89 c2500

[gcochran223]

i have a 89 c2500 350 manual tbi.

the rings are shot in it from lack of maintenance from the previous. the compression is not all even and varied with the biggest difference being like 30. i have had nothing but tbi issues since i have owned the truck. the truck will load up very easy and start black smoking and running like heck until i can get out on the road and get the rpms up for a couple miles.

would the reason for the tbi issues, running lean, etc be from the rings being wore?

i did put long tube headers and a tb spacer on the truck.plugs,wires,cap,rotor.

i have just never heard of anyone having this much problems with tbi as i have and i am leaning towards getting a goodwrench crate motor later this summer. and thoughts, opinions are appreciated, thanks ahead!

[bd]

The worn motor isn't doing you any favors, but probably has little bearing on running rich and loading up.  It's more likely that you have one or more sensors in trouble, leaking injectors, or basic outpoints like fuel delivery problems, vacuum leak, EGR bypassing, poor electrical connections, etc. 

Does the check engine light work and are there any trouble codes stored?  Have you checked fuel pressure?

[bake74]

     Worn rings usually create more of a blueish/white smoke, not black.

[jaredts]

     Worn rings usually create more of a blueish/white smoke, not black.

Agreed.  And low compression can be caused by valve problems, which is a much easier fix than rings.  A dry followed by wet compression check can usually tell you the difference.  A cylinder leakdown test can be even more conclusive.

[gcochran223]

well it normally smokes white. it will burn up too 2 quarts every 500 miles lol. the black smoke was just that one incident after my camping trip. it never smoked that black before. the check engine light does work but isn't on. its only been on once in the last 2 years and it was for some sensor i cant recall which one but it made it run like complete crap.

the truck had blown head gaskets and i replaced them and at the time of replacing the gaskets i got the heads redone with the new valve seals since the older chevys had a bad design or whatever. ever since i put the updated heads on its burned oil like crazy. it did smoke before the heads were replaced.

can the tbi setups be rebuilt i guess would be my next question also?

[gcochran223]

i replaced the map sensor last fall. thats what the sensor was

[bd]

...low compression can be caused by valve problems, which is a much easier fix than rings.  A dry followed by wet compression check can usually tell you the difference.  A cylinder leakdown test can be even more conclusive.

^^^^^^ Do this.

If the spark plugs have some mileage on them (aren't new), post pics of the business end of all the spark plugs in order by cylinder, so we can tell which plug matches which cylinder.  Also, post a pic of the top of the engine with the air cleaner removed.

Does it use any coolant?

[gcochran223]

the plugs are newer and i know some got fouled very quickly. it doesnt use any coolant. i will have to check with the mechanic on what test he performed. i believe he did a dry test. i can pull the plugs this weekend and reevaluate them. it runs great and has alot of power it just burns the oil and gets loaded up very easy. sometimes by accident ill start off barely in third and realize and go back in first and ill have to get the rpms a bit to clean it out.

ill enclose some pics of the head gasket change since everyone likes pictures.

[bake74]

     This weekend, as bd suggested, lay out the spark plugs as if they were in the truck and try to take some good pics of the electrode end.  This will tell a lot of how your engine is running.
     I would not think the tbi is what is causing your problem.  In your first post you said your truck was running lean.  How did you determine this ?
     Answer a couple of questions that have not been asked.
     Does your truck have a catalytic converter ?  Catalytic converters can become plugged up.  I have heard others say that their vehicles would "load" up (like you described), they would smash on the pedal and get a puff of black smoke out the tail pipe and run fine until it did it again and then they repeated.  Some of them said replacing the catalytic converter solved this problem.
     If you think about this logically, what would/could create black smoke in a gas engine/exhaust ?  Black smoke (or soot, because that is what the black smoke is going to be.  From a improper air/fuel ratio, which builds and creates the soot from un-burnt gas). 
     I see this at work with diesel fired burners all the time.  I even am dealing with it on my Charger (gas) right now because I did some modifications and my air/fuel went haywire and I had to tune it using a tuner to correct the air/fuel ratio for the computer.
     Does your tail pipe have a build up of what looks to be black soot or a black coating ?  (my charger does not blow black smoke, but the tail pipe tips turned black and that is how I knew something was off).
      Back to the cat, if you look at how they are make, the material inside can break down and become a clog in the exhaust, hit the gas hard enough and it can blow it around inside the cat a little bit, but will not blow it out.
      Anyway, a few things to think about.

[gcochran223]

i was told it was running lean by the mechanic.i have not done a fuel pressure test. it does have a new fuel pump for the record. the truck has no cats. it has headers into 2.5 true duals out to echo tips. both tips are covered in soot like you would see from a diesel tip.

[bd]

Black exhaust tips... the engine is running a little bit rich, not lean.

Do you have a 3/8" drive torque wrench, 6"+ extension and 9/16" socket?

Tell us more about this...

well it normally smokes white....

     ...under what circumstances?

Does the exhaust puff a spot of bluish smoke on the first start of the day?

Don't forget to follow up with pics of the spark plugs.

[bake74]

Black exhaust tips... the engine is running a little bit rich, not lean.

      x2, maybe see a different mechanic if he was telling you it was running lean.
 

[gcochran223]

it smokes white on start up and acceleration. it smokes all the time especially the drivers side. especially if i am putting a load on it. on the lean part that may be my bad, i might have meant running rich. i know terminology is important. i have the tools also.

[bd]

In a smooth slow pull, retorque the intake manifold bolts to 35 lbs-ft, following the manifold torque pattern shown in Figure 9, page 6A4-10 (pg. 684) of the 1989 Service Manual.  Were any of the bolts loose?

The white smoke is disconcerting.  Are you needing to add coolant periodically?  Rent/borrow/purchase a radiator pressure tester (image below).  Be very careful of scalding hot water!  How fast does pressure build in the radiator when the engine is started cold in the morning - don't let the pressure build above ~20 PSI?  With the engine off, does the cooling system hold constant 15 PSI pressure for, say, 10 - 15 minutes?