The startup doesn't sound that unusual for a cold start but begs the question how cold? TBI suffers the same problems in the plenum and ports as do carbureted engines but it has even less heat as the intake is water cooled or heated in this case. What looks like an exhaust cross over isn't the driver side goes nowhere the passenger side feeds the EGR so the intake doesn't get hot till the coolant does. The manifold still carbons up to a point where it doesn't supply enough exhaust to keep the EGR functional in terms of the amount of exhaust gasses available to the intake, this will set code 32. Additionally, cruise RPMs is where EGR is functioning, without enough exhaust gas the mixture falls lean because the intake is filling that space with air. If there is enough space in the computer logic and the O2 sensor is good it will add fuel whether enough to correct the mixture I don't know. Code 12 is the computer telling you it's alive and well. Code 22 could be a mixture discrepancy between the throttle position and the O2 data. OBD-I isn’t too discrete; the diagnostics require the tester to have an understanding of systems logical relationships rather than having the ability of the diagnostics to point and grunt "go here, fix problem".So as the title states i have a 1989 C1500 Scottsdale with a 350 TBI TH700r4. I belive it has the stock gears though i was told it has 3.73. Anyhow there are a couple different things.
First it has to crank 4-5 times before it will fire on a cold start, Hot start it will fire up with 1/2 to a full crank. I cant find any vacuume leaks. Starter was tested and is okay. All grounds are fine(dunno if that would even affect this). I have checked pretty much everything i can think to check except the TPS.
Second of all when going down the road when i give it throttle to speed up it kinda bogs down, i have to pretty much stand on it so it will rev up( come out of OD) and gain speed. It doesnt matter if its in OD though. Does the same in D, i cant gain speed unless i make it downshift otherwise it boggs. It idles fine. Runs a little rich i can smell the gas in the exhaust but i also dont have a Cat.
Here is a Ful;l list of everything that has been replaced in the last 6 months. Fuel pump, fuel filter,(oil n filter), pcv, plugs, wires,Dist(complete with cap and rotor), Ignition coil(ACDelco), Rebuilt the TBI yesterday, New injectors, CTS, MAP sensor, EGR valve, reset the timing with a light( just put it at stock 0* BTDC). I cleaned but didnt replace the IAC when i rebuilt the TBI it was pretty dirty but seems to work properly.
I cant for the life of me figure out what is wrong. It idles perfect great throttle response. Just boggs when doing about 40-60 and i try to give it gas like to go up a hill. I have checked everything 100 times to no avail. I do get a soft code from time to time after driving for a while but since its a soft code and i dont have an OBD1 scanner i dont know what code it is throwing ( i know no help there):nono: The only parts i havnt replaced or thought to really check until recently are the O2 which is a $15 fix and the TPS which run about $55 here. i dont know if wither would cause the problems i am having.
**Note** i have an adjustable fuel pressure regulator and when i redont the TBI i raised it 2 full turns. Seemed to help a little on the low end but not where i need it. Also i do not have a Tach or Pressure gauge. Not that it matters one way or the other but it will still burn the tires off, but only if i hold the brake(doesnt like to "peel out"). Sorry for the Long post.
A 1989 brings pictures of high mileage; high mileage brings pictures of a dying timing set. Chain stretch causes the cam to lag the crank which also takes the distributor with it. In the case of TBI the computer adjusts the timing which if this was a carb you'd be doing it and might become aware that constant distributor adjustment was an indicator that something was wearing out, in this case that's transparent till it gets beyond what the computer can patch up. Idle could be right but as engine RPMs pick up the computer may run out of authority to fix the problem. From that point on the spark would appear to be late this would clip further power increase is some amount if not total. With the brown/black wire disconnected so the computer isn’t playing with the timing run the RPMs up about 3000 then slam the throttle closed, with a timing light on the marks, if they move off and around the zero mark, you know the cam ain’t tracking the crank or the distributor is out to lunch in terms of a worn gear and/or bearings.