Turbo Dodge Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
62 Posts
Discussion Starter #1
Greetings,
I am having some issues with the factory alarm that is preventing my 1990 Daytona from starting.
The alarm has “woken” a couple of times in the last 20 years, but has been non-functioning for most of that time. It would never “arm” or even sound. A couple of times it lit “Alarm Set” light in the visual message center, but for most of the time it has been non-existent, a non factor. I always figured there was a problem with it, however as it never interfered with the functioning of the vehicle and I never appreciated the system, it was not something that I really cared about.
That changed recently. I jumped the ASD relay to drain the fuel tank in order to replace seals that had failed. The next time I connected the battery the headlights popped up, the parking and tail lights started flashing, and there was a ticking coming from the interior, behind the glove box. At this point, the fuel pump stopped working as well (I jumped the ASD and the pump would not turn, despite there being power at the pump).
I replaced the pump, changed the filter, and verified 55psi of fuel pressure at the rail. The pump primes when the ignition key is turned, and runs when the ASD is jumped.
However, from the moment I connect the battery the security module is ticking and flashing the lights, as though it’s been tripped. I have tried locking, and unlocking, both doors with no affect. I cannot get the alarm to turn off, and the car will crank, turn over, and immediately die. The SBEC is a Mopar Performance unit. I tried to start the car using two other SBECs I have, with the security module removed, with the same result.
I understand that the SBEC is looking for a signal from security module, via the BCM, to start the car, and that w/o that signal the car will not start. I visually inspected the security module PCB and there was no obvious evidence of damage.
I have the FSM including wiring diagram and I started probing the security module. There is no voltage from the driver’s door when the door is closed, and there is no voltage at the driver’s door ajar switch either. My initial thought is that the alarm will not recognize attempts to disarm it using door cylinder switches b/c it thinks the driver side door is ajar.
I realize this is an odd issue and I am in the position of fixing a system that was already broken. My goal is to get the security system working so I can remove it (while the vehicle is running) so all of my SBECs will no longer look for it.
As for questions, for those that have or are familiar with the system, is it normal for the security module to trigger when the battery is connected? I would like to determine if the security module is functioning as it should, or if this is an indicator that the module is broken, as that will inform my next steps.
I will admit that it is frustrating and almost unbelievable to be stymied by a 3o year old factory alarm that can’t be somehow bypassed or duped.
Thanks in advance for any feedback.
Robert
 

·
Administrator
Joined
·
24,463 Posts
As far as I was aware the way to reset the alarm was to lock/unlock either the driver or passenger door with the key.

If there is no power at the VTA Module and BCM "Door Ajar" terminals then you will need to remove the door panel and check the Door Ajar Switch" connector.

Do you have the 1990 AG/AJ Body Diagnostics Procedures Manual?
Do you have access to a scanner and appropriate cable to access the BCM through the CCD Bus Connector?

ELECTRICAL- CCD Bus Diagnostic Connector.jpg
 

·
Registered
Joined
·
62 Posts
Discussion Starter #3
Thanks Naj.

I do not have a scanner for the BCM.

I didn't have a of time to work on it last night, so I decided to skip the DS ajar switch and concentrate on the door key cylinder switches, as they actually control the disarming of the alarm.

There was no voltage at the module when either DS or PS key cylinder was turned.

I was going to start testing the PS cylinder lock switch wire at the door connector (behind the PS kick panel) when I decided to "jump" the PS door ajar switch wire (at the module) to the PS key cylinder switch input at the module. When I closed the PS door ajar switch the alarm turned off, and I was able to start the car. I promptly removed the module while the car was running, and after letting it run for a few minutes, turned the car off and restarted it.


Hearing the car idle again was very satisfying.

Thanks for your help.
 

·
Administrator
Joined
·
24,463 Posts
Question...:confused:

Why does your profile show VNT and 153 CI which would be a 2.5L? :shrug:
 

·
Registered
Joined
·
62 Posts
Discussion Starter #5
Believe it or not, this is not the first time you asked me this question. 1990 Dodge Daytona VNT. Purchased with a spun bearing almost 20 years ago. Didn’t know what I know now, so I replaced the bottom end with a new 2.5 short block from Chrysler. VNT let go shortly after I put it back together (not surprising), and it’s been a 2.5 with a Super 60 turbo, with supporting modifications, ever since. I was a lot more interested in going fast back then. It has been a good combination, the low end torque compliments the weight of the car well.
 

·
Administrator
Joined
·
24,463 Posts
Believe it or not, this is not the first time you asked me this question. 1990 Dodge Daytona VNT. Purchased with a spun bearing almost 20 years ago. Didn’t know what I know now, so I replaced the bottom end with a new 2.5 short block from Chrysler. VNT let go shortly after I put it back together (not surprising), and it’s been a 2.5 with a Super 60 turbo ever since.

My mind is not what it used to be, old age...

Happy to know there at at least two Daytona's in N.J. with an 8th Digit Vin Code "C". :thumb:
 

·
Registered
Joined
·
362 Posts
This is timely. I have what I believe is a similar issue that has reoccurred. Car is a 90 CS vnt car (no longer vnt). My car willl start and then immediately die after 1 or 2 seconds. (3 different SBEC's all result in the same issue). No codes of concern. My car does no have an alarm or power locks (1990 CS AGS cars were base model cars with the shelby motor/trans /suspension). My car seems to behave like there is an alarm issue. The 3 SBEC's were all socketed with non-factory calibrations (3 bar). Is it the BCM that controls the shutdown or does it signal the SBEC to do it and if so, does it use the ASD? I had this issue a couple of years back and installed another aftermarket SBEC and the problem went away so I assumed it was the SBEC, but now I doubt that all 3 SBEC's are 'bad'. The socketed SBEC's may have come from cars with alarms, I am guessing this may be an issue but why did it take two years to show up. Not sure how to even tackle this but it is frustrating. What might be the pinouts on the ASD, maybe it is not getting a signal?

Thanks
 

·
Registered
Joined
·
362 Posts
This is timely. I have a very similar issue with my 90 Daytona. It is a 90 CS AGS (was a VNT) car. So it had no power locks etc. It will start and then quit in 1 or 2 seconds. Tried 3 different SBEC's and all have the same issue. No codes that might be related. It behaves like you noted but I have no alarm. Perhaps these other SBEC;s came from cars that did have alarms. Had this issue a couple of years ago and another SBEC, cured it so I assume it was the SBEC, but now I am not sure (what are the odds of having 3 bad SBECs). Is it the ASD that causes the shutdown? Can it be bypassed? Do you happen to know where to find the what the pinouts on the ASD are? I was thinking that perhaps the ASD is not getting a signal and then shuts everything down. At a loss here.

Thanks
 

·
Registered
Joined
·
62 Posts
Discussion Starter #9
Naj can correct any misstatements. To my knowledge the VTS sends a signal to the BCM, which sends a signal to the SBEC to run the car. It’s not just a signal - it’s a “packet” of data - so there’s no way to jump or bypass the VTS. I don’t know exactly what the SBEC doesn’t do to prevent the car from running, but I believe it’s more than just cutting power to the ASD. I think it may not pulse the injectors as well. If the SBEC is looking for the VTS, the car will not start w/o a signal from the VTS.
Are you sure you don’t have the VTS? It’s a passive system, no key fob. If works off the key cylinders in the doors.
My system was dormant - it never worked until one day it woke up. Will the car run on the original SBEC that was originally in the car?
This is a good primer on the system: https://pbase.com/rmscott/factory_security
 

·
Registered
Joined
·
362 Posts
Back from vacation. My car does not have VTS. No power locks etc and no 'hood open' striker thingy and no box behind the glove box. It will start and run with the stock SBEC but it is not happy about it. I wonder if there is a different code to the eprom for the cars without the VTS? Something appears to be tricking the new custom calibrations into thinking that there is VTS. I am not knowledgeable about the various coding but that is all I can surmise. Not sure if anyone has delved into that part of calibrations.
 

·
Administrator
Joined
·
24,463 Posts
Just so we are on the same page...
1)The car will not start with a calibrated SBEC but will start and barely run with a stock SBEC?
Going by that I do not think you have a controller issue, I feel something that was done to the vehicle is causing your issues.
2)What was done to this car since the last time the car started and ran properly?

We are going to have to get back to basics using the stock controller to determine the cause of your no start condition.

Ready???
 

·
Registered
Joined
·
362 Posts
This actually started a couple of years ago. I was running a socketed sbec with a 3 bar calibration from a vendor. It worked flawlessly for about 3 years. Then one day I had a no-run condition. It would start but then immediately quit after a second or two. I swaped the ASD relay with new one. Tried a new distributor pickup. Even bypassed he MSD box. All with no changes to the no-run condition. So I put the original stock 2 bar calibration SBEC back in and the car started and ran (although not well due to the larger injectors, different cylinder head etc). So I figured I had a bad SBEC and then got another one with a similar 3 bar calibration. Everything worked, it started and ran just like the original calibration. Fast forward 2 years and now this one is doing the same thing. I have yet another socketed SBEC so I swapped one of the the 3 bar eprom (chip thingys) into that SBEC and tried that thinking that would determine if it was the calibration (eprom) or the SBEC board. Another no-run condition. Yesterday, put the stock SBEC back in and it will start and run.

In each case, nothing was done to the car. One day they started and ran, the next day they had a no-run situation with each custom cal. Each time the factory SBEC could start and run the car.
 

·
Administrator
Joined
·
24,463 Posts
You are obviously having issues with controllers, something is causing the controllers to fail.

I have no idea how Chrysler controllers operate, however...

Back in the 80's GM had a major ECM failure issue, the car would be towed to the dealer, diagnostics led to a faulty ECM so it was replaced under warranty, six month's later the same scenario was repeated and this happened countless times across the country.

GM used "quad drivers" in their ECM's, one driver would operate 4 components.
GM engineers determined that it was probably one of the four components being controlled that was causing the ECM death issue so they sent out a TSB instructing their techs to determine which quad driver had failed and then run continuity tests on the four circuits to determine which component/circuit was causing the quad driver failure in the particular vehicle.

Well, checking resistance in the circuits did not correct the problem, they were still experiencing quad driver failures and determined excessive amperage in the circuit was the cause.
They sent out a new TSB with instructions on how to actuate all of the circuits on the dead quad driver circuit and watch for higher than normal amperage on the circuit as the components heated up and that worked, as the faulty component ran and got hotter the amperage increased.

From that point on until OBD2 any GM vehicle that went to the dealer (or me) that diagnostics determined was a ECM failure the amperage test had to be run to find out what actually killed the ECM/quad driver so the replacement ECM would not suffer the same fate.

The question then becomes...
What is killing your controllers?
Constant voltage spikes, current looking for and finding an alternate path to ground through the controller?
The first thing I would do is verify All Controller Grounds have less than 5 ohms continuity to ground and none show continuity to ground when disconnected from the body/controller which would indicate the ground is shorted.
Be sure that all of your body/engine grounds are in place and mounted to a clean/dry surface and secure.
Be sure the alternator is properly grounded and all pigtails from the - battery are properly grounded.

If you have any aftermarket accessories on the vehicle such as sound systems, etc be sure they are installed properly and not using any controller circuits with their own ground circuits and their ground circuits do not have excessive resistance. (over 5 ohms)

You also stated you had an MSD Box, I know nothing about them, however...
Just using a MSD Blaster Coil which has the incorrect primary resistance for our vehicles has caused HEP failures, so an entire ignition system?
At this point you have to assume anything can be causing the problem.
 
1 - 13 of 13 Posts
Top