Electrical woos...runs great then loses power??

[hickmanfab]

So first off I have an '89 chevy 1/2t 4x4 350tbi (my step dad insists its a 400, but I know they never had F.I. 400, so I guess I need to get the numbers off the block), w/ a 700r4, 241.

Anyways I know it's a electrical issue but seeing if someone has ran into a similar problem.

The problem is that I will be driving and I will randomly loose power. It doesn't matter if the lights are on, trailer lights hooked up, etc. It happens at random and regardless of what I do.

I checked the alternator, battery, fuses, and tried w/o avail to find the problem but I can't seem to single it out. Is it a short or something bigger (i.e. ecu)?

I am trying to sell it so if it's a major issue so be it. I just need enough to pay off the danger ranger

 

[toomany]

Have you checked the battery cables? Look at the conections at the batter, starter and grounds.

400's were only produced from 70-80. So you don't have a factory one. Not saying that one couldn't have been swapped in though (wouldn't run the best with stock TBI).

 

[hickmanfab]

Ya I checked the cables, grounds and the starter. My grandpa got it at an auction back in 95 for my mom to drive. He swapped in a new motor into it and knowing him he would put a 400 in (hand like 10 laying in his shop), but he as passed away now so I can't ask him. Nor is there a paper trail b/c he did it all himself...on a side note I runs awesome (lights up the 32s like nothing) when the electrical doesn't go nuts.

Thanks for the reply...

Jake

 

[lectric80]

When you say you lose power, do you mean to everything? Meaning, gauges off, lights out, engine dies, stereo loses power, everything? If so I would start by checking the ground wire, and possibly even just swapping a new one in. Grounds rot from the inside out, so a bad ground wire might not be visible on the outside. Make sure it connected to a solid STEEL point on the block, anywhere else could cause loss of ground, although it shouldn't cause an intermittent ground issue unless it is loose.

Next pull the cables off the battery and make sure there isn't a lot of corrosion built up under the rubber shroud. I normally just cut this portion off to give the best possible connection from the side post battery.

Next check the fusible links. If one is bad you should be able to identify it by simply wiggling it around at the starter with the key on inside the vehicle. If the power is lost you know you have found the issue.

It is likely to be one of those three, as long as it is losing all power. If it is just losing the engine, or some other component you will need to get much more in depth about what is going out, and any circumstances (bumps, potholes, etc) that may contribute to the problem.

 

[hickmanfab]

By losing power i mean the engine loses power, volts drop down to about 6V, lights dim, etc. It doesn't matter if I hit a pot hole or not. But I will get a new ground cable. I did check all the grounds (ie take them off clean the connection put it back on). The battery is band new and will start all my other cars...thus no corrosion. But it is more then likely the fusiable link or the ground wire...Thanks.


Jake

 

[lectric80]

If it's dropping like that, I would suspect ground wire. Normally the fusible link is just going to burn off and no longer make connection, but ground wire is a good start.