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Unread 02-13-2010, 02:46 PM   #1
Dngrs1
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Ignition problem HEI and CDI

I have upgraded the ignition in my '79 CJ twice. First time I installed HEI. Better than stock but had some minor mid to higher RPM power issues. I decide to do the team rush with new distributor, large cap, 8mm wires and a Summitt CDI box, (gapped the plugs @ 45). Ran better than the HEI all around. The Jeep died and left me stranded on an outing in the desert a while back.It blew what appeared to be exhaust gasses out the carb. I suspected it was a valve timing issue so I replaced the timing chain and gears (chain didn't jump a tooth but was stretched a bit too much and needed to be replaced). Compression check showed 145-150.
Put it all back together and it idles fine but stumbles on accelleration and has no power. I rebuilt the carb and it helped, but still not right.
I decide to test the ignition by putting the HEI back in. Runs great. Just like it did when I originally installed the HEI. (Still has the mid-high RPM issue).
I'm wondering what could have happened to the CDI to make it die and now run like crap? With the team rush/CDI I have to rev it up and slowly release the clutch to get it to move or it will die under the load. No problem with the HEI.
Any ideas?

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Unread 02-13-2010, 03:01 PM   #2
rishar1
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could need a new cap and rotor check them for burn marks, cracks and build up.
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Unread 02-13-2010, 03:31 PM   #3
Dngrs1
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I guess pics are worth 1000 words

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Unread 02-13-2010, 03:46 PM   #4
TBailey
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Have you checked your distributor and cam gears.Sounds like you may have chewed up your cam gear with your HEI dizzy.
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Unread 02-13-2010, 04:22 PM   #5
-AC-
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But then it shouldn't run well when he puts the HEI back in. I run a DUI HEI and couldn't be happier with it. Don't know why your's doesn't perform well in the upper RPM's, but maybe advance springs not working correctly? Timing issue? All I have learned is be DARNED careful singing the praises of an HEI around this forum. Me? I like 'em...

OH! I see the problem! Your distributor cap is missing two posts! Alright, sorry. Ignore me. But, the above paragraph still applies...
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Unread 02-13-2010, 04:28 PM   #6
Dngrs1
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Maybe a little history is in order, here.
In 4/08 I installed the HEI. Ran with it untill 2/09 when I installed the MC dizzy with teamrush and CDI. Have been running that since. The Jeep died in 11/09.
It started running crappy while out in the desert and then died. Ran perfectly untill that day. The dizzy gears do not show any signs of wear and there was no metal in the oil when I pulled the pan last month. The Jeep is not a daily driver and it's usage could be measured in hrs. instead of miles.
Like I said, it runs fine with the HEI. I'm thinking the CDI is damaged but don't know why? (BTW, it's the model that Summitt has discontinued).
The CJ's bigger brother, the J-10 has the missing two terminals (401). Ha Ha!
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Unread 02-13-2010, 07:59 PM   #7
Fjguercio
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Quote:
Originally Posted by -AC- View Post
But then it shouldn't run well when he puts the HEI back in. I run a DUI HEI and couldn't be happier with it. Don't know why your's doesn't perform well in the upper RPM's, but maybe advance springs not working correctly? Timing issue? All I have learned is be DARNED careful singing the praises of an HEI around this forum. ...
Anyone using the HEI Distributor should be well read..... well read.... There are MAJOR ISSUES WITH THE USE OF HEI IN AMC ENGINES... PERIOD..... IT HAS BEEN PROVEN MANY TIMES. THE MAJOR ISSUE on this forum and why we jump on it so much when mentioned..... like this. "HEIs work in AMC but NO WARNINGS!!! of the MAJOR ISSUES"

Why would someone say it works well.... know the problems with AMC/HEI combos and not say any warning. That is what flames me to no end. Its a shame and a disservice to your local jeepers the guys you want to call your buds????

There are hardened steel gears all over the market, that can take you cam gear out
The fit of hei is a problem, too long a shaft can bind your oil pump, cause engine failure
The shaft diameters vary so changing gear is not alway straight forward
HEIs like to ground out via the internal weights to ground
HEIs have lots of advance, too much, and need to be recurved most often
HEIs have cause starter kick back from too much advance
HEIs have issue with gear engagement even with proper gear
HEIs are not designed to work with the high vac of amc engines
There is a list of 10 more or so of more reasons

HEI is EQUAL to the stock AMC DuraSpark if set up properly, the DuraSpark is easier to set up and tune your advance curve. So if you solve your durspark issues and follow the recommendations outlined by jeephammer and others your ignition will work wonders.... wonders...



The orginal poster.......... here is some additional info to try


The other tricks with teamrush and the CDI is to
Ground your head(s)
Put copper antiseize on the spark plug threads to help ground
Dielectric grease on, spark plug boots, plug wire contacts, rotar end, cap pivot point
Use PEMIUM WIRES only MSD or Napa Beldins Dark Navy Ones (ohm out your wires if you have issues or misses)
COIL... did you ohm out your coil or have you changed it in the past 10 yrs
AUX grounds... CJ is 30 yrs old if you have not added all the aux grounds you have missed the boat & recommendations
CDI Upgrade & teamrush (best you can get) did you retime and adjust your carb, then adj your time again. with your update... its a necessary step
FIND BEST TIME.. at min change initial time by 1 deg in range of 3 to 10 and see what works best and starts up best. Write the results down in your spiral book

If you want your 30 yr old CJ to run like a top you have to work at it a bit. Sounds like you were close but needed to do some more work. Take a look at the teamrush big thread by jeephammer... I just added 3 links that will cover some of this in more detail. I can also put them here if need. One poster already said the little tricks made his CJ idle and run much better.

Hope that helps,
Fred
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Unread 02-14-2010, 05:23 AM   #8
Dngrs1
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I appreciate your response and input, Fred, but I think you were a little hard on the "HEI guys". My HEI dizzy is a GM dizzy with an AMC gear. I like it but it seems to make the engine run flat at higher RPM's. Advance, or lack of it.
My fingers hurt when I type too much (I'ld rather turn a wrench) but what I left out of the original post was that when I installed the MC dizzy w/team rush I used a Molex connecter for the distributer connection. I later found out that Molex connectors don't survive well in under hood heat and it fell apart. I then used a 2 wire alternator connector. I noticed recently that the MC distributor has 3 wires; violet, orange and black w/ white stripe. The CDI only has 2 wires to the dizzy. The black/white wire ohms to the dizzy case (ground?). I never ??? connected the black/white wire. My bad.
Now, could the poor connection in the Molex plug and the failure of connecting the black/white (ground) wire have damaged the CDI?
I have since connected the black/white wire to batt ground and no change; perhaps the CDI is already damaged.
Keep in mind that the engine runs fine with the HEI; same plugs, wires, grounds,etc.
Anyone have a schematic of the Summitt CDI with inputs and outputs?
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Unread 02-14-2010, 09:26 AM   #9
JeepHammer
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OK!

Before this thread gets WAY off track...

1. The OP wasn't 'Completely Satisfied' with the HEI clone, or he wouldn't have changed to a Jeep/Motorcraft distributor & MSD module.

2. The HEI clone has a 'Mid Range' hesitation/bog that is probably too much timing under 'Part Throttle Cruise' that about all the HEI clones have.
Most of them have an advance curve set up for a Chevy V-8 engine, and that doesn't work with an AMC I-6 engine very well.

3. MSD Modules DO FAIL, just like any other ignition modules do.
I would suggest a 'Test Module' be wired in to replace the MSD unit for testing,
And if so inclined, run until the MSD module can be Serviced/Replaced under warranty.
MSD has traditionally had an EXCELLENT customer service, and repair/replacment has always be prompt and FREE.

4. I do suggest the OP tunes the HEI clone for his engine since the 'Hesitation' or 'Bog' felt in the 'Mid Range' is usually detonation/pre-ignition, and that is VERY hard on the engine.
This can be done with springs, or with a vacuum advance limiter.

5. Running the Jeep/Motorcraft distributor with an HEI style module costs about $25, and will answer the question if the 'Issue' is/was the MSD unit, or the Jeep/Motorcraft distributor it's self.
Remember, there is more than one component in the ignition system, and it could be the stator (Trigger) in the distributor, it could be the ignition coil, it could be power connections to the module, ect.

A 'Test Module' would answer a bunch of those questions, and keep the 'Better Curved' distributor in the engine,
And that would 'Verify' the rest of the smoother running ignition while giving the 'Smoother Running' module a chance to see the guys at MSD if something IS wrong...
--------------------------

In my OPINION...

He would be better off with a 'Test Module' set up to run the Jeep/Motorcraft distributor since the Jeep/Motorcraft distributor is set up with the correct advance curve for his engine,

And the 'Test Module' would also be his 'Self Rescue' if the MSD module fails on the trail someplace since it's already set up to plug into the harnesses after this...

The 'Test Module' made from a HEI style module won't be nearly as powerful as the MSD unit is,
But it doesn't come with the potential for problems he can't fix with the HEI clone.

Wiring for 'Test/Rescue Module' is fairly easy, and the 'Hard' part is finding a heat sink material to mount the module on. (I use salvaged aluminum heat sinks from computers, TVs, ect. but you can flatten out a beer can if you need to in a pinch! Anything to extract and exchange heat from the module.)

Wiring an HEI module to a Jeep/Motorcraft distributor.
Use what ever wire you are hooking up to the HEI to power up the 'Test/Rescue' module and ignition coil.



Some things that might make a 'Rescue' module more easily installed...

Distributor ADAPTER harness, plugs into stock distributor and lets you tap the Stator (Trigger) connections,
Compatible with MSD wiring... But does drive the price up on the 'Test/Rescue' module.

LINK: http://www.summitracing.com/parts/MSD-8869/

If your factory module wiring is still in place, this will allow you to plug into the factory module power connector on the harness.
Works for both the 'Small Red' wire on the MSD unit, and for powering up the 'Test/Rescue' module.

LINK: http://www.summitracing.com/parts/SU...0&autoview=sku

You will only need the black 'Bell Shaped' connector on the right with red & white wires coming out of it.

Last edited by JeepHammer; 02-14-2010 at 09:38 AM..
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Unread 02-14-2010, 12:56 PM   #10
Dngrs1
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Thanks, JH, that sounds like a perfect way to go. I can then test the ignition without the "suspect module".
BTW, it is a Summitt Racing module, not an MSD and they won't warranty it as it is more than 90 days old. They did, however, offer to repair it if I ship it to them for a fee. Since it is not a sealed unit and components can be replaced I can most likely repair it at work for free.
The HEI test module is also more practical to carry in the recovery box than the complete HEI distributor.
Thanks again JH I will give this a try.
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Unread 02-14-2010, 01:19 PM   #11
Fjguercio
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Might have had issues with the low voltage signal for fire from the distributor.

Since you rewired... these are low level signals and should be twisted 2-3 turns per inch to lower induced currents and noise from near by high voltage and switched wires. The coil wire power supply and sprark plug wires can cause issues. Do not run these signal wires parallel // to the other power wires and use the body pannels like fender and firewall as a ground plane. Its a magnet/coil type of induced signal wire and other // induced currents can cause issue too. Poor connectors could cause issue here too...... if you pick a new connector for this a gold plated would not be out of question either and the stock was was nickle plate (IMO).

Connectors.... we have old jeeps.... any connector should be cleaned if needed with alcohol or similar. Mate the connecor 8-10 times to clean the survaces and then add dielectric grease and mate for the last time.

So I agree with you connectors can cause issue but are convenient to have to have for work and replacement. The fire signal path also seems to be inquestion I would ck that path out prior to shipping off you CDI..... might also cause same issue with your hei test spark supply modual.
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Unread 02-26-2010, 03:36 PM   #12
Dngrs1
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Well, I had an HEI module from a distributor out of a '79 Blazer in the garage. I got a heatsink from work to mount it to. Wired it up per JH's diagram, installed it in the CJ and.....won't start. I hooked the CDI back up and it fired right up.
I figured the module was bad so I bought one at A-Zone and hooked it up and.....won't start. It acts as if the timing is WAY out. Doesn't crank smoothly, "jumps". Hooked the CDI back up and fired right up. With the ignition switch on, I measure 12.5V at terminal "B" and "C" on the module and 1.5V at terminal "W" and "G". Is this right? Does the HEI work with a Ford E-coil? or do I have to use the original coil? Kinda stumped now.
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Unread 02-26-2010, 04:10 PM   #13
Fjguercio
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the distributor fire signal is a low level signal.... meaning very low current and voltage. You mentioned above you replaced connectors, replacemnts melted, and I suggested you improve and look at that area. Since non of the 3 systems fire that might be your weak link.


If your question was the HEI modual can it fire a E Coil... yes it can.

In addition to the hei modual needing a heat sink you also need the proper heat sink paste to join the heat sink and Hei Modual or the modual can over heat and fail. The heat sink paste also becomes a regular PM and needs to be replaced regularly. Not all pastes are equal.... there have been a few posts on the right stuff to use but I did not keep the info.... but that info is here somewhere and might be in JH stuff too most likely
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Unread 02-26-2010, 04:38 PM   #14
Dngrs1
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There seems to be some confusion, here, maybe I typed it wrong, you read it wrong or you are thinking of another thread.
The Summitt CDI w/ Ford E-Coil and MC dizzy w/ large cap runs fine but no power under load;
The HEI dizzy runs fine overall, just less power at, say, over 2500RPM;
The HEI module w/ Ford E-coil, MC dizzy w/ large cap will not start.
I am trying to use the HEI module to troubleshoot the first setup (eliminate the CDI box); trying to find the "weak link" and repair it. I listed the voltages at the module to try and verify that they were correct. I am, at this point, ready to rip it all out and reinstall it (after taking the CDI to work to troubleshoot all the components).
I can put the HEI dizzy in and drive around with a smile on my face but thats not the point. With my luck it's probably a 10 cent capacitor.
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Unread 02-26-2010, 05:00 PM   #15
Fjguercio
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Quote:
Originally Posted by Dngrs1 View Post
There seems to be some confusion, here, maybe I typed it wrong, you read it wrong or you are thinking of another thread..
Nope... what i said is still valid and may not be understood by you. Since you have some electronic background lets try again.


Quote:
Originally Posted by Dngrs1 View Post
The Summitt CDI w/ Ford E-Coil and MC dizzy w/ large cap runs fine but no power under load;.
Distributor provides the fire signal.. Low level signal. The violet/purple and orange wires need to be twisted 2-3 turns per inch to lower cross talk or induced currents from high voltage switched wires. Wires that carry current have a magnetic flux around wire. Move the wire like motors/generators or switch the power on wire on/off the magnetic flux grows and collapses and yields results like the motor/generator generating currents. Twisting wires makes the current go opposite directions for each of the 1/2 pcs of turned wire you make by twisting. In this case the coil power wires and the spark plug wires are high voltage on/off wires that cannot be run next to the low level distributor signal wires. The signal wires need very good contacts, if you replace use gold contacts, dielectric grease, and run these wires by themselves next to the fenderwall and firewall to use as shield. These signal wires cannot be just crimped, cannot be done with cheap connectors, and very well could be part of your issue. The other switched wires will induce currents in the signal wires, cause false triggers at higher rpms esp, or could cause no good signals. Could also explain why things fall apart at operational or load or higher rmps.


Quote:
Originally Posted by Dngrs1 View Post
The HEI dizzy runs fine overall, just less power at, say, over 2500RPM;.
Typical issue... wrong advance curve and too much advance. I will also guess if you go further in rpms you get knock or ping. 2500 rpms would not put a smile on my face nor should it put one on yours. My 258 will do 4400 rpms pretty easy and do 3500 or 3800 pretty regular... 2500 is nothing.

Quote:
Originally Posted by Dngrs1 View Post
The HEI module w/ Ford E-coil, MC dizzy w/ large cap will not start. .
Could still be weak distirbutor signal or failed hei modual for excessive heat. Excessive heat esp is not fired because always at hot voltage ready to power coil. There are tests for that modual if you search. Heat sink past is manditory. The HEI Modual for stealth and the CDI may have different abilites to pic up the triger signal... the low level signal. Could also be the change in connectors or your solder job too.

So most of what I posted appplies and hope the helps you understand better.


Quote:
Originally Posted by Dngrs1 View Post
I am trying to use the HEI module to troubleshoot the first setup (eliminate the CDI box); trying to find the "weak link" and repair it. I listed the voltages at the module to try and verify that they were correct. I am, at this point, ready to rip it all out and reinstall it (after taking the CDI to work to troubleshoot all the components).
I can put the HEI dizzy in and drive around with a smile on my face but thats not the point. With my luck it's probably a 10 cent capacitor.
I think you have a few issues. Maybe post a few pics to photo bucket and put the links here so we can see. I am not convenced you have a CDI modual problem or issue yet.
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