PEGGED fuel gauge

[novamodeler3]

I know, another fuel gauge thread, but I need more clarification on how I can fix a pegged gauge issue.

From what I understand, the harness from the sending unit runs through the ECU?

Given the link >>>http://www.tahoeyukonforum.com/forum/showthread.php?t=73661

I recently performed an engine swap and my ECU is all but redundant. Is there any way I can re route the harness from the sending unit and to the gauge direct. (Jumping/splicing wires, etc?)

Diagrams, theory of operation, etc helps.

For the record, before the swap, the gauge read fine and only experienced the 'hummingbird' symptom while the cruise control was activated. All other gauges read correct (except the speedometer due to removal of 4L60E) and the pump functions well also.

Thanks in advance!

 

[SunlitComet]

Damn, another thread......













if you are pegged full then you have an open line somewhere. Unfortunately the pump on the 98+ go from 40-250 ohm while the gauge that fits all years still expects 0-90 like the first vortechs did.

 

[novamodeler3]

So, that explains the harness running through the PCM? I imagine it drops the resistance as it passes through it on its way to the gauge?

 

[SunlitComet]

sort of. the 96-97 vortec senders matched the fuel gauge. starting in 98 for better accuracy and primarily evap testing purposes the sender output was changed. because the pcm got involved with the evap testing upgrades for obvious reasons it was made to recognize the input and output the original dash gauge equivalent resistance needed to make it work correctly..

 

[novamodeler3]

So my options are...
New gauges altogether, Or new fuel sending unit from 96-97?

Then bypass the PCM direct to the gauge?

I've also lost my speedometer and odometer switching from 4l60e to 700r4. Potential for new (96-97) cluster and utilize a mechanical speedo to the new trans?

 

[SunlitComet]

the fuel pump modules were different as well as the tanks between old evap and new evap systems. not sure if you can put in an older model pump in the newer tank. However I think chances are good that you may be able to just swap senders. you will have to head to a parts shop to see what options you have.

---------- Post added at 08:57 PM ---------- Previous post was at 08:53 PM ----------

can you get a electronic speedo adapter for the 700r4? the tach can be reactivated but will have to be on the ignition coil to get the rpm synced correctly.

 

[novamodeler3]

At this point, I've found a fuel cell on Summit with a 0-90 ohm sender installed, as well as an external pump.

After I filled the tank yesterday for the first time in months, it leaks.. so for 280 bucks I get new tank, new pump, and compatible sending unit with factory gauge.. just need to fab up a good airtight access panel OR fab a flange thatll adapt to the factory filler neck.

As for the tach, it works fine with the new HEI distributor.

Gotta figure a way to get my speedo and odometer back though...