Im rebuilding a 89 350. I used to have an 86 305 TPI. I already got the 89 intake manifold. Two diffrenecs i can see. 1 no place for the cold start switch. I dont think that will matter b/c im gona use an 89 350 chip. 2. The egr valve on the 86 manifod has a "wire" coming from it. And the the 89 doesnt. Should i swap these? Also can i use my 86 Runners and plenum? Even if i have to install the coldstart to plug the hole in the driver runner. thanks Alex

 

You are refering to the EGR thermostat.

If you are going to use the 89 ECM and harness, and the harness has no provision for the EGR thermo sensor, you can use either valve, just cut the lead off the 86 EGR thermostat.

I'm not sure when GM dumped the EGR Thermostat lead, so you may want to check, just to be sure, that the 89 and up's have no thermostat.

 

Well im going to use my 86 wiring harness and i was just hopeing to just put an 89 prom in my ecm. and connect everything from there. Or cant i do that

 

Well.... I dunno. My current 88 harness is a lot different than my old 86 harness was, and both are different from the 89 harness.

I don't know if there is anything in the prom/pinout that would affect anything adversely. My 86 had an extra relay, and the other two appear to be different (at least in looks) as well. I don't know if those pins were reassigned in the later harnesses (which might affect what the prom thinks it's controlling or see'ing voltage from), nor do I know if the EGR thermo/Cold start pins were reassigned in the later harnesses.

IF NOT - I'd say you are likely to be okay. I'd look into some pinouts over the years, and see if anything was reassigned or changed, or if the extra leads were simply deleted from the clip all together.

 

The 86 uses an EGR temperature SWITCH.

When EGR is commanded via the EGR solenoid, that switch SHOULD see the increased temperature as the exhaust gasses pass through it. If it DOESN'T, the ECM doesn't see that switch work as it should (its just open/closed) and if EGR is commanded, and that switch doesn't operate, it should throw a code.

Dunno about the later stuff, just what I've dealt with on my setup. I *thought* later stuff actually monitored EGR temperature, but I'm not positive.

 

Made a big deal out of it being a "SWITCH".....



I'm sorry, it's a switch that performs every function of a thermostat, and in any other mechanical device would be know as a thermostat, in the nature that it measures tempature to control an action or activity.

 

You need to work on your reading comprehension, and your comprehension of how things work.

Go ahead and read your definition again, then look at my description. Thats right, the switch doesn't regulate ANYTHING.

Put a temp switch in place of a temp sender and see what happens.

As to your personal comments, if you can't take being wrong, that's your problem, and something you need to work on. If you can't discern that caps are a way to bring attention to something, without being a personal attack, you've got some real pride issues. Great way to make friends and get help, be a jerk.

I hope I get a chance to repay your kindness when you ask for info.



edit: For those that can't see what GOY posted because he edited his post, (not for clarity or correction of course) he previously posted a definition from dictionary.com for "thermostat" that stated a thermostat regulates temperature. Along with a comment about being picked on in high school or something. Since he was incorrect, (on both accounts lol) the EGR switch does not have the capability of regulating temperature at all, he has removed the evidence that proved it, in order to make himself look better.

As anyone that actually knows the system can tell you, The EGR switch simply indicates via the SWITCH (to the ECM) that the ECM's command to the EGR solenoid to allow exhaust gas through has been accomplished, and the engine is now seeing EGR.

Hopefully most people understand the difference between a switch and a thermostat and won't be misled by his posts.

 

What makes you think I'd even acknowledge your input? You might be *** and know everything in your mind, but there is always going to be someone with more accurate information than yours.