73DATSON Posted November 15, 2011 Report Share Posted November 15, 2011 Ok I have a L20B with webber downdraft. Car was running Ok I guess. I just changed for the webber sidedrafts quad. Now one of the sidedrafts are not working? No air intake to motor? And the third spark wire has no spark? There is no spark coming out from the third point on the disburture only the 1,2,4 point? Quote Link to comment
I'm BLUE Posted November 15, 2011 Report Share Posted November 15, 2011 bad spark plug wire ,,, replace as a set ,,, if you have points and condensor ,,, check point gap and replace if its been a while :) Quote Link to comment
datzenmike Posted November 15, 2011 Report Share Posted November 15, 2011 Swap the #3 wire with # 4. If the problem moves t the #4 wire then the wire is bad. If the problem stays on the sam plug then the distributor cap may be bad. If you have points be sure that they are opening and closing on all 4 positions. Just remove cap and watch while turning the motor over. Quote Link to comment
73DATSON Posted November 15, 2011 Author Report Share Posted November 15, 2011 I changed cap and rotor. I did the swap on 3&4 wire. I don't have points on the dis. It's electic. Quote Link to comment
73DATSON Posted November 15, 2011 Author Report Share Posted November 15, 2011 bad spark plug wire ,,, replace as a set ,,, if you have points and condensor ,,, check point gap and replace if its been a while :) I will change the wire as a set. Didn't do that? Just swap 3&4wires still no good? Quote Link to comment
73DATSON Posted November 15, 2011 Author Report Share Posted November 15, 2011 Ok I have a L20B with webber downdraft. Car was running Ok I guess. I just changed for the webber sidedrafts quad. Now one of the sidedrafts are not working? No air intake to motor? And the third spark wire has no spark? There is no spark coming out from the third point on the disburture only the 1,2,4 point? When I said point I meant to said the top of the DIS where the wires connect to. Quote Link to comment
datzenmike Posted November 15, 2011 Report Share Posted November 15, 2011 I changed cap and rotor. I did the swap on 3&4 wire. I don't have points on the dis. It's electic. This is getting confused. I'm not there to know what you have done so you have to describe everything you have done and in what order. Only you know what you've done. So the cap and rotor were changed before this problem or after? and if you just changed them did it fix the problem??? I will change the wire as a set. Didn't do that? Just swap 3&4wires still no good? Before you buy new wires find the problem. You may or may not need new wires. What does : "Didn't do that? Just swap 3&4wires still no good?" mean? It tells me nothing. Quote Link to comment
ggzilla Posted November 15, 2011 Report Share Posted November 15, 2011 If one wire is bad, no need to replace the whole set. If the other wires look good and work good, just replace the one bad wire. But definitely test it first. Don't replace what aint broken. If #3 has no spark, then swap 3 & 4 wries. Then observe: * If now #4 has no spark, it's the wire * If still #3 has no spark the cause is not the wires Quote Link to comment
73DATSON Posted November 15, 2011 Author Report Share Posted November 15, 2011 Ok. I change the carbs first. From downdraft to quad sidedrafts. One of the carbs were not working. So one of my friends pull out the spark plug wire and found out that it had no spark. So we open the cap and saw that the cap middle pin that touch the rotor was worn out so I bought a new cap&rotor, then we check for spark at the cap it self and #3 had no spark???? Quote Link to comment
datzenmike Posted November 15, 2011 Report Share Posted November 15, 2011 Alright. Now what type of EI dizzy do you have? The matchbox? Has a small black box on the side and under the cap looks like this... Or the remote igniter. Looks like this under the cap. If using the GM HEI igniter module I assume this is the kind you have???d . Quote Link to comment
73DATSON Posted November 16, 2011 Author Report Share Posted November 16, 2011 Alright. Now what type of EI dizzy do you have? The matchbox? Has a small black box on the side and under the cap looks like this... Or the remote igniter. Looks like this under the cap. If using the GM HEI igniter module I assume this is the kind you have???d . The second one I have. Quote Link to comment
datsunaholic Posted November 16, 2011 Report Share Posted November 16, 2011 Either way, if you're getting spark from 3 wires and not the 4th, there's only a few possible causes. 1) Bad spark plug wire 2) Bad distributor cap 3) Bad spark plug 4) Broken reluctor. All 4 are "replace part". It can't be the module, since it's always the same plug. It can't be the magnetic pickup for the same reason (if the pickup was bad it wouldn't fire at all). The reluctor would be the least common failure of the 4 above, but I suppose it's possible. But that means you need another distributor, or at least another reluctor. Quote Link to comment
datzenmike Posted November 16, 2011 Report Share Posted November 16, 2011 Check the four 'cam' lobes on the center reluctor for damage. #3 may be chipped off. Possibly the air gap between the reluctor and the pick-up coil is too wide. You can use a feeler gauge and set from 0.008" to 0.016" Quote Link to comment
motavated Posted November 16, 2011 Report Share Posted November 16, 2011 Man... usually what happens is that the damn distributor gets to worn out that I have seen the blades touch the sensor. I wonder if that could cause a problem? I would also check for distributor shaft play. I would maybe even change it if it has to much play... Mike beat me to it! Quote Link to comment
ggzilla Posted November 16, 2011 Report Share Posted November 16, 2011 What exactly do you mean 'no spark at 3'? Where are you looking for the spark? If you simply pulled the wire off the running engine, and it made no difference, that's a good test and indicates the cylinder is not firing. But it doesn't tell you the cause -- it could be a spark problem, or something else. If it were me, I'd do the most basic of tests. Get out the old compression tester (or borrow one) and do a compression test. You might find cylinder #3 has low compression compared to the others. Quote Link to comment
datzenmike Posted November 16, 2011 Report Share Posted November 16, 2011 Man... usually what happens is that the damn distributor gets to worn out that I have seen the blades touch the sensor. I wonder if that could cause a problem? I would also check for distributor shaft play. I would maybe even change it if it has to much play... Mike beat me to it! Good point. Shaft wear. I only mentioned chipped rotor or wide air gap. Quote Link to comment
banzai510(hainz) Posted November 16, 2011 Report Share Posted November 16, 2011 You might find cylinder #3 has low compression compared to the others. "Could be bad valve lash at the rocker arm" open the valve cover and ck both the intake and exhaust valave lash. To make this ez for you open the valve cover and point the cam lobes up on number 3 ,do the intake and if rocker is loose when cam lobe is up you know the valve is closeing. then do the exhaust. If rocker is tight then it needs to be adjusted. YOu ck the spark plug? when you say at # 3 wire you mean you pulleg out the spark plug with wire attached and grounded and see if theres a spark? Or you just pulled the wire off and you didnt fell a combustion cycle(noting changed when you pulled wire off) Or you take wire number 3 off at the spark plug end and place near ground to see if spark. But I notice one cant do that on good plug wire as you cant move the plug boot so EZ OK if your car isnt running good before the carb change you shouldnt do a carb change till you fix the proplem as you might induce another proplem with a already bad proplem and then its harder for US to fix over the computer. Most times its just a 1 to 2 hr fix if that at all Quote Link to comment
73DATSON Posted November 16, 2011 Author Report Share Posted November 16, 2011 Thx guys. I'll check it on Thursday too busy at work to mess with it. Will post up dates. Thx again. Quote Link to comment
banzai510(hainz) Posted November 16, 2011 Report Share Posted November 16, 2011 10 mins to ck this out. 2min to pull cover Quote Link to comment
73DATSON Posted November 17, 2011 Author Report Share Posted November 17, 2011 Does anybody know the compression number for a L20B motor? Quote Link to comment
datzenmike Posted November 17, 2011 Report Share Posted November 17, 2011 The compression value in PSI is dependent on how worn the motor is and the cam timing. How tight the valve lash is, a bent valve, broken valve or damaged valve seat or piston. Very very roughly 150 would be ok 175 would be good The question still remains about the spark. How are you testing for 'no spark third wire'??? Take the third wire off the spark plug and put an old plug in the end. Hold it on a good grounded surface (like the valve cover) and crank the motor over. Is there spark Yes or No??? Quote Link to comment
ggzilla Posted November 17, 2011 Report Share Posted November 17, 2011 All cylinders should be within 10% of each other. That's what is good. What you are looking for is: is #3 far lower than the others? Quote Link to comment
73DATSON Posted November 18, 2011 Author Report Share Posted November 18, 2011 Well first i would like to say THANK YOU ALL!!!!!!!!!!!!!! i got spark on all 4:-))))))))) it was exactly what mike said!!!!!!!!!#3 lobe pop off??? got it fixed. THX...... Now for the carbs are running rough,well one is the other one is not taking in air??? only when i hit the throttle they both feel good. is there a butterfly adjustment? in the carbs it seem like one of them is getting very lil intake of air? Quote Link to comment
ggzilla Posted November 18, 2011 Report Share Posted November 18, 2011 Glad to hear! I suggest you start a new Topic for the carburetor question. Quote Link to comment
banzai510(hainz) Posted November 18, 2011 Report Share Posted November 18, 2011 YOu have to Sync them. Quote Link to comment
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