Happy New Year,

I did some looking through the forum and could not find prior thread with answer.

I acquired a 1985 TPI 5.0L/700R4 Z28 two weeks ago. The car is complete. Every sensor appears original to the car. It had been running very poorly and would not idle when I got it. I spent a few days going through the ignition and sensors, disassembled the throttle body and cleaned it, cleaned the IAC, I adjusted the TPS and cleaned the contacts on the MAF. It had been running very poorly and would not idle when I got it. I confirmed the timing is at 6 deg BTDC. PO had replaced cap, rotor and ignition module with AC Delco parts before I got it. I assume because it was running poorly. I put ACD R45ts plugs in. The PO had put auto-lite plugs and when I pulled them, there were all oil fouled and #1 ground strap was bent onto the electrode. I boro-scoped cylinder 1 but no foreign material. Assume that it was poor install.

I got this running as good as I could but the motor has severe blow-by. Totally covered in sludge and when the intake heats up, it starts smoking under the plenum. It originally set codes 21, 32, 33 and 34, but after all my cleaning and adjustments, those all went away. It will idle with slight depression of the pedal. I had it idling for 5 minutes with as little pedal input as possible and it did not throw any codes.

I have two fresh 350 4 bolt main motors that I rebuilt last year and have run them in on my engine stand. I would like to swap in one of these 350s and put the TPI injection system and computer on the 350. The 1985 5.0L should be a 2 piece RMS and the two 350s are 2 piece RMS. Everything should line up. I could switch to a Rochester carb but I like the look of the TPI and FI is easier to live with in colder climate.

I am not trying to maximize performance, just want to get a fresh rebuilt V8 SBC in the car. I know the 305 has 19 lb. injectors and the 350's came with 22 lb. injectors. I previously had an L98 1990 vette and it was fun.

If I perform the swap, will it work OK or is there some reason that I would have to swap in larger injectors and reprogram the ECM? I want to avoid that as I don't want to get too deep in this thing. Just want to keep the fuel injection on this and not throw codes or have drivability issues.

At the same time, can I remove the AIR system and clean up the engine bay a little. Will that cause the ECM to throw a code?

Thanks in advance. PCOPP

 

Iirc 85 with the HLH 3200 Vette calibration used 24#hr injectors. It would be wise to consider the 870 to 165 ecm upgrade.

 

Thanks for quick reply. I will keep that in mind. First want to know if I can just swap in the 350 under the 305 setup and not mess with the ECM.

 

if you want it to run lean you can

 

Increase the fuel pressure, it'll be fine.

I once did a cat back, gutted cats, headers, 52mm TB. Never ran lean. Just bump up the FP.

 

That'd work just fine.

 

If I recall, the 3 things you'll need are:

350 prom
350 injectors
350 Spark control module??..... thing


and that should be it.

 

Currently have stock pump and stock regulator. I Measure 40 psi when I turn key and pump
cycles for 2 sec. Would I just be putting an adjustable spring unit and adjusting it to ne 42 to 45 psi. Everything else no change and use 19# injectors?

 

Don't NEED any of those things. They MAY be better than the stock....buuuut...they may not be, also. Stuff wasn't all that "tight" w/regard to programming back then.

 

Thats good to know. For years I thought you needed to repalce all that

 

I missed this. Yes? No? Maybe?

I would do what I've done in the past; put the hard parts together, get it running, then "Feed it what it wants", in the best/easiest way available. Yes, you would likely need an adjustable Fuel pressure regulator, or make yours adjustable. Then, play with base timing and fuel pressure to get it to run the best that it will, using those two things that you can influence.

Going from a 305 > 350, with no other changes, you're only going to increase power by 10 - 20 hp or so. Not much, so the fueling and timing shouldn't require large changes either. I've made way, WAY larger power gains with other changes and made zero changes to injectors or fuel pressure and it/they ran great. I've also gone from a stockish 305 to a 350 with the exact same intake, exhaust, configuration, etc. No changes...ran great.

 

Completely opposite of an experience I had working with a 1986 Z/28 years ago. It ran so lean that it would have smoked pistons and it ran terribly. The swapped 350 did not have enough power to pull itself through a wet paper bag until it had the larger injectors, correct knock sensor, correct knock module and the matching chip. Also had a L03 car that I did just basic exhaust work to. Took 350 injectors and a custom tuned chip to keep it from pegging the narrowbands lean at WOT. If the EPROM, ESC Module, Knock Sensor, and Injectors were irrelevant to how the engine ran GM would not have made and used completely different units for both setups.

 

Right. I guess I've just got "the touch".

Have you seen my thread on the "Hot 80's intakes!"? Where I got up to ~280 RWHP from that stock tuned, stock injector'd '89 350? Wha.....HOW???....

As a friend at my wedding said during his toast: "Tom shows what CAN be done!"

Who knows why others "can't do it".....I don't.

 

You started with the correct 350 components and had a properly functioning 350 TPI setup. You act as if I have not had to fix this stuff numerous times. Was not long ago I had to fix a LQ9 6.0L swap that was running a 5.3L tune as well. Even the newer LS P59 engine management was not capable of adapting well enough to run the larger 6.0L the way it should have ran. I have corrected the tuning in a couple of HT383Es GM claims is a bolt in for a L31 350 truck. Those run but not well.

 

I'm sorry that you completely missed the point, Fast. With your vast and radical "expertise" I'm surprised that you didn't pick up on the fundamental point of power gains...and the associated fuel requirements -regardless of displacement. Actually, I started with a 305 that was 170 hp and ended w/a 400 that was ~300 hp. The Kart is a completely different example that was simply....another example where there has been a large power gain, in this case, ~70 RWHP gain, w/o issues, no injector change, no tune change. Just an example....just to show what CAN be done. Did you read the part about the 305 > 350 swap w/o changing injectors (or tune)? 'Cause that was in there too.

Anyway, The OP's car will run, and run pretty good w/the 350 swap and basic adjustments. It'll be more fun than the 305 -if not a lot more powerful, and I'll help the OP get it done, rather than think of every reason why "it'll never run!"

Congrats on "Fixing stuff"....I was simply sharing what CAN be done. I can't speak to those who can't.

 

I am glad you took the time to do some basic testing to ensure that the ESC system is working correctly or even took the time to do any datalogging to ensure that you have decent fuel trims under varying load and weather conditions before giving advice on this subject. The knock sensor and ESC module need to match the bore size of the engine it is running at a very minimum or else you have nothing in the way of reliable knock protection.

I ran a 383 TPI setup on a stock 350 TBI PCM and chip. Fired it up and actually drove it. Does not mean it ran even close to correctly even though it did not set a single DTC.

 

I did tons of testing! There is an entire thread documenting my test results, and it's got actual, real, objective data! Check it out, some time.

Here is the first test that I ran...



You can clearly tell that the BLM's are ALL f'ed up! Just a total mess!

 

That same engine that has since failed. Wonder why.....Then again I don't have to guess why.

 

You can guess all you want, but from your statements above, it's obvious that you haven't a clue, thus, your implications are worthless and show us how little you actually know. I believe that you read this already: It was clarified in the "10x the tork" thread. Had nothing to do with the ESC, BLM's, INT's, XYZ', or LMC's. But, I get it....you're in VAN LAND! Everything is different (made-up) over in Van Land.

Since you're comprehension challenged, though, I'll spoon-feed you (again): It was a beater engine, that had been poorly maintained. That's it. Lack of oil changes + hi miles + beatage = spun rod bearings. It's a pretty simple concept for most peeps to comprehend.

I'll add, Sure am glad that YOU aren't doing the diag (touching) my stuff.