I just replaced the 305tpi motor with a 350 crate motor from GM and used my old tpi stuff and now the motor is acting weird sometimes. I replaced all the sensors except for the TPS and IAC. I put in a 350 knock sensor also. when i get on the gas and let off the car just shuts off. i think i may be running to o much fuel pressure( 52psi). I also have a new holley fuelpump and 22lbs injectors. I am waiting on a ED wright chip to come in. what could cause the car to just shut down? the tach also jumps around while driving. how can i work out these bugs the easy way. is there any cheap software out there i can buy

 

You, uh, did swap in a 350 MEMCAL and PROM, right?

If not, there is step 1 of your troubleshoot.

 

No i have not swapped in a 350 memcal? what is that and where is it located? I have a 350 chip on the way?

 

MEMCAL is the term for the "chip", the "limp home" resistor packs, and the plastic carrier they are both soldered to which plugs into your ECM.

If you have something on the way, make sure it's the whole MEMCAL and not just a chip (PROM), the limp home stuff is engine-specific. You can run fine with the wrong limp home setup, but if the ECM drops into that mode you'll have problems.

If you do a search on "moates" you'll find links to a free DOS app that lets a PC read data in realtime off the ALDL port of your car. Just add a cheap laptop and a cable (build your own or buy from AKM Electronics) and you can see what the ECM is doing. Invaluable tool for troubleshooting and tuning a TPI engine.

 

i just ordered the 350tpi replacment prom for my car at the dealershop and will be hooking that up along with a stage 2 Ed Wright piggy back chip. Hopefully this will help out this problem

 

I think you are going to have one too many chips.

 

UPDATE!!!!
I just installed the 350 prom I got from the dealer along with the Ed Wright pippy back stage 2 chip and the car does not run any better. It drives fine around the neighborhood but when I bring it back in the driveway,it idles up and down and then slowly dies. It will fire right back up and run for a few seconds then die again. I have an AFPR hooked up along with a gauge and it shopws 39psi when the motor is running at idle. Is this right? If not then how do i make it right and what should be a good setting for minor mods. (Check Sig.) There is no code being set either. I have replaced all the sensors on the motor with new ones except for the IAC and TPS. I have the IAC in the car, it is just too cold out right now to install it. The TPS is ready .054. The motor is brand new from GM and has about 20 miles on it. I tossed the 305 5spd in favor of a 350 6 spd. pleasehelp

 

Do you hear a vaccuum leak at all? I know when I first go tmy engine all back together, I forgot the Power brake booster vaccuum line, and the engine loped up and down, almost stalling... The IAC can't compensate properly when there is a vaccuum leak. Grab some Throttle Body cleaner and spray it anywhere there is vaccuum, listen for the RPM's to drop.

Your IAC passages just me dirty too? :/

:lala:

 

Its funny you mention a vacuum leak. When I assembled the tpi unit on the new motor i made sure to put new GM gaskets on. When I fired it up for the first time I thought I could hear air hissing coming from the bottom of the drivers runner on the intake. I sprayed TB cleaner there and the idle didnt move. I then took a piece of 3/8ths hose and put one end on my ear and the other in the area hissing area and I could hear what sounded like air moving. That same sound wasnt heard on the other side. Well, I used these allen cap dress up bolts to assemlbe my tpi and now I;d wished I never used them. I got them off ebay. They suck. The heads stripe right out when you torgue them down. How I can even take them off to put the stock ones back on. I have to fiqure out a way to get these off. will a vacuum gauge detect a leak at idle?

 

I got those same bolts!!! You know what the problem is with those?? The head size is 6.5mm!!! grrrrrr.. I had to use allen wrenches!!!

I am not sure if a vaccuum guage wil show it... but the Throttle Body cleaner always works for me /

Is there still a leak?

 

Yes, I think there is still a small leak there. I tried putting silcon gasket stuff there and it helped a little bit but there is no way I am going to stop air from rushing in there. I dont plan on keeping the stock tpi stuff but for now its all i have.

 

well... that may as well be your problem... it will not run good no matter what you do, unless you fix that leak.. I don't know how you achieved that... I didn't even reef my bolts on tight, and i am running fine...