Removed Aftermarket Alarm, Car Won't Start

[torresmd]

I spent all day yesterday removing an aftermarket alarm that was already installed when I bought my car. I decided to do this because my electric windows stopped working and so did my central locking. I carefully removed the alarm and all the massive heaps of wires and found a wiring diagram for the window and re-wired them. Now the windows work and I will tackle the central lock later. I buttoned everything up and now the car won't start. It turns over but just won't light. I can hear the fuel pumps prime as well. I think there must be some sort of kill switch. I an schedule to be on the dyno at TurboKraft on Monday. Please help me start my car!!!!!
Steve

[dad911]

Do you have any info on the alarm? Is this the 930 or the TT? Without more info, no way we can help.

There must have been a wire from the alarm tied to the ignition circuit. Retrace your steps.

[dshepp806]

Compare the existing wiring with the Bentley..


Doyle

[torresmd]

It is the 930. The ignition wires were cut and bypassed. I re-connected those. The car cranks strong but just won't start. I checked the fuses to the fuel pumps. They must have bypassed something else. I will try to take a pic of where the bypass was.

[torresmd]

Here are some pics of the spaghetti.
the wires on the right, white/blk and black were bypassing Yellow ignition wire. The red/yellow and red wires were spliced into two red wires.


This is where the bypassing seemed to take place. I simply reconnected the yellow wire and just removed the two other wires from the yellow connectors.



pic of the alarm brain.



Not sure if any of this helps, not sure what to try next.

[McLovin]

See if it'll start on a shot of starting fluid. If it does, you know the fuel is being cut somewhere.

Check to see if you are getting spark at the plugs. If not, your ignition is being cut somewhere.

Then you just need to trace it backwards until you find where the cutout is.

I usually remove the aftermarket alarm from any old 911 that I buy, I don't really trust them, don't like all that extra wiring, etc. But it's always an adventure. I usually try to figure it out the best I can before removing wires, but also start the car occasionally during the wire removal process. That way if the car suddenly doesn't stop, it's not too hard to figure out which wire removal caused the no start condition.

[rnewton1377]

There's a cute way to detect shorts. I haven't done it in a while, but I remember having the same problem with the '79 SC. It takes a continuity light with the negative lead clamped (vise grips) to the negative post of the battery (negative battery terminal needs to be disconnected). I believe you then touch the positive lead of the light to the different fuse outlets. If the light comes on or stays off (I don't remember which) you have a short in that circuit. Then you go through the circuit and try to find the problem. As I remember there were several, the window on the passenger side was one. Someone help me out here, I may have the hook up wrong....... I do remember it takes a while but it worked.

[rnewton1377]

The theory here is that as long as the doors are closed and the key is out there should be no power going to the fuses. If the light turns on then that means something is being grounded to the chassis and needs to be fixed. Some of the old alarm systems had kill switches and you have to get all of that stuff out of there. I remember watching 17 year olds working after school installing alarms at a fairly reputable dealer when my son was growing up. CHECK EVERYTHING!

[Kevin Stewart]

do a search on alarm bypass, you have to wire something back together cant remember what though, Kevin

[steely]

Try to sketch a wiring diagram of what it looked like before you took it out before you forget.
This and bentley will give you 2 references.

Did you remove or bypass any relays with the spaghetti? The aftermarket alarm may have included one for the starter or something else.

[john walker's workshop]

what don't you have now? no spark or no fuel pump function?

[dad911]

Google "APS255CH diagram" and you will find the wiring for the alarm at Vehicle Restoration Guides and Tutorials

Looks pretty basic, orange wire from alarm switches relay.

Check the simple stuff, the connections. Perhaps the splice connectors are breaking a wire, or the butt connectors not making contact.

Do you have a test light? Makes it easy to probe wires and connectors to see if there is voltage.

[torresmd]

OK so I pulled one of the coils and put in a spare plug and while pressing the end against the engine, I had my wife crank the engine. I did see a spark so I think that means it is not an ignition problem. Must be a fuel pump problem. How do I test the fuel pumps? I have checked all the fuses up front and in the engine compartment. I think I am making progress.

[john walker's workshop]

when wifey cranks the key, you can feel the vibrations from the pumps. one at the left side of the rear torsion tube and one behind the gas tank. turbos have 2 relays and a fuse up front, a yellow pump cut-off relay at the rear of the rear electrical panel, and under the driver seat, the outermost relay also relates to the pumps.

[torresmd]

Curious....... I was reading my bently and it mentions that cars with a factory alarm will disable the fuel pump. So I cannot seem to turn the switch with my key, and since I removed the aftermarket alarm and re-connected everything, maybe my oem alarm is the problem. Anyone know how to disable the factory alarm?

[1986911]

Below is a link to a post I made last year on disabling the factory alarm.

"No Cut" method for bypassing factory alarm

I saw your pictures of under your dash. Could you post some more? It may reveal your problem.

Also, check all of your fuses, maybe one blew in the process of you removing the old alarm.

[1986911]

Hey Steve, in the picture of the spaghetti. Where does the white and black wire (single relay on right) go? That might be your problem there. That relay looked to be the engine disable relay. Can you post a better picture of it to see what leg of the relay it was. Most of these cars since they had manual transmissions had the fuel or spark disabled by their alarms. All you had to do was push start it to bypass the alarm. No fuel or spark no go!

[torresmd]

Thank you very much for your help. Your link is very helpful and I will try that later tonight.
Here are some more pics. The first one is another set of wires that were bypassed. It is just next to the footwell blower. This bundle of wires appears to go into the drivers door. I reconnected them as well as the wires at the ignition bypass. So there were only two areas that seemed to be bypassed. The ignition yellow wire and the mysterious wires in the first pic.

The second pic is a better closeup of the relay. The white and black wire were wired into the ignition yellow wire. Hope this shows you what you wanted.

[1986911]

Before you tear into your car can you check where the white/black and black wire were connected to the factory wires. They should have been connected to whatever is causing your problem.

87a (black wire) and 30(black and white) are whatever is to be connected or disconnected in your case. At rest this relay has no power (in your case ground) going to it so your circuit is complete. Once you supply those orange ones with power or ground it should open the relay and interrupt your flow of power between 87A and 30.

The way it worked was one of your orange wires was connected to an switched power (ignition) source. The other orange wire went to the negative output of your aftermarket alarm. Lets say a thief tries to hot wire your car, he breaks the ignition lock and forces a screwdriver where the key goes. He turns it, it then supplies the car and relay with ignition power. Since the armed alarm is supplying that orange wire with ground the relay springs to life and disconnects the connection between your black and black\white wire rendering you car inoperable.

This is a supposition only, the only way to know 100% is to trace those 2 wires back to see if at one point the wires they are spliced into was a whole wire at one point.

Good luck

[911pcars]

All I can offer is to obtain the factory wiring diagram, then try to replicate the various paths from point A to point B per the diagram. Yank everything that doesn't look factory while observing the added and factory wire color coding. Do this methodically so you have an understanding of how the alarm disables the various electrical systems. If possible, a copy of the alarm installation schematic and instructions will be a big help.

For those of you contemplating an alarm system. Don't. Long after the alarm company has gone out of business, there will come a time where you or your tech will have to diagnose a no-start condition that's due to said alarm system. Your tech or other masochistic wrench will either advise you to cash in a portion of your 401K to pay for diagnosis or will suggest yanking the archaic system that has infiltrated your electrical system before it's had a chance to render your ride no-op.

Sherwood