voltage problem [ knock ]

[crazygn]

I cant find the problem with this car , it will run and drive with the batt voltage about 12-13 volts. But if i start to rev it high 3500-4000 and build boost the voltage on the turbo link says it drops any where from 6.0 to 0.3 volts. Then the car fells like the valve are floating and wont really rev and the knock gauge go's crazy, scan tool said at times 30* ret i hope that is wrong.

I had the alt tested and it put out 15 volts, the batt is new , coil is good and i try others and the same thing. I even put 110cam2 in it to day and the same thing . I dont no where to look now. How does it stay running at 0.3 volts and 30*knock ret.


help

 

[Russ Merritt]

Check for the dreaded positive cable/header short if the batt is still under hood.

 

[azgn]

May want to check your belt and tensioner. One local GN had a similar problem and turned out to be belt slip above 4000 RPM.

 

[crazygn]

I pulled the belt tight the other day , it seemed to help but it started again, i have the belt pulled very tight now.

 

[Tow Man]

Originally posted by crazygn
I pulled the belt tight the other day , it seemed to help but it started again, i have the belt pulled very tight now.

I doubt it's the belt! Even if the alt stopped turning all together, you should still have 12v (battery voltage)!

It sounds like a short as stated above or a bad ground! I would check and clean all connections and grounds before replacing anything else!

One other thing, Did it do this with the old battery? I have seen batteries short out internally! ( just a thought)

Good luck!

 

[crazygn]

no the old batt just died, i will check all the grounds and test some of the wires when i get up. It will be hard to test because it really only does it under load or boost. I might even put a new batt to starter cable on because it seems a little tight.

 

[Russ Merritt]

When you stand on the gas, the engine tourques to the pass side, possibly touching/burning the positive cable going to the starter, I've seen it 100 times, "it only does it when I floor it" yea no s$#@. Sounds to me like a connection somewhere. When you tested the alternator, did you test at the battery or the post on the back of the alternor? Do you have a volt blaster? Could be a problem with that. Make sure the wire on the post of the alt, that goes to the batt isn't pinched/frayed, possibly replace with 10 gauge wire, when you floor it, the car runs off that wire! It gives the batt the boost it needs for WOT

 

[crazygn]

I had a store test it on there machine. I dont have a volt blaster , i will check all the grounds , and wires to the starter and alt today and see what happens. My buddy will breing his meter down today and check some voltage out when i floor the car .

 

[crazygn]

ok i checked all the grounds and cleaned all of them , i also cleaned every end of a wire and batt . i even pulled the belt a little tighter. I started the car up and gave it some gas and i can see my low volts light on my dash starting to light up at wot. I looked for wires by the motor mount and header but it all looks fine. I have not hooked up a meter yet but will soon.

running low on things to check.

 

[Russ Merritt]

You are running out of options, it can only be two things if all the wires are right. you say the auto store checked the alt? do you have a friend with a TR? You could try his alt.

 

[crazygn]

Yea auto zone said it was ok , said it put 15 volts out. I have my little brothers on it now but we dont no if it work or not , its doing the same thing. Any thing else to check or test guys.


I just dont get it.

 

[Russ Merritt]

You said the positive wire from the batt to the starter was tight, maybe it's broke in the middle somewhere. It's got to be something stupid. Is the wire from the back of the alternator connected to the battery on your car or the starter? If it's connected to the battery & the positive wire going to the starter is junk could be your problem. My battery is in the trunk, and I went from the alternator to the starter to charge my batt (connected everything to the big post) That is also where the whole car gets its juice from (all the fusable links) I know you've checked all the wires but thats where I think the problem is. Does the engine turn over fast? Possible fusable link problem.

 

[crazygn]

Ok i checked the belt again, and marked it with a white line on each pulley and belt. If i start the motor and rev it the lines will not match back up. Thing is its a pretty new belt ,and fill good . I also pulled the belt so tight it wont go any more and it still seems to not mach the lines up. What can i do to get the belt to stop spining . If the store is open i'll pick a new one up.