| Author |
Message |
daffycanuck (24.64.223.203)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 24, 2002 - 11:35 pm: | |
Our bus shell came with a fairly complete set of gauages, some factory, some added on and all were unreliable.
We decided to ensure we new what our engine, air etc was doing by installing a complete set of 'Stewart Warner' HD Guages. We corresponded with SW via the internet to obtain proper guages and MATCHING sending units.
Three years later and I still cannot get some of the guages to work properly. ANY engine guage that requires a sending unit does not work properly with the exception of the speedo.
Engine oil pressure and water temp and transmission temp are the guages affected.
I have contacted SW via e-mail several times with no reply. I have double checked sending unit part numbers with local suppliers (in some cases purchasing additional units with no improvement). I have tested sending units with hot water and thermometer...guages read low with recommended sending units and high with others. All wiring was new 14 gu, but I rewired and also added and additional and larger engine ground wire.
I am very unhappy with the guages and moreso with Stewart Warner for not standing behind their product.....none the less there must be some way I can get these guages to work.
Has anyone an ideas?? The guages all run 12v from 12 volt battery and charging system.
By the way, fuel guages, volt guages, electric tach and speedo and air system guages work 100%. |
Oaepalmer (Oaepalmer) (208.164.96.223)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 25, 2002 - 12:01 am: | |
14 ga. wire might be the problem!
For the length of the run from the engine to the dash could have a dramatic effect on the guages accuracy...this is FF's dept. and I steer clear of his ricebowl.
Although I am not presently running Stewies, I have RELIED on them for many years in the past and until their product started being manufactured offshore, I didn't have a problem with their products.
As a matter of fact I am in the market for a pair of Cyl.Hd. temp guages with a 25ft leads on them to match the rest of the compliment of SW guages in my Van. |
DaveD (216.18.113.69)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 25, 2002 - 11:39 am: | |
14 Ga wire would strike me as sufficiently heavy for the limited amount of current flowing for gauge sending units. You may wish to check ground connections. This is often a source of higher than acceptable resistance. |
Chuck Harris - PD4104 (66.44.1.10)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 25, 2002 - 7:40 pm: | |
Hi,
What do, or don't the SW gauges do? It's kind of important to know. Hard to diagnose a problem when you haven't a clue what the problem is.
-Chuck
ps is your bus pos, or neg ground? |
Jayjay (207.30.115.124)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 25, 2002 - 8:05 pm: | |
It would take about 850ft. of #14AWG to produce one Ohm of resistance, and that is the threshold of reading fluctuation in an instrument. I too suspect a ground problem, perhaps with some eddy-currents and sub-harmonics due to the other instrument returns. Try adding a (temporary) second wire from the sending unit body to the instrument case. This is overkill, but it will eliminate the question of whether the ground path is defective. Check the applied voltage, and determine if it is too low (bad) or too high (worse than bad). If they are digital, be careful of capacitive loops. In that instance you should only ground one end of the circuit. Keep us posted! Cheers...JJ |
dougthebonifiedbusnut (24.218.115.126)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 25, 2002 - 11:09 pm: | |
hey daffycanuck Oaepalmer hit the nail on the head sw used to be the best until they started making out of country and jay jay is correct the wire size is probobly not the culprit but shielding the wires from outside electrical sources might be something you should try im curious as to where you are getting you signal for your tack and speedo as i am in the process o9f setting up mine right now and i dont what my options are if you get a chance could you tell me how you have it set up many thanks |
Jayjay (207.30.115.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 26, 2002 - 10:26 pm: | |
Hey Dougtbbn, these instruments run on milliamp signals, and should not have to have shielded wire. This is dinosaur analog stuff, and should be near bullet-proof. That's what throws me about his problem. If it were microvolt then I would suspect that problem. but not with a miilliamp signal. Cheers...JJ |
Eric (12.228.168.96)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 27, 2002 - 12:52 am: | |
Check the engine to chassis ground. If the engine is not grounded to the chassis, the guages (which I assume are using a ground near the dash) will not be getting the correct readings. Since these guages run on milliamps of current, the guage of wire to the sensors would not be a likley problem.
To test the ground attach a volt meter (DVOM), to the engine ground with an extension wire and the other meter wire to the dash ground. With all normal accessories on the reading should be less than 0.6 volts. 0.4 or below is good. |
Steven Gibbs (12.148.43.6)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 28, 2002 - 10:13 am: | |
The water temp and trans oil temp both operate under a very simple process. Batt power is applied to the I terminal and one wire is attached between the S terminal and the single terminal on the sender. Current flows through the gauge from the batt to ground (actually from ground to the battery, but that's another story) and the temp of the sender varies resistance to the current resulting in a reading at the gauge.
You said the senders and gauges react during a test with water, but read low. You also state the gauges and battery are 12v. Are you SURE the gauges are 12 and not 24 volt. Half of the the voltage will result in less current flow and low readings.
Also, check to see if a large resistor has been installed between your 12v and the I terminal. This would have been provided to allow a 12v gauge to operate properly from 24v. If so, remove the resistor.
Again, you have the hardest gauges to install, hookup, and configure set up and operatiing so if your problem is not a good ground it likely is a voltage mismatch. |
FAST FRED (209.26.87.50)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 31, 2002 - 5:51 am: | |
I have found that all these gages are very sensative to the voltage of the electric supply.
Most coaches have huge alternators and the voltage ( with out big blowers running) can get very high.
Place a digital V meter ( radio shack $15.00) on the dash and wire it into the gage supply, and see what you have.
The voltage can usually be adjusted at the V regulator , try a very low setting of only 13.2 , and see what you have going on.
Use a dedicated ground from the battery to the gage bank.
FAST FRED |