I just finished up a complete swap from a 305 TBI to a new GM 350 TPI. All sensors are new & correct, new GM TPI harness, new GM distributor, and a custom Ed Wright chip complete the package. I first was using a '730 ecm that I got from Ebay and thought that was the problem (cranks fine, but no spark from coil, no injector pulse & plugs are dry). So I swappped in another '730 ecm I pulled out of a '90 Firebird, but the exact same problem still occurs. The check engine light comes on when cranking as it should, the ALDL when grounded flashes code 12 as it should. It shouldn't be a VATS problem because it's disabled in the chip, the security light does not come on when cranking, and it always worked fine before the swap.

I am sure that I installed everything correctly and triple checked all connections. It sounds like something very simple is wrong, but to cause both no spark AND no fuel is what puzzles me! I have power to the coil & at the distributor. I also have 45-50 psi at the AFPR and I hear the new Walbro pump working. We had it hooked to Diacom software, but it would not link to the ecm (guy was using vin number from my '92 RS instead of the vin from the '730 ecm - could this be why?). Can someone offer some real suggestions based on experience? I would appreciate it as I've worked on this thing way too long to have it not start!!

 

Double check your distributor position. Did you use a new distributor, or the old one? If it is a new one, did you use the same module? The reason I ask is, I bought a rebuilt distributor for my new motor, and the module was bad in it. Took me 2 days and a couple of tear downs to figure it out. But I had power at the distrib, fuel pressure, etc, etc. but no spark.

 

It's a brand new GM distributor that had the module in it already...Would a distributor problem also cause no injector pulse?

 

ttt - anyone?

 

Yes, no distributor pulses, no fuel injector pulses. The DRP's
tell the ECM when to fire the injectors.

RBob.

 

Problem solved! I stupidly forgot to hook up the 2 wire distributor connector pigtail to the coil...left the whole thing out of the car!

Car started right up after retarding the timing a bit. Just wanted everyone to know that the dumbest thing can leave you with a parked car. Check the simple stuff! Thanks for the helpful replies. I knew it was ignition related...

 

Congrats man.

I have a 305 TBI and want to convert to TPI with a new 350. I understand what is envolved to do the conversion. Although, what did you decide on the fuel pump and fuel lines?

Did you take it to a test drive yet?

 

Thanks, Manuel.

I replaced the stock TBI fuel pump with a Walbro pump with higher flow (255gph I think). TBI uses no more than 15psi where TPI uses up to 50psi. The stock pump just won't cut it.

The only fuel lines I replaced were the hard lines to the TPI fuel rail and the rubber lines that connect those hard lines to the lines on the driver's side. I left all of the under chassis hardlines in place.

I took the car for a very short test drive, but the valves need adjusting and the timing is off, so I coulodn't really "test" it. I can tell it's going to be pretty strong, however. I hope to have it tuned and running right very soon, so I'll post results (Dyno run is planned as well).

-Scott