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-   Volvo 240, 740 & 940 (https://volvoforums.com/forum/volvo-240-740-940-12/)
-   -   Noob wants carb, not EFI (https://volvoforums.com/forum/volvo-240-740-940-12/noob-wants-carb-not-efi-66047/)

eprobe 10-03-2012 01:59 PM

Noob wants carb, not EFI
 
I'm working on my second 240 wagon. It's a 1987.

I've spent the last year getting it running. Wiring was rotten, transmission burned itself out, instrument panel melted, a/c went kaput, then the timing belt broke.

Now I'm going through and rewiring the overdrive, cruise control, trying to add ports to the new a/c compressor which didn't come with them!

Soon I will tackle the rotten, malfunctioning EFI system with its inscrutible, evil computer brain. I will replace it w/ a carb. like a Solex, which I can take apart in 10 seconds. I'll have to make an adaptor plate.

But I know it's not going to be as simple as slapping a carb on the intake. I've got to add a pressure regulator, for example, so the fuel line pressure doesn't blow out the new system.

I need some advice from someone who has gone this route. How to change the ignition timing system? What intake to use? How will tearing out the computer affect the instrumentation? What other changes need to be made?

There are no emissions requirements in Sanpete County, Utah, BTW. God willing, there never will be.

I've searched the forums (maybe not well enough!) but haven't found detailed instructions.

Thanks for your help!

pierce 10-03-2012 03:55 PM

the carbs that were used on a B21A/B23A engine back in the mid 70s were dual SU side drafts similar to 1970s british cars, not Solex downdrafts like a VW. good luck finding a manifold that will fit your B230F engine, maybe a european B23A manifold will bolt on, I dunno.

your car has two fuel pumps, you can probably remove and bypass the pressure pump thats under the car near the fuel filter, and run the carb just on the low pressure 'transfer' pump thats in the gas tank. plug the fuel return line as you won't be using it.

your ignition system will probably function just fine as-is. you'll need to replace the ignition related wiring thats decayed, but thats a fair amount less than the fuel injection wiring. The ICU (ignition control unit) has inputs from the engine coolant temp sensor and the hall sensor in the distributor. some early ICU's had a vacuum line too, I dunno if the 87 did or didn't.

net result will be lousy gas mileage or less horsepower/torque, pick one or the other based on the carbs you use.

oh yeah, do be absolutely sure to properly hook up the transmission-throttle cable, its not just a kickdown cable, it also modulates the automatic transmission's pressure to the clutches and bands, without it, the shifting will be horrible.

lev 10-03-2012 05:03 PM

You won't find any info on this operation for a reason... nobody does it. I suppose any modification is possible but that doesn't mean it's advisable.

eprobe 10-06-2012 10:01 PM

Very good advice, pierce! I wouldn't have thought of the throttle cable. I see it now--return cable from throttle body.

Volvo gets poor mileage already and some part of the fuel system is constantly on the fritz. Power is okay, however, when it runs.

Thanks!

pierce 10-06-2012 10:36 PM

a 240 wagon should get 25mpg typical and maybe 27 on the highway if you're not speeding ... if its not, something is messed up.


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