On my '89 305 TPI there is a sensor, like a temp or knock sensor on my passenger side head between the last two spark plugs. What is it?

Matt

 

That's the fanswitch for the 2ndry fan relay. This is the one you'd change if you want the fans to operate at a lower temperature than the ECM is programmed to turn the primary fan on.

 

The switch is in a coolant passage, right? I'm asking this because I have a electric fan now and I need a spot for my cold start switch( my car is a '85 TA but the engine is a '89 and I don't have any way to start the car cold except for a ton of cranking, thats another story though)

Thanks,
Matt

 

Hmm... There should be a hole in the front of the intake for the cold start switch. Thats where it is supposed to go. If youre using an 89 intake though, a switch wont help because the injector isnt there.

But to answer your question, yea its in the water passage.

 

If it's the '85 with the 165ECM, I think you can use an '89 PROM, with VAT's deleted. This would eliminate the Cold start injector all together, hence the switch too. You could leave the CSI in, just to plug the hole, or fabricate a plug and clean up the lower runner area up some.

 

I have considered that but I have the stock '85 ECM. I do, however, have a ECM of a '86 just in case. I don't know how to update though. I have a '86 harness too, but I was told it won't work with my guages. I'll try to talk to Morley, I know he said he swapped the 165 ECM in. Any other ideas?

Thanks,
Matt

 

Well, you could tap into the Tstat housing ir neck for the CSI sensor...that'd be pretty close to the stock location, so there would be much extra wire to worry about.

You could also plumb inline to the heater hose that recirculates, or even onto the TB coolant line as well. I'm sure if you look it over well, you'll find a few places to plumb into.

 

Repinn the 85 Harness to the 165 ECM requirements, Throw in a PROM with ARAP and !Vats, plus added cranking fuel Vrs Coolant temp, and your golden.

Or... Forget the whole 165 ECM and Jump strait to Speed Density

I love you Madmax.... heheh

 

Well, if he was going to go that route and swap to a 165, I'd say it'd be a waste of time. Already have to buy an ecm and maybe prom. Not much point in keeping the MAF at all in that case.

I read your post on the tech board, you said you are using an 89 base? You have some real problems there. There is no hole in the base for the cold start to do what it was designed to do, so hooking up the temp switch for the cold start will do absolutely nothing. The cold start injector is on the driver side, and its run by a thermal switch, not the ecm. The ecm knows nothing about if its working or not. It injects extra fuel into the intake, separate of the other 8 injectors. Without a passage for the fuel to flow through, the injector being installed, and the switch turning it on, the system doesnt work. Need all 3.

 

I had the runners off once already, and I had the cold start injector, the '86 runner, and a '86 fuel rail bolted on. The intake base had a hole for the injector to fit into but I couldn't tell if it went anywhere. I thought the passages necessary for the cold start injector were built into all the manifolds because the internal design never changed. Maybe I'm wrong.

I didn't have to purchase a ECM, I got it from a parts car my friend has. I will only need the custom prom burned. I also took the MAF and MAF relays in case I need them.(I think I would since I'd be using the new ECM.)

I considered going to SD but the cost and work necessary seemed too much for me. I'm only a broke high school senior with basic mechanic skills.

Thanks,
matt

 

Now I could be wrong, or maybe I'm confusing my Accel base with my stock '89 base, but I was sure that the base had the hole in it, but the runner did not have the provision of the hole?

I dunno, too old, too many kids, not enough time to wrench on my car anymore....