My 1981 242 B21F K-Jet will not start. The problem has been progressive - a month ago it very rarely would not start, and by sitting and waiting a minute or two, I could start it again. Now, it will not start at all.

Every no-start has been the same - the engine cranks over rapidly, the tach jumps slightly like normal, and the car simply will not start. If it would not start with the key, I could roll start it successfully, but now I cannot even do that. When the car did decide to start, I could turn it off and restart it indefinitely, but if I left it and came back, the odds of it starting were 50/50. It doesn't seem to matter if the car is warm or cold. Occassionally, the car will *almost* start the first time, and then refuse to start from there on out.

The engine runs fine once it starts - it has the same smoothness and power as my dad's 1981 242, which has no problems. It never cuts out or sputters, although it does run VERY roughly when cold - I attribute this to a bad thermal time switch, cold start sensor, or the fact that the car has 300,000 miles on it. (or any combination therof) Would these bad sensors cause this no start?

Otherwise, I have tried the following things:

-replaced fuel pump relay with brand new
-checked fuel pressure regulator for gas or smell of gas (none)
-checked for spark at all plugs (yes) and at coil wire (yes)
-replaced spark plugs
-replaced fuel filter
-checked for gas flow at filter intake - there seems to be more than enough pumped out both when i first turn the car on and the pump primes, as well as when I crank the engine.
-checked the compression (163/163/170/165)
-replaced the coil/plug wires

Also, the starter occassionally grinds when I start the car (maybe 1 in 10 times), which I attributed to a 300,000-mile-old flywheel (ring gear). I'm fresh out of ideas, and any suggestions are greatly appreciated, as I can't afford to take the car to a mechanic right now.

Adam

I'm going to go out on a limb here and say you have a couple problems.

First, I'm quite shocked that you'd have problems with a K-Jet car. So many people seem to have invincible K-Jetronic equipped cars... now that the laughing has died off... I'll offer a more serious suggestion. Lots of things could cause a poor cold start. K-Jet is rediculously complex. But the things I'd check would be the various check valves, the accumulator, and the cold start system (thermal time switch, coolant temp sensor, and cold start injector). Does it show that I don't like K-Jet and don't believe the people who claim it's just trouble free and never ever needs work? Gah.

Anyways. My guess for your current situation is that your timing belt has broken. If your engine is turning over rapidly, you've got little or no compression. A broken timing belt would cause this. So would cylinder walls that have been washed down with fuel (i.e. if you had an ignition problem and kept trying to start the car.. and kept dumping fuel into the engine).

Easy to check. Pop the oil cap and crank the engine over. If the cam moves, your timing belt is probably okay. If it doesn't, your belt is broken. If it smells like gas.. change your oil ASAP and then maybe dump some oil into the cylinders and turn the engine over by hand (22mm socket for the crank pulley in this case).

- alex

'85 244 Turbo
'84 245 Turbo

Just read your replies. If your tach is moving, your timing belt is obviously okay.

If your car is running poorly in the cold, I'd suspect a gunked up CPR and any of the previously mentioned cold start doohickeys that K-Jet uses.

You said you checked the fuel pressure regulator? There is no such thing in a K-Jet car. What did you check? The control pressure regulator? Where did you check for fuel?

Have you actually measured the volume of fuel from the fuel pump? Have you measured the fuel pressure (critical on a K-Jet car)? Have you checked that the injectors are working or at least getting fuel? Have you checked that the fuel distributor is getting fuel?

- alex

'85 244 Turbo
'84 245 Turbo

Sounds like maybe a fuel problem. Here are some things to try:

You have a new Fuel Injection relay, but do you know it's "picking" when you crank ? You should be able to feel it click. It takes 2 things: +12v from Fuse 13 (i think) to the relay coil, then pulses from the ground side of the IGNITION coil to ground the relay coil.

You could (as a quick test) force the pumps to run by connecting a temporary jumper from fuse 7 (left side, nearest door is always hot. right side is hot if fuse/contact is good) to fuse 5. Voltage applied at F5 will go both ways--"backwards" via left terminal to run Main pump, right terminal to run the prepump.

Also, there is the Lambda Relay on the left fender rail near headlight flasher. It must be "up" to power the Lambda CU and Frequency Valve, It gets picked by the FI (more than just a pump) relay. And does the FV buzz/vibrate? It should, if the CU is trying to regulate mixture.

Hope this helps,
--
Bruce Young, 940-NA, many 240s (one V8), '73 142, '71 144 (ex circle track car in CT), '67 144 (new), used 122 from '63 to '67

I have a '81, 242 B21F, K-jet, 290kmi. I suspect the cold start injector is not operating. This may be either a bad thermo-time switch (as you stated), the injector itself, or the wiring. The thermo-time switch is under intake #3. The white wire goes to the cold start injector. The blue/yellow wire goes to the other side of the cold start injector and then to the starter and finally to the ignition switch (through the start inhibitor switch if it’s an auto). This last wire should have 12V when the ignition switch is in “run” position. The thermo-time switch connects the other side of the injector to ground (through its mounting) to open the injector.

A easy way to check the cold start injector is to remove a small sliver of insulation from the blue/yellow wire at the cold start injector and touch a hot wire directly from the battery to the exposed copper wire (leave the injector plugged in). If the injector is good it will click when energized. Make sure that the other wire is continuous to ground. Another cause of cold start failure on the Kjet cars is the fuel accumulator which is mounted beside the main fuel pump, This device has a spring loaded diaphragm which is pressurized with gasoline by the fuel pump. Upon engine shutdown this pressure is trapped by the fuel pump check valve and the fuel pressure regulator valve (located in the fuel distributor) on the return end to the gas tank. This maintains pressure on the fuel system (including the cold start valve). If the accumulator is defective, the fuel pump and injection system has to start from zero pressure on every start. This causes a delay in reaching the operating pressure required to open the main injectors as the pump has to fill the accumulator first and then pressurize the system. If it were my car, I would perform a fuel pressure and leak down test. This will prove if the fuel pump is delivering adequate pressure to open the injectors and also show any problems with the accumulator and/or valves.

It takes three things for the engine to fire; Fuel, spark, and compression. Sounds like you have checked out the first two. How about the third? At 300,000, there could be a lot of reasons compression is not what it used to be. Have you pulled the plugs right after cranking/no start and looked at them? If wet with fuel, could be sticky valves - sticking open and causing no or low compression. Your coment that "the engine cranks rapidly", sounds like it is turning faster than you think it normally would. If true, this also may be an indication of low compression.

Probably worth $20.00 for compresion gauge if you don't have one or can't borrow one.

Fuel delivery could still be a problem. If pressure is low, or injectors gummed up, you may not get good spray pattern out of them. You can check by pulling them and directing the spray into a glass jar. Be very carefull with this test procedure.

I am just thinking out loud, but hope it may help you find a path.

Best of luck,

Dan

As I mentioned in my post, the compression is quite good at 163, 163, 170, 165, psi for each cylinder, fore to aft. The engine doesn't seem to crank any faster than my dad's car, nor any slower. Thanks for the idea about the injectors though!

Adam

And so vexed abnd bewildered by the cranking steel they wept, gnashed their teeth in utter despair and contemplated falling, bereft, onto their 10" screw drivers. Oh take heart....said the voice....for I say unto you that the Volvo to the evils of aluminum oxidation falls frequently to a sputtering and impotent box of Scandanavian Steel....and so I bid you go therefore to the driver's side and lift you the hood....their you shall find a 25 amp fuse....remove it...spit upon it and dash it to the ground...place dry emery paper inside the amp holder and...plunging to and fro' clean the inside of this haunted fuse holder....and therein replace with new.

This, then is my hypothesis and I hope and pray that it serves you well.

jack coyle

Except if his car does indeed have K-Jetronic injection, there will be no 25 amp fuse to fail.

- alex