Dodge Ram stalls with cueing mic..........

Brentd2183 · Post by **Brentd2183** » Tue Nov 18, 2003 1:31 pm

Been working on this truck for a long time, local radio shop did the first installs and my freind, Deputy Fire Chief wasnt happy with the troubleshooting. We have tried different radios, Radius to ones from the 60's and different antenna combos, both magnet and perm. Truck is a 1996 Dodge Ram 1500, when you hit the mic the truck shuts off, engine stalls.
Electrics still stay on but the truck stalls out, had the meter out and it VSWR at 2 better than the 8 when i found it, 60 watt radio, cant remember type, A/S 268 series antenna on magnet mount, its only mounted magnet because we were ex[erimenting, the hole on the roof is there from before, stalled the truck there and on the bed rails.
We moved the actually radio to the backseat, worked for a day, then back. Have tried tons of things, looking for help, heard about ferrites on ignition leads??? Any help is needed. Thanks.

P.S. New to the board, have about a year or 2 experience with radios, lights and sirens. Do most installs for my Fire Dept. freinds. I'll eventually post pic of my cars, 1990 Pontiac Sunbird 4 door.....dont laugh...hideaways in headlights, wigwags, Able2 remote siren, Whelen RR talon above mirror, whelen RR dashmiser strobe on lower dash, Able2 microthins under side mirrors, firebeams on back dash, 6 hideaways in rear tail lights. Motorola Radius lowband twoway, President Herbert CB, and Uniden BCT7 scanner.
Thanks, wow thats a long post.....
Brent

ESDA20 · Post by **ESDA20** » Tue Nov 18, 2003 1:51 pm

I definately want to see those pics.

KitN1MCC · Post by **KitN1MCC** » Tue Nov 18, 2003 4:36 pm

Hell i have the Same thing going on here with a 88 chev k2500.

the radio was in a 94 3500 he sold the truck.took the radio out.

he picked up this thing for 500 motor runs great and all. i think it has a bad alternator or crappy battery

eboe · Post by **eboe** » Tue Nov 18, 2003 5:11 pm

brent, try this to narrow it down. get another car battery and set it on the passenger side floor and hook the radio's power and ground up to that so it's running independantly of the dodge's electrical power. then key the mic and see what happens. i'm guessing it might have something to do with exactly where you're tapping in to the +12v. cars with OBDII computers can get pretty finicky when the voltage drops to the ECU. a 60watt mobile transmitting will pull a few amps.

apco25 · Post by **apco25** » Tue Nov 18, 2003 7:19 pm

I would look for RFI getting into the PCM for the truck. Make sure the radio and antenna grounds are good and that everything is at the same ground potential.. Check the battery and alternator for voltage drop and replace if needed.

Try using different antenna locations to see fi you can isolate the problem.

What band is the radio?

Do a search on Low Band Maratracs and CRown Victorias. We had a thread here where one of the members experienced the exact same problem with a specific batch of CV's.

Brentd2183 · Post by **Brentd2183** » Tue Nov 18, 2003 7:45 pm

Its wired directly to the battery, i've tried both Neg wire to neg post and to the chassis ground, at different spots with no difference, i have hooked the power up to a seperate battery aswell, i have a strange feeling that the truck's body isnt grounded all that well to the frame and ground, i've been thinking of a way to get a ground strap from the roof to the same ground point as the power, cant think of a good way to attach to the roof......And yes as most of you are assuming, its a lowband radio, one freq only, 33.7 Boylston Fire Freq. As an experiment i took a pair of jumper cables and place on on the radio antenna whip, the other end to the chassis, truck runs fine, i only hold it for a second, not sure of what possible prob could happen, but desperation is a horrible thing as some of you hve prob run into at some point. Thanks to all, keep with the tips.
Brent

hooknladder · Post by **hooknladder** » Tue Nov 18, 2003 9:37 pm

I have a '94 Dodge Ram with a 45W VHF Maxtrac and 100W UHF Maratrac with no problems. The power for both radios comes from a constant duty solenoid with a 4 guage wire run from the battery to the solenoid. The Maxtrac is grounded to the inner fender near the solenoid. The Maratrac is grounded to one of the seat bolts. The Maxtrac is mounted in a console on the floor near the 4wd shifter, the Maratrac is mounted to the wall behind the seat. Both antennas are Maxrad Mag mounts. If I fire up the Streethawk with 4 rotators, takedowns, alleys and flashers and key up either radio the volt guage dips a little and rebounds back up but that's it. Any ?'s reply back.

jim · Post by **jim** » Wed Nov 19, 2003 6:29 am

If the voltage drops then recovers when a large load is switched on, this is normal as the Mopars have a PWM alternator field circuit controlled by the PCM. There is a buffer in the circuit to add a slight charge delay on a large drop.

As for shutting down, it looks as if RF/EMI is getting in somewhere.
Remove the radio's power wires and wrap them into a nice twisted pair (Twisted Pear can help

). I tie all power feeds in the Ram into the OEM distribution box's main feed and ground to the firewall. Never had a problem on any band or wattage. You could try a ferrite bead over the power/ground wires AT THE RADIO. Also, try beads on different PCM harness bundles.

Use a better quality coax feeder, if it's a cheapie.
If it's a mag-mount...throw it away unless you're on UHF or higher.
If on lowband, you'll have tons of problems with power levels of over several watts. Take it from someone that has 1600 watts on their mobile 10 meter rig. If lowband, put the antenna on the roof where it belongs. "L" brackets even suck on lowband. Drill a hole- it's only a truck. When you sell it, slip a plug in the hole and the dealer will never even see it.

There is no frame-body ground problem on the Rams. In fact, these trucks have very good electrical systems.

Also, stop at your local Dodge dealer and have them print the TSB (technical service bulletin) on the installation of 2way radios in Mopar vehicles. It will give you more info.

Tech225 · Post by **Tech225** » Wed Nov 19, 2003 6:24 pm

I ran into the same problem on a US Forestry truck some years back. Problem was RFI getting into the engine computer. We solved that one by moving the antenna, you say you've already tried that so try shielding the computer and make sure EVERYTHING is well grounded.

RESCUE161 · Post by **RESCUE161** » Thu Nov 20, 2003 9:20 am

I have a '97 RAM with no problems.

I am using an Orion 110 Low band, 400 MHz Spectra (30 watt) and a 15 watt 800 MHz Spectra.

I suggest you check to make sure that the 'ground' that you're using is actually grounded. Also the ground for the antenna is actually grounded. I've seen NUMEROUS times that the antenna is not actually grounded and eventually burned up the radio...

Good luck

Jim202 · Post by **Jim202** » Thu Nov 20, 2003 3:28 pm

By any chance have you checked the ground on the truck computer module. Lowband plays havick with most trucks.

Had a cement company on lowband that would cause the speedometer to read about 85 MPH when you keyed the radio. They had the antenna mounted right on the roof of the pickup truck. Found out that if a couple of flat metal bars were mounted vertcle in the back window, it solved the problem. The rear window was somehow acting as a resonant member of the truck. Made the metal flat stock bars look like a gun rack. Used sheet metal screws to do the mounting with.

Also had to put a couple of bypass caps on the circuit board that fed the speedometer to finish removing any speed indication when the 100 watt radio wat keyed.

Jim

Brentd2183 · Post by **Brentd2183** » Thu Nov 20, 2003 9:05 pm

This truck actually got a new motor placed in it within the last year and a half, along with new computer from the dealer. I also thought that maybe the car alarm had something to do with it, i ruled that out quickly, the antenna is very well grounded, been trying mult. mounts, i will experiment again this weekend, try to keep everyone updated and thanks everyone for you advice, keep it coming, this weekend i think im breaking out the tin foil for the cpu mod.!! Thanks
Brent

jim · Post by **jim** » Fri Nov 21, 2003 12:08 pm

Since it had an engine replacement, chack that all ground straps were installed. I have seen more than one vehiclw with a strap that wasn'r connected after major engine work.

Mike in CT · Post by **Mike in CT** » Fri Nov 21, 2003 5:39 pm

A lot of times the fact that the radio is low band is the culprit.

My son has a 99 Dodge Ram 2500HD for his business. The 43MHz radio would completely stall the thing on key up (Syntor X9K at 50w). Installation was top notch.

solution?

he went to UHF and problems all gone!!

(he was itching to get off low band anyway!)

73,

Mike in CT
KM1R

jim · Post by **jim** » Fri Nov 21, 2003 7:19 pm

...so now you need a repeater to talk anywhere!

commtek · Post by **commtek** » Sat Nov 22, 2003 4:15 am

While low band does have some quirks, a properly installed system works very well. Seems like a lot of shops around here just don't understand that the antenna placement and tuning needs a little more attention to detail than VHF or UHF.

wa2zdy · Post by **wa2zdy** » Sat Nov 22, 2003 5:14 am

I've never had a radio in my personal vehicle for 6m or VHF low band. I have run 100w on 28-29 MHz, but that's it.

But FWIW, here's a thought. Here in Monmouth County NJ, the county road dept is on 37.xx something and the county DPW is on 45.xx something or other. Both depts use quarter wave whips ball mounted on the side of the front fender of their Ford F150 and Dodge pickup trucks. The big dump trucks too.

So it can be done. I think the RFI measures described above are solid. If they don't work, come back and we'll try more. I will be putting low band stuff in my "new" 1990 Ford Ranger. Soon. !

Good luck.

apco25 · Post by **apco25** » Sat Nov 22, 2003 10:14 am

Ball mount on the front fender of an F150? yikes that must be ugly as hell!

jim · Post by **jim** » Sat Nov 22, 2003 4:08 pm

Does anyone remember the factory Dodge truck option in the 70's that gave you an OEM ball mount on the driver's side upper half of the "B" post?

There's no band like low band!

Besides....it's always fun when some smartass grabs your 1/4 wave ballmount or whip and you send 300 watts into them

Dodge Ram stalls with cueing mic..........

Dodge Ram stalls with cueing mic..........

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