Author Topic: Question on aftermarket gauges and EFI  (Read 4368 times)

Offline Da67goatman

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Question on aftermarket gauges and EFI
« on: September 13, 2011, 02:44:32 pm »
My printed circuit board for behind the gauges recently kicked the bucket, have intermittent lights ad gauge readings.  I have always wanted to add a trans temp gauge and a vacuum gauge in my truck, so I have been thinking about scrapping all the factory gauges and doing a custom layout with all 8 aftermarket gauges.  I have not yet bought the gauges because I don't know I can get them to work.  My questions all relate to the installation wiring so that everything receives proper signals.  All gauges are electric, except Vacuum and come with their own senders.  Vehicle in question is 1989 Suburban 350 TBI 700r4 factory electric speedo.  On the EFI the ECM needs reading from all kinds of sensors to make adjustments, temp, rpm, speedo etc.  How can I do this and get everything to work?  I know my luck isn't good enough to have factory senders the same as the aftermarket,  so I was under the impression that I had to run both senders for each thing and route the gauge part separate from the factory ECM senders.  That seems like a lot of waste to have 2 circuits for each.  Normally I wouldn't have any problem installing gauges, except its EFI.  Thanks in advance.

P.S. Here's a gauge for reference

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=250688179175&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
<Pitcrew>
1989 R2500 Suburban mild 350 TBI 700r4 10.5" 14bolt 4.10 w/ 33s
1992 fullsize Blazer 4x4  35s no lift, 4.10s, Hella driving lights, TJ Flares, Huge bumpers, Snorkel, custom interior

Offline topp

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Re: Question on aftermarket gauges and EFI
« Reply #1 on: September 14, 2011, 12:43:29 am »
AFAIK, all your gauges (oil, temp, volt) are not routed thru the ECM.
The speedo is electronic (a sender on the T-case(4x4)/Tranny(2x2)) and sends a VSS signal to the ECM.
'90 Suburban TBI 350

Offline Da67goatman

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Re: Question on aftermarket gauges and EFI
« Reply #2 on: September 17, 2011, 07:09:21 pm »
So I use the factory senders for the ECM and the aftermarket ones for the gauges?  I know the ECM needs temp readings and speed so I can't just use the aftermarket ones. Can I use the factory senders with the aftermarket gauges and just tap into the harness that plugs into the printed circuit?  I don't know anyone that puts in gauges in an EFI vehicle or I would ask them.  Maybe this is a topic for a tuner forum, they are more up to date in their drivetrain and instrument clusters.
<Pitcrew>
1989 R2500 Suburban mild 350 TBI 700r4 10.5" 14bolt 4.10 w/ 33s
1992 fullsize Blazer 4x4  35s no lift, 4.10s, Hella driving lights, TJ Flares, Huge bumpers, Snorkel, custom interior

Offline Captkaos

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Re: Question on aftermarket gauges and EFI
« Reply #3 on: September 22, 2011, 11:00:34 am »
all the factory stuff has 1 set for the gauges and one set for the ECM.

Offline slammed79

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Re: Question on aftermarket gauges and EFI
« Reply #4 on: September 23, 2011, 12:55:58 am »
I believe that Painless Performance makes a gauge harness that you can use to do away with the pcb alltogether. That'd also be handy if you decide to go with aftermarket gauges.
74 C10 Long bed 350/SM465 Lowered on 20's

Praise the lowered