First of all I have a 90 s10 4x4 blazer vin z 4.3 l. I have a re-manufactured block and everything is new from the edelbrock preformer intake to the oil pan. I have a rough idling vehicle and i do not want to mess up the new parts. I have to break it in though, but I would like to fix this problem first though.

Syptoms

Rough Idle
No acceleration
stalls

.... as far as i know so far.

Thank you for any replies given.

 

Have you checked for vacuum leaks? Maybe a hose is off or something.

 

Have checked all emission lines can not seem to find anything broken or loose, let alone cracks or holes. Thank you for your response.

 

Spark plug and gap ok? Also, is the puel pressure good (9-13 psi) and the fuel filter clean?

 

Spark plugs are at .o35. I have not checked fuel pressure but looks like a good mist is coming through the two injectors. New fuel filter already installed.

I was wondering if this could be a timing issue, no vacuum advance timing, but HEI (electronic). thank you for your quick responses everyone.

 

It is off topic but I also would like to do a throttle body rebuild... I cant seem to figure out how to get the injector wiring harness out of the throttle body? Can anyone help me with this problem or am I going to have to cut and splice again.

 

Have you set the timing after the new engine was put in place? To set the timing, a timing light is required. Disconnect the brown wire that is inside under the dash, just above the carpet, and to the left of the transmission tunnel (the connector itself may be under the top edge of the carpet).

Have you tested for vacuum leaks? Carb cleaner or an unlit propane torch can be used to trace along vacuum lines and gasket surfaces to test for a vacuum leak. You will be listening for a change in the sound of the engine.

The throttle body should just have a rubber grommet that you pull out with the wires. On some other non-GM vehicles I have worked on, the terminals had to be removed from the connector at the injectors and pulled through a hole in the throttle body, but I don't think that GM TBI units were this way.

 

thank you for asking I did not disconnect the wire under the carpet my mistake.

vacuum leaks are not detected so far have only done emissions, but i did leave the 4x4 vac connections disconnected.

the wires are in the connector do they need to come out of the connector to come out with the grommet from the throttle body? still not clear for me.

.... More symptoms put in drive and reverse and it puts and stalls and even died once.

is this sensor (tps, iac, map,) related. have not replaced yet...

 

Step 1 - correctly set the timing.

Step 2 - check for vacuum leaks. If there are any vacuum lines open, that IS a vacuum leak. They all need to be plugged, not just left disconnected.

 

ok i will plug the lines. thank you for letting me know again. is this wire on the passenger side tan/black? <-- distributor wire for timing to be disconnected.