tpi prom type ### ???

[74mike]

ok it getting close to spring, its time to get the computer going i think.
i've bought a 7165 ecm from a wrecker to go with my 88 maf tpi, but when i open the door i find i didnt buy the chip that runs it.

the tpi is from a 1988 305ho iroc, and its sitting on a 70's 4bolt 10:1 hotter hydraulic lift cam 355cid
should i get the factory upgraded 305 chipset ( to match the 19lb injectors ) or
the factory chip but tell them it's for an 88 350 iroc ( and buy 24lb injectors ) or
spend a sum of money on a hyperchip.
any experience or any help is appreciated

 

[KANE]

Yes-

You will need a chip for a 350. The differences are in the fuel demands and fuel maps as well as the signal from the TPS.

I would tell you that the easiest way to get a good chip is to go through someone like Howwell electronics, Arizona Speed and Marine, Street and Performance.

I like TPIS but they are rather pricey. You will spend about $110, and if you heve the engine the way you want it, you may not ever spend it again! Oh, sure the ECM will go out... but the chip won't!

 

[KANE]

Oh- you can use the 305 injectors but you will need to bump up the pressure on the rail..... I don't remember how much but I think its like 30 psi or so.

 

[74mike]

thanks DarkShark78, i know that the higher pressure will give a better spray pattern and finer mist but im worried about a lean condition at 120mph + (not that id do something as fun as that ) do u think the 19lb will keep up ? i will have a afr monitor as well as tunercat software to monitor/trend...

 

[74mike]

thanks DarkShark78, i know that the higher pressure will give a better spray pattern and finer mist but im worried about a lean condition at 120mph + (not that id do something as fun as that ) do u think the 19lb will keep up ? i will have a afr monitor as well as tunercat software to monitor/trend...

 

[patsnitrovette]

i had the 19lb injectors and the 305 chip in mine while i was getting everything setup and it worked fine ----120+ im not so sure.I replaced my injectors and went with 24lb.i picked up for $50 from a forum member and i had a prom made from jeff debuhr -moderator here on the c4 side for $150 shipped.You could leave it alone and bump the pressure up to 50.heres a chart normal pressure should be about 43-44


Injector size @ 43.5 psi

Pressure (psi)
40 45 50
19 lbs/hr 18.20 19.30 20.35
22 lbs/hr 22.05 22.35 23.55
24 lbs/hr 23.00 24.40 25.75
30 lbs/hr 28.75 30.50 32.15

 

[KANE]

Pat has the right info-

I didn't have my GM fuel inection book handy at the time...... sorry!

 

[74mike]

hi pat, looks like even at 50psi i'll still be short maybe, something else to play around with i guess what kind of fuel pump do u use( im changing my mind and am putting an external on as its much easier and more accessible)
how is your new chip working now ? did u have any knock / ping problems with the old firmware (305) ? i'll be using the esc setup for advance control ( automagic ), hoping it works right the first time.

 

[patsnitrovette]

im using a 96 vette pump inside my stock tank,but ill be swapping to and external soon.The new chip is alot more responsive now but it seems to take awhile longer to idle down but spring and summer time it should be fine,i havent got a chance to try it out on the road yet putting the interior back in this week then ill give it a run.I was getting alot of false knock with the sidepipes so i was told to take it out of the block and ground the casing ,so it tricks the computer,it seemed to work.

 

[74mike]

pat, ur saying u have removed the knock sensor ? how does ur esc advance work ? i was thinking of using the earlier hei with vacum/mech advance but i think i like the knock sensor control( in theory ). unless u can get the chip to ignore the spark control and error codes ?