70 L46 won't rev

[Mike F.]

I just started having an issue with my 70 L-46 this week. It doesn't want to pull past 4500rpm. I also have the Lectric Limited pointless ignition. I'm going to try another coil this week. If that doesn't fix it, I'm going to re-install the points and see where that gets me.

[Dave S.]

Re: 72 LT1 Issue

I just started having an issue with my 70 L-46 this week. It doesn't want to pull past 4500rpm. I also have the Lectric Limited pointless ignition. I'm going to try another coil this week. If that doesn't fix it, I'm going to re-install the points and see where that gets me.

The fuel bowls may be full of shellac from sitting. That will reduce the volume of fuel available causing the engine to max out on rpm's. Once I cleaned out the bowls my 70 LT-1 went to 6500 rpm just like it should.

[Mike F.]

Re: 72 LT1 Issue

The fuel bowls may be full of shellac from sitting. That will reduce the volume of fuel available causing the engine to max out on rpm's. Once I cleaned out the bowls my 70 LT-1 went to 6500 rpm just like it should.

My car never really sits (the OP's may have). I just drove 1200 miles (roundtrip) for the New England Regional. The quadrajet is freshly overhauled as well. I'm fairly certain it's an ignition issue. Which item....well, that's another story.

[Timothy B.]

Re: 72 LT1 Issue

I just started having an issue with my 70 L-46 this week. It doesn't want to pull past 4500rpm. I also have the Lectric Limited pointless ignition. I'm going to try another coil this week. If that doesn't fix it, I'm going to re-install the points and see where that gets me.

Mike,

When is the last time the sparks plugs were cleaned and the spark plug wires checked for resistance..

[Mike F.]

Re: 72 LT1 Issue

Mike,

When is the last time the sparks plugs were cleaned and the spark plug wires checked for resistance..

Two days ago, as part of the trouble shooting process. The plugs have around 4000 miles on them (all very close in color/condition). The wires ohmed out from 10k (shortest) to 17k (longest).

[Mike F.]

Re: 72 LT1 Issue

Mike,

I would be thinking about replacing the wires, when I replaced the wires on my 67 I seem to remember the new short wires at approx 4-5000ohms. How old are the wires?

The wires (Lectric Limited) are about 2 years old.

I just got off of the phone with Lectric Limited Tech Support. Was told that a high performance ignition coil with very low resistance (under 1.2ohms) have been known to cause problems with their breakerless ignition. I'll have to measure my coils resistance tonight.

[Timothy B.]

Re: 72 LT1 Issue

Mike,

Start the engine in the dark before you take anything apart to see if you get a light show going on, you will then get a idea where to start.

Keep in mind after you get the resistance of your ignition coil call M&H fabricators as they are the company that makes the Breakerless SE,. Lectric limited is a retailer of this ignition upgrade, my thought is that it will work or not work but I could be incorrect.

[Mike F.]

Re: 72 LT1 Issue

Mike,

Start the engine in the dark before you take anything apart to see if you get a light show going on, you will then get a idea where to start.

Have already done this, all ignition shielding has been removed (except boomerang shielding), no light show.

[Timothy B.]

Re: 72 LT1 Issue

Mike,

If the engine just goes flat like there is no fuel then check the pump pressure to eliminate that. I would be surprised if the breakerless is at cause, call M&H and explain the condition and see what they say first.

[Duke W.]

Re: 72 LT1 Issue

Mike,

I would be thinking about replacing the wires, when I replaced the wires on my 67 I seem to remember the new short wires at approx 4-5000ohms. How old are the wires?

The OE type RFI wires should measure no more than 5000 ohms per foot of wire length, and the front four on a SB are about three feet long.

Duke

[Mike F.]

Re: 72 LT1 Issue

Update - Changed coils and that seemed to fix the problem for the 20 mile test run. The "offending" coil was the BR 270 repro (1.3 ohms), approximately 1 year old. I stuck in a 20 year old coil (1.8ohms)that came with the car and it ran great. I'll drive it for a few weeks and see what happens.

Thanks for the help.