240 One problem fixed now other one has come up

Last month I posted What the Heck is Going on? 81 Volvo 242 B21F-MPG WILL NOT SPARK HELPPPPPP PLEASE. Well The problem was that I had routed the ground wire from the ICU that should have been gone to the grounds at the cold start injector to the micro switch and visa versa. Now Im getting good spark. But im only getting a light put put put then nothing.No matter what I do its the same put put put . change coil/ move dist/ change spark mod./ ect ect It seems like when the starter is not engaged maybe no spark. Is that possible? Car has a rather new fuel dist. Brand new injectors and pumps and relay and cold start injector. Any help is deeply appreciated. Thank You

What do you surmise is causing the "putt putt putt"? Are you implying that it's air/fuel or spark related?

Buy a civic and don't mess with It? Your car sounds hacked. No way to tell what's going on from your block of text. Sorry to be rude, but it's the honest truth.

Does it run on ether?

Is the ignition timing correct?

Is the cam timing correct?

Compression ok? Just because it's ok doesn't mean cam ti.i g is right.

Get a labscope and pressure transducer and learn to do 4 stroke analysis. Jk. I am hoping to train myself in this in hopes of finding mechanical issues with only a spark plug pull.

yes all of those things are good enough to get it to started more than it is . I think its only getting spark when the starter is being cranked. Im sure its a wire that has a problem. When I always turned on the key{ before the last 2 months} I would hear a hum {in the engine compartment for about a couple seconds. Now that hum comes at the end of cranking the starter. Go ahead think what you like and say what you will .

"Going to get started better than it is"

On kjet when starting and then running the spark changes from using the 12v boost from the starter to a ballast resisto to cut the voltage down. If the ballast resistor is open. You only get spark when cranking.

. . . It seems like when the starter is not engaged maybe no spark.

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Here is the ignition schematic I posted to your other thread.



Note that the full voltage to the coil while starting is routed through contacts in the starter operated by the solenoid to one connection on the ECU. There is no external resistor to reduce the RUN voltage so apparently that is done internally in the ECU.

The difference between START and RUN is that the coil power comes unfused from the ignition switch in START. In RUN coil power comes from the ignition switch RUN position, again unfused.

So, it has Mopar ignition? It has spark? It sputters? It's CI FI / K-jet?
It has 3-wire Bosch idle motor/constant idling system the electronic idle motor mounted to the valve cover? Or 2 wire bi-metallic spring Auxiliary Air Valve (see identification on Dave Barton's harness page and probably countless other places for identifying pictures?).

Compression, Timing, air/fuel and spark? What's been verified? Using what methods?
Got a book for it? Timing light maybe? Way to remove spark plugs? Fuel pressure gauge? Half way decent digital volt meter?

Fuses clean and proper copper fuses with good contact? If you jumper the fuel system relay, does the frequency valve buzz?
That hum or buzz is/was probably the frequency valve. It's next to the fuel dist, it's essentially a nozzle-less EFI fuel injector designed to run ~80psi.

dl242gt said:

On kjet when starting and then running the spark changes from using the 12v boost from the starter to a ballast resisto to cut the voltage down. If the ballast resistor is open. You only get spark when cranking.

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Unless it has Mopar ignition, in which case it's powered at full 12V and the coil has a ballast resistor built in IIRC and the Mopar box controls the dwell...

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Kjets On a Plane said:

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Yeah forgot about that early 80s kjets with mopar setup.

It's a 240 so start by cleaning the fusebox and fuses, then pop the cover off the fuel pump relay and check for cracked solder joints. If those aren't the cause of your problem now, they will be sooner or later so you may as well fix them now.