Dr30 Cutting Out At Random And Won't Start Again For At Least 15 Mins...

[0R10N]

Just wondering if any of the FJ20 gurus can help me out as I've got a rather bizarre problem with my DR30 sedan. Ever since I got the car in late December it's had a nasty habit of literally dying on me at random while I'm out driving. So far the problem has manifested itself every 4 times out of 5, and as you can imagine it's starting to fray my nerves because I get too scared to drive the car and it ends up sitting in the garage gathering dust!

The only warning I get of impending failure is that the engine starts to misfire and cut out, slowly at first but then more and more violently. Within a couple of minutes (5 at the most) the car will then stall. It turns over, but won't fire at all.

Eventually after waiting for a while you can turn the key and the engine finally fires, but one of three things will happen:

1. it will rev up to around 1500rpm, but die again straightaway.

2. it will run, but idle like crap, as though it's not running on all four. If you give it a rev or try and hold the throttle partially open, it'll miss, pop and fart like hell. If you put any load on it, it soon dies but you can start the engine again and repeat the whole process.

3. it will run perfectly as though nothing ever happened.

This has happened to me about ten or eleven times now, and each time I've just stopped and waited a while between attempts at turning over the engine. Each time there's a delay of anywhere between 15 minutes to an hour before the car will start normally (option 3 above) and I can continue on my merry way.

As I said it doesn't happen all the time - I recently went on a trip out of town in the sedan, travelling 1000km over the course of five days and the car didn't miss a beat at all. On the worst days it occurs multiple times in one journey, and a 20 minute trip turns into a 4 hour nightmare of waiting.

Today I had an appointment with a suspension workshop to have a knock in the front diagnosed, so I came home from work during my lunchbreak and picked the DR30 up. It started and drove perfectly fine for about 10 minutes until I got to about 5km from my final destination when it started exhibiting the warning symptoms above, on the friggin' motorway of all places. I promptly took the first exit I could (which luckily, happened to be the one I take to get to work) and coaxed the poor car into the work carpark with literally seconds to spare - the engine died just as I cruised into my parking space

Went inside and did some work for about 15 minutes, then decided to go back to the car and see if it was fine again. Wouldn't fire, so I went back inside and tried again every 10 minutes after that. On the next two attempts the car fired, but died straightaway. The attempt after that, it ran for about a minute and idled like crap the entire time. Finally on the last attempt it fired and died, so at that point I just left it, cancelled my appointment with the workshop and worked for the rest of the afternoon.

Three hours later hometime rolls around. to my surprise the car fired up as though nothing was wrong, and I got home without any trouble at all. Was it all just a bad dream?

Anyway, ever since the problem started manifesting I've tried swapping bits and pieces over from my DR30 coupe (which runs perfectly fine) to see if I could isolate and diagnose the fault, as well as testing various components. The sedan is now running the coupe ECU and fuel pump controller, the AFM has been tested and seemed to exhibit no issues, and I have yet to test/swap the TPS and O2 sensor (at the suggestion of StageFumer11). Fueling system has also been inspected and given a clean bill of health. I'm now beginning to suspect the problem could be related to either the coil, leads and/or distributor cap, as today on each attempt at getting the car started I did a few tests to see if any spark was being generated. With the car turning over but not firing, there is no spark at the spark plug end of the lead, but an erratic spark at the coil. It then became progressively difficult to come to any conclusion during each of the three stages mentioned above but by the time the car started running like a bag of poo (stage 2 above) the spark from both ends was still erratic and not in time with the firing cycle at all.

So after all that, my question is: could there be a component within the coil or distributor that fails after a period of time, such as a transistor that starts overheating and takes an unspecified amount of time to return to 'normal', or should I be focusing on something simpler (e.g. spark plugs) or more complicated? I'm prepared to swap the coil from my coupe over, and the leads as well, but the distributor looks like it's going to be a downright royal pain in the arse to change. And of course, the parts will all need to go back onto the coupe in the long run once I've finished restoring the interior and other various things.

Apologies for the long spiel but I guess the more background info I give, the better. If any more information is required, I'll do my best to provide it.

Thanks in advance

Ed

[V8skylineMAN]

your fuel pump is begining to die. when it gets hot it gets tight and pumps slowly. which in turn makes it hotter and tighter.....untill it stops. once it has cooled, 10-15 mins later, it runs like nothing is wrong.

took me a good few weeks to find thats what it was, my old skyline did it to me a few years back.

[0R10N]

your fuel pump is begining to die. when it gets hot it gets tight and pumps slowly. which in turn makes it hotter and tighter.....untill it stops. once it has cooled, 10-15 mins later, it runs like nothing is wrong.

took me a good few weeks to find thats what it was, my old skyline did it to me a few years back.

The fueling system on the sedan's already been checked and given a clean bill of health, it's also running an upgraded Bosch pump. You can actually smell the unburnt fuel coming out the exhaust while it's cranking over, so it's definitely OK. (Not good for the bores I'd imagine )

It's been suggested that I replace the PCU (ignition module), apparently they are notorious for failing, so I'll do that when I get home from work.

Thanks for the tip anyway.

[BensDR30]

The fueling system on the sedan's already been checked and given a clean bill of health, it's also running an upgraded Bosch pump. You can actually smell the unburnt fuel coming out the exhaust while it's cranking over, so it's definitely OK. (Not good for the bores I'd imagine )

It's been suggested that I replace the PCU (ignition module), apparently they are notorious for failing, so I'll do that when I get home from work.

Thanks for the tip anyway.

Could be the CAS in the dizzy dying - a common problem in the RB30E. Swap over the distributors next.

(Or by a can of freeze spray & give the distributor body a good dose when it plays up next.)

[66yostagea]

Check the Pressure Regulator. Disconnect the return line to the tank and make sure it does bypass fuel.