1990 VNT Daytona electrical gremlins.

[gvare001]

The car died on me this morning on I-95. To make the story short, when you turn the ignition to the on position, every relay under the hood starts actuating non stop, the alarm light goes on, the check engine light flickers really fast non stop also, so I can't get any codes, and the car won't crank. I need some help please, this is all very confusing.

[90Dodgevnt]

Check your grounds at the starter and at the battery. Safe bet that at least one is bad...



Mike




The car died on me this morning on I-95. To make the story short, when you turn the ignition to the on position, every relay under the hood starts actuating non stop, the alarm light goes on, the check engine light flickers really fast non stop also, so I can't get any codes, and the car won't crank. I need some help please, this is all very confusing.

[gvare001]

I've check all my grounds, and everything is OK, but the car still doing the same. Could the factory alarm be messing things up, or is the computer fried? :(

[butchsuppe]

Check power to grd for shorts.

[MiniMopar]

It's either an intermittent ground or power feed. How do the battery terminals look?

[gvare001]

I just replaced my battery terminals, and nothing. Now I'm even getting hazard lights and the alarm light flashing when on. How can I diagnose a bad ECM? MiniMopar; do you think the asd relay could be the problem, and where is it located on a 1990 Daytona?

[RoadWarrior222]

Take it out, clean contact, resocket, see if it works again. Wriggle the crank position sensor connection.

Have seen this sort of thing happen on mopars from the wierdest things though, my minivan will spaz out if I turn off the key with the rear wiper and demister active, next time I try starting it everything flashes, the front wipers do a sweep... seen others do similar stuff for stuck power door lock actuators. (Lock and unlock all your doors manually and give them a slam)

Don't know how long you had power off for the battery terminal replacement. So if it was quick, try leaving the battery off for half an hour to an hour. I'd also try bumping the engine to a different position, just in case it's some wierd combo of sensors stoppong "just so" combined with an alternator brush bridging coils or something. Can either jump direct from battery to the starter for a quick blip or do it with a socket on the crank, or put it in gear and roll it a foot or two...

Anyhoo, best of luck gremlin hunting.

[gvare001]

I replaced the ASD relay, now the other relays are quiet when on, and the engine light stopped flickering too. I get no codes by the way. So now, the fuel pump doesn't prime when I turn the key to on, I can crank but no start. I ran a + to the + on the coil and I hear the pump working and the gas circulating in the FR.

[RoadWarrior222]

I guess I'm just assuming that you'd know if you threw the cam belt. It's probably looking for cam and crank signals in the right sequence now, before it turns fuel and spark on, so if your camshafts are turning and your cam timing is okay, then start looking at those sensors. Presumably it triggered auto shutdown for a reason connected with those, but the glitchy ASD relay did the "demonic possession" thing instead.

[gvare001]

Wierd, wierd, wierd, I removed the fuel rail to check for any leaky injectors, and when I put the + to the coil, the injectors start putting fuel out, and a lot of it.

[88_pacifica]

sounds like the injectors are stuck open(aka they are not "cycling").. Were they sputtering or constant?

[gvare001]

Constant.

[88_pacifica]

sounds like the electrical "pulses" are not working which would tip me to either a bad SMEC or the possibility that one of the wires controlling the injectors is pinched or not grounding properly on the fuel rail. I would triple check for any "pinched" or "loose" wires in that general area and if that comes back bad, you may be able to borrow another known working SMEC just to verify that they are firing properly.

It is not critically important that the other SMEC is VNT or even that the car runs with it. All you need to confirm is that the injectors are firing properly...

[gvare001]

Im going to my local U-pick tomorrow, there's a VNT Lebaron, with the SBEC in it still.

[88_pacifica]

sweet... :thumb:

[gvare001]

I replaced the ECM and nothing!

[sdac guy]

Wierd, wierd, wierd, I removed the fuel rail to check for any leaky injectors, and when I put the + to the coil, the injectors start putting fuel out, and a lot of it.

Under normal operation, the injectors will have a constant 12v supplied to them and the SBEC will send a ground to each injector to make it fire. The coil, injectors, and fuel pump are all on the same 12v feed. So if you supply 12v to the coil and the key is not on, the SBEC may be enough of a load that it appears as a ground to the injectors causing them all to fire. If that is the case, all you have proven is that the injectors work.

Just applying 12 volts directly to the coil is not really a valid troubleshooting method as the results may be unpredictable.

Barry

[88_pacifica]

nothing..? As in it's still not working correctly, or that now it is not working at all?

Barry is right... that is what I was thinking as well. I would still focus on the grounds on the rail or that it is the SBEC.

[90Dodgevnt]

Here are some tests you can run right from the 1990 Powertrain Diagnostics procedures...

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0010.jpg

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0012.jpg

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0011.jpg

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0013.jpg

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0014.jpg

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0015.jpg

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0016.jpg

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0017.jpg

http://i2.photobucket.com/albums/y43/90dodgevnt/scan0018.jpg

If you are still stuck are this, pm me or post here and I can scan more.


Good luck

Mike

[JDAWG]

a 90 vnt doesnt have a ground for the injector wiring harness, the pcm grounds each injector through the pcm itself. I went through that a few months ago. Just a fyi

[90Dodgevnt]

Ok, so far you have swapped out the ASD relay and you are not getting the fuel pump to energize, correct?

(1) Check for spark (fig #4).

(2) Test the ASD relay (fig #6)

If your ASD relay is not allowing the pump to energize, check your wiring for a bad link/ground/bad relay. If the relay and wiring are good, then…

(3) Check the fuel pump for power (pull the connector and us an ohm meter)

If you get to the pump and you have no power, re-run the tests again to make sure the fuel pump is bad, otherwise you may just waste $120+ for a fuel pump that didn’t need replacing.

Good luck

[gvare001]

I check for voltage at the fuel pump, there is 12V when you flip the switch to on, but the pump doesn't prime.

[gvare001]

Latest update; I'm getting 12V at the black wire that goes on the - at the coil. As a result I get a small voltage at the pump and fuel injectors even with the ASD relay off, WTF!!!

[gvare001]

Okay, if I disconect the coil two wires, the pump primes , but I get no voltage at the green wire on the coil, and I get some voltage at the black wire that goes to the - on the coil.