Isspro R8503 not working right?

[AKimmel]

I am having a problem with my new tach for my truck. I'll start from the beginning. I bought a dakota digital tach interface SGI8 and hooked it up to my factory tach output and the tach didn't work. I was wanting to use an autometer tach off my factory plug. I then tapped into the wire straight from the crank sensor and the tach came to life and worked up to 1500rpm's then dropped off. I sent it back to dakota digital and they tested it and said it was fine, so I got my money back. So I figured the SGI8 must not jive with the factory output, but I know the isspro works. So I ordered the R8503 and hooked it up this afternoon, and it wont read below 1200-1300rpm's. I didn't buy the isspro wiring kit because I read its a waste of money. I called isspro and they couldn't help me. I'm wondering if my computer is bad? I really don't want to but a computer to find out. Is there a way to test the factory output and know if its my computer or do ya'll think it could be the tach. Isspro said I could send it back, but they were willing to bet nothing was wrong with it. Thanks, Alex

 

[MeritBadge]

When I got my R8503 I too thought the Isspro wiring harness was a waste of money, so I hard wired the guage straight to the factory plug, it didnt work. So I got the wiring harness, and in the signal wire there is a filter, hooked it up and tach worked great. Not sure whats getting filtered or how much, don't really know a whole lot about them, but the tach works great and thats all I cared about.



Good Luck

 

[Greenleaf]

I have installed only ISSPRO tachs and can tell you that MB is dead on. You will never get the tach to work correctly with out that filter in the wire harness.



Tach model R8503 is used with the R8912-92 harness.

BTW Im very surprised your writing about the R-8503. I was told the flat faced gauges from ISSPRO are no longer made. This is why I have only been installing the curved face gauge(s) like tach no. s R6503 and R5503

 

[AKimmel]

I just ordered it this past tuesday, and they said that they had 35 in stock and didn't say anything about not making them. I did try this morning tapping into the crank sensor for the tach input and it works correctly up to 1800rpm's then it falls off like the tach did using the Dakota Digital box. I am wondering if my crank sensor air gap is too big. The book says I think . 049 to . 051, and mine is way more than that, but my A/C, alternator, and cruise all work with no problem. So the computer has to be recieving the signal, unless it doesn't need it once the engine is running and thats why the tach is crapping out straight off the sensor. I guess I may buy the harness from isspro, but its hard to spend $50 bucks on some wiring, even with the filter. But, if thats what it will take I guess I'll have to do it. Thanks for the info, Alex

 

[AKimmel]

I got my harness yesterday, installed it and guess what? It didn't work at all, not even above 1200RPM's like it did before. I talked to Don at isspro and I guess I'm one of the lucky ones that got a harness without a filter in it. It has the red shrink tube bulb on one end, but he said he's seen it once before where the filter didn't get installed on the little circuit board under the shrink tubing. I checked continuity from one end of the wire to the other and it doesn't read anything, so I'm pretty sure the filter's missing. I sent the harness and tach back to have him check them out, hopefully it will work when I get it all back.

 

[Mopar_Tim]

does autometer make a tach that works with the first gens? what do you all think about them?





i only ones that i have found go up to like 10,000 rpms and that just doesn't see like it would be worth it.