[Ray Cox]

do your self a favor and check check the button inside the cap and the rotor, dont ask how i know that one! thanks jack Gadosh! it will run fine untill under a load. myn even did burnouts fine and Hp passes fine but as soon as I added nitrous or made more power boom!

[johnta1]

2- MSD ignition boxes
3 MSD caps
2- MSD rotors
2 set of plug wires MSD & now Moroso
4 sets of NGK plugs
2 MSD coils
extra ground strap
Been through the carb twice to clean.

Sounds like he already did the cap/rotor thing a few times?

[johnta1]

Have you tried fattening up the carb?
(fuel delivery verified good, I take it?)

[adam woodmancy]

ive changed several sets of multiple plugs and cap and rotors

checked the igniton box ground over good when i swapped boxes. it all looks good.

[ponjohn]

Did you back off on the valve springs while the engine was sitting?

[adam woodmancy]

yes, that, and drain and change the oil was the only thing i did to it after i pulled it out.

[jdw_poncho]

I had the same problem with two different issues.

Do both dist have the two colored wires coming out of them? Im assuming you have the two wire MSD distributors? So you just hook up the dist plug to the grn/vilolet wires from the 6al?

Make sure if you are using the extra length harness, that the dist mag pick up wires are not swapped. I bought a used ready to run from someone on here and the wires were swapped in the connector. Look up the instructions on the MSD site and it should say which wire is pos and which is neg. Or just use a small pick and unlock the connector and push the wires out and swap them. Best to just check the wires out.

2nd time I had this issue the rotor phasing wasnt correct. You may need to call msd and ask if a reluctor lines up with the mag pick up at TDC or at a different angle. Since I use a crank trigger and the dist mag pick up for my cam sensor on a efi engine, it has to be set at a specifc angle. It almost sounds like the spark is crossfiring in the cap which is usually because the rotor isnt phased with the dist cap stud.

Drill a hole in the top of the dist cap next to the #1 wire. I usually drill a 1/2" hole using a unibit.
Shine a timing light while its running and see where the rotor is compared to the stud when it fires. Then raise the rpm's and see what it does.

BTW dont stick your fingers down by the hole whiles its running. trust me.......

[BB70]

Have you tried running it with all the wires unhooked from the alternator ?
Trace and inspect all power feed wires for the ign system.
It would be nice to have a inline spark tester on the coil wire or a timing light hooked to the coil wire to see spark consistency.

John

[Chipped Tooth]

I second what Jdw poncho said !!!!!

I had them issues too.

[jimmy daniel]

Interesting topic since I'm going thru the same thing. I have the digital 7 with Pro Billet dist. I've swapped everything you've mentioned as well as two different carbs. I can fill a one gallon gas can in 15 seconds so fuel should be ok. Sounds good, idles good, leaves on the transbrake at 3800 and then is just ragged. Pulls pretty good but just not clean. You can hear the surging sometimes popping from the outside. Rpm graph on race pak is jagged and never smooth. Any other ideas?

[ponjohn]

Valve springs?

[jimmy daniel]

Pretty new springs but no, I haven't checked them. I will check them tomorrow for sure! Thanks

[grnmnstr]

I had a similar issue this past year.

I was about to check the valve springs as well, and then I noticed a small, broken retaining ring from one of the rockers.

[grandville455]

Originally Posted by hp 400 dave

Did you check timing? The MSD will change the timing around from box to box. I found a change from the dyno's box to mine of 7 or 8 degrees.

Interesting, was it retarded or advanced from one box to the other?

[jimmy daniel]

Valve springs checked 240 lbs with my moroso pull gauge. Everything looked good. Added a ground strap....I'm running out of guesses now.

[J.C.you]

.....same deal here with a s 10 we were playing with at the end of last season. Has a 6al with billet distributor,with start retard, just basic simple stuff.

Fires up fine, burnout fine, on the transbrake fine, release brake off the line and under load the thing pops, misses for approx. 60', levels out and runs clean the rest of the quarter.

Thinking something going on with the distributor.

[janderson]

Had a "popping /missing" issue down track a couple years back, turned out to be the tach.

[estep455]

just had this same issue on my sons dragster. I changed the ignition box and it sounds different but wont know if it fixed it or not until we get to the track in the next week or two. I could hold the rpm up and it would cackle and shake. everything fine during burnout and on 2 step but then go crazy at release of transbrake I believe it was trying to go on the rev limiter. I will post results hopefully this weekend.

[HWYSTR455]

Originally Posted by jdw_poncho

...Do both dist have the two colored wires coming out of them? Im assuming you have the two wire MSD distributors? So you just hook up the dist plug to the grn/vilolet wires from the 6al?

Make sure if you are using the extra length harness, that the dist mag pick up wires are not swapped. I bought a used ready to run from someone on here and the wires were swapped in the connector. Look up the instructions on the MSD site and it should say which wire is pos and which is neg. Or just use a small pick and unlock the connector and push the wires out and swap them. Best to just check the wires out.

........

I had this issue with it breaking up under load, and the pickup wires were correct as per the instructions. I decided to try swapping them anyway, and that cured it for me. I even called MSD regarding, and they basically said well, if it's running good now or that way, leave it. Thanks.

Try it, see what happens, it can't damage anything.

Wonder if that box with them swapped came from me!?! Heh-heh!


.

[lakefect]

are you sure that pump is big enough for alky? iam thinking its in the back of the car correct?