Engine and Transmission Tech

New V6 3.4 GM engine (and car) is now running (finally) but am experiencing "no start" after running.

First run at highway speed was everything I had hoped for 5 years! Yesterday a 12 mile run to City Desk at Victoria British to pick up more parts was pure joy. When returning home, stopped on drive to clear garage space and the car would not restart. Best I could describe was as if the battery was near death but volt meter showed 14V and quick check with volt meter confirmed 13.5.

30 minutes later, it fired right off. Suspect was heat related but gauge never went beyond 185 F. When we first began firing up the engine after installation, we experienced the same thing after just a few minutes... put in new MSD Blaster coil and new electronic module in the distributor and it seemed to solve.

Any ideas or suggestions? Do I need a newer starter motor? Current starter is already shielded with aftermarket heat blanket from exhaust header. If not, other suspects?

Thanks in advance
Don B.

Heat soak, maybe? Hold the accelerator to the floor to restart. I have a bit of this even with a carb spacer.

Quote: Best I could describe was as if the battery was near death

Heat = resistance. Is your exhaust close to your starter? How about the battery cables? They make asbestos shields for starters for this reason. It's an especially common issue on higher compression engines. I've solved the problem before by wrapping the starter and using larger gauge battery cables. I had a friend with the same problem because he attached the ground cable to an exhaust manifold bolt. Moved it to the starter bolt and the problem was solved. Good luck.

Hey Don,

What are the details on your engine combo.
Sounds like a carb and distributor?
Like Jim said. Battery cable routing to the starter could be the culprit.
Doing a couple of simple voltage drop tests will deal with that.
If you're not familiar with doing them let me know and we'll walk you through it.
The other big one is ignition timing issues.
But we need to know what you are using and how it's set up.

Cheers
Fred

Fred, Jim and Carl,

Thanks for the tips... First, we had a very nice gathering for Bill Young's Celebration of Life yesterday at Bill Davidson's house. Good turnout, great weather, and lots of Bill Stories for all to enjoy. 1/2 the driveway was taken up with the Roadmaster.... and a couple of other MG V6s. We DID wake up the neighbors!

The engine is a pretty straight forward 60 degree V6 3.4 GM with Holley 390. MSD coil and stock dist. for ignition. Nothing trick. Seeing the close proximity of right header/exhaust pipe (I have side mufflers and heat shields) so pipe makes two bends (SS flexi-couplings) to get to muffler system on each side.... I had already covered the starter motor with flexible heat shield blanket (as well as fuel line from tank) in the same vicinity.

Cold, engine starts immediately, idles at 950 and responds well in all gears and conditions. Multiple stop/starts in garage or short runs... flawless. It sure seems like "heat soak" (as if I really understand beyond the obvious).

Again, only visible (audio) clue is... as if battery was almost totally flat. Give it 20 minutes and good as gold.

I would appreciate the offer to walk thru your voltage drop check issue and will confirm location of ground.
Thanks.
Don B.

Don, I think I would try another starter. I have heard of issues with brushes or other internal components, or even the solenoid where it wouldn't carry full current to the windings. If your lights don't dim when the starter is cranking slow it's either the starter or something in the high current circuit and my money would be on the brushes.

Jim

Don,

Chevy V8 starters are known for hot start problems. I don't know if that applies to the V6 or not. The cure for the V8 problem is to make sure you have a good 12 volt supply to the "start" terminal on the solenoid when cranking. To test this, you can jump directly from the battery terminal on the starter to the "start" terminal when the car is hot. If it starts fine when you do, then you need to use improve your ignition switch to starter wiring connections, or add a relay.

I'm just taking a wild stab here, but it might be worth a try.

What is the story with the starter, age, mileage, not new?

If the starter is still getting too hot with the heat blanket, I really like ceramic coated headers. Have the next piece of connecting pipe that runs by the starter coated as well. Not sure what to do with the flex-pipe. I had my headers & the Y-pipe done. Big difference with under hood temps.

hello it's me from Michigan if your car will not fire hot it probably needs a balance resistor on the coil. If your car will not crank over hot it probably needs about 10° of timing removed just because your timing is correct all in does not mean your base timing is correct for starting get the car hot where it will not crank over and back to timing up a real quick test pull The coil wire and see if It cranks over with no ignition At all that is the first place I would look I hope that helps you

PS nothing worse Than getting a brand-new bike for Christmas and not being able to ride it

Sorry for taking so long to get back to you Don.
The world just keeps whizzing by while I try to untangle my 8 track.
Anyway, onto the voltage drop tests.
Get your car into the failure mode. IE warm it up.
Haul out your trusty volt meter and connect it between the negative battery post ( not the clamp but the actual post on the battery) and the casing on the starter. Now crank the engine over. While the engine is struggling you will get a voltage reading. It needs to be less than 0.5 volts. Anything higher means that you have a problem in the connections, the starter connection to the engine block (paint) or with the cable.
Now do the same thing with the positive side. Battery post to starter lug this time. Same deal, more than 0.5 volts is trouble.
If those two check out then connect the volt meter across the two battery terminals and check the battery voltage when cranking.
Absolute minimum is 9.5 volts, 10 or more is better. anything less means your battery isn't up to the challenge.
If that's good, then onto the start terminal at the starter. Voltage between that terminal and the negative post of the battery needs to be within 0.5 volts of the cranking voltage that you measured at the battery.
If all of that checks out fine, we then come to the sticky part.
Without more sophisticated testing. You have to roll the dice and take a chance.
Is the starter itself bad or is it a tuning issue?
Tom's idea of shorting out the ignition is a valid one.
But for me, a good starting system should be able to power through a timing tragedy and turn the engine over regardless.
So my money is on a new starter. Get the baddest one that will fit, and make a heat shield for it.
Heat tapes, blankets, wraps et al. work but they also trap heat into the starter.
Build an actual shield that lets air flow around the starter and you'll be a happier man.

Hope that helps.
Cheers
Fred

I don't think the 3.4 has big enough pistons to stop a healthy starter except perhaps during a firing event which occurs before TDC. Even then it will turn the engine at all times outside that firing event.

Don is as competent as any of us, my money is on the starter.

Jim

I had an auto electrical business for years. GROUNDS! Add more grounds. Be sure to hard groun everything.

Summary to-date
First... thanks to all who added insite and suggestions!

Electrics seem to check out... added heavy duty grounds to frame
Headers were previously ceramic coated but added heat wrap from header down tube to muffler
Built an aluminum heat shield surrounding bottom 2/3s of starter from exhaust pipe.

Looking good so far but have not had a serious long run in Kansas heat to confirm.

Again, Thanks to all. Buy you a beer in Colorado!
Don B.