Really need some help. My problem is that my engine floods and won't stay running. The details are - it's a 1987 305 tpi with 700r4. It has been changed over to speed density. I'm using a Painless harness, changed everything that was required to convert to speed density. I have the correct in tank fuel pump. I have replaced the fuel pressure regulator with a new Delco regulator. I have replaced the ecm but not the prom. I have replaced the injectors. What can be the problem? I'm about ready to pull all of the tpi stuff off and go with a carb. I would rather stick with the tpi but it's making me crazy. Thanks in advance for the advice!!!!

 

the ecm was changed to a speed density computer?

 

Yes, 730.

 

What did you do with the cold start injector? SD did not use one...

 

I didn't do anything with it, the harness doesn't have a connector for it. Just says leave it or get the block off kit.

 

If there's no electrical connection, it shouldn't be open, but I wonder if it's stuck open... Have you done a fuel pressure, and a fuel pressure leak down test?

 

I don't think it's stuck open. I have done the fuel pressure test and I've got around 40lbs of pressure. Still have pressure after several days of sitting.

 

"Around 40lbs of pressure".... It sounds to me like you may not have a good handle on exactly how much fuel pressure you have. Maybe you should check it agian?

With stock injectors (are they stock?) and a stock FPR, you should have 43-44 psi. Some people check this with the engine running and the vacuum line to the fuel pressure regulator disconnected. I've also read that some people check this with just the key turned on, engine not running, but I don't know if they give the same results. I need to try that....

Other than that I'm not sure what you could try. Maybe it's not the injectors at all. Let's see.... The IAC could cause it to run rough and maybe stall at idel.

Has it ever run well after the change over to SD? Wait a minute... Are you saying that you changed over to SD and used the same PROM from the MAF system? Or that you changed to a SD ECM and have the SD PROM? Is the PROM that you are using for a 305 SD?

 

The fuel pressure was at about 43lbs, engine off, key on. That was with the new regulator.
The engine floods as soon as it's started. To keep it running I have to keep the rpm high but that only lasts for about 10 seconds then it dies for being flooded.
I haven't had the engine running well since the change over. I did change to a 730 ecm with 305 automatic prom.

 

I don't have a SD car so I guess that I'm probably not be the best one to help you. It seems that maybe there's a problem with the air flow/MAP sensor...?

 

The map sensor is new. Had to buy it for the conversion. Had to get a new knock sensor also.

 

check the spark and make sure it is strong

 

this is the problem, you need to run the $8D 7730 code, not the old MAF prom

 

I did change to an ecm with prom out of a '90 that had a 305 automatic. I then changed the ecm whith another but not the prom, used the prom from the first 730.

 

was it running fine before the change to SD? were you using the painless harness before the change?

 

The engine was pulled from a running '87 Trans Am. It has about 80,000 miles on it. I have it in a '41 Chevy now. Yes it was running fine. Bought the Painless harness so that I could run it in the '41.

 

Still sounds like you're not getting a vacuum signal to the MAP sensor, or, the coolant temperature sensor is not functioning, or maybe one bank of injectors is grounding on the pull down side, forcing them full on.

Do you have a scan tool? Check the codes, and coolant temperature, MAP reading, etc.

 

I'm pretty sure the map is getting vacuum (I'll check it again). The injectors are functioning correctly (checked them with the rail out, coil wire unplugged and turned the motor over). It's not showing any codes right now (it will sometimes show a code 43). I haven't checked the voltage on the sensors. Do you think it could be the prom?