TPI Fuel system

I have a 80-90 LB9 with a fuel pressure problem. It will start and idle for about 30 seconds. As soom as I give it any gas it dies. The fuel pressure at the rail is 0-10. If I check it at the pump its 40-60 psi. I used air pressure and slowly blew it into the rail inlet and saw the pressure = the air pressure( 10=10 20=20 ect.) At around 45psi the regulator opened. I did that a few time then hooked back up the fuel punp. Now I have 20-40 psi at the rail (Engine not running)It started and ran good for a few seconds. Checked the fuel rail psi again and it was back to 0-10 psi. All I can figure is the fuel regulator is bad, getting stuck open. Before I change the diaphram(its a real pain in the but to get to and change) is there anything else that can cause this? Should I just put on an after-market regulator in the return or inlet line?

Thank you
Doug  

OK. Now I'm getting 42psi at the fuel rail. It will idle but as soon as I give it any throttle it dies. Running psi is around 40. Is there a sensor that can cause this. Guess I need to figure out how to get the readings from the ADL as its not connect to the dash yet. BTW I'm guessing its a 90 engine since the ECM is a 7730

Thanks  

If I wanted to convert this to a cab what is involved? Intake, carb(have a 600cfm holly) fuel pump change I'd guess. What about ignition? Would I need to change the distributor and add an MSD 6x control box?.

I've changed about everything MAP sensor, fuel pump, filter, regulator diaphragm.

Changing the regulator diaphragm does allow it to run above idle but runs like crap like still starved for fuel but the psi is in spec. Test the TPS and it test ok 1.6k ohm to 24k ohm.

I can't get a reading from the ALDL so I can't get any trouble codes. The ALDL is wired up correctly as far as I can tell.

I doubt its the ECM, I think they ether work or don't work.

Just acts like these is a bad sensor still but not much more to change.

Thanks
Doug  

i want to stop you at this point.....

you need access to a service manual ...  or online data subscription.....

much of the info you will need is at this link..

http://www.fastbird93.com/Diagnostics.htm

start at the lower right corner of the web page.... there are 5 linked pages.. print hard copies of those pages... check your fuel system for proper operation...   you will notice its listed in the NO DTC section...

Fuel System Diagnosis
    Description  Page 1  Page 2
    Chart  Page 1  Page 2  Page 3

you will also need to print these few pages

Fuel Pump Relay Circuit
    Description
    Chart


when you don't get a check engine light...  there is a whole series of charts for won't flash code 12...



there is a lot of stuff to check... before throwing in the towel on the TPI>...

the ECMs do have a failure problem lately...

it really sounds like you might have 2 different problems....

follow along.... this is going to require a bunch of testing... and a LOT of reading....  

i did post this link to the TPI wiring diagram on your other thread... you will have to copy and paste to view and print it...

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/09/91/6f/large/0900c1528009916f.gif  


keep an eye on your messages above... when logged in.. i might send you a link to help...  

waynep7122

Thank you very much. I totally agree there is more than one problem. I will try your suggestion and follow up

thank you again
Doug  

Well I put in the new Bosch III's and it solved the problem. I think I had many problems and this was just the last fix. On a side note, I had to use the top 0-rings from the old injectors to keep them leaking from the fuel rail. The old ones are .01- .02" bigger. I'm not saying the wrong ones came with the injectors, it could be the fuel rail. I tried to look up the part number to be shure what year it was from but it doesn't match any PN I could find. 17083347 is stamped on the fuel rail.

Thanks to all
Doug  

Just want to give a big thanks to Wayne for all his help. It would have taken much longer if not for his help

Doug