Hi, Recently had to replace my alternator due to it dying after the P/S hose split. car was fine but then appeared to overcharge, the Engine control fuse blew which I replaced but keeps blowing. so last night I replaced the alternator with a brand new one hoping this would resolve my issues however this is also blowing the same fuse, the previous alternator was charging around 13.99v and the new one I have just fitted is charging at 15.4v I have check around for shorts and ground wires but cant see any issues there. Anyone resolved this issue? I'm going through the service manuals to try and figure out what could cause this. two new alternators down and no luck
If it's the 10a fuse I'm thinking of. Alot of electronics use this fuse Such as boost gauge/lights/vtc gear solenoids Find this listing of all the parts that run off that fuse and follow all the wiring you will eventually find something. I personally kept blowing that fuse because the black with red trace wire on the vtc solenoids were touching ground.
Voltage .....won't blow a fuse it's amperage that causes a fuse to blow. The fuse is supposed to blow once the capacity of the fuse is exceeded, so for all intents & purposes the fuse is doing what it is designed to do. You have to determine what is connected in the circuit protected by the fuse. Your new alternator is over charging at 15.4VDC, not good!
Haven't had a chance to tackle this yet but the weekend is near, After investigating a little further it would seem there is a buzzing noise when accelerating up to 2,000 rpm and stops if revving higher than that, it only starts after the car has been driven a couple of k. Could it be related to the EGR solenoid?
But the voltage is regulated from to 14.1V to 14.7V! Hi JRhys, Its a bit short on information to give anything but fun wild guesses here - and so that's exactly what is happening here in the posts - and so I can do no better. It actually helps if you state the type and model (i.e. JDM 2+2 1992 Auto) and its even better when you can post a video as noises and parts can be hard to describe - (i.e. engine control fuse can relate to a few fuses, so specifically where the fuse is located can help narrow it down as wiring diagrams look like a bowl of spaghetti even at the best of times - this part was the most important part). Accurate and full information leads to an accurate and full diagnosis Firstly - I will have to assume "P/S hose" means Power Supply Wiring Lead and not the Power Steering hose (I.e. P/S hose fluid leaking directly onto the alternator wiring etc.) Some educated guessing: Buzzing at higher revs is often associated with alternator charging output as its the alternating current that your actually hearing, whether it be through a device like a solenoid /chime or even a wire etc. It's normally related directly off the alternator itself (or the back-end of an alternator line) The anomaly: The anomaly of V values here is quite evident: So I must ask how are you testing the alternators for voltage? Its just that voltage regulators are very good at regulating voltage to the values specified! Your alternator is internally regulated to output at the 14.1V to 14.7V so 15.4 is way to high even for any alternator (old or new) and 13.99V is just short of the 14.1V but still outside the values, so I am wondering whether its your multimeter, the test point, testing probes, testing method or alternator that's a problem here. (or one of the problems) Back to the wild guessing part again: It could still involve loose alternator connections/ any one of the many faulty solenoids / some short circuiting (likely you have this as well somewhere) or anything else including a faulty chime (behind the dash you say) or a check light (or anything else that you could find in the car :rofl:), but this is all just guessing based on lack of information supplied and doubt in my mind as to whether the testing has been done properly - but there is definitely something is a miss with the voltage figures you are quoting and this needs to be sorted before you do anything. I am even wondering if the first alternator regulator was fine and was only dropping the .2V (13.9V instead of the 14.1V) due to a short circuit in the system placing a V load drop on the alternator whilst testing (it would explain the blown fuse but does not fully explain the 15.4V on the new one). So a test on the armature/ stator and diodes would have confirmed or discounted this in the first place, as I am now worried you may be chasing your tail here as well as replacing perfectly good alternators. (It's easy to test them and much more accurate to test each lead independently then a voltage mean average head test or test across the alternator leads or even a clamp meter (another mean average test lacking accurate accuracy) - see you tube if you don't know how) The relevant diagram for this problem is around EL- 25 depending on the FSM that's relevant to your model (charging circuit diagram) and the nearby alternator testing section. In summation: Whilst I suspect the alternator is fine and the testing method / or test unit is the problem - The alternator still really needs to be confirmed as serviceable by proper testing before you do anything (even though it may be new) - and the fuse blowing needs to be clearly identified with the exact position and the colours of the wires running from it (or connector ID) - only then can I help you further - as its one thing to go wild guessing and have you chasing your tail, but to stick my head in the FSM to chase my tail in various bowls of spaghetti's for many wild guesses is another story. Wiring issues are a logical and systematic process of doing checks and eliminations - you cannot bypass any testing based on assumptions Hope that helps somehow...... with something.........somewhere.... Cheers JC :zlove:
Getting the regulated regulator above 15.4V I have been reviewing this given its rather a cryptic problem regarding the voltage output of a supposedly new alternator being well over max charge value and so interests me (I like gremlins :rofl I will try to explain by logic / reasoning so you can understand better (I don't know your experience in electricals) The fuse that keeps blowing and the previous alternator V value suggest that you are short circuiting somewhere - that's almost guaranteed. The fuse is related to this issue and can be traced back from there. But its also possible for an alternator regulator to be also fooled by a minute crack in the wiring or loose connection and only this would explain the voltage increase if the alternator and your testing method were o.k. When the electrons have to jump from wire to wire or over dirt or grease in the wire of a regulator /charging circuit line, (talking really fine cracks here that you may not even see) before it can jump, the alternator will sense no or little flow of power getting through so the regulator will increase the voltage as a result (thinks your battery is flat and wants to give more power (Amps X Volts equals Watts)). When the voltage is increased the ability of the electron to flow over the obstacle is increased and some or even most power is then able to flow as a result, however the problem remains (regulator sensing its hard to get total power through without increase voltage) and so the alternator regulator stays in a state of confusion and the voltage remains increased beyond the max value to keep enough power going through (this is when you see regulators let more than max value voltage if they are serviceable). This suggests that you have at least two problems 1. A short circuit The indicator for this is a blown fuse (which you have) and.... 2. A Loose connection/ almost invisible break in the charging system wires (or even possibly a loose fan belt) The indicator for this is an increase in voltage at idle and higher RPM but less total power If it can still flow some power but at a reduced rate with a higher voltage - the alternating frequency can amplify and create a hum of the alternator through the wiring itself (its why we use suppressors) and its quite possible that the charge light (or any devices including the wiring itself) can hum instead of lighting as your hearing an alternating frequency from the alternator itself which normally means, its directly connected somewhere to a charging circuit line! Given you say nothing was wrong prior to the event, its quite possible both problems are related and that the problem is almost certainly in your charge circuit and most likely directly involved in the alternator harness or connections. The alternator light..... does it come on at any time - especially at idle - a no means that the charge circuit/ regulator is definitely being fooled at 15.4V- a yes means it recognises the problem (either one is a sign!) The previous alternator may just be older and hence the V variation (but still good, just not as good as the new one - lol) You say you had problem with the P/S hose split killing the alternator (must have meant oil was dripping on to the alternator itself killing it) - did this affect or melt any of the wiring harness when the alternator short circuited from the oil? Are you positive the alternator leads are the correct way around and tight and free of dirt / grease/ oil etc.? When you replaced the alternator and harness, did you replace the cable back onto the engine mount holder so that its held up high and not pinched between the body and alt when adjusting the belt. (I doubt the problem is that your belt is loose but check since you only need to put a hand on it to tell) The actual hum where the speedo may not be the problem but a side effect of the problem (frequency transmission) just as the alternator / regulator sounds fine - the problem is both the short circuit and the open circuit (one may have caused the other since its only a new problem) In summation of all of the above Your best and fastest solution is to track down the blown fuse wire and follow them to the charge circuit, you will find both problems or at least one problem on the way! You can also resistance test each wire off the alternator to back track as well if your having difficulty locating it If you can specify exactly which engine control fuse is blowing (location/ connector and colours) with model details - I might be able to guide you more. Hope this is more helpful than my last post (needed time to think it through logically as there is nothing logical about a regulator not regulating properly - ) and hope it also explains the anomaly of the alternator regulator voltage being 15.4V. Cheers and good luck JC :zlove: P.S. this quickly turned into a book - :rofl:
2.56 vpc is in range of boost charging However boosting your battery for long period of time will result in water boiling and over spilling from the cells, given that battery is flooded cell - most car batteries are flooded cells...
