black smoke

[bigred]

My 8v92t is a "smoke roller"on take off. When I stop at a red light etc and start to take off ,I get a moments hesitation and heavy black smoke from the tail pipe .best way to describe it is ,it is like a gas engine with a flooding issue Have had it to a mechanic but he said he couldn't find anything out of the ordinary     

[luvrbus]

Mechanical 8v92's will smoke on take off but a DDEC shouldn't

[blue_goose]

More than likely the throttle delay has been taken off.  Put it back on and it won't smoke but not as much power taking off.
Jack

[bigred]

That is one of the things that I am having now !! When this happens ,it IS very week on take off.I mean this thing ain't going to "squeel "a tire when things are working right ,but when this thing does bog down ,I mean it is like it ain't  going to move .This is the electronic engine .Where is the Throttle delay located???

[chessie4905]

If this is an electronic engine, then you have some other issue. Have it checked for codes. Maybe waste gate solenoid failure or some other issue.

[eagle19952]

That is one of the things that I am having now !! When this happens ,it IS very week on take off.I mean this thing ain't going to "squeel "a tire when things are working right ,but when this thing does bog down ,I mean it is like it ain't  going to move .This is the electronic engine .Where is the Throttle delay located???

oops missed the year and model .... 

under the valve cover... not on yours

see below

[Iceni John]

Turbo boost sensor?   How much boost pressure do you get under load?   Or a bad injector?   What codes are there?

John

[Bill Gerrie]

I'm pretty sure a 93 Prevost will be an electronic engine. Sounds like your turbo isn't spooling up fast enough. Could be it is starting to fail or there is an exhaust leak before the turbo.   

[luvrbus]

Red your engine doesn't have throttle delay,where do buy fuel ? the bio fuel from Love's will make a 8v92 DDEC do weird things 

[bigred]

The mechanic did check for codes when I first complained of this and it did not show any.Of course ,as usual ,it never acted up one time when he was checking it .It travels along happily in 4th gear with about 10 lbs of boost .It does seem like the boost gauge hesitates momentarily when this lag happens.Is there a way I can recheck for codes or does it have to have the Detroit scan tool?I think this was an Ido10t question but I asked it anyway!!

[luvrbus]

Does the check engine light ever come on when this happens ?

[blue_goose]

When I posted about the throttle delay, didn't know it was an electronic engine.  Your problem is too much fuel and not enough air.  Now that said it may not be easy to find.  I will tell you like I have told others a Silverleaf will be one of the best things you can buy.  Do you know if anyone has turned up the fuel in the ECM.  What is the max boost you have on a hard pull.  If you come off the power and then back on hard at cruse speed dose it make smoke? 
Jack

[luvrbus]

There is a sensor behind the pulley that has 8v92 embossed on it clean the sensor and connection with a good cleaner they build up oil and grease and do strange things.You might have your guy check the timing on all the injectors they set on .1520.Also you could have have injectors going bad.Your problem takes awhile,have you check the fuse holders going to each cylinder bank ? 

[Bill Gerrie]

10 lbs of boost isn't enough if you were on the throttle. I run 10 at a flat grade but goes to 20 if full throttle.

[B_K]

I also had an 8V92 DDEC act that way once and Don Farchild led me right to the problem as the "Boost sensor" attached to the blower next to the right side valve cover. (looking at the engine from the rear or curb side as I tell many people.)

Looks like a standard GM MAP sensor. But trust me it's not a MAP sensor and it will have to come from Detroit!
   BK