Sounds like a fuel delivery issue to me. Do a fuel pressure and leak down test.
Key on engine off, should get 62psi (nothing lower than 60) and should not leak down below 55psi in 10 minutes.

 

so I'm confused now. I let it rumble up to 1 bar or so on the digial guage. The higher the temp got. The btter the engine runs. But I'm worried. I got light white smoke out the back. But when I chcked the oil, and what not. I didn't have any sign of any issue. SO maybe it was because the truck has been sitting mostly instead of going places. I would hope Either that or I blew something up. sigh. I would hope not it is a fuel issue. Because I replaced th fuel pump, fuel filter, spider injector, nut kit (aka fuel return). and check the fuel lines. Unless there is a slight leak some place. I didn't have money to do the sending unit though.

Josh

 

Just rebuilt the top end of my engine. Rebuilt heads , cleaned intake, full gasket kit, new nut kit for spider new distributor and new plugs. Runs rough at idle and a lil high when cold . Go to drive it and its just gutless. The Cat, EGR , Map sensor are relatively new 2yrs out. Triple checked the timing TDC compression stroke. 0 degrees and plug ECM back up. Can't find the culprit . Btw no codes as well.

 

So I went out and data logged using rt tuner pro. I have been doing this for a couple of days. Well my digital dash started flaking out and I noticed the bulb under the hood started going dim and bright. Good thing I was recording the data stream. So I'm like okay. Try a few things. Rev it up a few times. Okay dash still flipping out (worse when reving up). Then I decided to pull the power on the system wih using the power window switch. Truck gets worse. Then back to normal. Dash gets dim. Light under hood dim. But once I let go af the windows switch. (this also happens when turning on and off heads light, etc ,etc anything to pull more power on system.) So I got back and look at the data log. Most the time the power is sitting between 13.8 to 14.1 volts. But once in a while that range goes bigger. like 12.8-13.8. This is I assume when the dash and hood light starts to pulsate. When I hit the window switch. It dropped down to 9 volts. Then everything else follows suite. Spark advance goes to almost 0. Injectors low power. Etc. Drain on system. Now keep in mind. This is new alternator. battery, battery cables. It was doing this before I replaced this last year and before the rebuild. I check codes again. All the other sensor are running just fine. Never did loose a communication with the ecm. Truck is up to normal temp. Mostly jut idle. I got to be pulling my hair out. Also I expected to go out and log with a no start. Like I posted above. But Just like it showed up. No gass smell, no flood, no kill battery. Problem is gone. So I proceded to just log and record. Touch wires and wiggles stuff around while watching the monitor program. Nothing. Just nothing. I was going to attach the scan file. But it is above the limit even in zip format.

Anyway, andy idea on the power issue? At least I got a scanner now. SO when the truck goes nuts when rough idle. Hopefully I can catch it. Geeze a few more new sensor and I'll have them all replaced.

Thanks for any help,

Josh

 

Mine is up to full power. The big problem I had is that few days I was driving it after the rebuild. The problem happend out of the blue. Then went back to normal. Right after the rebuild. The truck started right up and ran great. Then about 1 month in at a stop light is when I had the idle or whatever the problem was. Then a few montsh ago was the power loose. The new thing was the turing over and smell of gass. But had spark. Then just as it came for a few weeks. (AKA I didn't run it every day.) It was gone. I was sortof bumed out that the problem went away bofore I got the tunning cable. Esp the it ran really rough until it warmed up. But from what I was reading. The sucking noise I heard it mostly the egr valve getting stuck. Even though it was cleaned on the rebuild. I think that is 1 problem I have out of 3 or so. I'm going to have a fuel break down test again on it to. just to make sure. I'm trying to get my brother to check everything again. Spark plugs due to the o2 sensor being unplugged and truck running tons of gas on them. Cap and rotor to make sure they look okay. But the mechanic was correct. When my truck is running. With the exception of a slight rumble. Everything tests out fine. Now take what I say with a grain of salt. I'm not a mechanic. So that is why I'm trying to get my brother. The certified mechanic to look at it.

 

So I found a thing on the internet to test grounds and how to test.So I said fine I found 2 ground wires on the firewall in the engine compartment. Test them without the truck running. Fine I get 12.x volts. I even tested the battery wire to the gounds points. Fine same reading. Okay. Good. So then I started the truck. That is were the fine begins. (I hope it isn't me.) the power reads 14.X volts and then after a while it starts fliping out. 9. 10, 11, 14. I was thinking it was going along with the missing but no. It is not. But dang down to nine. THen back again to 14. So I checked the dash and I don't see anything flikering that I noticed. Most of the time it was at 12+ if not back at 14. Um okay. So I figured I would try it with the key on. But not running. Nah it is fine. Just as before except you can see the voltage off the battery drop. YOu know. 12.8, 12.7, 12.6, 12.5 etc. etc.

So any ideas?

Also the alternater I got 2 years ago has the voltage regulator inside of it from what I could tell. I didn't see a way to remove it unless you open up the back panel or something. once again this is a 93 s10 blazer vortec v6.

Thanks,

Josh

 

Vortec is great for power! But when things go wrong... CHA CHING!!! That's why I love the TBI! All very simple, and easy to build up for performance. Through reading all of this thread, I never did see once whether or not you checked timing properly? Also, I would make sure the wires beneath the dash and steering wheel were ok, not shorted out or anything. I had an issue once, where a wire got pinched somehow beneath the steering wheel mounting bracket. Cost me $700 to trace that problem down. Fixed it, and my truck ran properly again.

 

Okay so I still have 2 issues. I have the dash flpping out (digital dash) that when it does the power goes nuts. I now have the power tester and even through the cig lighter. It will dropped the power down. So say I'm driving along and notice the digital dash start freaking out. Then I say turn on the head lights or use the power window. The voltage drops out big time. Almost enough to kill the truck. A few things to add to it.

1. When I hit the turn signal sometimes it goes away.
2. Just driving along. Sometimes it just goes away.
3. Turning off and restarting the truck does not help.
4. Sometimes the truck runs a little rough (Aka power drop to fuel injectors)
5. Does not care if I hit bumps or anything. still goes on.
6. It can go away for like 1.1/2 month and then go on for days.
7. Does not seem to be a temp thing.
8. It does do it most of the time when the truck is.
9. It does it most of the time just driving along.
10. Sometimes it will do it right when I start the truck.

etc, etc. My mechanic has Fridays off so when it happened this Friday I was not able to take it in.

Also I have not had a stall in along time. Since I Replaced the fuel pump and realized that after I replaced it. The gas gauge is now off. So. I just full the tank up more. So I hope it was just a bad pump and gas gauge being off.

Then the other issue is running a little more rough on certain days. When the engine is warm. Also can do it cold. But this is even more of a far out problem. I can go 3 months with a slight rumble in the engine. Then like the other day. It was pretty bad. Now when I press on the gas. It seems to run fine and has power. The only thing in the area I can think of. it is getting warmer outside up in the 80's.

Also this last round the two issues seemed to be related. First the dash started wigging out with the power issue. Then during that time. the truck starting running a little poor. But not at the same time the guage was wigging out. Unless of course I pull additional power from the system. AKA turning on head lights. etc, etc.

As you know. I replaced the alternator, battery cables, battery, etc, etc. Even after rebuilding the engine. It has this problem before and after. I have been checking the trucks wiring and nothing out of style. I did find why the radio was wired up wrong and fixed that wiring. I was hopping that would fix the issue. But after 1.1/2 months here it is again.

Radio. They removed the glove box light and used that for a ground. Then they used the positive from the rear windows latch button. All I did was found the blown fuse. Replaced it. Did my power test and re-wired the stereo up correctly. I thought maybe that fixed the issue. But it did not. So now at least I can go and get a glove box light socket now and light. But that is a low item on my list.

Also I noticed somebody else kind of posted the same thing and yes I also found the shaft on my distributor worn out and thus replaced it during the rebuild.

Yes I still need to check my spark plugs.

TTFN,

Josh

 

You say you did a visual inspection, but did you check for burned wires where they cannot be seen easily? E.G. underneath the steering column. near the mounting bracket, etc.? Any accessory wires near pinch points? Like door hinges, hood hinges etc.

 

I have been slowly going through all the wiring that I can. Within reason you know. That is how I found the stereo power on all the time. I known that the stereo was not wired in correctly. So I took a few hours trying to check out all the wiring in the fuse box and more under dash wiring. That is when I found the blown fuse. Replaced the fuse and now my power good worked through the stereo harness. So I was able to fix the hack wire job. I was wishing that maybe the hack wiring job was back feeding into the system once in a while. But nope. no luck.

TTFN,

Josh