Sick as a dog and then suddenly all good

manga_blue · Postby **manga_blue** » Thu Mar 26, 2020 3:19 pm

Nothing like a good puzzle, is there?

I filled up with 98 at the local garage. One or two kms out from there the car started spluttering. I barely made it home and put the car in the shed. Tried it again a week later and still very sick, felt like fuel/injector problems. Checked at the local garage - no reports of dirty fuel from that outlet. So it's a problem with the car. Sigh.

I backed it out of the shed this morning. Still missing and this time clearly blowing out unburnt fuel in the exhaust. Ah ha, spark issues I thought!

Went and had a cup of coffee before opening the bonnet and checking that I could still easily pull COP leads to see if I could isolate it to one cylinder. Then started the car. MASSIVE backfire into the inlet manifold during start-up.

Car now purrs like a kitten. WTF happened?

Postby **Okibi** » Thu Mar 26, 2020 9:18 pm

Stuck injector?

manga_blue · Postby **manga_blue** » Fri Mar 27, 2020 9:45 am

Okibi wrote:Stuck injector?

I had been thinking faulty CAS or dry solder in the COP system but I must admit stuck injector is a better guess. All the more so because I probably don't have to do anything about that except drive it a lot.

bruce · Postby **bruce** » Fri Mar 27, 2020 12:47 pm

Your title made me think you were sick as a dog.
When does a car get sick, it may run like sh!t...

PaulF · Postby **PaulF** » Fri Mar 27, 2020 12:53 pm

bruce wrote:When does a car get sick, it may run like sh!t...

When does a car run? It doesn't even have legs. It may drive...

It's almost as if one word can have multiple meanings.

manga_blue · Postby **manga_blue** » Mon Mar 30, 2020 5:29 pm

It looks like it is either the CAS or else it's time to give the ECU another bath. Driving on the highway the engine is switching off on all four momentarily. It's not a one or two cylinder miss or splutter. When it switches off the tacho drops as well, even if road speed keeps the revs up.

greenMachine · Postby **greenMachine** » Mon Mar 30, 2020 8:49 pm

Bit of a coincidence that it started immediately after filling up. I'd drain the tank, really drain it, and refill with clean fuel from another source. If you can get at the fuel pump, check the sock for blockage and signs of crap. Maybe even replace the fuel filter (not the sock but that too if needed)?

:mrgreen:

Aiming Faster · Postby **Aiming Faster** » Wed Apr 01, 2020 3:25 am

Someone here has mentioned an issue with ignition switch electrics, and battery power (fuse downstream to ECU?) becoming intermittent.
I once used graphite to lube ignition keyhole tumblers, graphite got onto the electrical contacts, caused misfire / cutting (out on a motorbike).
Good luck.

Red_Bullet · Postby **Red_Bullet** » Wed Apr 01, 2020 8:10 am

Just needed a good fart.

manga_blue · Postby **manga_blue** » Wed Apr 01, 2020 1:40 pm

As always the fart was only temporary relief. :oops:

Both fuel and spark seem to be shutting off together. It's like I have a toddler in the passenger seat playing with the kill switch. I'm thinking it must be power to the ECU, inside the ECU or a key signal to the ECU (like the CAS).

It's hard to get time for this because being locked down means I finally have to finish the kitchen cabinetry.

93_Clubman · Postby **93_Clubman** » Wed Apr 01, 2020 3:46 pm

Phil, symptoms sound very similar to when a cap or caps leak & damage the PCB in a 4AGE 20 Valve Silver Top motor ECU. Not unknown to occur in NA6/8 ECUs, but not as common as aforementioned. Hopefully it's not as bad as that, & an ECU bath does the trick.

manga_blue · Postby **manga_blue** » Wed Apr 01, 2020 4:36 pm

Thanks, hope it's not that. Contacts in the ROM socket on this one may be a candidate too. This is the ECU that I socketed back in 2008.

I think I'll bath the ECU first. If that doesn't work then I'll just pop in a new EPROM. Next step is to replace the circuit board in the CAS (Mania sell them). Then it gets harder. Last resort, you don't happen to have a spare BPF6, do you?

Red_Bullet · Postby **Red_Bullet** » Thu Apr 02, 2020 10:22 am

My old V6 Camry a few years back began throwing out huge plumes of white smoke and lacking power. After much head scratching...Anyway, at idle I put a stethoscope on each injector. What became clear was that 2 injectors were running at twice the rate of the other 4. Theorising here, Getting too much fuel in two cylinders caused the ECU to cut fuel to the other 4 making them run very lean. Don't really know where the smoke was coming from but there was a LOT of it! Maybe the lean burn was burning off carbon from piston tops.

Pulled the ECU to bits and found capacitors had leaked causing adjacent tracks on the circuit board to be shorted together. These were the tracks for the two injectors that were running at double rate. Each time the ECU commanded one of those injectors to open, then two opened.

Cleaned board and replaced capacitors, ran fine for years after.