Possible for resistors to go bad or fry?
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From: S.Cali, OC!
Possible for resistors to go bad or fry?
Alright guys, got a question.
I have:
single turbo setup
kgparts bosch 1680cc injectors and rail.
10watt 10ohm resistors from radioshack.
Ive been running this fuel setup for about 7,000 miles now and between 2 turbo setups. Is it possible that a resistor can go bad. What are some things the car might do if one did.
My reason for asking is, ive been able to boost fine and one day on one of my drives, it just started to seem like it would flood out when i would start to come onto boost. And after i pulled over the car and checked all my connections, a tiny bit of smoke came from under the UIM. The car runs fine up until the point i start to boost then it feels like its flooding out. Would a bad resistor do this?
Fuel pressure is fine, i changed spark plugs and oil. everything else seems to be in order.
I bought some 25 watt 3 ohm resistors from rx7.com
Just wanted some input before I drop them in and change the tuning around a bit
I have:
single turbo setup
kgparts bosch 1680cc injectors and rail.
10watt 10ohm resistors from radioshack.
Ive been running this fuel setup for about 7,000 miles now and between 2 turbo setups. Is it possible that a resistor can go bad. What are some things the car might do if one did.
My reason for asking is, ive been able to boost fine and one day on one of my drives, it just started to seem like it would flood out when i would start to come onto boost. And after i pulled over the car and checked all my connections, a tiny bit of smoke came from under the UIM. The car runs fine up until the point i start to boost then it feels like its flooding out. Would a bad resistor do this?
Fuel pressure is fine, i changed spark plugs and oil. everything else seems to be in order.
I bought some 25 watt 3 ohm resistors from rx7.com
Just wanted some input before I drop them in and change the tuning around a bit
E = IR, Voltage = Current times Resistance
W = EI, Watts = Voltage times Current
With the alternator putting at 14.1 volts
10 ohm resistor
5 ohm injector
14.1 = (I) * (10 + 5); 14.1 = 15I, I = .94 amps
Watts = 14.1 * .94 = 13.254 watts
Now the resistors are 2/3 of the load, so they consume 2/3 of 13.254 watts.
13.254 * 2/3 = 8.836 watts.
They should be safe.
Normally resistors do not increase in resistance when they go bad, they normally descrease. The extra current flow then burns them up or other stuff in the circuit untill so there is no current flow.
W = EI, Watts = Voltage times Current
With the alternator putting at 14.1 volts
10 ohm resistor
5 ohm injector
14.1 = (I) * (10 + 5); 14.1 = 15I, I = .94 amps
Watts = 14.1 * .94 = 13.254 watts
Now the resistors are 2/3 of the load, so they consume 2/3 of 13.254 watts.
13.254 * 2/3 = 8.836 watts.
They should be safe.
Normally resistors do not increase in resistance when they go bad, they normally descrease. The extra current flow then burns them up or other stuff in the circuit untill so there is no current flow.
Joined: Oct 2001
Posts: 6,279
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From: Florence, Alabama
maybe something is shorting... since you mentioned smoke.
i recently bought an FJO Peak and Hold convertor to drive my secondary injectors. in the process of removing the resistors from the secondary circuit i found that the injector wire had broken at the solder and had been only held together by the heatshrink wrap which had finally fractured. it appeared that only 2 of the 12 strands had recently broken and the rest had been fractured for some time.
do carefully check your wiring at the resistors.
howard coleman
i recently bought an FJO Peak and Hold convertor to drive my secondary injectors. in the process of removing the resistors from the secondary circuit i found that the injector wire had broken at the solder and had been only held together by the heatshrink wrap which had finally fractured. it appeared that only 2 of the 12 strands had recently broken and the rest had been fractured for some time.
do carefully check your wiring at the resistors.
howard coleman
Thread Starter
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From: S.Cali, OC!
E = IR, Voltage = Current times Resistance
W = EI, Watts = Voltage times Current
With the alternator putting at 14.1 volts
10 ohm resistor
5 ohm injector
14.1 = (I) * (10 + 5); 14.1 = 15I, I = .94 amps
Watts = 14.1 * .94 = 13.254 watts
Now the resistors are 2/3 of the load, so they consume 2/3 of 13.254 watts.
13.254 * 2/3 = 8.836 watts.
They should be safe.
Normally resistors do not increase in resistance when they go bad, they normally descrease. The extra current flow then burns them up or other stuff in the circuit untill so there is no current flow.
W = EI, Watts = Voltage times Current
With the alternator putting at 14.1 volts
10 ohm resistor
5 ohm injector
14.1 = (I) * (10 + 5); 14.1 = 15I, I = .94 amps
Watts = 14.1 * .94 = 13.254 watts
Now the resistors are 2/3 of the load, so they consume 2/3 of 13.254 watts.
13.254 * 2/3 = 8.836 watts.
They should be safe.
Normally resistors do not increase in resistance when they go bad, they normally descrease. The extra current flow then burns them up or other stuff in the circuit untill so there is no current flow.
Thats funny, i was about to send you a PM to ask you directly about my issue.
Anyways, just wondering...I think i read on a post by damian that the ohm of the injectors are 2.8.
so...
14.1 = (I) * (10 + 2.8); 14.1 = 12.8I, I = 1.10 amps
Watts = 14.1 * 1.10 = 15.5 watts
15.5 * 2/3 = 10.25 watts.
Right? or no, I dont know you are the powerfc master.
If i were to go under there and check for any broken wires or shorts, i might as well change the resistor to the 3ohm rx7.com ones. How would i adjust for that timing on the powerfc?
Joined: Mar 2001
Posts: 31,837
Likes: 3,234
From: https://www2.mazda.com/en/100th/
maybe something is shorting... since you mentioned smoke.
i recently bought an FJO Peak and Hold convertor to drive my secondary injectors. in the process of removing the resistors from the secondary circuit i found that the injector wire had broken at the solder and had been only held together by the heatshrink wrap which had finally fractured. it appeared that only 2 of the 12 strands had recently broken and the rest had been fractured for some time.
do carefully check your wiring at the resistors.
howard coleman
i recently bought an FJO Peak and Hold convertor to drive my secondary injectors. in the process of removing the resistors from the secondary circuit i found that the injector wire had broken at the solder and had been only held together by the heatshrink wrap which had finally fractured. it appeared that only 2 of the 12 strands had recently broken and the rest had been fractured for some time.
do carefully check your wiring at the resistors.
howard coleman
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From: S.Cali, OC!
Alright, i swaped in the rx7.com resistors, havent looked at the maps yet.
But i came accross something else.
one of the things i notice about the car, is i hear alot of noise coming from the engine, on and off. Usually when its warmed up. Also my vacuum is at 10 at 800 rpm. Think i got a leak somewhere.
Does it sound like a vacuum line, or is it possible i blew my intake manifold gasket. Its a metal one, so i dont see how it could blow considering i havent been boosting it. If it sounds like its just a vacuum line, im betting its the one on the lim, the only one thats hard to get to.
When I pinch the map sensor vacuum line and nothing happens, does it sound like my car is also stuck in limp mode, thats why its kicking back and spits out a ton of fuel if i try to boost. Is there even a limp mode on the powerfc?
The car drives and idles fine tho.
But i came accross something else.
one of the things i notice about the car, is i hear alot of noise coming from the engine, on and off. Usually when its warmed up. Also my vacuum is at 10 at 800 rpm. Think i got a leak somewhere.
Does it sound like a vacuum line, or is it possible i blew my intake manifold gasket. Its a metal one, so i dont see how it could blow considering i havent been boosting it. If it sounds like its just a vacuum line, im betting its the one on the lim, the only one thats hard to get to.
When I pinch the map sensor vacuum line and nothing happens, does it sound like my car is also stuck in limp mode, thats why its kicking back and spits out a ton of fuel if i try to boost. Is there even a limp mode on the powerfc?
The car drives and idles fine tho.
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