Best Ground Setup for HEI?

[Tomahawk30]

Hi all,

I have a 69 GMC project that I recently picked up. 383 engine w/ manual transmission. I drove it the four miles home OK (ran real rough, but the PO had suspected a fuel issue), but when I went to jump in to run it to the DMV, it started, went about 10 feet, and died. The engine will turn over fine (until the battery gets too weak anyway) but doesn't want to fire. When it has been sitting, I can sometime get it to fire. I even got it started a couple times, but it didn't really want to run. Fuel supply is good. It has been changed over to an HEI setup, and I know the cap and rotor are good as I swapped it to my Impala and it ran like a champ. However, I'm only getting about 8.5 - 9v at the feed to the battery port on the distributor when starting, and just over 12v when the key is in the run position. I ran a new 10ga feed wire to the switched battery port on the fuse panel, with no improvement. After a few hours of online research, I'm starting to suspect a ground issue. I think I'm going to rewire most of my engine electrical anyway, but wanted to get some feedback on grounding. I have the main heavy wire from the negative battery post to a lug attached to the front of the engine block, and a short jumper (probably around 12ga) from the battery post to the fender. Am I correct in guessing that this is too long / too little of a return path for the distributor? Should I have the rear of the engine grounded to the firewall and do away with the jumper at the negative terminal, or should I keep both?

Also, when rewiring for the HEI, do most of you wire to the fuse panel, or is it better to feed from the wires coming from the back of the ignition switch assembly? Should I supplement the HEI feed with a second 10ga from the old ignition power terminal on the starter to insure that I get the full +/- 12v while starting? I've read the HEI conversion FAQ, but from what I can tell, I'll be REPAIRING a previously incorrect installation. Some of it appears to have been changed (the hot lead to the fuse panel) while others I'm not so sure about. There's still two leads on the starter, rather than just the one for HEI. If nothing else, I should at least have a passable knowledge of the electrical system by the time I'm done...

[Richard H.]

With your starting issues and the hei , kinda makes me wonder if your engine is grounded good in the first place? Plus engine to firewall?

[Tomahawk30]

Originally Posted by Richard H.

With your starting issues and the hei , kinda makes me wonder if your engine is grounded good in the first place? Plus engine to firewall?

I don't think there is a ground strap between the engine and firewall, just the one from the engine to the battery, and the short one between the battery and passenger side fender right next to the battery tray. Was thinking of grabbing a ground strap at NAPA on the way home and throw it one if it isn't too damn cold tonight. I really miss having a shop to work in.

[Longhorn Man]

if the battery cable is bolted to the block, as the OP described, then the HEI is grounded where it is clamped to the engine's intake.
If it cranks over till the battery is dead, then it has a good enough ground to fire.
Your voltage is as good as it'll get. It's lower when cranking becouse you are putting all the battery power to the starter. Same reason why your headlights dim when you crank the engine. It goes back up when you let off the key becouse you are no longer putting a load on the battery... again, like your headlights.
You need to see if you have spark when cranking the engine over.

[Tomahawk30]

Originally Posted by Longhorn Man

if the battery cable is bolted to the block, as the OP described, then the HEI is grounded where it is clamped to the engine's intake.
If it cranks over till the battery is dead, then it has a good enough ground to fire.
Your voltage is as good as it'll get. It's lower when cranking becouse you are putting all the battery power to the starter. Same reason why your headlights dim when you crank the engine. It goes back up when you let off the key becouse you are no longer putting a load on the battery... again, like your headlights.
You need to see if you have spark when cranking the engine over.

I'll double check the spark again tonight. The odd thing is when it was sitting at the PO's house, it always fired right up first try, but after driving it home it started this. Bad luck? Karma for talking him down that last $500? I will say that I was barking up the wrong tree initially, and I think it may have died from lack of fuel when I first got it home (damn incorrect fuel gauges!). I may have just ran the battery into the ground trying to "troubleshoot". I threw it on a 24 hour trickle charge and it actually started the when I first hooked it back up. After that, all cranking, no sparking. Is there any way that with anything less than absolute full charge on the battery that it would crank, but not fire? I'd think it would at least cough and sputter, but it doesn't sound like it is firing at all.

[cparman]

take the dust cover off of the dizzy. Once you do this look carefully and see that there are 3 terminals in the cap. You should have two wires on either side, and the center one is a ground for the coil. Remove the coil and you should see a strap coming from the center to bend around and go under one of the bolts that fasten the coil. If you do not this may be the problem, might have killed the coil also.

If you are not sure you have spark, you might grab a plug wire while cranking and see if BITES YOU!! ha ha

[Zeke's Garage]

Have you had the HEI module tested to make sure it's good? I've had bad ignition modules cause all kinds of weirdness when trying to troubleshoot a no-start problem.

Also if you've run a new 12v wire to the HEI, go ahead and remove the one that is coming up from the starter, it's no longer necessary.

[Pyro]

While you should have a ground strap from the engine to the body, this isn't your problem. It's cranking good so I'm sure the dizzy is getting the power it needs. Are you positive it's not a fuel issue? Sure sounds like one. HEI modules do go bad and it very well could be the problem but double check the fuel system first, make sure the carb isn't gummed.

If you're going to rewire it then hook it up as it originally was off the ignition key.

[Tomahawk30]

There definitely seems to be plenty of fuel making it to the carb, but I don't know for sure that it has sufficient pressure. I don't have a shop to work in, and it has been too damn cold to be out there working on it much! There is no external HEI module. It's the GM style with everything in the cap. I haven't done anything to the lower end of the distributor yet, but I swapped the cap with the internal coil from my 65 Impala and the one from the truck worked fine in the car. If anything is bad, maybe it is on the distributor itself. Lots of stuff to try, but I'm just holding out for a day that I can work for more than 10 minutes at a time without my fingers going numb!!!

I should clarify on the old lead from the starter as well... There is a second lead on the starter, but from what I can tell (pretty shoddy wiring was done at some point, so lots and lots of crusty black tape!) it isn't hooked up anywhere now. I'm going to gut it all and redo it just for the sake of cleanliness I think.

[seldomseen65]

Originally Posted by Zeke's Garage

Have you had the HEI module tested to make sure it's good? I've had bad ignition modules cause all kinds of weirdness when trying to troubleshoot a no-start problem.

Also if you've run a new 12v wire to the HEI, go ahead and remove the one that is coming up from the starter, it's no longer necessary.

ZEKE'S GARAGE; YOU HAVE THE RIGHT IDEA,ON THE HEI MODULE,,I HAD THE SAME PROBLEM WHEN I HAD A 79, FIREBIRD,, THE MODULE WOULD STOP WORKING AND THE ENGINE WOULD STOP RUNNING,,AND IT'S ALSO A GOOD IDEA TO CHECK ALL THE GROUND STRAPS,, THERE SHOULD BE THREE OF THEM, ONE TO THE BODY TO ENGINE,,ONE TO FRAME TO BODY,,AND ONE TO BATTERY TO THE ENGINE BLOCK,,THAT I HOPE WILL HELP SOLVE THE PROBLEM..GOOD LUCK :Chevy:

[Tomahawk30]

FINALLY some decent weather to work in! Since my last post, its been more of the same. One day I'll jump in and it fires right up (and runs like crap) and the next it wont' even try to fire. Today I started by pulling the old distributor and taking it in to see my buddy at NAPA. We tested the module, and it tested fine. The dizzy itself had seen better days, so for the sake of being thorough, I went ahead and picked up a remanufactured complete setup (minus the cap and coil, which is already new and known good from its brief time on my Impala). I brought it home, dropped it in, and checked my TDC using the not-so-precise method of putting my thumb over the #1 plug hole until it blew off when my friend bumped it over. The rotor was pointing roughly to the 7'oclock position. I pulled the dizzy back out, rotated the fuel pump with a screwdriver to the position that would place the rotor pointing roughly at the #1 plug hole and the #1 wire on the dizzy. Put it all back together again, satisfied that I should at least be close enough to get it to cough, sputter, or even backfire. Nothing. Cranks over like crazy, but not a single fire. If it was simply timing, I should think that I'd at least get misfires or something, correct? I checked my voltages on my HEI battery feed wire, and with the key on I had roughly 12.5v. While cranking, it dropped to 10.5v. I can visually see sparks from the #1 wire when I check it with either a plug or a screwdriver near the frame. Am I correct in thinking that I am probably OK to move past fire as the problem? I'm definitely getting fuel, as you can smell it after any amount of cranking and I can hear it spray when I manually work the throttle and activate the accelerator pump. I can't necessarily vouch for the quality of the fuel, but the fact that some days it fires and runs, and some days it doesn't makes me think the fuel is sufficient to at least run like crap. So my thinking tonight is that maybe I have a carb problem? I know we need fire, fuel, and air... I'm running a Carter carb (numbers show it as the equivalent to an Edelbrock 1405 or 1406 if I remember correctly). Is there anything with the carb that could completely starve it for air and prevent any ignition? I have one more sunny day tomorrow to try whatever I can come up with, and after that I may just find someone a little better and troubleshooting to get her running again... Any thoughts, suggestions, and good natured ridicules are welcome!

Jake

[Longhorn Man]

Originally Posted by Tomahawk30

...good natured ridicules are welcome!

you have no idea what you just invited! LMAO!
Try twisting the dist a little left and right as someone tries cranking the motor. A stock style air filter is a good thing to have on there to contain shooting flames. (just in case)

[VetteVet]

Originally Posted by Tomahawk30

FINALLY some decent weather to work in! Since my last post, its been more of the same. One day I'll jump in and it fires right up (and runs like crap) and the next it wont' even try to fire. Today I started by pulling the old distributor and taking it in to see my buddy at NAPA. We tested the module, and it tested fine. The dizzy itself had seen better days, so for the sake of being thorough, I went ahead and picked up a remanufactured complete setup (minus the cap and coil, which is already new and known good from its brief time on my Impala). I brought it home, dropped it in, and checked my TDC using the not-so-precise method of putting my thumb over the #1 plug hole until it blew off when my friend bumped it over. The rotor was pointing roughly to the 7'oclock position. I pulled the dizzy back out, rotated the fuel pump with a screwdriver to the position that would place the rotor pointing roughly at the #1 plug hole and the #1 wire on the dizzy. Put it all back together again, satisfied that I should at least be close enough to get it to cough, sputter, or even backfire. Nothing. Cranks over like crazy, but not a single fire. If it was simply timing, I should think that I'd at least get misfires or something, correct? I checked my voltages on my HEI battery feed wire, and with the key on I had roughly 12.5v. While cranking, it dropped to 10.5v. I can visually see sparks from the #1 wire when I check it with either a plug or a screwdriver near the frame. Am I correct in thinking that I am probably OK to move past fire as the problem? I'm definitely getting fuel, as you can smell it after any amount of cranking and I can hear it spray when I manually work the throttle and activate the accelerator pump. I can't necessarily vouch for the quality of the fuel, but the fact that some days it fires and runs, and some days it doesn't makes me think the fuel is sufficient to at least run like crap. So my thinking tonight is that maybe I have a carb problem? I know we need fire, fuel, and air... I'm running a Carter carb (numbers show it as the equivalent to an Edelbrock 1405 or 1406 if I remember correctly). Is there anything with the carb that could completely starve it for air and prevent any ignition? I have one more sunny day tomorrow to try whatever I can come up with, and after that I may just find someone a little better and troubleshooting to get her running again... Any thoughts, suggestions, and good natured ridicules are welcome!

Jake

There's your problem in red. Somebody's moved your fuel pump.
J/K

Sounds like an intermittent firing problem to me. When it just cranks over and no fire, try running a jumper from the battery positive to the HEI bat terminal. If it starts then you've got a wiring problem and if it doesn't then your dizzy may be bad or timing or fuel may be the issue. It sounds like you've covered those already though.

[Tomahawk30]

I didn't mention it in the previous post, but I did try slowly rotating the dist while someone was cranking (a few times actually) and it still never fired. As for the air filter... I'd be stoked at this point to see flames! That would at least indicate progress!!!! I have tried the direct-to-battery jumper in the past, but not since replacing the dizzy and getting the rotor lined up closer to where it should have been. The truck has had trouble since I brought it home, so I'm not ruling anything out as being a preexisting problem. I suspect that the timing was WAY advanced when i got it judging from the rotor position when #1 was on the compression stroke (pointing toward the front of the passenger side of the block instead of the driver side).

[sleepertruck72]

If the fuel is good, and the spark is there, maybe the balancer has slipped and you cant get accurate timing with a timing gun ? I would turn the engine by hand until you were sure the #1 cylinder is TDC of compression stroke. The finger in the hole may get you close, but not good enough IMHO... Good luck anyhow

[Tomahawk30]

If I can get away from the wife's gardening honey-do list, I may pull the valve cover and put a stopper in number 1 to be 100% that I'm at least close to where I need to be. Might pull the fuel line and throw some fresh supreme down its throat just to verify that my fuel isn't half water while I'm at it...

[HEI451]

For ALL vehicles, primary ground should be from negative post on battery to ENGINE, then, from engine to chassis/firewall.

If the IGN or IGNITION terminal on the fuse box only delivers 12 volts or lower, and the battery has higher voltage, check connections, wires for corrosion not only on terminals, but up inside the insulation on the wire strands.

When the ignition switch is in either start or run positions, IGN terminal voltage should be within one tenth of a volt difference of battery voltage. Now, when the starter is in operation, both battery and IGN terminal volts will be LOWER than at other times, because the starter is sucking up more volts than when the system is running

I have also seen extensive corrosion in the firewall plug connectors inside the plug on the engine side of the fuse box, causing low voltage readings at fuse box terminals. Simply remove the holder screw on the terminal, pull the firewall plug off the back of the fuse box, clean both, use a SMALL amount of boat trailer wheel bearing water resistant grease and put it all back together.

[WTexChevy]

Jumped timing chain? Those stock plastic gears are notorious for slipping. If it's a 383 it'll have a 400 balancer (has a notch on the outer ring) and may have a different timing mark than will line up on a 350 timing cover. Verify TDC on number 1 by pulling a plug and having your finger on the hole while someone (a starter button is real handy here) bumps it over. It'll blow your finger off the hole at TDC. Looking at the rocker arms will lie to you as it could be at BDC on the power stroke and still have valves closed. While you're doing this, stick the plug in the wire and lay it on the header and look for a spark. Check to see if the rotor has any black on the bottom side of it. ANY black near the center would indicate rotor is burned through and will not fire.

Hope this helps!

[Tomahawk30]

Sooooo.... She's running like a champ now. I knew it would come down to something simple. Let me preface this by saying that I'm pretty sure the timing was advanced about 30 degrees when I got the truck (based on how far off my rotor was when I checked TDC last weekend). I've checked plug #1 repeatedly, and it has always looked, if not clean, at least in pretty good shape. On a hunch (read a thread regarding plug gap on an HEI 383 this morning) I pulled the #1 plug and checked the gap today. It was only gapped to between .025 and .030. Uh-oh. Ran to NAPA, grabbed a new set of plugs and started swapping. Every one of them was gapped to between just over .020 on the low end and at the highest .035. Gapped the new ones to between .040 and .045, bumped the starter and the thing roared to life like nothing ever happened. I didn't know whether to laugh or cry. I dialed the timing in a little closer, adjusted my idle mixture and my idle stop on the carb, and it runs like a brand new engine. Turns out the thing even has some pretty serious cojones!!! Threw me back in the seat when I did a quick road test and put the throttle to it! Just goes to show... If you assume ANYTHING is fine, its NOT!!!! Thanks for all the help and suggestions by everyone. Hopefully my screwup will save someone else a lot of time!

[HEI451]

No matter which HEI version is used, spark plug gap should be no larger than .045...period. The specifications GM had for .060 and larger only led to coil/module failures, and all those gap specs were revised back down to .045 maximum.

[sleepertruck72]

Glad to hear you got it figured out