Cascade Crew

[scott in wa.]

Hello all, its been a while but we have the car running with the new 350.
Its got some serious horse power. was a 305 now a 350 .060 over.
hot cam, all roller, ported heads, holley AFPR to 50 lbs, with 305 injectors



I buy passed the coolant to the throttle body and keep blowing the hose of the coolant vacuum valve that the heater hoses go into.
Its that plastic thing with the vacuum line on top.
Can I take this off? how do I route the hoses after I do?

Got a few other problems like idle surging, when I un plug IAC it doesn't do it. Bad IAC ???? did clean it but didn't help.

get a code 12 some times, o2 sensor?

all air smog stuff is gone.
thanks
Scott an son.

[Twilightoptics]

With that much upgrade and still 305 injectors, you'll need a 350chip and to atleast bump the fuel pressure to around 52 to compensate for the small injectors.

If you want to run the coolant hoses without the vacuum actuator... all you do is cap off the hard line near the frame/header. Let it run from the firewall to the radator. Then one line from the manifold outlet, over and around to the firewall.

[scott in wa.]

Thanks for the info.

1.by removing that vacuum valve will It be hotter??? run different??
2. when I unplug the IAC it stops surging, is it bad? I cleaned it but didn't take it apart.
3. Iam running all the 305 sensors, including the knock sensor, what will this do to the motor?
4. I get a code 13 once in a while, o2 sensor??

Iam running about 50 psi on the fuel rail (can't get it to go any higher). when I step on it, it halls. total smoke show.
it will spin the tires it 2nd gear also. I put a 2500 stall converter in it and modified the front pump to eliminate the tcc.
I put some headman shorty elite ceramic coated headers on as well.
but when I hooked up the rest of the exhaust we did lose allot of power, needs custom exhaust.

thanks much
scott and son.

[Twilightoptics]

All that valve does, is when you set of the heater to come on, it opens to allow coolant to flow through the heater core. I've run without one for a long time now. Some say they can tell a small difference that it's warmer inside the car, but I really doubt it. All the older cars had coolant free flowing through the heatcore full time with no problems.

Wont run any different, if anything you might see a decrease in engine temp because there is somewhere for the heat to dissapate, but again unlikely.

Not sure about the IAC thing, when you unplug it, it just means the ecm isn't controlling it and its constant. Something is telling it to surge. Might need a new o2. Sounds like it needs more timing. You NEED a 350 prom. You "can" run on the 305 one, but it's pretty cheap to get all timing tables/running routines to match your engine better. Idealy you need a custom tune. Try putting your base timing at about 10DEG BTDC. Might help a bit. With a 305 knock sensor, it wont sense knock. The 350 knocks at a difference frequency than the 305, thus the sensors are different.

Is it code 12 or 13? 12 is normal when you check codes. 13 is o2. Check your TPS voltage. Should be something like .45v closed and 4.00ish at WOT. Turn the throttle blade screw in more to open the throttle blades, this will make the ecm less dependent on the iac.

Burning the tires off isn't much indication of anything. Too many variables with tire type/size/gear/driving etc. I used to go by that too but sometimes I could burn the tires off better, and be slower in the 1/4.

Check the o2 wiring etc, maybe replace it. According to my shop manual:
\ Engine at normal op temp (above 70ºC)
\at least 2 minutes of engine time after start.
\o2 signal voltage steady between .35 and .55 volts
\throttle position sensor signal above 5% (about .3volts above closed throttle voltage.)
\all conditions must be met for about 60 seconds.
\If the conditions for a Code 13 exist, the system will not go closed loop.

Probably need a scan too to monitor the o2 readings.

Make sure all your checks and things are dont will the engine is warmed up. The ECM has different modes based on temp.

[scott in wa.]

wow thanks

As far as the prom goes, right know can I just get another computer out of the wrecking yard from another 350 car?
or maybe just the correct chip?
I wonder how much it will be?

Is it tough to change just the chip??
are there more than just one type of computer in these things?
or will I need a serial number off the computer?

with that prom from a 350 car, correct knock sensor, and correct esc.
maybe it will run better at idle.

thanks
scott

[Twilightoptics]

The TPI cars with a MAF sensor used the same computer 305/350.

In 90 then went to speed density and changed computers.

Since you have an '87 with the cold start injector you need to find a 350 CHIP(just chip) from an 87 or 88. '89 they ditched the cold start injector and added the VATS Vehicle Anti Theft System.

Chip changing is as easy as changing ram in a computer. ECM is under the bottom dash cover, just about the floor on the passenger side.

Prom/Memcal/Chip all the same thing. Plugs into the ECM(computer.)

Call your GM Dealer. Tell them you want the chip part number for an '87 Vin 8 350 TPI IROC-Z. Then go to www.gmpartsdirect.com and get it for 50-70$