Thread: Runs great for 20 minutes then dies

G`day ,

are all plugs the same colour , they will give an idea .

All black fuel , all light electric ( simplified )

resistor pack works as 2 seperates 4 and 4 so both sides would need to fail at once , don`t know about heat .

if you have different colours from each bank then resistor pack or related .

Have you looked at the coolant temp sensor and does it blow black from the exhaust .

Faulty sensor can let it run cold but signal ECU to give too much fuel when hot .

Look at the plugs and work out if it`s fuel or electric .

Not just a dirty fuel filter, or fuel pick up is it? Once stopped the gunk/chunks float away and it takes a bit of time to block the flow again, or at least that's what was happening on my Series.

Originally Posted by PLR

G`day ,

are all plugs the same colour , they will give an idea .

All black fuel , all light electric ( simplified )

resistor pack works as 2 seperates 4 and 4 so both sides would need to fail at once , don`t know about heat .

if you have different colours from each bank then resistor pack or related .

Have you looked at the coolant temp sensor and does it blow black from the exhaust .

Faulty sensor can let it run cold but signal ECU to give too much fuel when hot .

Look at the plugs and work out if it`s fuel or electric .

I did have a look at the plugs while I was doing the rings and other work, they looked fine to me, I even compared them to the Bosch catalogue and they appear to be "normal". They weren't wet, or white, but maybe a bit on the dark side.

I've been meaning to replace the temp sensor for months now, but I keep putting it off because the multimeter is reading it within spec according to the RAVE manual. I might just replace it anyway or at least try substituting it for an appropriate resistor to simulate a hot engine.

I haven't seen it blow black smoke, except when it was throwing a hiss fit on the highway today (was just about stalled, revs were so low alternator light was on) I didn't want it to stall then and there so I planted the accelerator to the floor and with wot it fired back up, loads of black smoke, but it soon died again within seconds.

I've got an external ignition amplifier on the passenger side wheel arch, tacho signal is derived from this, but I didn't see anything abnormal on the tach so I don't believe it's ignition. New dizzy cap, new plugs and new leads all round, plus I've rebuilt the dizzy, so I'm pretty certain it's not ignition. Amplifier not getting hot, the coil does, but so does the old one I've not long taken out.

For the time being I'm thinking of building my own resistor pack, but with voltage regulators, capacitors and a cooling system of sorts, should actually be rather cheap to build, if it's only there to supply a specific voltage range to the injectors, regulated voltage would be far superior to a giant resistor. I've also got plans for a visual testing rig to keep an eye on the coolant temp sensor while driving. A few LED's and an lm3419 ic should do the trick.

Originally Posted by isuzutoo-eh

Not just a dirty fuel filter, or fuel pick up is it? Once stopped the gunk/chunks float away and it takes a bit of time to block the flow again, or at least that's what was happening on my Series.

I'll have a look at the fuel filter, but I've got a fuel pressure gauge I can get my hands on for free in the mean time.

Just a brief update, today I modified the injector resistor pack with a heatsync and moved it away from the original location (right above the exhaust manifold) over to on top of the passenger wheel arch next to the coil. So far it's been idling for about 30 minutes without any signs of stalling.

So I may have fixed the problem, but idling in the driveway is a wee bit different to driving on the highway. I'd imagine at 110kmh it would be running a tad cooler with the fresh air moving around it, so I don't think it's a heat issue anymore.

I'm waiting for it to drain it's tank now so I can check on the fuel pump and seal, while I'm in there I'll check for any contamination or blockages.

Anyone have any ideas?