SPA Boost/FP guage problems

[0966Sy]

Recently purchased a SPA dual Boost/Fuel Pressure guage from Dave at SPA. I have have had some issues with the guage ever sence the install. Dont get me wrong, i am very pleased with the guage, it is very good quality and has lots of functions and detailed instructions. The fuel pressure is dead accurate compared to my mechanical guage (both from the fuel rail) during idle and cruiseing. (PROBLEM 1) It acts weird on me sometimes once i've been driving the truck for almost an hour. The fuel pressure readings start bouncing all over the place, it has given me 130psi and as low as 10psi. I am using the remote fuel line off the rail from RPM. (PROBLEM 2) The boost guage i am very dissapointed with, it only gives me -11/-12LBS of vacume at idle. I have compared it to my mechanical autometer and i still get 19-20lbs of vacume, i get the same on DM. Even the boost is inaccurate on the guage compared to these. At this point i am clueless, mainly on the boost. This guage was $320 dollars and i expected for it to be accurate. I have followed the install instructions and have checked the voltages on the wires and all looks good. The only thing i can think of is i have the 16bar sensor's, i read somewhere that the 4bar is or can be more accurate but how? The sensor's also have to be grounded themselves, i take it the FP sensor is grounded on the rail from the braided line. The boost guage sensor i have grounded and it has not made a differance.
I have the sensors mounted on the driver side fender well, nice and sturdy. And i kept all the wires away from ingnition wires as it asks.

Im sorry for the long post, but i had to vent all this crap out. If anyone has had any experience with these guages on our trucks that could help i would realy appreciate it. My only choice now is to maybee try the 4bar sensor's which Dave wants to sell them to me for $75 a peice. He would not exchange my sensor's. :-? Thanks Dave

O' well im about to give up, anyone have any suggestions on new accurate guages.
Thanks'
Erik

 

[SY2932]

I have two SPA gauges in my truck so, I get 2X's the fun:
http://huryde.station180.com/gallery/view_photo.php?set_albumName=mikecampbellakaSY2932&id=aad
http://huryde.station180.com/gallery/view_photo.php?set_albumName=mikecampbellakaSY2932&id=aae

Problem one: Sounds like you need to get a restrictor for your fuel pressure like everyone else with a SPA FP gauge:
http://syty.net/phpBB2/viewtopic.php?t=24047&highlight=spa+gauge
However, it's odd that yours is stable for an hour or so before it starts to spike...

Problem two: You will not need a 4 bar sensor to get your boost readings accurate. If I remember correctly, all SPA gauges come with 16 bar sensors. The BIG thing is to make sure that your range setting, or "ran" in the menu, is set to 16 bar. If it isn't, your readings will be WAY OFF as I found out when I first installed mine :-? :
http://syty.net/phpBB2/viewtopic.php?t=19740&highlight=

A malfunctioning sensor is another possibility. When I was shopping at Lowes for a brass barbed fitting for my boost gauge, a sales associate who decided to "help" me decided to try and play "catch" with my sensor and dropped it about five feet onto concrete :evil: . Lowes ended up paying for that one as testing it with my Mityvac vacuum pump confirmed that it was toast. If you don't have a Mityvac, you should be able to rent one from an auto store. Mine is a fancy one that will do both vacuum and pressure. HTH's

Mike Campbell

 

[0966Sy]

Mike,

Thanks for the links, i remember seeing the fix for the FP sending unit. I have the newer style guage and there is not an option labled "ran" in the menu. I will check to see if their is a simular option.

 

[0966Sy]

Ok, for the record :x I call Dave at SPA again and tell him i have not solved the inacurate boost reading's yet. He helps me trouble shoot for a few, and come to find out the sensor has less than 1 volt of output. When they are to be operating at 1-5 volts. Ok, so he say's the sensor is bad. He is sending me a new one in exchange of the old one. The FP sensor operates at 1.8volts, last time i took the truck out it gave me the correct FP, untill i got home :roll: Turn the truck off start it back up again and it is giving me 1-3psi of fuel :evil: Not to mention the stupid boost sensor is now giving me -1-0psi :x :evil: At this point i am totaly dissapointed with the $320 "TOP OF THE LINE" digital SPA guage 0X . I am giving dave a call tommarow to see if he will replace the other sensor. All i have to say is that this guage will be up for sale for a decent price, hopefully with two new sensor's for whomever wants to deal with it. I will be ordering some Autometer Ultra Light guages soon.