1987 Crx Si Honda Civic Blinker Turn Signal Fluctuates With Rpm
#1
Posted 19 October 2020 - 07:49 PM
i connected my volt meter at the battery. checked voltage several different days over different rpms. i figured my regulator was fine. was concerned bc i refurbished one of my oem 1987 densos. Wondered if there was an alt problem.
frequency changed over the next 2 weeks. the it was fast all the time. so one of my blinker bulbs finally finally burnt out. replaced the bulb and it went away
odd was it seemed to blink fast turning right or left. then once bulb finally blew, it blinked fast on left only matching side of blown.
i may still have a grounding issue, but 2 weeks later w new bulb and alls good
fyi. was a weird deal. was about to replace the blinker module
this is the first funky electrical issue ive had so far beyond my fuel pump intermitten due to solder joint on main relay
#2
Posted 21 October 2020 - 08:38 AM
I installed a higher capacity fuel pump, and when the blinker is on the fuel pump noise and revs changes in time to the blinker. My guess is that the voltage supply is affected by the blinker unit. Haven't opened it, but I have had cars were the blinker is a heated wire that goes red hot and changes length and breaks the contact, then starts again. That heating would chew up voltage enough to affect things at the end of long wires. 12 volts drops off pretty quickly with distance.
"I can't believe it - Ive just been passed by a sh!tbox"
#3
Posted 21 October 2020 - 10:02 AM
I'm experiencing a similar issue with my fuel pump. Fluctuates with wipers as well as turn signals and headlights. Checked voltage at the pump and it's dropping below 12v with the headlights on and the blinker on without the car running. Not a ground issue either as I grounded it straight to the battery and am having the same issue. Think I might try freshening up the solder on the main relay next. Not sure where else to look from there.
#4
Posted 21 October 2020 - 10:34 PM
Very odd sounds like ground issues. I have a Waldro 255 fuel pump and no issue like that.
Victor
86 K24 Powered CRX SI (HPDE-4 NASA & TA-AB Time Attack)
85 CRX DX totally original
07 Harley FXST Softail
2021 Tacoma Tow/Daily
#5
Posted 22 October 2020 - 01:50 PM
Very odd sounds like ground issues. I have a Waldro 255 fuel pump and no issue like that.
Very odd indeed. My pump is low on voltage as well. When I provide a ground straight to the battery the voltage does not increase and also does not cure the tone change issue when adding load to the system (voltage drop). I also ran both positive and negative direct from the battery to the pump terminals and this got me the proper voltage but it would still change tone with load. I feel like something is drawing too many amps that is effecting the entire system but its hard to say. The blinkers have the biggest effect by far. Also just like greasemonkey my car runs rough with increased system load but I mainly only notice it at idle.
Edited by Shibby_cbs, 22 October 2020 - 01:53 PM.
#6
Posted 22 October 2020 - 05:29 PM
Check your fuse box for signs of overheating. In the years I have owned mine I had the fuse box replaced once or twice. I remember the last one got to the point that the only way to get the care to start was to wiggle a specific fuse to get it to contact and fire. That only lasted so long before I had to swap it.
Victor
86 K24 Powered CRX SI (HPDE-4 NASA & TA-AB Time Attack)
85 CRX DX totally original
07 Harley FXST Softail
2021 Tacoma Tow/Daily
#7
Posted 23 October 2020 - 05:07 PM
fyi, i recall my oem fuel pump changing humming pitch when idle w blinker. i seem to remember that going on for ever and just assumed it was normal. mines the original 259k pump as installed from factory. original wire harnesses. not molested. only electrical mod is a 40w radio i installed in 1998
i can borrow a thermal camera from my neighbor. he uses it on roofing. that’ll show warm spots in fuses
point of this: check ur blinker bulbs. i never would have imagined it
#8
Posted 23 October 2020 - 06:41 PM
A little background on my car if it helps. Before I got the car it had sat in a gravel lot for about 6-7 years and from what I could tell somewhere else for another 3 or so. It had 77,000 miles on it when I got it about 10 months ago and have put another 1,000 on it. To get the car running was essentially a matter of repairing a couple wires under the hood and taping into the fuel pumps ground just where it comes into the car from around the back of the gas tank. The rear half of the harness that powers all the rear lighting and wiper and also includes the fuel pump ground was chewed to peices from squirrels. I later on rebuilt that harness with soldered and heat shrinked connections with the proper size wire. From everything I can tell the wiring is perfectly adequate in that area of the car so I don't really think the issue is there. That being said I found out recently that between the main relay out to the pump and the pump +/- posts I am losing an entire volt. Keep in mind whether its running with that lost volt or running straight off the battery it still changes tone significantly and drops volts with the signals on and only slightly with things like headlights and reverse lights. The alternator is brand new as well but the battery is used but seems just fine as far as daily use starting of the car goes.
With it having sat so long is it possible that a good portion of the relays have contacts that are maybe glazed over or corroded causing a spike in amp draw? At this point it is the only thing I can think of though I'm no electrical system expert and am sure there are more things to consider. What do you guys think?
#9
Posted 17 November 2020 - 10:30 AM
when the alt is running, the regulator keeps the volts steady around 14-14.5vdc
my blinker always causes my fuel pump to hum in rhythmic iscillation as my blinker goes now that i think of it. must be a response time thing on the regulator built into the alt.
turn ur headlights one at idle, engine slows, then speeds up again as the regulator corrects for amp draw
i replaced my oem alt last year w another lower mileage denso oem 1987 alt. my fuel pump still hums the same when blinkers run at idle. i still have the original 260k fuel pump in the car. if u have an aftermarket, or larger pump, it will draw more amps and i’d assume the humming oscillation would be more noticeable
when working on my other cars, i notice after cleaning the fuel pump filter sock in the pump, not the tank, the humming quiets down
suggest u start another post on the other electrical issue ur having. purpose of this post was to highlight the strange issue noticed as a light bulb was on verge of failing. i recall reading consumer reports years ago. they rated electrical system on these cars to be poor. i’ve not had any unnormal issues w this car since 1993 up until now
keep us posted if u figure it out
#10
Posted 18 November 2020 - 10:53 AM
perfectly normal for battery volts to drop as you load more current w accessories turned on. google v=ir equation in a physics lecture
when the alt is running, the regulator keeps the volts steady around 14-14.5vdc
my blinker always causes my fuel pump to hum in rhythmic iscillation as my blinker goes now that i think of it. must be a response time thing on the regulator built into the alt.
turn ur headlights one at idle, engine slows, then speeds up again as the regulator corrects for amp draw
i replaced my oem alt last year w another lower mileage denso oem 1987 alt. my fuel pump still hums the same when blinkers run at idle. i still have the original 260k fuel pump in the car. if u have an aftermarket, or larger pump, it will draw more amps and i’d assume the humming oscillation would be more noticeable
when working on my other cars, i notice after cleaning the fuel pump filter sock in the pump, not the tank, the humming quiets down
suggest u start another post on the other electrical issue ur having. purpose of this post was to highlight the strange issue noticed as a light bulb was on verge of failing. i recall reading consumer reports years ago. they rated electrical system on these cars to be poor. i’ve not had any unnormal issues w this car since 1993 up until now
keep us posted if u figure it out
Definitely agree with you here. The only thing is that it seems to be much more dramatic on that specific circuit. There are a few interesting things I have discovered since. While I do get voltage drop with any added load it is much more pronounced when using the turn signals and reverse lights specifically. Looking at the fuse panel they share a fuse. The other interesting thing is that when I turn on the hazards they do not cause the significant voltage drop that the turn signals do. Considering they use the same lights and relay thats a significant detail. Just looking at that it seems like the uncommon denominator would me the multifunction switch. The other thing I didnt really consider was that the fuel pump itself might be the thing that is putting the high load on the system and the signals might just be putting it over the edge. I have since changed out my fuel pump for a new Bosch unit and the difference has been mind blowing. I can no longer even hear the pump turn on when I flip the key in the morning. The only reason I know it has turned on is because the new pulsation damer I installed on the pump vibrates with the initial burst of fuel. There also seems to be less of a load on the system but I have yet to actually verify that. I can say that I no longer hear or see any effect on the car when the signals are on though maybe still a slight difference in idle stability which I am still trying to sort out.
#11
Posted 04 December 2020 - 08:45 PM
i bought a 129k car. let it sit for a few years. i fired it up and the pump was really quiet. then it got noisier after a few minutes. I parted the car out at that time. when i removed the fuel pump, that little cone filter was full of rust. my assumption is noise can be caused from pump overworking from clogged filter at the inlet of the pump. i didn’t open fuel tank to check the sock
glad the bosch worked out
keep us posted on anything new u find. age is giving us quirky issues
#12
Posted 11 February 2021 - 11:28 AM
I don’t drive mine on the street that much but I did yesterday and have to say I did notice the noise. Almost sounds like a ground loop in a stereo system. Another observation is my turn signals seem to flash very quickly yet all of the lights are working.
Victor
86 K24 Powered CRX SI (HPDE-4 NASA & TA-AB Time Attack)
85 CRX DX totally original
07 Harley FXST Softail
2021 Tacoma Tow/Daily
#13
Posted 16 November 2023 - 03:37 PM
Did you ever solve this? Suddenly I have this issue now. Pump is very loud while running as is fan and sounds like the entire electrical system is humming. Only thing that changed was my little off track event and the fuse box issue with the brake lights. Going to start checking connections and grounds also got another fuse box may swap that in to see if it fixes it.
Victor
86 K24 Powered CRX SI (HPDE-4 NASA & TA-AB Time Attack)
85 CRX DX totally original
07 Harley FXST Softail
2021 Tacoma Tow/Daily
#14
Posted 24 November 2023 - 03:05 PM
My OE fuel pump noise off the 129k car was caused 100% rust clogging filter. This car sat 3-4 yrs and allowed rust to form from non-use. Once I restarted the car, clogged the filter and made the noise
I installed this 129k pump into the beater after cleaning it out and the filter. Have put maybe 30k since and it’s been nice and quiet.
Another experience w a pump….. the beaters pump was original and was pretty noisy. Scary bad when temps were around 0F. This one had 260k/34yrs of use. Placed my finger over the inlet to test suction and it barely had any. This one was noisy due to wear/age
saw ur other post that ur issue ended up being rust in ur filter as well. Glad u got it resolved