spark spark plugs and it ran slightly better for two days. I was happy then.... briefly.

The following day I went out to start it from cold. It started, gave a couple of loud backfires and a cloud of smoke. Hit the ignition again, it gave one almighty backfire bang that Alamagordo, New Mexico would have been proud of, and subsequently it hasn't started, though it turns over easily. Haven't checked whether the muffler is still intact - don't really care as it's due for replacement when I get it going. Battery is high-capacity, less than six months old, and fully charged with a smart charger, so that's eliminated.

I thought it may not have been getting fuel, and since the fuel gauge was dodgy anyway, I replaced the fuel pump with a new Goss unit.
(Found the reason for the dodgy fuel gauge: one of the plastic integral body tangs holding the spring tensioner had broken off and was lying in the bottom of the fuel tank, so the bottom pickup of the fuel pump had been sitting on its side - hence the occasional running out of fuel problem with the gauge showing 1/4 tank, but I digress; it clearly needed replacement anyway!)

Confident as all-get-out, I tried firing up Jill but again, no start.

Started fault-finding with the gleaned knowledge from this group, and figured I'd replace the crank angle sensor because it had never been done and was a possible point of failure. No change. Yes, done correctly as to spacers etc.

Rigged up a fuel test gauge, which tells me I'm getting anywhere from 45 to 54 PSI at the test port behind the intake manifold while cranking - BUT when I first switch the ignition to position II, the fuel pump doesn't fire up, which apparently it should for the first few seconds at position II. That's the odd thing that stands out to me.

I had previously jumpered the inertia switch, so ruled that out, after again testing with a multimeter that there was indeed 12V going across the jumper.

Getting frustrated, I checked both spark and compression at each cylinder while SWMBO turned the key, and am comfortable there's enough of both. Compression seems to show anything up to 15% maximum to minimum variation across the cylinders, which doesn't seem that bad for something that's been towing a couple of tons whilst being fully loaded on thousand-kilometre trips every couple of months for the last six or so years.

The Nanocom swears the vehicle is not immobilised, the alarm etc was disabled, the plip locks/unlocks and is detected, electric stuff all seems to work (except the door locks, which I'm presently replacing the electric motors in, to keep myself amused), instrument lights as they should be, and it shows I have cranking revs of around 120 (even though the tacho needle doesn't move). I note that the BBAC doesn't seem to work, and the fuel flap release only works occasionally, but that's just minor tinkering stuff when I get around to it. Sorry, digressing again...

My next thought was the interior fuse box/IDM, which I'd replaced three years ago because the original was badly corroded.

(Replacing it also fixed my high-beam indicator at the time, so there's a useful bit of trivia for you; seems to be a good indicator, if you'll pardon the pun! Second vehicle I've had it happen on, and it's the first giveaway that an IDM is compromised by corrosion.)

Sure enough, slight corrosion at the tracks at the bottom, so replaced it with an eBay special that I disassembled and checked before fitting (I now have four of the damn things plus the one in Jenny). Did all the Nanocom processes - still no joy on starting. Tried another dodgy one as well - no difference, so reverted to #3 as being in the best condition. Thoroughly cleaned, looks impressive.

Tried replacing various relays, checked every single fuse inside and out with the multimeter for continuity. Pulled the MAF plug - no difference, still won't start. Replaced the MAF - same result. Pulled the IACV, put half a can of throttle body cleaner through it, replaced it. No difference.

Squirted a half can of starter fluid up the intake while SWMBO cranked it - again, no ignition. Weird, right? I definitely have spark, fuel pressure at the test point, so what gives?

Getting more antsy, I pulled the main under-bonnet fuse box out completely, disassembled it, and noticed some faint traces of an oily fluid between the layers, and minor corrosion tracks on the vinyl between a few fuse and relay contact points. Thoroughly stripped it back to metal and plastic, put it through the dishwasher (Fisher and Paykel is great at this stuff; the pieces came out absolutely like new!), carefully rebuilt it, refitted, replaced fuses and relays, tested every connection with the trusty multimeter, and all seemed right with the world. Unfortunately, the big moment came and went unspectacularly - still turns over like it wants to start, but doesn't quite make it.

Overreaching now, maybe, but pulled both the IDM and BCM on different days and checked the circuit boards with bright light and magnifying glass. Absolutely no sign of burn chips/corroded tracks, plugs are in good nick, doesn't look like they've ever been exposed to moisture. Cleaned with electrical circuit cleaner just in case, replaced, re-Nanocomed just in case - no joy, no difference.

I have plenum gaskets on order (and about a week away since I'm at least half an hour from the nearest town), so I'm girding my loins whilst contemplating (and dreading) pulling the injectors, but I'm also thinking maybe it's a timing chain problem? According to half a receipt by a previous owner left in the glove box, it was changed at 200k, so maybe I'm not quite there yet. Just as an "in case, and I wanted a spare anyway", I also have an eBay special BCM wending its way towards me at the speed of a galloping snail, and am seriously considering a US ECM p/n NNN100460 - I gather they can be made to work in place of the NNN100470 I have, and they're considerably cheaper than the ~$400+ minimums I see occasionally on the 'net. Thoughts?

And that fuel pump non-initialisation at position II still bothers me... something's just wrong about that, although I'd never really noticed it happening before anyway.

I've also changed the alternator and belt a year or so ago, when the pulley failed 50km down the road from a paid LR specialist service (!) of course.

Outside chance it might be ignition coils, but I'm a little dubious since I seem to have good spark. All the earths I have inspected look good; nothing dodgy to see here. Battery cables seem adequate, new MAF sensor - I'm running out of simple ideas here...

Anyhow, apologies for the long-windedness, but if anyone has had previous experience of this sort of issue, I'd appreciate a few random thoughts from those with experience. Jill is cranky, and SMBO is cheesed off that Jill is getting more attention than she is.

When I had my muffler issue, it was intermittent initially, usually after harder acceleration (e.g. climbing Toowoomba Ra or overtaking a road train), but not restricted to. The muffler looked new, externally and pressure could be felt when cranking.
Mine failed structurally, internally.