babyfood1217

Heres the deal...

-Christmas eve I got my truck back from the shop, new long block from OERI all mounted up, all old parts transferred back in.
-Weekend after Christmas I tear the dash apart to replace the heater core. Badly clogged and damaged, so I had the shop simply bypass it and run coolant only to the rear core.
-The weekend after New Years, I got the hoses needed to hook the front heater core back up. Did so, amazing heat, and I started noticing the issue described by a few on this board that 4crawler addressed/remedied by installing a two-stage T-stat found here That should be in at the dealer tomorrow morning.
-Yesterday, I finished the 500 mile break-in of my new motor, so I drained the oil, changed the filter and checked over everything I just did. I also installed a new engine temp sensor and a new oil pressure gauge sender. The old sensor were feeding to aftermarket gauges, and I know the aftermarket sending units likely came with the gauges (looked at similar packages at the store.) The sensors I put in were OE sensors (from napa) brand new. I had to wire them into the aftermarket gauges as the factory cluster I have is only have operable (temp/oil pressure don't work, hence the PO's install of aftermarket gauges), but with the OE sensors hooked up to the aftermarket gauges, the gauges spike and stay pinned at the max. I know the engine is running properly, so am I right in assuming the OE sensors simply won't work with the aftermarket gauges? I just bought a new SR5 cluster from a member on this board, so soon I can hook OE up to stock, but should I be considering anything else?

Even though the truck has a fresh new powerplant which was properly broken in, I'm a bit leery about driving blind (without gauges to help me keep track of how things are running.)

-Chris

peow130

i drive blind every day...
i don't have a fuel gauge, oil pressure gauge, accurate speedo, or tachometer.
if it's running fine then you'll know if something goes wrong when it doesnt run well..

thedanned

Im always leery about driving blind, X90000000000 if I had a new motor just past the break in phase.


I would imagine you would run into problems trying to run aftermarket gauges with Toyota senders.

babyfood1217

I guess I'll try putting the old senders back in and see if they read differently. It's either that or wait a week until the new cluster comes in, and that would be a stressful week. I can't find in my FSM manual a way to test the output of sending units/sensors? Could I test them with a multimeter to figure anything out? I'm just not sure how the factory cluster gauges are wired verses the aftermarket gauges. Maybe the spiked/pinned A/M gauges are the result of too much current going to them (grounds where there shouldn't be?) God I hate electrical issues...

Jay351

Are you sure you got the proper senders for your gauges? and you're sure you wired them right?

Sounds like there is something wrong, usually when there is a bad/no connection the gauge likes to go full... at least with factorys ones in my case

babyfood1217

yeah, I guess my original post is way too wordy... I'll try this again.

Factory cluster is only receiving signals from tach, fuel, charging, and speedo. The oil and temp gauges do not work, so the PO installed aftermarket gauges to monitor temp and oil.

Following an engine replacement, I had to do a 500 mile break-in, followed by an oil/filter change. I also replaced the temp sensor and oil pressure sensor, but I replaced them with OE equipment, not the aftermarket sensors that come with the aftermarkets gauges (Sunpro brand, available at walmart, farm & fleet, maybe autoparts stores.)

So now with OE sensors and aftermarket gauges, I'm getting super high gauge readings (actually, oil pressure immediately pins to the max, and engine temp rises twice as fast as it normally did, pins at max, and stays there.)

Before the new sensors were put in, the old sensors (aftermarket) were registering on the old gauges just fine (actually, the oil pressure stopped working months ago, so i'm not sure if it's a gauge issue, a sensor issue, or both.) The 500 mile break-in yielded proper engine temps, and despite not having a functioning oil pressure gauge, I can assume a brand new engine would be proving decent oil pressure.

I have a new factory gauge cluster on its' way to me as we speak, so once that gets here and I can figure out some wiring issues, I should have all OE senders feeding a factory cluster, no aftermarket stuff.

So i'm wondering if my pinned gauges are the result of OE senders feeding aftermarket gauges, or could one suspect that in the exchange of sensors and oil and a filter, my engine is all of a sudden f***ed. Doesn't rightly seem possible, but I'm just uneasy about driving around a recent money pit without knowing at least a little how it's performing

Am I just freaking out here?

-Chris

4Crawler

iTrader: (3)

Guages and senders are typically a matched set. That is the guage is is designed to work with the resistance range of it's sender. Aftermarket gauges are often designed for a different resistance range. Also on oil pressure, there are two types of senders, one is variable resistance for an analog gauge and the other is a simple on/off switch contact for an idiot light. Running a switch-type sender and an analog gauge is bad news, as the gauge works by sending a known voltage to the sender and measures the resulting current. Problem with a switch sender is it is either infinite or zero resistance (open or short circuit) and that can play havok with the gauge electronics.

babyfood1217

god that makes me feel a little better. When I get my new cluster in, I'll for sure put the OE senders in, but I think for the time being, I'm going to pull the OE senders and put the aftermarket ones (gauge matched) back in. They gave me proper readings, and I think it'll ease my nerves what with the new motor and all. The guy at toyota said the same thing when I gave him the run down (likely the variances between sender signal and gauge) but reading it seems more easing.

BTW, just picked up a two stage T-stat. Throwing that in too. Pricey little devils

I'll keep you posted with the results. I'm praying that when the new cluster comes in and works properly so the OE senders can go back in and I can be happy. Until then, I've got to try to decipher a beat up old FSM and find the wire colors for the oil pressure sender and temp sender leads. PO cut them when he installed the aftermarket stuff, and I don't know what is what. Anyone happen by chance to be looking at their engine bay anytime soon? If so...

Wire color/connector type going to the oil pressure sender and engine temp sensor please. Pics work too

Thanks!

-Chris

babyfood1217

A/M sender put back in, works just fine. 2 stage T-stat put in, temp issue disappeared and truck temp read perfect!

C'mon new cluster, get here asap!

-C

Kiroshu

After market and OEM don't mix. Once you take away that OEM part it will never be the same.