Diagnose my 240....

itsabitsa

240 wagons are a long-standing favourite of mine - I even learned to drive in one! I was looking for a hack to get about in, and found a sorry looking (but rust free and clean) 240 wagon that had been standing for several years. I've done timing belt, engine mounts, fluids and filters, but I've got a couple of issues I just can't figure out; can anybody help?

1) It misses badly when cold, idles on 4 cylinders (with occasional miss) when warm, but starts to miss and lose power when given more than 1/3 throttle. This is worse when facing up hills, hot days, and stop-start traffic. I've replaced the fuel filter and in-tank pump. The injectors have been checked, and one is down *slightly* on the others. The plugs are a little bit dirty, but equally dirty (so I don't think it's consistently missing on one cylinder). The MAF has been cleaned, inspected and refitted. The fuel system has been flushed and it's had injector cleaner through it. It seems to be getting a good spark on all plugs, although I have noticed the coil arcing when I've been playing with the leads when the engine is running.
Is the main fuel pump the most likely culprit? Is there anything else that might cause this?

2) The overdrive doesn't work. I don't understand electricity, but know that the fluid levels are good and the relay under the dash clicks away merrily. Is there a common fault/ issue that would cause this? My first guess would be solenoid, but I'm open to suggestions before I start messing around with it/ ordering parts.

Long-term, I'd love to do an engine transplant with an LS1, but for now I'll settle for four working cylinders!

lasercowboy

1) Could be one of many things: fuel pumps, air/fuel intake, leads, or fuses. The last is the easiest place to start. Check really carefully the fuses for the fuel pumps. They are a bugger for giving this type of intermittent lumpy running problem. You might need to sand/polish the ends of the fuses themselves, and the brass bits they clip into.

For fuel pumps, if the in-tank pump is weak, then you can get the symptoms you're describing. It's a bit of PITA to diagnose and fix, but someone will explain the details.

2) This is a really common fault, but having never had a 240 with overdrive (auto or manual) I'm no expert here - but don't worry, there are plenty around who are!

Slowbrick

Have you done plugs? Your coil arcing suggests there is resistance building in your ignition system. Replace the leads if you havent done so already. Also change the cap and rotor.

itsabitsa

Thanks for the responses! I'd only checked that the fuses were still 'good', but haven't checked for corrosion etc on the terminals, so that will be my next step. I've already changed the in-tank pump (helped a little bit) and tried a spare set of (used) leads which made no difference whatsoever. Part of the reason I reckon it's the pump is because it will idle happily in neutral with the nose pointing down a steep slope, but will miss if pointing up a steep slope. I'm assuming the fuel pump is working significantly harder due to gravity?

I might be suffering from a bit of confirmation bias though!

egads (she/her)

Do these have dual pumps like 240's? What you describe is classic in tank pump failed symptom

Angus242164

Given that the fuel pump pickup point is a little forward of the centre of the tank, I guess it's possible that it may be starving for fuel when the fuel level is very low in the tank, but if it still does this with half a tank or more, I think you can rule it out as the pickup point will be well and truly submerged at all angles.

Can you be certain the in-tank pump is running? It may not be getting power.

Put a new set of leads on, a new cap and rotor on the dizzy, and new plugs if they haven't been done already. Arcing at the coil suggests a major resistance somewhere in the system, and used high tension ignition parts are a waste of time.

If none of this helps, I suspect your MAF sensor is the cause, they are a very common failure item on these cars. Unplug it while it's missing and see if it improves.

Ramrodfunk

Overdrive not working is most likely the solenoid.
There is a mod you can do which will bypass the solenoid if you don't need to have the button on the gear stick to work. It just leaves overdrive on all the time which is no big deal .
A quick internet search will show how to modify the solenoid. It involves making a very small "canal" between the two oil-ways on the solenoid.

However, I have bought a new solenoid which turned out to be faulty so I re-installed the original solenoid and realized it wasn't the solenoid but plastic covering on the wiring had deteriorated so badly it was shorting out on the under body.
I recovered the old wiring and it has been fine ever since.
If I was you I would try the mod before paying for a new solenoid. It will only cost you a couple of hours work and you can decide if you really need that button to work. Especially if you intend to change the gearbox in the future.If you're not towing stuff or going up steep hills you probably won't even notice.

It might be worth while having a good look at your fuel pump relay if you will be changing all those other fuel related items. I've had a relay with a crack in the solder joints inside the relay. Apparently the quality of the original solder can be suspect after many years of work. You can re-solder the "dry" joints but you may need good eyes or a magnifying glass.
I'm not saying it's just the relay but like the solenoid mod ,it is an easy part to eliminate from your fuel supply woes.

Vee_Que

I would not mod the solenoid. Locking out od is a useful function of the car and the issue is probably wiring.

Slowbrick

OD not working would most likely be the switch or the little blue relay behind the dash. OP does the little arrow light up on the dash when you press the button or nothing? Id be chasing those things first before messing with the solenoid.

itsabitsa

The orange O/D light on the dash works. The relay clicks. But nothing happens! I'd be reluctant to lock out the overdrive - reaching 110 kph is hard enough work already! When messing around with the electrics, I notice that neither the rear wiper, lighter, or antenna are working (how did I miss this?).

I've been running the car with at least 3/4 full tank to minimise the load on the pumps. The posts above made me wonder if perhaps the wiring for the in tank pump is a bit dodgy and intermittent. I will investigate further and report back.....

Ramrodfunk

Just to make it clear...You do have an automatic box ?....
..If so you would NOT be "locking out" the O/D.
In fact you be making the O/D permanently on, so you would only be losing the function of the button to make it drop down to 3rd gear.
The O/D is designed to be on all the time .The button is for towing or steep inclines where the gearbox might jump in and out of the higher ratio gear.
That's why the light is OFF when the O/D is used.
The light being off doesn't indicate O/D is engaged ,instead it indicates only that you have pressed the gear stick button and your button is working.

A quick internet search will confirm it has been done by hundreds,maybe thousands, of owners around the world without issues.
IPD in the US ,a reputable parts supplier , has a blanking plate that does the same function as the mod.

ipdusa.com/products/4793/110397-automatic-over-drive-solenoid-bypass-kit

Here's a good write-up on how to do it.

brickboard.com/FAQ/700-900/TransmissionAuto.htm#AutoTransOverdriveProblemsSolenoid

By doing the mod you also lose the need for the relay ,the button on the stick and the dash light as they become redundant.
Just checking the O/D solenoid cable to make sure the cable's plastic covering is intact and not shorting on the gearbox or under body is easy to do , and the first thing I would do.The cable is prone to falling to bits from old age.

Speaking from experience it's super easy , a couple of hours work and there's lots of write-ups on the net for guidance.
If your changing the gearbox then you won't be paying for a new part that will be trashed eventually.
Just sayin' ...It's nothing to fear..
Good luck.