305 tbi issues. Advise??

[GM 4 Life]

My junk has me stumped. It's a bone stock rebuilt 305/rebuilt 700r4 & 3:73 gear w/ about 3,000 mi. on all. It has the following new or rebuilt items: rebuilt tbi, new egr valve, 195 t-stat, new coolant temp sensor, new fuel pump and hoses, new batt cables, battery and all new vacuum lines. It also has a new ignition module, plugs, cap n rotor & msd coil. It has good grounds on the motor & frame. It runs intermittantly sluggish taking off from a stop & under normal acceleration it feels sluggish at times running down the road to where there is more gas pedal pushed than at other times to maintain a set speed. It also has an intermittant miss that comes and goes.This all happens with the engine cold or warmed up to temp, but worse when cold. It also smells rich out the pipes constantly. I just figured my mileage up and i'm getting 21 mpg. I did verify that the timing is correct, but it seems to like 2 deg advanced the best. I am wondering if the dizzy shaft itself is worn out or its the tps, map, esc, the fuel injectors or???? giving me this problem. The injectors look to have the correct spray pattern. Any info or guidence will be greatly appreciated. Thanks in advance.

[James McClure]

GM, you don't mention the MAP or oxygen sensors?? Both, if defective, will cause you a rich condition. Did you check for codes? 13 is O2 rich, 33 or 34 is MAP and 45 is rich but not O2 sensor related IF, memory serves. It's been a long time since I messed with computer controled engines. jim

[GM 4 Life]

There are no codes at all using the jumper wire method. And yes I've disconnected the batt, then drove it etc.That is also why I'm completely stumped, & to be blunt, where I live, Every garage I've EVER taken a vareity of vehicles to in the far past said they know all about my issue at hand & it'll be a piece o' cake to fix,but then the vehicle comes out the shop worse than before it went in and all the monkey ass hats can say is "DUNNO MAN" pay up, so I have zero option to just "pay" someone to figure it out, At the same time i dont want to blow close to 300.00 to replace all the sensors/ modules etc. myself while chasing my tail. I tell ya I'm about ready to **** can all this computer crap and throw a carb on it because when its running right its a screaming lil truck for what it is.

[Jonboy]

You need to have someone put a scanner on it to see what the sensors are doing. a CTS reading out of spec will cause it to run rich. If you really are getting 21 mpg, then it isn't too terribly rich. Did you check for vacuum leaks?

[GM 4 Life]

Yes I checked and replaced all vacuum lines and fittings, then sprayed starting fluid around them, the intake and tbi whwere it bolts to intake while running, the motor never revved up or even changed pitch when sprying the starting fluid. The rich smell isnt as big an issue as the sluggishness and int. miss. Btw, what is the CTS?

[Jonboy]

Coolant temp sensor. If it is open, the computer will think the engine is cold, and dump fuel accordingly, like a choke. It is located in the front of the intake; most likely to the right side of the thermostat housing.

[GM 4 Life]

I repalced it and it has not changed the attitude of the engine, nothing that I have replaced as I stated in my original post hasnt really affected the stated problem.

[chevymotocross]

Checked fuel PSI at the TBI?

[GM 4 Life]

Havent checked fuel pressure. Would i remove fuel lines from back of tbi? what gauge would I need to test? What should the correct pressure be? Thanks in advance.

[lindstromjd]

Gonna throw a stupid suggestion out there, because I had a similar "intermittent miss" problem once. Check all your spark plug wires and make sure they're right. I had #7 and #2 mixed up, even though I was certain I had done it all right and couldnt figure it out for the life of me what was wrong until someone else looked at it and pointed it right out. I felt like an idiot after that little incident...

Humor me. Try it. Take all the wires off and re-do them.

[GM 4 Life]

Just went and retraced them one by one, they are correct. I wished it were something that simple,just now it's started blowing the 20 amp fuse for the clock, dome light and cig lighter. I have used the same radar detector the same way for 6 months out of my cig lighter, no problem, now when i replace the 20 amp fuse in the box and plug the detector in it immediately blows the fuse, it's dark so I'll fiddle with that new bag of worms in the daylight. Ahh, the joys of the old truck gremlins. This thing is trying my sobreity tonight.

[lindstromjd]

Originally Posted by GM 4 Life

Just went and retraced them one by one, they are correct. I wished it were something that simple,just now it's started blowing the 20 amp fuse for the clock, dome light and cig lighter. I have used the same radar detector the same way for 6 months out of my cig lighter, no problem, now when i replace the 20 amp fuse in the box and plug the detector in it immediately blows the fuse, it's dark so I'll fiddle with that new bag of worms in the daylight. Ahh, the joys of the old truck gremlins. This thing is trying my sobreity tonight.

Well, that one sounds like a bad ground somewhere that shouldn't be there. Too bad it wasn't the plug wires... it's never the easy stuff when we want it to be, and it's always the easy stuff when we don't expect it. Typical old trucks.

[GM 4 Life]

Yeah I hear ya on that one lindstromjd. I like your quote you have. I just let go of a sweet lil sonoma tonight. It was a small block project that never happened thanks to purchasing my square.