maroguy1

85 Irock tpi 305 bought the car in pieces with a good body. Installed a 70's 350 that was bored to 357. Vortec heads sd baseplate stock runners stock throttle body. No emissions capped everything off. It starts fast and runs for a couple of seconds then kills. I can keep it running if I flip the throttle but it back fires thru the exhaust. Fuel pressure is steady at 50 psi and vacuum is about 20 near idle. Timing is rite on around 0 degees. No black smoke at all. It has a crane cam and 19 lbs injectors are from a ford 302. Which were working fine when pulled. Also my knock sensor is not hooked up where does it go?? I never saw the original motor so I don't know. Any help will be greatly appreciated!!! This is starting to mind boggle me!!!

onebinky

iTrader: (1)

Base timing for the TPI is 9 deg. advance if I remember right. Try changing that and see where it leaves you. Also, when you set timing, you need to unplug the little brown diagnostic plug for the computer advance, set timing, then plug it back in.

onebinky

iTrader: (1)

Also, depending on duration and LSA, that cam may be to much. TPI doesn't respond to large changes very well without reprogramming.

CaptPicardsZ28

I would agree but also he should have MAF which is much more willing to adjust itself to mods then a SD system. I modified the crap out of mine before changing to SD and it ran pretty well too. Your knock sensor should be accesible from underneath the car next to the starter. Also, you have plugged off your emissions. You may only get it to run decent with a custom chip. Set your TPS and IAC valve to their proper settings as well.

eric305TPI

Sounds like its leaning out after start up since you can keep it running by giving it AE fuel. First I would put the 22LB/HR injectors that came on the 350's originally and go from there. Make sure your closed throttle tps voltage is .54 +/-.06. Double check the timing with the Tan/Black wire between the distributor and the ecm disconnected(disconnect wire, then start engine and set timing, shut off engine and reconnect wire). Enough for now good luck.

maroguy1

Timing is a little bit hard to adjust when it won't idle. I have set it to 0 degrees and advanced it a little bit from there. I do have 19 lbs. injectors I bumped the fule pressure up to 55 and it stays there steadily. The Cam is a comp Cam not a crane and summit said it should work fine with a TPI. Thanks for the help I have a littel bit more to go off of.

Morley

Timing on the 85 TPI is 6* BTDC. The 85 code may be where your problem is, it has more things hard coded into the ECM than the 165 ECM's. Also, i believe someone mentioned the injectors being too small? I agree, 19 lb/hr isn't going to get it with that engine.

eric305TPI

Just curious but have you pulled a plug after it dies out to see what they look like?

ploegi

Uh, not to seem stupid here... but....... Are you still running with the stock 305 chip???????? If so, I am not surprised it won't idle.....

maroguy1

The plugs look normal. Yes I am trying to use the stock 305 chip. How much does a custom chip run and where is a good place to get one? The reason I stayed with the 19lbs injectors is that I emailed tpis and they said to stay with them and just add a pressure regulator. That way they will spray harder and atomize the fuel better than a larger injector. Does this sound correct?? Thanks for the help!!

ploegi

Ok, with the 305 chip. it is NOT going to provide enough fuel for a stable idle. You need to get a chip for a 350, just to make it run halfway decent. you may want to look into getting the stuff to do prom tuning yourself. It is WAY cheaper than buying a chip that probably won't work anyway.......


EDIT-------> Also, get the bigger injectors!!!!!!

Morley

Ditch the 870 ECM. It is an albatros. Do the repin & splice for the 165 ECM, Getthe ECM and a TPI calpack for it (if it doesn't come with one) The ECM will run about $50 on E bay and you'll need 2 $14 relays 2 $20 relay sockets (pepboys) or go to the junk yard and get the sockets and relays for $0. Get a larger set of injectors (the SLP 25# ones are a good price and work great at $100) Prom burner $80-$150 (depends on which one you want) programs to scan and burn...Free

kevinz85

would'nt a ecm out of a 85 corvette with tpi work ?

Morley

If it were a stock 1985 350, or any 350 with the same cam, heads, induction & injectors, yes.

maroguy1

Thanks for the heads up on the slp injectors that is a pretty sweet deal. I think i am going to pass on the ecm swapping I will get a chip burned alot less work and expense. Thanks

Morley

I thought so also, but due to the VERY limited support for the 870 ECM and the fact that a lot of the parameters that are programable on the 165's are hard coded into the 870's circutry. So, for about $150 I swapped to the 165 ECM, including relays, wiring, prom burner, a Craig Moates adaptor and a cheap $50 laptop for scanning/burning. The swap took 4 hours total and runs like a raped ape.

maroguy1

Well I think i found the problem I happened to unplug the mas sensor it thru a code but it was idling nice. So I am thinkin the sensor is bad. Just ordered one so hopefully I can get it to idle to time it and maybe just maybe someday drive it. Also just ordered injectors and a custom chip so hopefully this will work out. Thanks for the input. Also the cam I am running is mild. If you are interested the part # 12-314-4 at compcam.com

Captain C

Here are a few things to think about:

1. The Ford injectors may not have the same load as the Chevrolet injectors. Some years were a lower ohm load (4 vs. 16 I think) depending on the year IIRC. They are not compatible.
2. The knock sensor not being hooked up will cause it to run like garbage!!!!!! I just had that problem and it surged really violently.
3. The 85 Corvette had the “exact” same 870 ECM as the Camaro, just get the Corvette PROM and run it in your car. I’m doing that right now. Leave the Camaro CALPAK in your computer. Since you have 55# of fuel pressure, do that before you change the injectors.
4. When you can afford it, change the injectors to at least 22# injectors; go to 24# if you have a cam in it.
5. Spray your existing MAF with electrical parts cleaner. You might be surprised at the results.
6. I’m not sure what you meant by the “SD” base. If you meant “Standard” base, the intake won’t match the bolt pattern or the ports of the Vortec heads. The bolt pattern can be fixed with a lot of work....
7. If you meant “Speed Density” then you have other issues. Again, the bolt pattern won’t match but it can be fixed easily. Sounds like you have done that. The ports still won’t match giving you potential vacuum leaks or at least cruddy flow. The Cold Start injector is non-existent if you are running this setup. Therefore until the car warms up, it won’t idle worth beans. You will need to convert to the 165 computer and get an 89 chip. The 89 was the first year they removed the cold start injector. The programming is set to run richer until the car warms up.
8. The runners may have a vacuum leak in them where they bolt to the intake. I’m not an expert on the EGR ports on the later model units. All my notes are on a different computer. However, if you look deeply on this site you can find that info.
9. 6* was stock for that year car. Depending on the cam, you may want to try more. I run a ZZ4 cam in my 85. With the Edelbrock induction and headers it loves 16* advance. With the stock runners and base I would suggest 10* with that same cam.

maroguy1

The sd base is the scoggin dickey base intake for tpi and vortec heads. The cam is mild. compcam 12-314-4 I installed a knock sensor for a 350 nothing changed.

maroguy1

New mas sensor 24lbs injectors and custom chip is on its way!!!

Captain C

Just got a chance to check out your cam specs. A stock Corvette 350 chip will work great with your cam. It was about $50 at the dealer when I got mine.

With that mild of a cam, I would suggest 10* initial timing. Testing at the track will determine what works best....

Even if you have a bad MAF, you should be able to get the car to idle. It's a pain, but it can be done. Start the car and try to "ease" the throttle high enough for it to stay running until the car warms up. No blasting the throttle!!!!! If you do that it won't go into "Limp Home" mode. Once it goes into limp home mode you can set your timing. You can even drive it if you are easy on the throttle, i.e. no hot rodding....

maroguy1

I called my local dealership and they wanted like 90$ for that chip. I can get a custom chip for 75$. It was worth a shot. My new injectors and sensor came today it will be on tomorrow.