I noticed this weekend that my 2yo ISSPro boost gauge is acting up. It shows about 5psi all the time, even with the engine off, and sometimes more at idle. I think it's a little more accurate at highish boost levels - 20-24psi - but may be reading a little higher than MAP there, too. I suspect the issue is with the sensor or harness, as the gauge needle goes all the way to the 0psi stop when the sensor is unplugged. Are there known resistance levels for the sensor that I can check before replacing it?

Mark

 

have you tried unplugging it yet? Mine was at 20 constantly. I just unplugged it and started the truck.....then shut it off and plugged it back in. Good to go

 

Are you direct read or are you running the transmitter to an electric gauge?
my electric gauge has done that since new, normally 2 to 10 pounds after the sweep before starting the truck.
one time I whacked the transmitter with a wrench and it worked right for a while.

 

Running the 0-40psi ISSPRO EV2 from the old AIH hole direct to the gauge.

 

Well I'll be. I had unplugged it and plugged it back in, but that didn't change anything. Unplugging it and starting the truck did, though, at least for one start. I'll drive it over the next few days and see if it stays fixed. Thank man!!!

For anyone else who's looking - and that might be me if this doesn't stay fixed - I did find the ISSPro troubleshooting guide. It has you measure voltage rather than resistance, but should be enough to help if I need it

I don't think they are supposed to behave that way, but I could be wrong. Does your boost gauge go to zero when the truck is running and MGP is at zero? That's the important part, I suppose, and mine had stopped doing that.

Mark

 

Its been about 3 months now...still working as it should.

 

no when it starts above 0 it only goes down to where it was when it did the sweep, sometimes it will correct it self while driving.
but honestly with all the vehicles I have this one only gets driven maybe 100 miles a month if it isn't hunting season.

 

I went for a test drive the other night and the gauge worked properly for a few minutes, but then began reading high again. When I turned the key to on just now, sure enough it read a pound or two of boost on a cold motor, when Forscan was showing -0.1psi. As soon as I moved the gauge to remove it, though, it moved to 0psi. Moved it back and it read high again. That leads me to believe the issue is a poor contact, either at one of the wires into the orange connector on the back of the gauge, or the connector itself to the gauge. I reseated the connector and cap that holds the wires in place and it appears to be working, but I'll need to drive it some to know if further diagnosis and correction is necessary.

Mark

 

Mark, I have had three issues with my ISSPRO EV2 gauges since they were installed in November of 2015.

1. Failed fuel pressure sensor. A free sensor and snubber was sent by ISSPRO fixed that.
2. Loose connection/wire on the back of the EGT gauge. I reseated the wire and made sure the plastic clamp was secure. Fixed that...
3. Failed microprocessor in the EGT gauge. I performed some troubleshooting of my own before calling ISSPRO and they confirmed my results from the tests. They sent a new EGT gauge free of charge and that fixed that.

All of these issues were 5+ years ago based on my memory, but I do a brain dump each night when I sleep.

 

Good diagnostic observation.

Hopefully, your re-seating the connection will hold.

I've always thought I wanted ISSPRO gauges... even before the EV series was created. Later on, I was particularly interested in the ISSPRO Performax series... with up to 17 gauges on its own data bus.

Over the years, many a forum user has reported having issues with ISSPRO gauges, and likewise reported that ISSPRO resolved the issues by graciously sending new parts.

So why haven't I bought ISSPRO then?

Because the Banks analog gauges that I installed 23 years ago have not had any issues. I have patiently waited for them to present a hiccup after more than two decades of baking on the A pillar in a truck that has never been inside of garage or under a cover or in a building since it was built, but the Banks gauges remain as reliable as rain and refuse to quit.

So perhaps I'll never get the chance to adopt the appearance of thru-color backlit factory match needles and numbers. But I do appreciate not having to diagnose, service, and/or periodically replace instrumentation. Even if the replacement parts are free, the inconvenience isn't.

If the connection on your ISSPRO wiggled loose before, it may wiggle loose again. Would a section of heat shrink over the connection help keep the connection together?

 

Thanks for that info!! It's good to know ISSPro took care of you.

It's funny you say that, as my ancient Western Diesel gauges were working fine when I removed them a couple of years ago, after 18 years of service. I wanted a matching fuel pressure guage, which is the only reason I swapped them all out. Well, that and it just seemed wrong to have to check the A-pillar for boost leaks... FWIW, I matched the factory lighting with a green Sharpie on the bulbs when I installed them, and they still matched perfectly after all those years.

The connections on the ISSPro guages are punch downs, not unlike a keystone connector for an RJ45 jack, if you're familiar with those. If it works loose again, which seems likely, I punch them down on fresh wire and tape the cover down with some tension.

Mark