Engine cuts off plus electrical problems

[calettso]

Let me start off by saying I have checked the archives and current postings and have not found any postings on my current problem.

I have been working on my friend’s car occasionally for about two months now doing minor maintenance. I changed her oil and oil filter. All went well. About 1 week after, I decided to check into electrical issues that she had way before I touched the car.

List of electrical issues: Drivers seat does not move automatically when the car is turned on or work intermittently. Also there is a parasitic battery drain.

Car Information: 1991 Q45.

Initial Approach: I decided to check into the parasitic battery drain after the oil change. The battery was being drained in under 10 hours of the car being off. I followed the suggestions in the posting zerothread/202345. I pulled fuses and found that with the car off, two fuses caused a significant battery drain.

Diagnosis: The Dome lamp circuit and Radio Power Antenna circuit when the fuses are in and the car off caused a high current drain. As much as 1.3 Amps current drain combined with the car off, doors closed, and keys out of the ignition.

Temporary Rectification: I removed both fuses from those circuits. My friend does not need either, as her antenna is broken and the interior light is not crucial to operation of the vehicle. Current draw was brought close to the level found on the form posting I mentioned above and the car battery holds the charge. Woohoo!

The New Problem: We figured we would leave the car that way until I can trace the current drain problem. After I did that however, the car cuts off in cases when she is decelerating or not pressing the accelerator. Don’t make sense to me. As stated, the antenna is broken and the dome light works perfectly fine. It seems ridiculous to believe that critical circuitry was placed on the circuit with the dome lamp and/or power antenna. However, this is all I can come up with unless this is coincidental and something else went wrong at the same time.

New Rectification: Before she starts her car now she replace the fuses and when she parks for a long duration of time meaning more than 6 hours she pulls the fuses out. So far this has worked but clearly this is a pain.

My Questions: 1) Does anyone know what can be causing the current drain on these circuits? 2) Are there any critical components connected on the dome lamp and/or antenna circuitry? 3) If so which one contains this critical component and what is it? 3) Is there a quick fix or any suggestions to fix both issues?

Thanks.

[maxnix]

Tell us about the bulb and sockets, please.

OEM antenna?

Any other previous work on the electrical system?

[qsiguy]

Welcome to NICO and I have to say that's a nice descriptive write up of your issue. That is rare.

I looked over the factory service manual for the '94 since the '91 isn't available for the computer that I'm aware of. Normally they are similar enough. I did not see anything obvious that would cause the engine to stall with those fuses removed but there are so many systems in the Q I may have over looked something. There are some power signals that reach the BCM (body control module) through the interior fuse but I wouldn't think that would cause the engine to stall. Since the stalling problem goes away by reinstalling the fuses (assuming from your description) then it's probably not this but...if you changed the oil filter from the top of the engine make sure the MAF plug isn't loose or intermittent. It's quite common for the MAF plug to get dislodged by an oil filter change from the top since you will most likely put stress on the MAF plug while doing it. Something to check out...

The interior light circuit for sure and maybe the power antenna circuit can draw an amp or two for a few minutes after the battery has been connected or after you turn off the key and close the door. You want to make sure when checking the amp draw you let it sit for a while so all circuits settle and shut down. Also, there is some amp draw you will experience if you don't disconnect the alarm switch under the hood, if your's is equipped with one. It's on the drivers side near the power steering reservoir. Either close the hood, unplug that switch or put something on it.

Make sure all of the interior and trunk lamps shut off when the doors and trunk are closed and the key is off. One lamp can draw an amp or two. The power antenna has a timer that could draw some power for a short time, make sure it has time to shut down.

Anything aftermarket installed in the vehicle? Security or audio system? Those would be the primary items of concern.

[96Qowner]

I also think MAF troubles for the stalling when coming to a stop. It would not be related to the fuses or current draw, but that's one of the symptoms of a dirty or intermittent MAF connector - very common. A confirmation would be bucking under acceleration.

[calettso]

Tell us about the bulb and sockets, please.

OEM antenna?

Any other previous work on the electrical system?

Bulbs and sockets? Can you be more specific? What information do you need to know about the bulbs and sockets?

The antenna as far as we know is the original antenna but it is broken. No longer a part of the car.

We do not know about any previous work on the electrical system. She is not the first owner.

[Q45tech]

When you finally give up or get tired of pulling fuse our S. Cobb location [Byron] can troubleshoot for you @ $85 per hour.

First try discoing the antenna motor electrical connector [on antenna assembly] which discos the antenna timer module.

[calettso]

Welcome to NICO and I have to say that's a nice descriptive write up of your issue. That is rare.

I looked over the factory service manual for the '94 since the '91 isn't available for the computer that I'm aware of. Normally they are similar enough. I did not see anything obvious that would cause the engine to stall with those fuses removed but there are so many systems in the Q I may have over looked something. There are some power signals that reach the BCM (body control module) through the interior fuse but I wouldn't think that would cause the engine to stall. Since the stalling problem goes away by reinstalling the fuses (assuming from your description) then it's probably not this but...if you changed the oil filter from the top of the engine make sure the MAF plug isn't loose or intermittent. It's quite common for the MAF plug to get dislodged by an oil filter change from the top since you will most likely put stress on the MAF plug while doing it. Something to check out...

The interior light circuit for sure and maybe the power antenna circuit can draw an amp or two for a few minutes after the battery has been connected or after you turn off the key and close the door. You want to make sure when checking the amp draw you let it sit for a while so all circuits settle and shut down. Also, there is some amp draw you will experience if you don't disconnect the alarm switch under the hood, if your's is equipped with one. It's on the drivers side near the power steering reservoir. Either close the hood, unplug that switch or put something on it.

Make sure all of the interior and trunk lamps shut off when the doors and trunk are closed and the key is off. One lamp can draw an amp or two. The power antenna has a timer that could draw some power for a short time, make sure it has time to shut down.

Anything aftermarket installed in the vehicle? Security or audio system? Those would be the primary items of concern.

When you say change the oil from the top of the engine I am assuming you mean that I remove the filter from above rather than from under the car. I was under the car when I changed the oil filter. I bought a fitted oil filter wrench. I am assuming everything went well since there was no oil leaking from the bottom of the car.

I am not familiar with the MAF plug can you provide me with more information? Also can you send me a copy of the FSM for the 94 Q45 or one similar enough to the 91 Q45? I am curious about your theory. It could be the cause.

As for the stalling issue and pulling the fuses, we have tested this theory a few times and so far so good. However, she has not been removing and replacing the fuses enough for me to say for sure that it works always when the fuses are in the socket. I am not ready to make this claim because the car did not always stall when decelerating or at a stop with the fuses out. More testing needs to be done.

[calettso]

I also think MAF troubles for the stalling when coming to a stop. It would not be related to the fuses or current draw, but that's one of the symptoms of a dirty or intermittent MAF connector - very common. A confirmation would be bucking under acceleration.

I will definitely check the MAF plug. I need more information on it however. Description? Purpose of it? I Know it is close to the oil filter.

I have never experienced the bucking while accelerating. All I know is when decelerating or at a stop the car sometimes stalls. The first time I experienced it, I did not even realize it until she told me. She noticed when she tried to accelerate again. She was unable to accelerate. The car went silent and the dash lights came on. We coasted into a parking lot.

[96Qowner]

Here's a tutorial on cleaning the MAF:

http://www.q45.org/maf.html

Since that was written, we've decided the problem is usually in the plug itself. Either the pins become corroded, or they loosen over time - simply crimped to the wiring. Clean up the connector plug and the MAF element and see if that fixes the stalling.

[qsiguy]

The MAF (Mass Air Flow) sensor is on the outlet of the airbox. It as a single plug on it that is prone to become loose or have an intermittent connection. This will cause idle problems and more. The ECU doesn't know the volume of air entering the engine so it freaks out. When this has happened on mine I've just had to wiggle the plug and push it in and the problem clears up.

Since you changed the filter from the bottom you should be ok but it's worth a try. What happens is when you reach down from the top the plug gets pushed on and can get loose.

Is the idle RPM ok when it's not acting up or does it always idle low? Idle Air valve may need cleaning or adjustment if it always idles low. That sits directly in the back of the intake plenum (spider looking thing on top of the motor)

There are quite a few suspect areas, you will just need to narrow it down via process of elimination.

Here's a link to where you can get service manuals in PDFhttp://www.nicoclub.com/FSM/Q45/

[calettso]

I was writing to you about 2 months ago, about a problem with my friends car. The car was having electrical problems as well as stalling out while she was driving. The electrical issues is still not solved, but the problem with the stalling was much more important. I want to thank you for helping me solve that issue. It was the MAF plug that was the problem. I went to auto zone and bought the electrical spray for about $5, sprayed down the switch and she has not had an issue since then. Thank you to all the people on this forum who read about my problem and tried to help.

[maxnix]

Do check the bulbs (OEM or Sylvania LL) and the sockets and the wiring for overheat and/or corrosion damage.