Hey all, posting this from mobile so please forgive my formatting here. I am having a serious issue with my 240 wagon (which is also my only vehicle, adding to the stress).

Yesterday I drove 80 miles to a friends house, which is a normal trip for this wagon. On my way back my car stalled about .25 miles from his house. The rest of the drive was filled with stalls and near stalls. This is an automatic by the way.

So, here’s what happens. The engine will be running fine, then suddenly the rpm just goes all over (doesn’t shoot up, it’s an up and down in a decreasing way). Sometimes the tach drops to 0, then pokes back up to 800, then back down until recovery or death. The car makes the cartoon “my car is breaking down” noise, has a gas smell/maybe burning smell. It always starts right back up again but the issue will return at intermittent intervals.

I swapped out the fuel pump relay and the replacement seemed to help, so for diagnostic reasons I put the old one back. I have a switch and wires set up to jumper the pumps and bypass the relay. When it tries to die I hit the switch (no luck). I put in the new relay and same issue.

I also tried cleaning the connections on the ignition amplifier, but I’m not sure if the loose connection I found (pin coming out of the rear of the connector) was something pre-existing or if I did that. I would drive the car but there just isn’t a good place to break down around here, so it’s terrifying. Idling in the driveway it’ll sit happily for a long time with no issues until I shut it off.

Hopefully this makes sense. I’ve owned this car for 5 years and have overcome everything it’s thrown so far, but have never been able to make it stop smelling like gas. Everyone says it runs beautifully but rich.

Also it will not run without a MAF. It might for a few seconds but it usually stalls. People always suggest to unplug it and try but I’ve never been able to.

Here’s a list of everything done in the last 2 years that might be related:

Wires, cap, rotor, plugs
intake manifold gasket
fuel injectors
engine temp sensor
crank position sensor
exhaust manifold and flange gasket
02 sensor
timing belt plus front seals (May last year)
fuel pressure regulator
both fuel pumps
fuel filter
in tank pump sender (new)

 

where does it smell like gas, front or rear .. or both?

 

some 89 LH2.4's have a suspect ECU with a pink label, these have a Bosch part number ending in -561 ...

See this table: https://www.volvoclub.org.uk/faq/Eng...ReferenceChart

 

I guess you could say both, but I just smell gas when in the driver seat after stalling out. The car has always run rich despite taking a couple blasts from the part cannon.

 

I went out and checked and I do indeed have the pink label -561 ECU. I think the ignition amplifier is my actual issue since tapping it kills the car, but this does now have me worried. I'm a college student who mostly eats ramen so another expensive car part isn't preferred but this wagon always does get the best. My local yard has a 240SE with the ECU intact, though I have no idea why the car is there and if the ECU is good. Plus the passenger footwell has standing water..

 

If the problem is with the ECU I wouldn't expect to smell gas when the engine cuts out since the failure of the pink label ECUs is in the circuit that drives the fuel pump. Failure of the circuit would mean the pump won't run and therefore no gas. Also you mention that you have a switch in place to bypass the relay when it fails and that didn't help. This kind of rules out a fuel supply issue. If you do spring for a replacement ECU, make sure it is an LH 2.4. They would all be post '89 years.

 

I have been looking for an ECU just to get rid of a well known bad part, but have been having a harder time being sure of which ECU to get. I followed the chart and found a decently priced 0280000935 unit. The chart says it's a good sub, but this one is advertised for a 940 and online I see no one mentioning installing this in a 240. I'd hate to get this and have it not do the job.

 

1989+ 240's and non-turbo 940's use exactly the same engine and transmissions. ECU and ICU are interchangable assuming they are the same EGR or non-EGR. Many of the newer ECU's don't use the cold start injector, they just increase the spraying on the main injectors, but you can leave your cold start injector in place, it won't do any harm