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XRi Ignition Module Drop Out

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PSkahill

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70 Chevelle SS LS5
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Discussion starter · #1 ·
So I installed one a few months ago and all was fine..Its 454 with a stock points distributer and stock AC Delco coil.

All is good and the car runs fine but there seems to be a drop out (like it shuts off and turns back on in millisecond) especially when its hot. Its an intermittent stutter and and under acceleration. Its just fine at speed otherwise though.

I installed per the instructions with the coil attachments..etc.

I also dont run any vacuum advance and have a base timing of 18deg.

One thing I noticed that the plate the module and the points stat on did have a little bit of play or a wobble in it but it has never affected it with the condition above previously.

Anyone had this issue at all?

Thanks Pat
 

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#4 ·
Under the master cylinder, the firewall feed thru. It is common for the connections to corrode and turn green. Clean them with fine sandpaper or steel wool and coat with dielectric grease. Disconnect the battery 1st.
 
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#6 ·
I don't have a suggestion for the new module but You would also probably benefit from connecting the vacuum advance and put a stop to limit to about 10 or 12 degrees. It made a huge driveabilty improvement for me having the extra timing for idle and part throttle driving.
 
#8 ·
NO, an "internally resisted" coil does not resist the points and condenser in electronic point replacement ignition (drop-in) systems. To properly resist the coil and ignition unit, the resistor has to be in place BEFORE the coil and ignition unit, coil internals only resist from the positive post on the coil into the primary coil windings, not the ignition unit.
 
Discussion starter · #10 ·
Thanks guys. So the car ran fine for a few months and now it’s having the issue.

If it were something like a required resistor wire would it not have acted that way from the time I installed it?

How would I know I do or don’t have a resistor wire in place or already installed.

Where would I look for it?

Also it seems to act up when the car is hot.. like I could drive it for 20mins and no issues. Once shut off for a few minutes and I come back to it then I would notice the problem.

The bulkhead connector is clean and secure with no signs of corrosion btw.

Thanks
Pat
 
Discussion starter · #13 ·
Bob Tiley said:
I don't have a suggestion for the new module but You would also probably benefit from connecting the vacuum advance and put a stop to limit to about 10 or 12 degrees. It made a huge driveabilty improvement for me having the extra timing for idle and part throttle driving.
Click to expand...
Thanks Bob. Im pretty happy with how it runs and drives otherwise..I dont believe this issue is a vacuum/timing one at all. If it winds being one ill go back to what you suggest above.
 
#15 ·
Sounds like it could be heat effecting the electronics in the module. Did the installation include thermal grease between the module and the distributor? Any chance the module is still under warranty? Trying another module would be a good test, but probably too pricey to experiment...
 
Discussion starter · #16 ·
Jim's69Ragtop said:
Sounds like it could be heat effecting the electronics in the module. Did the installation include thermal grease between the module and the distributor? Any chance the module is still under warranty? Trying another module would be a good test, but probably too pricey to experiment...
Click to expand...
I believe it did have thermal grease. I can clean the old stuff off and add more. I’ve got some from my PC I built if that would work.

Or even try a new module as well.

I too somehow think it’s related to the heat as it’s only an issue when the car has been running, shut off and sits for 15mins or so.. then whe I go back to drive it, and it’s got the issue. It’s also fine at hwy speed and rpm..


So the 12v I’m seeing is correct at the coil?

Thanks
 
Discussion starter · #19 ·
Texas Squirrel said:
You will need to put a ballast resistor on that 12v wire going to the coil. Real easy to do.
Click to expand...

Is that whats causing the drop out do you believe?

I see from some research that it seems to be the case with these sometimes and it needs a resistor.

So just something like this?


If I go to Petronix and a Petronix coil with a resistor built in will that work? I may be wrong but I though they had an "all in system"

Im probably wrong about this but would that white wire in the picture be the resistance wire that comes from the bulkhead connector?

Apprecaited!
 

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#20 ·
PSkahill said:
Is that whats causing the drop out do you believe?
Click to expand...
Yes I think that is what is happening. You need a resistor before the coil, not a coil with the resistor built in. I looked for some Fast XRI instructions and this is what I found. It seems to confirm what I was trying to tell you. You might want to use it as a reference. The resistor you showed is what you need.
 
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