Hi guys I have a 89 firebird originally a 2.8 car, but I just swapped to a 305 tbi. Got it ready to run tried cranking it, it'll fire and try for about 3-4 seconds then just turn over. I rebuilt the tbi and it's spraying out a nice cone shape. I unplug the injectors and after bout a second it'll try like crazy till the excess gas is gone, but never runs. Oh yeah it also pours gas out of the headers most of the time with fire *****. I've checked the timing and timing chain all is good. Any suggestions? Thanks

 

Sounds like no spark, or firing way out of time. Maybe dizzy is 180 out?

 

I checked that already. It's got spark checked that too. I did some research and the fuel pump from the 2.8 multi port that was in it originally in the car is putting out too much gas for the tbi it's psi rating is 65-95 psi and the tbi pump is 12-17 psi.

 

That will do it lol I haven't messed with any of these smaller than the 305 tbi I own. If the regulator in the tbi is still good, you could prolly ad another regulator into the system before it to bring the pressure down to that before the tbi reg. That would save from buying a pump as well as keep you from having to drop all that mess to drop the tank.

 

The stock 2.8 pump should be fine:

https://www.thirdgen.org/forums/tbi/...fuel-pump.html

 

Oh, more confusion then. If I turn it over for 2-3 seconds it'll nearly have the bowls filled with gas. I'm bout to swap it to carb and forget about all this computerized mess

 

Are you are your fuel pressure regular is good?

 

If the stock 2.8 pump is rated at minimum 65 psi and the tbi pump only puts out 17 max then his stock 2.8 v6 pump is way overpowering the regulator isn't it?

 

The regulator should be able to keep up. It's very common for TBI guys to to use the TPI fuel pumps to make sure that the fuel pressure stays up (such as what was posted in that thread I linked to).

 

Subscribed for info

 

Another question - what exactly did you do/replace when you rebuilt the TBI unit?

 

New injectors, O rings, seals, gaskets diaphram.

 

I did some searching and found several people saying that their car would flood badly when their CTS failed.

(ie https://www.thirdgen.org/forums/tbi/...-flooding.html)

Note: I requested that this thread get moved to the TBI forum as this really isn't related to the V-6 to V-8 swap, it's an issue with the TBI setup. It would get more exposure and more people experienced with TBI there.

 

What AmorgetRS posted about the CTS, I was scrolling down to post the same. If the CTS terminals are corroded (common) replace it and the connector for it. You may also find that it is just unplugged which reports the engine coolant being -40* C or F.

Note that holding the go-pedal on the floor while cranking is a clear flood mode.

RBob.

 

Wow, I knew that the sensor going bad would cause it to run rich but didn't know it would flood the car. That's something to keep in mind. It's a cheap enough part.

 

Thanks. I just looked and it is broke. But I also changed the iac and it seems to have help also