The Reaper

Ok I've spent about 3 hours straight searching on here and I've got about 8 tabs of this site open at the moment reading on the whole 305-350 ECM diff. I've yet to see a pic or find out where the 350 chip is located. Im pretty sure its inside the ECM, but before I go ****ing with things I probably shouldn't.... I figured I'd ask first. If this info is loaded in search, sorry for the repeat. I kinda ran into a search overload when I searched and got 100+ threads that were completely irrelevant. So heres the deal. I bought the car a few weeks ago, its got a 350 TPI with an auto tranny in it now. According to the VIN, it was born a 305 TPI. Im pretty sure that during the swap they got the 350 SGI as a whole engine, so having the right injectors is probably not the issue. But I'm unsure if the PO knew to put the 350 ecu/ecu chip in. So before I spend $50 on the right ECM/chip, heres what I got.




Also, while looking for the ECM, I found this. AC Spark Plug?

RBob

iTrader: (1)

The Service Number shows it to be the 1227165 ECM. Which is correct for '86 through '89 with a TPI. Will need to open the small cover (2 screws) and get the broadcast code (BCC) off the chip. It will be a 3 or 4 letter code.

With that we can tell you which year and engine the PROM is for. See the MEMCAL/PROM sticky up top for an idea of what to expect.

Yellow box is the VSS buffer.

RBob.

The Reaper

Thanks for the quick reply. I'll check that out.

The Reaper

Ok so I have the APYU 3516 chip which I assume is the correct chip for a 350 TPI auto from what I found in search. So that settles that I guess. With that being said, I found a little more useful info here which kinda throws me in a loop. The tach for the 305 TPI it originally had redlines at 5500, but when I rev my engine, it seems like the rev limiter drops off at about 4700. Now,as weak as this engine is in it's current condition, I'm sure it's not making much power than high anyways, it just confused me that the smaller displacement engine rev'd higher (I guess). I assumed it only did this due to being automatic, but I don't know.

Also, its sputters and bust out really bad between 4k-4500 90% of the time whether its under load or sitting still. I'm trying to get my buddy to bring his vac line tester home from work for me and I'd like to do the TPS test I read on here while I'm at it, but is there anything else I should consider? I'm going to try and get some pics of the engine bay and a few videos later today.

After replacing the broken OEM oil pressure sending unit with a sunpro with copper tubing, another thing I noticed was the oil pressure being really high. The factory gauge only goes up to 60psi.... but when I get on it a little and when its warming up, I'm getting 80psi. It eventually drops to 25-40psi at idle (depending on when it wants to idle at 650 or 1k lol) . Is this normal/safe?

Also, I'm trying to figure out what this engine came out of. The PO claimed it was a crate engine with a mild cam.... which I didn't believe either considering how nasty the engine looked, no way it was a crate engine with only 12k miles and a "mild cam" from a craigslist seller usually means "the timing is off", which it was.... and I'm still not sure I got it right case the timing marks are gone from the balancer. Anyways, so I looked at the flange on the driver side as many threads here have said and all I can see stamped is "GM 5.7LG" with "SGI" under it. The only other numbers I've found are on a little spot welded plate on the front, bottom, driver side near the pulley and I've googled and searched here for those numbers and found nothing. Is there any other signs? I noticed my valve covers are center bolt where as a few I've seen here had outter bolts, but I didn't know if that pointed a big finger anywhere. I'm assuming it's out of another camaro, but this thing is weaker than any other 350 tpi I've ever been in stock. Way weaker.... btw, gas mileage is completely horrible. I put around and probably get 10-16mpg. I know its an old V8.... but that seems waaaay off.

RBob

iTrader: (1)

APYU is for a 5.7l with a 700R4.

I would check the injectors, make sure that they are 22 #/hr. The breaking up at high RPM may be due to lack of fuel.

RBob.

The Reaper

How do I go about checking them?

RBob

iTrader: (1)

There will be numbers on them. Then search on those numbers.

RBob.