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Discussion Starter · #21 ·
Test the wires going from the HEP to the SMEC or swap in another SMEC.




U can use any SMEC 88-89 t1,t2,2.5 t1 (supposedly Tbi smec will run on 2 cylinders) just to see it run.
Also in reverse you can take the SMEC out of your car and try it another one just to test it.

Final option is to get DRB2 scanner and look at the hall effect pick up output. or whatever checks u can do with it (I've never used one)

If you are in New England I have a couple lying around or you could bring yours over and plug it into my car and see if it starts..
You all have no idea how much I appreciate y'all sticking with me through this. Thank you! I am sure we'll figure this thing out.

I have traced the HEP wires all the way back to the SMEC harness and they have continuity. Also, I have another SMEC and I have tried it out only to get the same results. Now, I have NO IDEA if the second SMEC works, I bought it second hand and never put it in an otherwise running car.

Aireskcar - That is an awesome gesture, thank you!!! However, I am all the way down in Houston.

-Tim
 

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You all have no idea how much I appreciate y'all sticking with me through this. Thank you! I am sure we'll figure this thing out.

I have traced the HEP wires all the way back to the SMEC harness and they have continuity. Also, I have another SMEC and I have tried it out only to get the same results. Now, I have NO IDEA if the second SMEC works, I bought it second hand and never put it in an otherwise running car.

Aireskcar - That is an awesome gesture, thank you!!! However, I am all the way down in Houston.

-Tim
If you want to ship it to me I can plug it in the car and test it like I did with this SBEC.

Or cover shipping I can send you one of my spares to test. I think I have 2 2.5 T1 SMEC'S and my 88 town a country 2.2 T1 SMEC that had a weak voltage regulator so the alternator would charge between 12.8 and 13v.
 

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Again, just to verify, there is constant battery voltage at the + coil when cranking?
If there is you do not have a HEP issue.
If you have battery voltage at the + coil with the ASD relay manually actuated and you touch/remove the jumper from a known good ground and there is no spark from the coil secondary wire to ground then the coil is faulty or the coil secondary wire is open or has excessive resistance.
 

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I am going to send you the "No Start/No Spark" diagnostics straight from the Chrysler Powertrain Diagnostics Manual.
The only difference is this is for 1990 2.2L/2.5L Turbo engines, if asked to check/trace wiring to the controller you need to use your 88 wiring instead of the 90 images shown in the diagnostics.
I will not have time to do it today but will get it to you by the end of the weekend.
 

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1)Is there a factory or aftermarket alarm system in this vehicle?
2)Is TPS closed throttle voltage below 2.50 volts?
3)Do all controller grounds have less than 5 ohms resistance to ground?

Here are the No Start/No Spark diagnostics from the Chrysler Powertrain Diagnostics Manual, remember, this is from a 1990 FSM with a SBEC, you will need to use the pinout for an 88 SMEC when you run these diagnostics.
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Discussion Starter · #26 ·
NAJ and all.....
Thank you again for sticking with me. I am out of town now and won't be back until Friday night (gotta go do my job for a while to pay for all these HEPs....). I hope to get a chance to work on the diagnostics provided since Thursday this coming weekend.

I promise to keep everyone posted.

-Tim
 

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Discussion Starter · #29 ·
I did have about a half hour this afternoon to mess with this. I had to work on the daily driver a little unexpectedly, so before I put everything away and cleaned up I decided to try a few of the tests per the troubleshooting guide provided by NAJ back on Aug. 6. Tomorrow should be a free day, I can dig a little deeper but here's where I am for now:

NAJ, Aug 4:
Again, just to verify, there is constant battery voltage at the + coil when cranking?
If there is you do not have a HEP issue.
Not full battery voltage, no. 9.3 to 9.5V
I think we have ruled out the HEP.


NAJ, Aug 4:
If you have battery voltage at the + coil with the ASD relay manually actuated and you touch/remove the jumper from a known good ground and there is no spark from the coil secondary wire to ground then the coil is faulty or the coil secondary wire is open or has excessive resistance.
No spark. I have tried two coils and the secondary coil wire seems to be fine with about 502 ohms per in of resistance.


1)Is there a factory or aftermarket alarm system in this vehicle?
2)Is TPS closed throttle voltage below 2.50 volts?
3)Do all controller grounds have less than 5 ohms resistance to ground?
1. No. At this point, if someone wants it - they can have it. (frustrated joke)
2. I will check tomorrow
3. This is a great question. I have checked all the controller grounds for continuity to ground because I wanted to make sure I didn't just miss a ground wire when I re-installed the motor, but I don't know about what the resistance is. I will check them tomorrow.


Here are some other notes I took today in the half hour or so I had:
Test NS-1 notes:
16.1 kOhms on secondary coil wire which is 31" long; ~520 Ohms/in
With the secondary cable disconnected but grounded, I got about 9.3 to 9.5V at the positive terminal on the coil. This is below the 10 V mentioned on the troubleshooting guide. (The battery is fresh.) Earlier, in the thread this was brought up and discussed that this is the proper voltage.
The voltage at the ASD to the coil wire was same as above when cranking. The voltage at the "rd/wt" wire (I think it was red in my '88, but I don't remember) was full battery voltage.
According to the diagram, this says to replace the wire from the ASD to the coil. However, I checked continuity from the + post on the coil to the ASD it remains unbroken. One thing of note, on a whim I checked it's continuity to ground and it was also continuous to ground. I guess that makes sense since the coil is grounded, but could it mean that there is a short in the wire?

Tomorrow, I'll pick back up on the testing provided. I don't have an OBDII scanner per the instructions, but it seems like most checks can still be made with my multimeter.

Thanks again everyone!

-Tim
 

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Are you disconnecting the wires from the coil when your checking their continuity? The coil should only be grounded when being fired by the smec. Is the battery voltage at the battery it’s self the same as the voltage going into the asd relay?
9.5 volts during cranking doesn’t seem unreasonably low to me.
 

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Discussion Starter · #31 ·
2)Is TPS closed throttle voltage below 2.50 volts?
3)Do all controller grounds have less than 5 ohms resistance to ground?
2. I am not 100% sure how to check. I checked the voltage across the three terminals with the key on. The voltage across VT/WT & OR/DB was <1V, across VT/WT & BK/LB was ~4.9V, and across OR/DB & BK/LB was also ~4.9V.
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3. Results:
Pin 1 - 5, 0.3 Ohms
Pin 1 - 15, 0.4 Ohms
Pin 1 - 16, 0.4 Ohms
Pin 2 - 2, 0.3 Ohms
Pin 2 - 6, 0.3 Ohms
Pin 2 - 7, 0.3 Ohms
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I have already given my results to test NS-1 yesterday. So, I'll pick up with the results from NS-7:
Since I don't have a diagnostic tool, I assumed the tool was somehow tricking the computer into closing the ASD relay so the sensors would all think the car was running. After I jumped the ASD I went to work.
The first test was to check voltage at the "-" terminal of the coil with the wire disconnected then check it again at the wire itself that would normally be on the coil. Both tests gave 11.7V. The flowchart recommends replacing the coil. This is already a brand-new coil, but perhaps it is bad? (I popped an old one in I had laying around and still no spark on the coil secondary wire, so I doubt that's it. Nonetheless, I am going to order another one.)
I removed the ASD jumper and moved to the second page of NS-7. Note that pin 1 - 19 on this diagnostic corresponds to 2 - 12 on my '88. The resistance of the wire connecting the "-" post on the coil to pin 2 - 12 was <1 Ohm. (The "-" wire was disconnected from the coil during the test.) The flowchart says to replace the controller. (n)
Next, NS-13:
Again, I had to use some assumptions to check the resistance in figure 2 but I checked the BK/LB wire back to the SMEC pin 1 - 4 and got 0.3 Ohms.
Next, was to test the voltage across the gray distributor connector. I got 9.5V between the BK/LB & OR terminals and <1V between the TN/YL & OR terminals.
Finally, I checked the resistance of the TN/YL wire back to the SMEC pin 1 - 26. This was <1 Ohm. The flowchart says to replace the controller. (n)(n)

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So, here I am. I have another SMEC, but I bought it used and I have never put it in a running car, so I have no idea if it works either. Hopefully, I just got a bad coil - but that's unlikely. I may be taking some of you up on testing this SMEC out.

One thing of note, the old engine that came out of the car had the distributor go out on it in our last race. If I recall, the rotor popped off somehow. We replaced the distributor and got the car running, but we lost compression #4 cyl (unrelated); so I disconnected that injector and we raced on 3 cyl with the boost turned down. Yeah, the car ran terribly but was making laps. That shortcut got us within 15 min of a checkered flag when another unrelated wheel issue ended our day (racing is hard). Anyway, I only bring that up for two reasons; 1) The car was 'running' before using this SMEC and 2) None of that should have fried the SMEC, right?

-Tim
 

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2. I am not 100% sure how to check. I checked the voltage across the three terminals with the key on. The voltage across VT/WT & OR/DB was <1V, across VT/WT & BK/LB was ~4.9V, and across OR/DB & BK/LB was also ~4.9V.
View attachment 282203
3. Results:
Pin 1 - 5, 0.3 Ohms
Pin 1 - 15, 0.4 Ohms
Pin 1 - 16, 0.4 Ohms
Pin 2 - 2, 0.3 Ohms
Pin 2 - 6, 0.3 Ohms
Pin 2 - 7, 0.3 Ohms
View attachment 282204 View attachment 282205

I have already given my results to test NS-1 yesterday. So, I'll pick up with the results from NS-7:
Since I don't have a diagnostic tool, I assumed the tool was somehow tricking the computer into closing the ASD relay so the sensors would all think the car was running. After I jumped the ASD I went to work.
The first test was to check voltage at the "-" terminal of the coil with the wire disconnected then check it again at the wire itself that would normally be on the coil. Both tests gave 11.7V. The flowchart recommends replacing the coil. This is already a brand-new coil, but perhaps it is bad? (I popped an old one in I had laying around and still no spark on the coil secondary wire, so I doubt that's it. Nonetheless, I am going to order another one.)
I removed the ASD jumper and moved to the second page of NS-7. Note that pin 1 - 19 on this diagnostic corresponds to 2 - 12 on my '88. The resistance of the wire connecting the "-" post on the coil to pin 2 - 12 was <1 Ohm. (The "-" wire was disconnected from the coil during the test.) The flowchart says to replace the controller. (n)
Next, NS-13:
Again, I had to use some assumptions to check the resistance in figure 2 but I checked the BK/LB wire back to the SMEC pin 1 - 4 and got 0.3 Ohms.
Next, was to test the voltage across the gray distributor connector. I got 9.5V between the BK/LB & OR terminals and <1V between the TN/YL & OR terminals.
Finally, I checked the resistance of the TN/YL wire back to the SMEC pin 1 - 26. This was <1 Ohm. The flowchart says to replace the controller. (n)(n)

View attachment 282210 View attachment 282208 View attachment 282211
View attachment 282207 View attachment 282206 View attachment 282209

So, here I am. I have another SMEC, but I bought it used and I have never put it in a running car, so I have no idea if it works either. Hopefully, I just got a bad coil - but that's unlikely. I may be taking some of you up on testing this SMEC out.

One thing of note, the old engine that came out of the car had the distributor go out on it in our last race. If I recall, the rotor popped off somehow. We replaced the distributor and got the car running, but we lost compression #4 cyl (unrelated); so I disconnected that injector and we raced on 3 cyl with the boost turned down. Yeah, the car ran terribly but was making laps. That shortcut got us within 15 min of a checkered flag when another unrelated wheel issue ended our day (racing is hard). Anyway, I only bring that up for two reasons; 1) The car was 'running' before using this SMEC and 2) None of that should have fried the SMEC, right?

-Tim
Actually if you pull the spark plug wire off while it's running there's a warning that you can destroy the computer. I think NAJ has the warning in one of his diagnostic pictures
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We did disconnect the spark plug wire and the injector connector, but not while it was running.
So the spark plug wire was always on whenever it was running?

If it was taken off before starting it and then running after it would still cause damage because that energy would have nowhere to go and it would back feed into the coil or jump all over causing damage to the electronics...
 

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So you currently have no codes?
Are codes the same when trying each smec?
Don’t assume the hep and or distributor is good just because your asd is functioning, these do turn on even before you crank the engine to prime the fuel pump in the 88/89 cars, this may be different on the newer cars I know my 92 has a separate fuel pump relay. To test this I would unplug one distributor plug then crank to see if you still have 12 volts at the coil, then try the other one, then both. Easy test but I would be interested in your findings.
Good luck, don’t give up success will come.
 

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Multiple posts have been made since you sent me the results from your diagnostics in Post #29, I am ignoring/not reading any of those posts or listening to any other ideas until these two things are corrected/repaired.
1)Battery Voltage
NAJ, Aug 4:
Again, just to verify, there is constant battery voltage at the + coil when cranking?
If there is you do not have a HEP issue.
Not full battery voltage, no. 9.3 to 9.5V
I think we have ruled out the HEP.

a)What is battery voltage at the + coil with the ASD Relay manually actuated with the KOEO? (Key On, Engine Off)
If it is above 12 volts then proceed to step 2, if it is not, continue with step 1.
The engine controller needs a minimum of 10 volts to function properly, 9.3-9.6 volts is NOT acceptable.
The battery needs to be fully charged and tested under load to be sure it is good, static battery voltage has to be in the 12.4-12.6 range and no lower than 9.6 volts cranking (starter draw).
If the battery voltage is within the correct range of 12.50 volts across the battery terminals (and battery posts, check both ways to be sure there is not excessive resistance between the battery terminals and battery posts.) but you only have 9.5 volts at the + coil with the ASD manually actuated then you have excessive resistance in the ASD output circuit or a short in the ASD output circuit to another circuit that is drawing away voltage.
Until you get proper battery voltage at the battery itself and then proper voltage at the + coil with the ASD manually actuated you CANNOT proceed any further.

2)Ignition Coil

NAJ, Aug 4:
If you have battery voltage at the + coil with the ASD relay manually actuated and you touch/remove the jumper from a known good ground and there is no spark from the coil secondary wire to ground then the coil is faulty or the coil secondary wire is open or has excessive resistance.
No spark. I have tried two coils and the secondary coil wire seems to be fine with about 502 ohms per in of resistance.
a)If you have proper voltage (Minimum 12 volts) at the + coil with the ASD Relay manually actuated and you make and break the connection to the - coil and there is no spark from the secondary coil wire to ground then that coil is faulty or you did something wrong.
If you cannot get 12 volts to the + coil with the ASD manually actuated you can remove both wires from the coil, connect another 12 volt power source to the + coil and make/break the - coil connection to see if it makes a difference.
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Until these two things are corrected you cannot proceed further.
 

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Still would like to know if code 54 is still present, and if so why???? Has anyone ever seen one of these car run with that code on?Not likely.
I might need to go out to my 89 and unplug the hep see if the asd still activates, just curious really, because I know it’s activated before cranking to prime the fuel.

I really hope that you can get this figured out soon, and hopefully you haven’t been getting faulty new hep’s, I’ve been there took buying 2 aftermarket ones before I spent the money on a mopar hep that actually worked but of course that was back in 05’ when they were still available. Anyways good luck, and try to follow NAJ’s procedures it’ll pay off.
 

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Still would like to know if code 54 is still present, and if so why???? Has anyone ever seen one of these car run with that code on? Not likely.
A few times members of this group have had a car that was running (with other driveabilty issues) and set a Code 54, to this day I still do not know why or how, the only explanation I have is that stray voltage (from somewhere) is interfering with the and/or changing the sync signal the controller is seeing, sort of like an intermittent "hiccup". Remember, the controller only see's the sync signal one time per distributor revolution.
 

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A few times members of this group have had a car that was running (with other driveabilty issues) and set a Code 54, to this day I still do not know why or how, the only explanation I have is that stray voltage (from somewhere) is interfering with the and/or changing the sync signal the controller is seeing, sort of like an intermittent "hiccup". Remember, the controller only see's the sync signal one time per distributor revolution.
Good information, thank you
 
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