Need help 350 in my 91 caprice runs bad after 4 years

[Schurkey]

I had the 350 swapped into the 91 Caprice 4 years ago it was from a 1992 C1500, it ran good the whole time, recently in the winter time it was close to about -30c and I hadn't plugged the car in overnight.

I don't plug my vehicles in, either--although I make sure everything I don't store for the winter has a functioning block heater. No big deal.

When the car started it sounded like a tractor really high idle, I changed all my spark plugs, distributor cap, rotor, ignition coil, coolant temperature sensor, fuel filter, spark plug wires, intake air temperature sensor and EGR valve. The map sensor had been changed just a couple months before I got the engine changed 4 years ago.

Lotsa replacement, zero diagnosis.

After replacing everything and scanning the OBD1 I don't have any engine codes

Define "scan". Sounds to me like you used a code-reader, not a real "scan tool".

What tool did you use?

I have 305 injectors on the 350 and the ECU and the TBI unit had not been changed when the engine was changed.

Of course that's a problem. You NEED the 350 injectors, and you SHOULD HAVE the 350 programming; although I don't know what differences there might be between B-body and GMT400 programming.

The TBI units were kept to there same vehicle for Hood clearance reasons.

Isn't the height of the TBI units exactly the same?

I tested the TBI injectors with a 9-volt battery and they both make the clicking sound. I'm wondering if the ECU could also be damaged from that.

Did you disconnect the wire harness to access the electrical connections on the injectors? If so, the computer wasn't damaged.

I need to change my injectors to the 350 ones.

YES.

I am wondering if it could be intake manifold gasket.

Possibly.

It bogs out and dies under acceleration especially in drive and reverse. When it is in park or neutral I can rev it more

What is the fuel pressure at key-on, engine off, at idle, and under load?

Connect a REAL "scan tool", verify EVERY sensor and computer output. What are the fuel trims? What are the IAC counts at idle? Do the O2 sensors work properly? What is the O2 sensor cross-counts?

Any chance the catalytic converter is plugged/melted?

 

[racecar]

I don't plug my vehicles in, either--although I make sure everything I don't store for the winter has a functioning block heater. No big deal.


Lotsa replacement, some diagnosis.


Define "scan". Sounds to me like you used a code-reader, not a real "scan tool".

What tool did you use?

I used a paperclip to read the DTC codes from the engine light flashes

Of course that's a problem. You NEED the 350 injectors, and you SHOULD HAVE the 350 programming; although I don't know what differences there might be between B-body and GMT400 programming.


Isn't the height of the TBI units exactly the same.

Did you disconnect the wire harness to access the electrical connections on the injectors? If so, the computer wasn't damaged.

Yes i did

YES.


Possibly.


What is the fuel pressure at key-on, engine off, at idle, and under load?

I haven't pressure tested anything yet

Connect a REAL "scan tool", verify EVERY sensor and computer output. What are the fuel trims? What are the IAC counts at idle? Do the O2 sensors work properly? What is the O2 sensor cross-counts?

Any chance the catalytic converter is plugged/melted?

There hasn't been a catalytic converter on the car for the past 6 years

 

[Schurkey]

I used a paperclip to read the DTC codes from the engine light flashes

Time to connect a REAL scan tool, and a fuel pressure tester. You learned nothing from the paper-clip, so no diagnosis was done.

 

[racecar]

Timing was the problem, when i put a bluestreak cap and rotar in it fixed one problem and create another and because they were not oem the degree was off a bit, it runs normal again and without 350 injectors still.

 

[GoToGuy]

Huh, did you put a timing light on it? Blue streak is decent quality. How is timing off with a cap and rotor?
Your guessing right?