190SL won't start!

[hgupta]

I just replaced my solexes with weber carbs this weekend, and I am still having trouble starting. Fuel is definitely getting into the carbs, and the engine is turning over due to the starter. The trouble appears to be electrical. I pulled the distributor wire a little bit out of the cap, and did not see any arcing while trying to start, and there was also no arcing at the coil end of the wire either. The points,and rotor are new, and the distributor cap is in pretty good shape. What should I check next?

[Jim Villers]

Next stop … get fire. To test the coil, insert a plug wire from the distributor into the coil with the plug sitting on top of the valve cover so you can see if it sparks. With the distributor cap off, open and close the points manually; you should see a spark and hear a snap every time you open the points. If you don't get a spark, check voltage on the positive side of the coil. Then check wires, connections at the points for a possible grounded wire. If all of this is OK, try it with the engine turning to open the points and look for spark. When that works, install the rotor, cap and center tap wire and replace the plug wire in the distributor but leave the plug on the valve cover. When turning the engine, you should see spark at the plug. If so, you are done and it should start. If it still doesn't start, try spraying starting fluid down the carburetor. If you have spark, it will start or do something.

[hgupta]

Thanks Jim. I've tried the starting fluid in the carbs, so I know I have no fire. When I open and close the points manually, does the key need to be in the ignition in the run position? I am actually a kind of lost when it comes to the coil and distributor... before getting this car I only had a 300CD...no electrical worries. Anyways, without the distributor cap on if you were to open and close the points manually, will you not get one hell of a shock, and how does the coil "know" when you are opening and closing the points? I did just buy a bumch of electrical tools like a multimeter and current/ continuity tester. Is there a good way to use this right now? Which is the positive side of the coil?

[bstreep]

You do need to have the key in the "on" position. Did the car run before you put the new Webers on?

Try not to be in electrical contact with the coil or plugs or points - not dangerous (unless you have a pacemaker, maybe), but for most folks, it's not a very pleasant experience. You should get a spart at the points if you open and then close them.

[hgupta]

Thanks guys!
Bill, the car was not starting when I changed the carbs, but I thought it was because I accidentally left the key in the ignition over night. Now I realize that I must have burned something out. Okay, I just went outside and tried two things. First I used a light bulb current sensor between the positive side of the coil and the engine block, and it lit up with the key in the on position. Then I tried to manually get a spark by putting the center wire if the distributor cap to the engine block (still connected to the coil) and opening and closing the points. No spark. What does that mean, a bad coil?

[hgupta]

I broke out the multimeter. It should 12.14V at the positive side of the coil and continuity with the engine block at the negative side. Then I tested the distributr cap and it showed coninuity at each side fo terminals. When I tested the spark plug wires... none of them showed continuity. I can't explain why..it doesn't make sense, but I am going to go pick up some new spark plug wires now.

[hgupta]

Okay, new coil, new spark plugs, new spark plug wires to accompany my new weber carburetors and new air filters. And the darn thing won't start!!! There was an electrical problem but I think I fixed it. The engine seems to want to start, especially when I pump the gas; it occasionally sounds like it might but then it doesn't. Starting fluid does help it along briefly, but it doesn't catch. What should I try next?? The webers came prejetted, but there weren't any instructions that came with it, so I just bolted it on as I thought it should go. I took a guess about how the linkage should be...when I press the accelerator, the throttle levers do go down in unison (not all the way down, but mostly). Do I need to adjust the idle mixture and other screws? How do I know which screws do what? Like I said, there are no instructions. Ugghhh...this is frustrating!

[Jim Villers]

Hemant …. Lots of things going on. Try to focus on one at a time. Don't worry about the carburetor adjustments until it actually runs. Focus on the electrical system until you can see spark at a spark plug. Do not worry about not getting connectivity through your plug wires with your multi-meter; the wires have very high resistance to elimate radio interference. Back to trouble shooting … connect the multi-meter to negative side of the coil and ground. When you open and close the points the circuit should open and close. You should see the same open and close on the meter when you turn the engine over with the starter. If you do not get this open and close connectivity, you installed the points incorrectly, one of the connectors is probably touching ground or you are missing an insulator washer on an electrical connector. When you get this working, then check the coil with a plug wire from the coil to a plug on the valve cover, key on, open and close the points and you should see spark. After this works, reinstall the rotor, distributor cap, plug wires and center coil wire and with the plug on the valve cover, check that you have spark to the plug when the engine is turned over.

At this point, it should couch, sputter or do something or we need to do some more checking. Again, focus on electrical until it works correctly.

[hgupta]

Thanks Jim
After getting the new coil, the electrical side seems to be okay. With the spark plugs taped to the top of the engine block, I could see them firing in order as I turned the engine. I put them back in and tried to start the engine. It almost runs if I pump the accelerator pedal. I sprayed some starting fluid onto the air filters and that seemed to help a little bit. I think I am almost there. Where do I go from here??

[Jim Villers]

Next step, get the timing close. Do you have a timing light? I'll assume not; Bill Streep, chime in if I say anything incorrect. The object is to get the spark plug to spark at the correct time. Since it "tries to start", it is close. On the driver's side front of the engine, there is a metal pointer next to the crankshaft pulley. There are marks on the pulley; TD, 10, 20, 30 and 40 to indicate Top Dead center, 10 degrees rotation etc. With the car in 4th gear, rock the car forward to turn the engine until 20 is opposite the pointer while the numbers are counting down. Now do the spark plug on the valve cover again with the plug wire to the coil. Loosen the bolt at the base of the distributor so that you can rotate it. Turn the key on and rotate the distributor back and forth until you see a spark. You want to stop rotating the distributor while it is being rotated counter clockwise and at the point of the spark. Tighten the distributor bolt; replace the spark plug, wire and center wire. The timing is now set to 20 degrees before top dead center in a static condition. Bill or Arthur check my direction and static setting.

Also check the carburetor idle jet adjustments. The four adjustment screws on the base of the carburetor where it joins the manifold should be adjusted to one and a half turns.

Try to start it again and see if we made any progress.

[bstreep]

Jim,

Good explanation. Since I haven't had a problem starting mine in a while, I can't remember the static setting, but I'll check it in a little while. I always set my timing to between 35-38 degrees at 3000 rpms (or higher).

[ctaylor738]

I might suggest an easier way to check the timing.

Rig a wire from the small terminal on the starter long enough to reach the battery. Pull spark plug #1 and touch the wire to the positive terminal on the battery while watching the pulley as described as the engine turns over. Make sure that the 20 degree mark is aligned with the engine on the compression stroke. You can either look at the cam lobes for #1 to make sure they are closed, or listen or feel for the compression.

At this point, the rotor should be pointing at the #1 wire. If it is close, you should turn the distributor until #1 fires. If it is 'way off, you may have to re-position the distributor.

BTW -Is gas getting to the carbs? No problems with pump or filters?

My $.02.

[hgupta]

Thanks Jim and Bill.
I don't have a timing light, and I have no problem picking one up on the way home from work if it helps--but you guys may have to guide me in using it. My car is parked in my driveway which is pretty steep and the front wheels have sunk into the mud, so rocking the car forward is nearly impossible. What about jacking up the rear of the car and turning the rear wheels instead? I can't wait to try this... my roommmate almost bought a timing light yesterday because he wanted to learn to set the timing in his '66 mustang. Is there anything else I may need from the autoparts store on the way home?

[Jim Villers]

The timing light is all that you will need. The objective of rocking it was to turn the engine; you may be able to do that by turning the fan while keeping the fan belt tight. If you have a 22mm socket(?) or a US socket that will fit the bolt in the center of the crankshaft, you can turn the engine that way. If you get a timing light, that might be easier. Buy a timing light with an "inductive" pickup.

Attach the red and black clips of the light to the battery and the "pickup" to the first plug wire (forward). With the light trigger pulled, the light should flash as the engine is turned over. Aim the light at the timing mark on the front of the engine, with the engine turning over, the flash of the light should "freeze" the timing mark so you can read it. Rotate the distributor until it "freezes" at about 20.

Adjust the carburetor idle jets and it might run.

Good Luck.

I'll bet you that your problem is a short between the points and the wire to the coil. If your distributor is new, check where the wire goes through the distributor to make sure it has the proper insulating washers.

If you were getting spark and fuel your car would make an effort to start. The timing wouldn't be all that far off since the distributor is indexed.

If everything was removed from the car and your timing is way off and the car won't start, you can follow this procedure to make sure its all set up correctly:
I call this the toilet paper job, and it never fails!

With the spark plugs out turn the engine with a wrench (gearbox in neutral) and have your friend put his thumb over the spark plug hole on the #1 cyl to check for pressure. When he gets pressure then you know the enging is coming up on the compression stroke in that cylinder. Then watch the timing mark and set the engine to the correct static timing. (Jim or Bill or ?? what is the right number?) When you have the engine at the right point, then you can set the points. Loosen the distributor clamp so that the distributor turns freely in place. Then turn it so the points are closed. Take a piece of toilet paper and carefully pry the points open and slip the paper in between and let go. Now hold onto the paper being careful not to tear it...just pull gently and turn the distributor slowly around. When the points just barely begin to open the paper will slide out. This is where your spark will occur. Now put on your rotor and look where it is pointing. Make sure that corresponds to the wire on the cap going to the #1 cylinder. Check the remaining wires to make sure they go to the correct plugs according to the firing order.

Give everything a once over and before starting the car. It should start. Once your car is running you can check the timing and set it again for full advance while running if you prefer.

Good luck!
Eric