Ongoing HEI Ignition module problem
Safety Car
Joined: Nov 2004
Posts: 4,991
Likes: 5
From: The Pines South Jersey
I have been running an MSD 6AL with Accel cap & rotor , Accel Super coil for 3 yrs with no problems , stock module too . One thing I did was to run a dedicated ground wire from the dist to the engine. Also double check the short harness as reccommended earlier for a crimp or chafe. MSD coils are "different" from most others , they tend to confuse some ignition analyzers....don't know why but they do . Try a different coil for the next go and Good Luck ! 
I'm intrigued by the idea of running another ground wire, although it seems to me that the distributor body is pretty well grounded to the engine already. Do you think running the ground to the chassis might be more fruitful as this would tie the ground to the battery and chassis wiring better? Perhaps a huge honkin' ground strap from the engine to the frame might help?
including stock module and tried a dyno tune module to see any gains
Thread Starter
Racer
Joined: Dec 2000
Posts: 385
Likes: 0
From: Blue Ridge GA
there is the battery ground at the back of the left cylinder head. put your ground on that wire ground, it goes right to the battery.
I think more grounds, the better anyway, so add your ground.
But you know what? I'd go back to totally stock, and give that a try. if you don't blow a module, add the MSD unit. if then you ruin a module, i'd contact MSD and get their impression of what's wrong. it sounds like a capacitor that builds up some voltage, and when you turn the key, it zaps right into your module, blowing out a sensitive component.
There's also a possibility that the car ECM computer might have the same problem, can u borrow a computer to try? something is pumping more voltage into the modules than they need.
Just for grins, can u get to the computer, disconnect the computer connectors, and ohm the wires to the distributor connector.
d5 (EST bypass) the one that has the timing connector on it ---tan wire black tracer
d4 (timing control) the white wire on the plug
B3 (reference low) the black wire with the red tracer
B5 (distributor reference) the purple wire with the white tracer.
see if when you put an ohm meter from the computer plugs to the dstributor 4 wire plug, you get continuity.
DON"T try to ohm the distributor unless you got another module handy because you will blow it out using the battery in the meter.
if those are ok, I know there's a ground wire on the module or the module plate. go from the plate/ground to the battery negative cable.
if that's ok, return it back to stock and see what ensues.
Chris
I think more grounds, the better anyway, so add your ground.
But you know what? I'd go back to totally stock, and give that a try. if you don't blow a module, add the MSD unit. if then you ruin a module, i'd contact MSD and get their impression of what's wrong. it sounds like a capacitor that builds up some voltage, and when you turn the key, it zaps right into your module, blowing out a sensitive component.
There's also a possibility that the car ECM computer might have the same problem, can u borrow a computer to try? something is pumping more voltage into the modules than they need.
Just for grins, can u get to the computer, disconnect the computer connectors, and ohm the wires to the distributor connector.
d5 (EST bypass) the one that has the timing connector on it ---tan wire black tracer
d4 (timing control) the white wire on the plug
B3 (reference low) the black wire with the red tracer
B5 (distributor reference) the purple wire with the white tracer.
see if when you put an ohm meter from the computer plugs to the dstributor 4 wire plug, you get continuity.
DON"T try to ohm the distributor unless you got another module handy because you will blow it out using the battery in the meter.
if those are ok, I know there's a ground wire on the module or the module plate. go from the plate/ground to the battery negative cable.
if that's ok, return it back to stock and see what ensues.
Chris
I strongly suspect the short wiring harness into the distributor because I know there is a loose joint on one of the wires in the coupling. Does anyone know where I can get a new harness or, alternatively, a new connector to hook into the distributor wiring.
I know that the base of the distributor is grounded into the block.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I got a replacement harness from the stealership, if I remember correctly it was for a Cadilac...can't remember the year...but some of these are obviously inter changeable...expensive, if memory serves..$85. I would think you could get creative and make 1 if you have some weather connections.
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
I was able to get the 2 pieces from the distributer out, from the dealership. Mine were very brittle especially inside the distributer, mine has an MSD coil in cap, stock module (no apparent gain w/aftermarket), and no 6al in the set-up.
Last edited by mseven; Jan 22, 2007 at 10:02 AM.
Thread Starter
Racer
Joined: Dec 2000
Posts: 385
Likes: 0
From: Blue Ridge GA
Where does the other end of the harness hook up? I ask because it is really, really tight behind the engine and near the firewall.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
If I remember right, the harness just plugs in 8-12 inches from the dist. BUT, I had to pull the dist. to get at it...you're right..very tight, in fact I'd say impossible to get at without pulling the dist. once it's out it's easy.
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
edit....Rick you must be a fast typist
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Thread Starter
Racer
Joined: Dec 2000
Posts: 385
Likes: 0
From: Blue Ridge GA
I am guessing you are refering to the other distributer connector. Yeah there isn't much room, it goes into the main harness attached at the firewall. You might be able to disconnect it with the cap off. I pull the distributer because on mine that harness peice (from the distributer)doesn't have enough wire for me to work on (it also has that white plastic retainer (flat pin)to hold the weather pack together).
edit....Rick you must be a fast typist
edit....Rick you must be a fast typist
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
connector
the metal part of the connector doesn't dry out, but the plastic gets really brittle and hard. If you still have a connection problem,try making 4 jumper wires with the pins on them, and plugging them in one by one, and then wrapping them with electrical tape for driving around for 6 months, tywrapping them in place.
see if that gives you some extra length to do some troubleshooting with.
see if that gives you some extra length to do some troubleshooting with.
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
What is the best source for the connectors? I'm thinking my old dried out connectors might be the problem. One pin doesn't have a real tight connection and I'm thinking some arcing there might be causing my problem. So, if I could replace the connectors the whole harness might work better. What do you think?
Mine on the inside was brittle and the plastic was brown in color. When I removed them the tabs broke, so I felt it was a matter of time before it was cooked. While this may not be the culprit, taking it out of the equation and using the heat sink grease (not dialectic) wouldn't hurt, also having it apart it will give you a chance to inspect and test with a vohm (meter).
Thread Starter
Racer
Joined: Dec 2000
Posts: 385
Likes: 0
From: Blue Ridge GA
the metal part of the connector doesn't dry out, but the plastic gets really brittle and hard. If you still have a connection problem,try making 4 jumper wires with the pins on them, and plugging them in one by one, and then wrapping them with electrical tape for driving around for 6 months, tywrapping them in place.
see if that gives you some extra length to do some troubleshooting with.
see if that gives you some extra length to do some troubleshooting with.
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
Tech Contributor
Joined: Jun 2004
Posts: 20,659
Likes: 953
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
JFB has a good point. Mixing different ignition parts without knowing the electrical characteristics of the components is just an expensive crapshoot. I'm very familiar with the stock ignition setup, but not the MSD add-on. How is the MSD unit wired in, given that the stock ignition module is still retained?
Thread Starter
Racer
Joined: Dec 2000
Posts: 385
Likes: 0
From: Blue Ridge GA
JFB has a good point. Mixing different ignition parts without knowing the electrical characteristics of the components is just an expensive crapshoot. I'm very familiar with the stock ignition setup, but not the MSD add-on. How is the MSD unit wired in, given that the stock ignition module is still retained?
Since I had this problem BEFORE I put the MSD on, I think the problem is elsewhere.
Drifting
Joined: May 1999
Posts: 1,478
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From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
Here are the GM part #s from the Dealer's Guide which should cover the parts you are looking for:
1986-91 Distributor /Ignition (L98)
=========================
1892261 .. TERMINAL BLOCK, (INCL CAPACITOR)
1986260 .. TERMINAL BLOCK, (TO ELEK PKG)
1977207 .. POLE PIECE AND PLATE (2 wires)
1986-91 Distributor /Ignition (L98)
=========================
1892261 .. TERMINAL BLOCK, (INCL CAPACITOR)
1986260 .. TERMINAL BLOCK, (TO ELEK PKG)
1977207 .. POLE PIECE AND PLATE (2 wires)
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
Here are the GM part #s from the Dealer's Guide which should cover the parts you are looking for:
1986-91 Distributor /Ignition (L98)
=========================
1892261 .. TERMINAL BLOCK, (INCL CAPACITOR)
1986260 .. TERMINAL BLOCK, (TO ELEK PKG)
1977207 .. POLE PIECE AND PLATE (2 wires)
1986-91 Distributor /Ignition (L98)
=========================
1892261 .. TERMINAL BLOCK, (INCL CAPACITOR)
1986260 .. TERMINAL BLOCK, (TO ELEK PKG)
1977207 .. POLE PIECE AND PLATE (2 wires)
Racer
Joined: Sep 2005
Posts: 271
Likes: 0
From: New Freedom PA
Possible HEI fix
My 86 has eaten ignition modules about every 6 months since I've owned the car (7 years). I carry a spare and have gotten to the place I can swap them out in about 15 minutes. It's a real pain when it happens and it is raining out.
It always happens after I've driven somewhere, shut it off and then try to restart, the motor just turns over but it won't start. Swap the IM and everything is happy again.
I've tried expensive ones and cheap ones and they all go out in about 6 months. Someone on this forum told me it was the pickup coil, so I swapped out to a new Accel distributor and they still blow out. I do have an MSD 6 AL and remote coil, other than that, the ignition system is stock.
I've heard that somebody builds an IM with a circuit breaker on it. If these things work I'd like to try one. Does anyone have any experience with them?
It always happens after I've driven somewhere, shut it off and then try to restart, the motor just turns over but it won't start. Swap the IM and everything is happy again.
I've tried expensive ones and cheap ones and they all go out in about 6 months. Someone on this forum told me it was the pickup coil, so I swapped out to a new Accel distributor and they still blow out. I do have an MSD 6 AL and remote coil, other than that, the ignition system is stock.
I've heard that somebody builds an IM with a circuit breaker on it. If these things work I'd like to try one. Does anyone have any experience with them?
1. Use ONLY the clear Di-Electric gel that comes with the module, NOT white grease , Axle Grease , or anything else , that gel takes away about one third of the heat from the Module. Heat is the biggest problems with HEI Modules.
2.Purchase only Name brand parts , I prefer Standard or AC Delco on this part , this is one part you should NEVER purchase by price only. the Walmart brand Modules to not have a good quality Circuit Board inside like the good Modules.
3.If you do need a harness of any kind , find a parts store that caries Standard Ignition parts , They will have or should have an Illustrated ignition parts book specificaly for ignition parts. Standard or Blue streak has allways had every HEI part and or harness for my repair projects.
4. BEST REPAIR/ I use and recomend the MSD HEI Module conversion kit for two reasons:
1.Replaces factory style modules with a large version made in USA by MSD , but stiil mounts inside the cap for a nice stock look.
2.The MSD module comes with the harness you need and is designed to work with their own products and extends the RPM range way past where your engine will rev. Stock modules are done by around 4500-5000 RPM anyway , their module is good to 8000 plus. Here is a listing at MSD for the whole kit , you can purchase just the Module if you want to.
check it out at:
http://www.msdignition.com/dist_82.htm
let me know how you make out...
DESERT