1992 2.5L 5spd with 177,000 miles. OK so driving around town pretty hard hauling motorcycles all day. Once in stop and go the truck died (unusual), but started right back up. Then, on the last stop of the day, I shut down the truck, went into the store, came out, and the truck would not start. Crank crank nothing. I fiddled around with it, found there was no spark, unplugged and replugged various sensors and the SMEC and battery and all kinds of things, finally it started. Woohoo lets get out of here.

So then about 10 mins later it dies, I go thru all the usual head scratching and cursing until I remember a post on here a while back about the ASD. So I yank that out, toss in the relay from the rad fan (fan now operates via toggle switch, anyways), and away we go without a hiccup. 45 mins later still driving strong. Throughout this entire process, we threw no codes. I even ran a diagnostic once I got home, codes 12 and 55, all normal.

So I recognize that the ASD could be faulty, and I am more than willing to accept the possibility that replacing the relay will be a permanent repair. But I also imagine that it is in there for a reason. My question therefore is, what trips the ASD relay? My manual is woefully vague about this. Where should I go looking for problems which may have blown the relay?

Thanks in advance

 

First don't let the ASD name confuse you. Actually the computer activates the ASD to engage the positive feed to the coil and fuel injectors. When you turn off the key it shuts down the power to those circuits. Check out the FAQ for a full write up on it.

The Notorious splice is a common problem for No Start issues. For Idling issues the IAC, Idle Air Control. This is a common problem for stalling during Idle or low throttle.

 

I thought the ASD (Automatic Shutdown Relay) kills all power in the even of an impact to the vehicle like a accident?

 

No it is not meant to. The name comes from when the key is turned off then the circuits loose there positive input, so it shuts down the engine.

 

Yeah, when you turn the key to ign the PCM provides power to the ASD (shifting power from the center connector to the top one - terminal 85 to 86, or something like that). That ASD relay powers your ign coil and fuel pump at the same time.

I'd say test your IAC and check your grounds.

 

I too thought the ASD was something along the lines of what Oxygen said, since I swapped in a new relay and the truck was good to go for at least the 45 minute ride home, would that indicate to you guys that the relay had simply gone bad? Or would an underlying problem like the IAC or grounds have caused the relay to blow? Remember, in the parking lot the only "repair" I preformed was changing out the relay.

Thanks for your patients I would like to avoid blowing out an endless stream of relays if I can avoid it.

 

Relays are known to eventually wear out as they have moving internal parts. If this is the first time you replaced your relay, you could see how long you get. It might have fixed the problem? Have you checked all your wiring and grounds?

 

Don't do what I did with the ASD, jump the relay, worked fine for awhile but eventually burnt the driver for the coil in my PCM. Wow takes 7 days to order one for a 94 Dakota. The truck would run fine and for no reason just shut off and not start, 10 minutes or more some times, it start up fine run fine until the next time it would shut off. Did all the usual checks that I see everyone do on the net. The ASD relay goes bad intermittently will drive you crazy. So before you go changing a bunch of good parts like I did pull the ASD relay and bypass it with a paper clip. DO NOT LEAVE IT IN THAT WAY. If the engine starts and would not before you have probably found the problem. If you find that a new relay does not solve the problem as in my case, put a switch under the dash run the wire to center 2 slot where the ASD plugs in, just don't forget to shut it off when you turn the key off. I got a discount on my insurance for having optional kill switch. So good luck with them trucks.