I posted earlier on my engine not running properly after a rebuild I just completed. This is the other link for detailed info. on the build: link didnt work...it is on page 2 of the "Engine Swap" category under the title "350 with 305 heads question..."

Anyway, I found out my fuel pump relay wasnt working so it wouldnt get fuel to the rail until it built up oil pressure and allowed for fuel pressure...in other words it took a lot of cranking just to get fuel. Now it has fuel pressure when I turn the key, but it still takes a bit of cranking to fire...not near as much but more than I think it should take. About 5 or 6 cranks of the engine once warm...not sure about cold yet. Have to double check.

Moving on, the scan tool is showing that it is still running lean...so I guess in combination with the fuel pump relay it was taking forever to start. My question now is this. With the 19lb injectors and set up I have, what can I do to richen it up? Is that all controled in the PROM or is there somethign else I should do? Thanks.

 

no ideas even?

 

You should probably put your setup here. Nobody like gonig to different threads to read crap. Any codes ? Whats the setup ? It helps if your sig has that stuff in it. If people gotta work to read your stuff , you won't get anywhere

 

Only reason I didnt put it was because it was a long thread with a bunch of info. I will add it here.

Alrighty, the engine was a 350 from the factory but somewhere along the line got switched to a 305. I had to rebuild the motor and used a 350 4 bolt roller block with my 305 HO heads. I replaced every sensor with the 350 specific ones as well as the ones that were interchangeable just to make sure all ym sensors were new...well except the IAC...it is clean and ok to reuse. I have a stock spec 350 roller cam, MSD blaster coil, cap, and rotor, reprogrammed the PROM for 19lb 305 injectors, eliminated the VATS, cold start (even though it didnt have it, just in case as the intake had the setup on it), EGR, and AIR system. Aside from the raised compression, the motor is stock. I used dished pistons to bring it down some.

I recently found the fuel pump relay faulty and replaced it. That was causing it to have to crank for a few seconds before it even built fuel pressure until I had oil pressure to engage the pumps. Now it starts a little faster but still takes a bit longer than Im happy with.

Also, it is running lean based on the O2 readings...they are below 400 more than above according to the scan tool. Not terrible, but wanted an idea as to what I could do to richen up the mixture some. IS that all controlled in the PROM meaning I have to reprogram it again? Or is there something simpler?

 

hey man i think i might be having pretty much the exact same problems.... im using a 350 with 305 heads too, we should be able to help eachother here. give me your email and your AIM name if you use it.

anyway, what car are you running??? is it mass air flow? or map sensor? also, yes i'm pretty sure tuning the chip is the only way to make the car run more rich, thats assuming everything in the car is running correctly... sensors, relays, etc. you need to change the injector constant, put a lower injector constant to make the car run more rich. (tricks the computer into thinking the injectors are smaller, so it injects more fuel to compensate for smaller injectors)

 

You may need more baseline timing than less, which also needs to programmed into the ECM.

If you don't mind answering the following:

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No problem...though I am not sure on some of these...
1. no...but the starter I have turns the motor over just as it did prior to the raised compression. Plus I used a dished piston to try and keep it reasonable.
2. stock gap on AC Delco platinum plugs. I forget off hand what the standard gap is...but Im using that.
3. Yes, it has the 1227165 ECM.
4. Im not sure, but I checked the number on the PROM and it is out of an '89 Trans-AM with a 350. Im not sure how to verify the actual programming though. I use a company called TPI Parts to have it done.
5. I do not believe the heads were decked as they were in good condition when I had them reconditioned. Basically, I am pretty sure they were not brought down any which would have raised the compression even more or the machinist would have told me...at least I hope :-p
6. The heads are all stock parts and were not ported...just checked/replaced any weak springs, etc.
7. Unknown...sorry. Its not on my build sheet here Id have to ask themachinist and hope he remembers.
8. I think you may have helped me find an issue here...upon reflection, I bought head gaskets for the car from NAPA and I dont think I told them it was for a bored motor...my luck thats an issue right there. How far over would the gasket hang? I probably would have noticed that?
9. I use premium now to try and avoid knock and ping...93 octane. I was trying to avoid running race fuel as my cat is still hooked up...not for long. But in the meantime, I was hoping I could get away with 93.

I tried adjusting my base timing some...but I may give that atry again. What base would you reccommend starting at to experiment? retard or advance? Im not so good with timing hehe. Its at 6* now...so try 8* or 4*? Thanks.

 

Actually the gasket bore is larger than the cylinder
Get the gasket and piston part numbers from the build sheet, or the builder.
You really need to know the static CR.

 

Well, I will run by there on monday and try and get an exact ratio and what cc dished pistons I have, etc. But he told me in conversation that it is around 10:1...give or take a little. I am guessing it is closer to 10:1 and over than lower.

I assembled the motor though and looked through all my receipts and must have thrown that one away. I may just be worrying here for nothing because I am pretty sure I told the guy I had it bored when I bought these parts and by the end of my build they knew all my info. off hand as I was in there a hundred times it seems like. Anyway, assuming I never find what gasket I put in there, what would be the symptom of a standard bore gasket on a .030 over block? Since the gasket bore is a bit larger, it should be ok then right? Please say yes hehe.

 

No problem with the gasket bore, but the thichness would be, which should not be less than .041 inches for a zero deck height, or a couple of thousanths in the hole to keep the valves from poking the pistons, and if quench is important. You don't want to be quessing about these parameters.
If you know what the CR should be the piston, compression height, and rods can be back calculated.
Deck height minus rod length minus 1/2 of the crank stroke = piston compression height.
9"-5.7"-1.74"=1.56" piston compression height, or
9"-6"-1.74"=1.25" piston compression height.
For a 10:1 with 58cc heads you'd need a -13 cc dish piston with a 1.56" compression height, and 5.7" rods, or 6" rods and 1.25" piston compression height. The estimated CR is about 9.2:1 with the 5.7" rod and 10:1 with the 6" rod. Hp generally increases with compression, and so does temperature which isn't good for iron heads and running lean just adds more heat.

 

Well, I set the PROM to kick the fans on earlier as well so it now holds around 180* or so...as opposed to the almost 200-220 normally...though i havent been able to run it in traffic stopped for too long yet. I will definitely get a hold of that build sheet/engine builder ASAP to get the numbers exactly..Id like to get this sorted out. I appreciate the help so far.