Ignition Problems

[70Buick464]

When the engine is under no load, like just free reving in neutral or park, the engine revs fine to 6400 rpm, but when under load and making boost it hits a wall at 5000 rpm and will not go any higher. The only thing different from the engine dyno to my car is that the dyno used a 7al box, and i use a 6al box. Since they dyno used a 7al they put a 7al cap and rotor on it, are the 7al cap and rotor not compatable with the 6al box and coil?
Other things, i only have a small wire grounding the battery to the chassis, which worked fine on the last motor and setup but didnt have the msd then or near the power. I have a ground going from the battery to the motor, should i put one from the motor to the frame?

Any other suggestions on what it might be?

[Metal]

-Plug gap is the same?
-Hows your fuel system/fuel pressure? Remember on an engine dyno you only have a short straight pipe going from the cell to carb. no long pipe length/twists and turns/filter, etc. like on a car.
-The cap and rotor shouldn't make a difference, although im not a big fan on msd's caps. Seen too many crack within a very short time period.
-I would replace the ground wire with a bigger wire. That may not be your problem but it needs it anyway.
-Make sure you have a ground from the msd box directly to the battery.
-What type of coil are you using?

If funds are available, in the future i'd take the car to a rear-wheel dyno. It's just hard to tune an engine on a engine dyno, because once the motor goes into a car there are too many variables that will change a tune.

Keep us updated bro.

[brianj5600]

I would definitely look at plug gap. The dyno ignition is more powerful than what is on the car and may have been able to spark a bigger gap. It is free to close it up and retest. I put an extra gound on mine to rule out a weak one. It is not free, but very cheap. Car like people can start to show their age as they near 40. I don't know about Buicks, but old Mustangs can be funny about grounds. From headlights being dim to funny acting guages to bad running engines can often be traced to weak grounds.

[ReefBlueCoupe]

Any time I hear of ignition problems and an MSD box is involved, it's usually the problem. I don't know why that company manufactures such garbage, but a lot of people have bad MSD boxes. The only thing they have going for them is that they will repair them cheap or free, but then there is downtime and a hassle.

Borrow someone's working ignition box and see if that fixes the problem.

[70Buick464]

the plug gap on the dyno was 35 and i closed them down to 30 and the problem didnt go away. Fuel system is a1000 with -8 lines all around, i have elec. fuel pressure guage and air fuel guage, and i have plenty of pressure and a/f is good also.

[Disney Lincoln]

It sounds like the ignition might be retarding too much. Are you using a BTM box??

[70Buick464]

It sounds like the ignition might be retarding too much. Are you using a BTM box??


No btm box, i just have the timing locked at 21. 7#'s boost right now. Could to little timing be causing this?

[Disney Lincoln]

NO, if it's locked you have enough.

[70Buick464]

NO, if it's locked you have enough.

Ok, im confused. You said it sounded like the timing is being ******** to much, as in not enough timing, right? then i said i have 21 degrees, but its fine if its locked? I dont know, im just asking.

Would not enough timing cause this, or would not enough timing just take away power?

I guess i need to take care of the grounds first just to eliminate that, but the cars going to nashville this week to have the trans redone again then hopefully to the chassis dyno to get everything tuned in perfectly, if i can afford it.

[Disney Lincoln]

Yes, not enough timing would cause this. I was wondering if you had a BTM on it and it wold retarding too far, to say, 10* ATDC or something. But you said it's locked at 21,so that isn't the problem.

[70Buick464]

Yes, not enough timing would cause this. I was wondering if you had a BTM on it and it wold retarding too far, to say, 10* ATDC or something. But you said it's locked at 21,so that isn't the problem.

Ok, thanks. I guess ill just do the 2 ground wires and go from there. Its running rich so i know it needs to go to the dyno to get rejetted so hopefully they can figure it out there. Probably a lot easier where everything can me monitored at once.

[ReefBlueCoupe]

MSD box.

[brianj5600]

I have had good luck with my MSD box. It is on it's 4th car and already had it's 20th birthday.

[ReefBlueCoupe]

I have had good luck with my MSD box. It is on it's 4th car and already had it's 20th birthday.

I don't think they made 6ALs 20 years ago. Which one do you have?

[Disney Lincoln]

I too have also had really good luck out of MSD boxes. Never had one fail.

[70Buick464]

Ok, i took off the ground from the battery to the block today and it was all discolored like it had been over heated or something. also the only other ground was from the battery to the frame but was a really thin wire.

would a bad ground like these two wires cause the miss or problem at high rpm? i know its not the positive side which gives off the power but just trying to eleminate everything first.

[Disney Lincoln]

Yes, it's possible for a bad ground to cause this.

[70Buick464]

well, car got picked up today to have the trans rebuilt for the 2nd time in 1 month. ill just have to wait and see if that changes anything when i get it back.

[brianj5600]

I don't think they made 6ALs 20 years ago. Which one do you have?

It is a 6A.

[Metal]

It's really a hit or miss thing on msd products. Some people have good luck, others don't. I've had good luck with my dig. 6 box for 5 yrs now. My msd distributor was causing an internal vacuum leak around the slip collar(which is a horrible idea created by msd). RTV sealer fixed that problem. Also their caps are not made as thick as they used to be, I've had a few crack within a short time period. Switched to an Accel cap and working great so far.
The accel cap also has side vents to reduce moisture, heat, and ionized crankcase vapor(this produces the carbon trails), making the cap/rotor last longer.

MSD aswell as most other aftermarket companies are just producing more quantity than quality these days, so things don't get the needed attention to detail that businesses used to have years ago.

[JWebb]

Valve Springs.

[70Buick464]

heads are brand new, no chattering or anything comeing from the valvetrain. like i said earlier, i didnt have this problem on the engine dyno, its just something different from the dyno to my car

[JWebb]

Did you have the blower on it on the dyno?

[70Buick464]

Yes, had the supercharger on the dyno. It made a lot more on the dyno than what im running now. Right now im only running 7 psi on pump gas. On the dyno i ran up to 12 psi and had no problems, so only running 7 now should mean less problems, and def. not valves floating.

Right now im hoping on the ground wires, the one going from the neg. battery post to the block was really discolored, and didnt have one going from block to frame. Did have another wire going from battery to frame but is was a really skinny wire.

Once i get the trans back in the car next week ill take it to the track on friday and see if it happens again then just go from there (probably the chassis dyno).

Other than this and the trans im really happy with it so far. I ran it friday and ran 7.6 @ 93 mph; and this was done having to shift at 4800rpm, instead of 6000rpm cause of the ignition problem im having, allong with having no 2nd gear, so i had to shift from 1st to 3rd. before half track i was allready at 5k in 3rd and just kept it there the rest of the way down the track. I think having my trans redone and being able to have 2nd gear, and finding the ign. problem and shift at 6k i should be able to get 7.0 @ 100 easy.

Not to bad for 4000 lbs.

[ReefBlueCoupe]

7.6 @ 93 with problems is awesome.. I can't wait to see what it does when it's all sorted out.

[70Buick464]

ripped the gears out of second, drum and sprag were destroyed as well.

[brianj5600]

Is that a burnout miss hap?

[70Buick464]

no, it went out before i ever got to the track. i just raced on a f'd up trans cause i knew it had to come out anyways.

[ErinC@CPE]

Whats the ETA on the trans? If its not a ground problem we should be able to track the problem down pretty easily on the dyno.

Erin

[ReefBlueCoupe]

Does RPM have their own dyno?

[ErinC@CPE]

No. I started my screen name back when I worked there. I now own a shop in Nashville and we have a Dyno-Dynamics.

Erin

[ReefBlueCoupe]

Well that's good to know.

[70Buick464]

Ill be racing tonight, everything is allready done and all it ended up costin me was a tow bill.

Either way ill be sending the car back down to carma performance hopefully early next month wether the ignition problem is fixed or not. Its running really rich so ill have that tuned to get everything perfect.

All the trash from the trans went into my converter and ruined it as well, so untill i get mine sent away and rebuilt a little tighter and anti ballon plate installed im borrowing one from a friend. The converter i run is a 2800, the one im running untill i get mine back is a 4500. We might say that if traction permitting, it gonna take of a lot faster, probably scare the crap out of me since last week i ran i never took off as hard as i could in 1st and now with the higher stall and actually trying to take off hard its going to be a big rush.

[lightning_2000]

good luck maybe you will dip 6s;)

[70Buick464]

well, no racing tonigh, the converter i borrowed was way too loose for my setup. Just time to have my converter gone over and tightened up a little and everything should be fine.

[393Bird]

I think a lot of the problems with MSD stuff, is the poor installations by the users, like mentioned, grounds, poor power connections, and not removing them while doing welding on the vehicle. I was advised to make it easy to remove when installing, so I could remove it from the car while any welding was done. I did it with quality quick disconnects, and even pull it during exhaust work. Over 5 years with a Digital 6+, and never a stumble. Mounting them in a cool dry place is important also.

Good luck on getting it resolved.

[brianj5600]

Is it together? If all goes well which it should, I will be at the hill. It would be cool to line up a couple 40ish year old cars for a little fun.

[70Buick464]

Im waiting to get my torque converter back, i had them tighten it up to a 2500 stall and anti baloon plate. Then at the track ill have to see if the ignition problem went away.