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Belt tensioner ??????

robzombie4551

robzombie4551

robzombie4551
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land of the lost. TAKE YOUR COUNTRY BACK
I put a new remy alt. from A/A on 2 weeks ago along with new belt,and new W/P.from R/A.

Well less than 2000 miles later the rear bearing is shot and it stopped charging.

The tensioner seems fine, no binding/dirt or rust and has a pulley I bought 8 months ago on it.

It goes through the full range with a ton of resistance/ is this normal for this tensioner?

Bad alt.?or maybe time to change the tensioner? It is the original.

How do I know if it is bad. Usually they bind or break the spring, or they get wobbly. This one has none of that.Can I check it with a torque wrench and see if it has to much tension, and taking out the bearings. I know if it happens again in the next few weeks A/A will not honor the lifetime warranty,as it is limited, IE to what they feel is in their best interest not mine. BTW the old alt. was changed due to the diodes not the bearings and it was on there for atleast three years.

TIA.:mad2::mad2:
 
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For the $30 something I wouldn't risk another alternater and the rest of the belt driven accessories. There is one worn spot inside the tensioner that may only slightly bind it in a too tight position or something else is pulling to hard causing the alt. to take the extra load because it is first to the tensioner. Check the A/C clutch idler bearing and the other driven accessories.
 
Also check the main pulley for torsional stability and have a very high quality belt. Of course check the grounds and alternator housing to engine grounding and charge wire connections. Note poor alternator ground will cause poor charging/and diode burn out. A loose positive post on passenger side took out my last alternator. You don't want the charging to jump in and out.

The tensioner pulley is respectably strong I use a cheater for ease so I can take my time threading the belt appropriately. I suspect it was a dud alternator. I have had the tensioner at full stroke and belt stretched out for many miles on my last belt and it did not take out any accessory???.

There are a couple replacement tensionsers shop around and make sure you get the one with the square hole for ratchet gripping to take off tension. iirc it was gates I bought a while back with the hole.
 
Older style accessory brackets[93-96?] don't have a tensioner with the square hole.
 
I have replaced every accessory since I have bought the truck, AC comp./PS pump/WP/Alt./ idler pulley/ and the crank isolator pulley that bolts onto the crank.

I do however believe that I have a ground issue, and when they tested the alt. today when I brought it in they said it was still working and that it just wasn't putting out full voltage. I didn't tell them that the grease flying out of the rear bearing might have something to do with it. Anyway, when I put it on 2 weeks ago the gauge in my truck would flucuate, but as time went on like about a week later it would reach the 14V and stay there. Sometimes it will just drop down to 12V and a minute later bump back up to 14V. So I do believe I just got a bum alt. but now burnt diodes again within a two week period?

My ? now is what grounds do I check. My batts. are new and all connections there are good. I have checked the ground straps near the D/P and they are in need of replacement. The ground on the intake pass. side was just cleaned over the summer. What else?????
 
Are your voltage readings at the battery? The gauge in the dash really isn't accurate. Have you eliminated the connector behind the glove box with only black and red wires? It supplies the ground for the whole dash. The connector is undersized and will melt inside. A bad blower motor can cause enough draw to melt that connector.
A binding tensioner will take out the front bearing on the alt first usually. rears seldom go out.
 
Make sure the passenger side positive post is clean and the spacer too. Make sure it is tight and the lead spacer hasn't gotten corroded under rubber cover or eaten up by the "barbs" on the battery cables.

Someone correct me if I am wrong but the case of the alternator should be equal to negative post potential. and or same + to alt case as + to - on either battery. See if the bracketry is corroded or not getting good ground to both batteries???

Also check the main wires at the back of the fuse block under the hood near the brake resivor on the fender. The voltmeter is not all that accurate but a good relative guage. If it bounces or moves much without a big load ie after glow then something is wrong. The blinkers will slightly twitch it if you really watch it but really it should recover to ~ 13.8 - 14.2 +/- Volts and stay steady and only move when a large load cuts in/out. Anything else indicates an issue I believe.
 
Excessive current burns out these alternators. They do not self regulate their maximum output to a safe level the diodes can take with the 'limited' cooling this unit has.

The grease coming out of the rear bearing indicates high heat in the rear section of the alternator. Past and repeated diode failure indicate a cause. Bearing failure was a secondary failure after the grease seal melted from high diode heat and the grease was boiled/flung out of the bearing. (I suggest you did not get a bad bearing.)

Here are some ways to burn up diodes:
Sparking, but not continuous, shorts in large wiring. Specifically the alternator charge wire as the fusiable link is not near the alternator but on the other end of the wire. Starters hanging in could also be a unfused wire issue. Cuts or problems with the main battery cables; 1993's hit the battery pan and wear through. Fusiable links may not burn through for intermittent shorts that can shock fail a diode. (Shock is a sudden high current and temperature that can crack (open) or melt (short) a diode's glass like silicone innards.)
Sudden high current from a short causes one diode to fail by shorting out. The shorted diode will generate extreme heat until it burns open or another diode(s) burn out or another component fails. This high temperature can melt down other parts or cause a fire.

What is the battery voltage before you start in the morning measured by a digital volt meter? 12.5v or more? A slow drain could run your batteries down. Same with a battery that has a shorted cell. Charging low batteries esp AGM Optima type units are known to fry the output diodes on alternators esp. these weak undercooled units.

When your volt gauge drops off with the engine running... This is a load so big that the batteries are being discharged as you have gone over the alternator's rating at that RPM. Like when the Anti-lock motor starts up. Or is could be the short acting up. Last, would be the alternator failing due to damage or defect.
 
I tested the batt. voltage with my DVOM and it's at 12.41 before I started ,also have the gmtd. plugged in and it's at 12.41 so I know it's accurate. Also after starting it is at 13.4/5. on gmtd and dash reads 14. It did turn over a little slow and I had to cycle the glows twice before it would start. It is a little cold here 50* not that it should have had to cycle twice and the volts never went below 11. during glow cycle. I do have new G/Ps. I think the controller is on it's way out. IAT was at 39.5 so I don't know why the glows are what I would call short cycling. I do have the glow times extended on one of my tunes and that eliminates that prob,I only bring this up because I shouldn't need to override the stock program to to start it. The voltage stays steady and doesn't fluctuate like before so I may be all set. Only time will tell. If there is something I'm missing feel free to chime in.
 
Have the battery load tested? Volt test is not sufficient, it won't show any shortage.

How is the cable condition? I know you said connections are good but how is the cable itself.
Put the DVOM, test the resistance or voltage loss accros each cables. Also measure resistance on each ground.
What size of cable is used?
If I were you, I will peel off that nice red/black rubber cover on the connectors if you have not done so.
Brush the inside real good with wire brush.
 
Yes, I had them tested. I may have a current drain somewhere because if I charge them overnight, I have an 8 station charger, It will spin over like no tomorrow and fire right up. It's only the first start of the morning that gives me trouble and if I let it sit for three or more days it really turns slow.
 
The bearing could have just been lowgrade junk. Most stuff these days are. I generally go to a local builder for Alts and Starters but even the parts they are using now are junk. It's near impossible to get anything of reasonable quality anymore. Chinese made junk, all of it. I went through 3 starters in my 8.3l Cummins before i got one that worked for more than 3 months. Stuff is just horrible. Still should not be going dead but if they tested the alt and it's not putting out...try another one.
 
Dome light going on in cold weather due to a bad pin switch?

Charge your battery, let it sit for 3 hours disconnected and then measure voltage. Leave disconnected overnight and remeasure voltage. Should be within 5-10 degrees outside temperature of 12.41v measurement. This will give you the full charge voltage of the battery for a specific temperature. This way you can tell if a current drain is taking the batteries down or you get a reading 0.3v lower for the same temperature after full charge indicating the battery is close to failing. Some charts would say you were at 75% of charge, but, temperature makes a big difference in voltage.

Load tests and the expensive tester at parts stores can give you better info on your battery's health and SOC.
 
Went out this morn. and checked the volt. and it was the same as yesterday,12.41. Then started it and it fired right up although it was 70* this morn. and gmtd. said 14.5 and also the M/Meter the same. Came down to 13.5 after about 5 min. of idling.

Checked G/B and door switches and they are fine, the front ones don't work anyways unless you wiggle them with the door open and then they come on. Under hood light I always leave disconnected so as not to drain the batt. when working on it, which is every week crankme69. BLOOD EVERYWHERE, and lovin it.

Could the batts. not be getting the glows hot enough or not staying on long enough, if I over ride or double cycle them it starts right up. If not when it does catch [while feathering app],[If I don't feather it, it won't catch when real cold] it chugs for a second or two and belches white smoke . Then smoothes out and runs clean.
I think I have it narrowed down to the glow circuit, as when it's cold out the glow times stay the same as when warm, and I have to feather the go pedal when cold to get it to start if I don't use the tune with extended glow time overide.

Also took it for a ride and the gmtd. was 4/5 lbs. higher on the boost than my gauge, also it topped out at 16.86 lbs. on the gmtd. Is that the physical limit of the software and how accurate is it, as it said turbo boost [calculated].
 
My 95 did the same thing. Something about the OBD1's I could never explain but they don't seem to start as good in cold as the OBD2's. What you are describing was the same as my Tahoe. I just lived with it. IIRC Chrisk1500 had the same problems with his old ones too. Don't remember if he ever figured out why either. I always had to feather my 95 a bit. I had speculated possibly worn IP.
 
You can very easily see if your belt tensionioner is within spec by looking at the travel lines on top of it. there should be a scribe line on the pendulumn (Piece with the pulley on it) and 2 on the piece which bolts to the motor bracket. these are max and min travel marks. with the belt and all accessories on if it is not between these two lines than your spring is either to tight or to loose. Some show max and min on them but the cheap stuff they are coming out with now doesnt. You just have to figure out which way by looking at it. With the rear bearing going i would say its not likely your tensioners fault and probably just a junk bearing. as many have stated already. Parts quality has steadily declined since china has been copying everything and mass producing it using substandard materials.
 
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