Hey Everyone.

Installed a Yaesu 8800 ham radio into my 99 Jeep Cherokee.

I was playing around with it today, talking to some friends, and noticed my oil pressure drops to zero, and my check Gauges light comes on. Its only when Im on simplex channels, but when I get into the 444mhz or 446mhz, my oil pressure doesnt change and it stays the same.

Im assuming its just the RF interfering with the sensor, but if anybody else knows why, fill me in. Im curious to find out why the gauge drops to zero.

Thanks
DKCherokee

 

radio is interfering with the electronics, if it is ONLY happening a certain freqs and NO other time.

 

this has nothing to do with your problem cause i have no idea about that but, what kind of range do you get with your radio? i just started thinking about a ham vs a cb so any info you have would be appreciated!

 

I can talk to another HAM radio operator in simplex anywhere from 15 to 30km's away, via the ground waves. If I get into the UHF frequencies, it is longer range, and then using a repeater I can get way farther.

I was listening to a guy today that lived in Oregeon, and he was coming in nice and clear. I live in Victoria, BC, Canada, and thats a long distance away.

And yes, the dashboard is just a big circuit, so I may have to re-route my antenna wire to the other side of my Jeep.

 

In my line of work ive seen RF interfere with instruments before but not with pressure gauges usally turbine flow meters, but anything is possible I would try moving the antenna first, if that doesnt work I would try rf suppressors next. The ones I use are doughnut looking things to go around the wires to the sending unit. Hope this helps.

 

Just re-ran my antenna coaxial cable, hoping it would solve the problem.. but nope, still my oil pressure drops whenever I talk on the radio.

Im clueless.. may just buy some RF suppressors and install them.

 

Do the other gauges act funny??

Which power output settings are you running???

How do you have the power for the radio ran??

I'm wondering if the power draw for the radio isn't causing an issue...

 

unhook the supply to your radion and connect it to a independent supply ie spare batterry if its the same then you know its rf interference

 

Ran into this with my Buick after I installed my 8800. I ended up running the hot to the battery the long way, all the way under the seat to the passenger side and through a new hole in the firewall. I also added two ferrite cores. I cannot tell you which solved the problem, but the problem was solved.

I love my 8800, but I think I will be putting my Alinco in my Jeep.

73's, N8WLU

 

Just my oil pressure gauge acts funny. Temp gauge, fuel guage and battery gauge all act normal. I have my Radio on High power, but turned it down a bit, and it still happened. I have my power for my radio ran on the passenger side of the Jeep, from the headliner down the A pillar and into the engine bay straight to the battery.

 

I need to go and get some Ferrite cores I do believe, after checking everything, RF interference seems to be the problem.

Thanks for your help.

 

Reminds me of my friends 98 Grand Cherokee when he took the invisible fence collar off his dog and put it on the Front pass floor the trans would act all funny.

 

You are right on the money with rf interference, the cluster (some functions) operate on bus messages from the pcm, your oil pressure guage is not hard wired... the bus voltages run @ approx 2.48 v ...woudn't take much to mess that up!

 

Thanks captainwoot.

And its only the oil pressure gauge that gets messed up everytime I transmit. I will look into buying some RF beads or suppressors. Any clue where to put them once I get them? (Ie: Around the wires coming from the sensor? Around the back of the dashboard wires? etc etc)

 

Do a double loop through the cores with your coax first, about 6" from the radio. With the loop you may need to do some minor tuning, but should be minimal.