Ken,Chris and Tpis

[maxrevs85]

Iknow you guys have spoke with Tpis more then a few times so, I have a question. Pertaining to their prom,I bought there level V and one of the things I listed was that I'll be using a 180 thermo stat and the specs on the paper I got with it, shows this. My question is will this prom control when the fans come on and off or will it require new switches? Thanks guys.

 

[Bob86ZZ4]

I would call them up and talk to them. Or, you can just start up the car and wait for it to warm up and see when the fan comes on. Then you will know what temp it comes on at.

 

[Ken]

Your fan switch is a separate control from the PROM I believe. The pusher fan temperature sensor is located in the driver side head between #1 and #3 cylinders.

_ken

 

[Bob86ZZ4]

I think that's correct about the pusher fan. But the main fan is controlled by the prom, I think.

 

[maxrevs85]

I have talked to TPIS, my engine has most of there mods. I also know that ken and Chris talked with them more at this point in time and was just curious to what they might have said on this subject. I'm sure I'll be speaking with them when the engine is finished and installed. We've had a few conversation already.

 

[maxrevs85]

Ken, thanks.... Bob ,thanks to you too.

 

[Ken]

Hey Dave, Bob's right about the main coolant sensor; it is located in the front of the intake manifold and the signal is sent to the ECM. Your booster fan is a separate sensor in the driver side head. You can get a sensor with a lower set point at which your fan turns on, and they also have a kit with a switch that you can use to shut the fan off when it isn't necessary, like when you're at highway speeds. The lower temp sensor enables the fan to come on at 185° but the engine never gets cool enough (185° or lower) to shut them back off.

_ken

 

[maxrevs85]

Hmmm ,food for thought .......that helps alot......just doing some forethought on what I might need to do when its time to fire it up. Would like to heave the right sensors screwed in ,if possible, before the engine gets set in. I'll call TPIS and get the right stuff coming. Thank a bunch again. :cool

 

[89ZZ4]

Dave:

In the "For What It's Worth Section" My ZZ4 Crate engine with the TPIS Mini Ram/ZZ-409 Cam/TPIS Level VI Chip/TPIS Headers and cat back is running with all stock sensors and a 180 degree thermo. The crate engine is also using the original vette oil pan and oil pump but the Z51 package comes with the extra coolers package. More HP - more gas - more heat. The stock L98 ran steady 185 to 188 both oil and water and when you got on it a couple of times they would climb to 193-196 oil and water. The new combo runs 186-189 water and 188-192 oil cruising and when you get on it a couple of times I"ve seen the water get to 197-199 and the oil will get up to about 209-213. I think the stock level sensors would work fine - as Ken said they will trigger at least one of the fans and it won't turn back off as it's always going to be over 185 water temp. You will have a great package no matter which way you go on the sensors.

Phil (aka 89ZZ4)

 

[69MyWay]

Dave,

I have no personal experience with the TPiS chip. The suggested a stage VI for me. Jeff here has been tempting me to buy this crazy little machine and try burning my own.

The computer does regulate when the fan comes on as a result of the temp sensor in the head. There is a faker/lower temp sensor you can buy that will make the computer turn the fans on early.

The chip will just tell the fans to cycle at a lower temp as well.


I don't trust either one of them. I have been using a fan control relay kit from hayden for years in most of my cars. It uses a snap switch in the radiator and wires seperate from the computer.

I have it now turning on at 180, and off at 170 ish. In the warm weather and with the a/c, I am still running around 210 with both fans kicking, bumper to bumper traffic etc.

 

[maxrevs85]

Thanks Chris and Phil. This has been good feedback. The radiator seems to be in good shape .I'm not sure if its original or not. I guess you never know till you get it get it running. I could have it presseure checked . Its clean though. I think I'll leave it all alone untill its necessary to make the change. Dang ,cant wait.
Thanks again, and to you to Ken.

 

[-=Jeff=-]

Jeff here has been tempting me to buy this crazy little machine and try burning my own.

Who ME ???

Yeah, Burning PROMs is not easy.. takes some time to get it right. This is why aftermarket PROMs are so much $$$. But Even they cannot get it 100% correct with the first one. Granted most PROM burners have been doing this for years but still every motor has its own little quirks that will need fine tuning.

I had a Tuner PROM in my Vette when I have the old ECM it was WAY rich. when I looked at the PROM on the computer it was still set for 22# injectors and I stated on the form for the PROM that I had 24#. I got it real close to perfect.. But since I swapped to the 1991 ECM and Dash I am starting from scratch again.

 

[boblx2a]

Tpis

Dave,
I too have an '85 and have just overhauled the fan system this past weekend. Having gone through a host of nightmares this is what I learned.
There are two fans and two relays. The fan in front, in the fan box, appears to be the main fan and is controlled by a thermal switch in the head on the left side of the motor, carefully tucked in between plugs 7 and 8. yeah, have a party! The relay for that fan is on the left inside fender well. The other fan is the one you see in front of the engine and it's relay is back behind the battery. Well on my car it was lying loose hanging by the cable and there was an empty relay back behind the battery so I assume that is where it was supposed to have gone.
There is another sensor, as ken pointed out, between plugs 1 and 3 on the right head. I asume it is used by the ECM to fire that relay back behind the battery.
I installed Ecklers 200 degree switch which now turns them both on at 207 degrees and off at 86 degrees. Been driving the car for 3 days now and it has not yet got warm enough to turn them on.
All I can be sure of is that normally, in an '85, the left switch turns on the front fan. The rear fan may be turned on by the ECM or the right switch or both. But I like it the way it is now. Nice and predictable.. No ECM involved and the temp drops like a rock when those fans come on.

Good luck with it, you seem to have lots of help.

 

[maxrevs85]

Thanks Bob for the info . It will help make short work of figuring out the relay part.

Jeff ,I hope I'm not in for a tuning nightmare with the new prom. I think TPIs is pretty good and reliable and I think they will be of some assistance.

 

[-=Jeff=-]

Thanks Bob for the info . It will help make short work of figuring out the relay part.

Jeff ,I hope I'm not in for a tuning nightmare with the new prom. I think TPIs is pretty good and reliable and I think they will be of some assistance.

Dave,

Ask TPiS if they are willing to adjust the initial PROM after they send it to you if you take DIACOM readings.. Like I said it will be close but not perfect

 

[maxrevs85]

Ok I will ask them. .....Diacom readings ? i dont remember what that is.

 

[-=Jeff=-]

Ok I will ask them. .....Diacom readings ? i dont remember what that is.

DIACOM or EASE Diagnostic readings.. similar to Auto Xray but you use a laptop

 

[maxrevs85]

Uh oh....I dont own a laptop and doesnt it take a special program to run it.....Man , I am sooo not up on the computer end of this set up. I was hoping it would be a plug in and go deal . But , its not going to be the case, right? In havent been able to find any info that realy talks about the tuning process. What should I expect?

 

[-=Jeff=-]

try here for some info

http://www.thirdgen.org/techbb2/forumdisplay.php?s=&forumid=16

but you may be just fine with a PROM as well

 

[maxrevs85]

Wow thats a coincidence, Its the same site that TPIS sent me too for info on upgrading to the 86 ecm which I saved. They told me that the problem with the 85 ecm is that it doesnt have the capabilities to down load enough info fast enough. The web site confirms that and shows the difference. The changeover appears to be more then I might want to tackle . So if i get a laptop and the necessary connectors, will I need a certain program to run it? (I have know Idea what the proper terminology is ) ;stupid