I purchased the ARAP bin part number 16134193 for the 89 Vette and installed it in an '89 Iroc L98 MAF, reset the computer and put the timing back down to 6 degrees..... But now I have a problem....the primary fan(the one on the drivers) side stays on all the time????? Any ideas? It didnt do it with the stock bin. On a good note the car idles a lot better and seems a bit peppier. Well that fan always running makes me think that the car is in limp home mode.....is there a way to check? When I turn the key to on but dont start it I get a solid SES light and no SES light while driving so I dont know.
Thanks for any help!!


[This message has been edited by BlueZ89 (edited April 19, 2001).]

 

You need to reverse the logic for the Fan Request Input. I had the same issue when I went from my 88 bin to the ARAP bin. I sent TunerCat an email with this condition, and they quickly updated the $6E TDF, by adding a new ECM switch. This allows you to change this request to "normally open".

It fixed the problem for me.

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Best ET 14.413 @95.57 without
pulling valve covers or manifolds.
Also with stock 2.77 rear end!!!

 

I there a way to do this without a programer.....I just bought the ARAP bin from the dealer so I cant reprogram it....can I buy a relay with the opposite function...you know normally closed or normally open? Dose anyone have any info on what relay I would need? Can I just buy the primary fan relay for an '89 Vette?

[This message has been edited by BlueZ89 (edited April 19, 2001).]

 

I think the problem is the pressure switch in the a/c line. Try unplugging the switch or place a jumper on it.

 

Is this switch available in the 89v4.ecu file that has been made available?

 

Yep, it's under the Flags tab, A/C Pressure Switch Specification Byte pull-down, the flag labeled N/O. The '88+ cars have a Normally Open pressure switch while the earlier cars are Normally Closed.

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Greg Westphal
'87 IROC 305TPI/A4

 

Ah, got it thanks.

Anybody know what flags b2 and b4 are on that same byte?

On my stock '89 APYU b2 and b4 are both flagged, while the ARAP only has b4 flagged.

 

MikeT 88IROC350 wrote:
You need to reverse the logic for the Fan Request Input. I had the same issue when I went from my 88 bin to the ARAP bin. I sent TunerCat an email with this condition, and they quickly updated the $6E TDF, by adding a new ECM switch. This allows you to change this request to "normally open".

When did they update the $6E def file?
According to the version #'s, I have the most recent one and I don't see it in there...




[This message has been edited by LeeH (edited April 20, 2001).]

 

I have an '89 Iroc-Z so why is the fan on then if only 88 and lower cars had this problem? Could I just get a different relay?
Please help!!

 

So I couldnt just but a normally closed relay for the fan but instead I have to get the chip reprogrammed? What is different abou the newer cars that use this type of bin? Why do the fans not stay on for the '89 and higher but my '89 stays on? I have no access to a prom burner cus I just bought the ARAP bin from GM. Please Help!

 

I guess you could probably replace the A/C pressure switch with the earlier style; I don't have my schematics in front of me to tell me if anything else uses the pressure switch though.

If your A/C system is sealed you obviously don't want to do this because you'll lose your A/C charge. If it's open/discharged, then you could probably just either unplug it and let it hang, or unplug it and put a jumper wire across (I forgot which one...)

 

B2 and B4 are for the highway mode spark advance. B2 enables it if the tranny is in 4th gear, B4 enables it if the torque converter clutch is locked.

------------------
Greg Westphal
'87 IROC 305TPI/A4

 

Maybe we can get that into the next 89v?.ecu file

 

I checked my service manual on this Fan Request input to the ECM. It is the Fan Pressure Switch that is causing your fan to go on. It is a normally open switch, and closes when the A/C pressure reaches 233psi. There are NO relays involved in this particular issue, so please do not think you can fix this issue by changing a relay. You could just pull the connector to the switch, and short it out, as a quick fix, to turn your primary fan off. I would also avoid changing out the pressure switch, as mentioned above.

Since you have an 89 IROC, I am surprised that you also have this issue with the ARAP bin. Kind of tells me that GM used the same AC pressure switches in many different year cars. Like I said above, it is logic condition in the ARAP code. Maybe they designed it for cars without AC??

As far as the update to TC's $6E TDF, they probably have not actually released an update with this new ECM switch added. I'm sure they need to make a whole bunch of changes, before they release a new TDF. I just emailed them with my request, and they sent me an updated TDF. So they must have this option available, for other folks who need it.

 

Well since I am pretty much screwed......and I know this request is not allowed on this board....but I have no other options other that to spend $200 on the programming equipment but I do not have the money...Would someone in Illinois like to help me out...I would like to get the memcal I purchased fixed....so here it comes...is anyone willing to reprogram the chip with a fixed ARAP bin for me? I will pay all shipping costs but it would be even better if I can actually meet with someone to reprogram it, I live in Burbank..... My email is lrnelson5669@home.com

Thanks!!

 

I will let Tim decide whether to leave this post open or close. Under the circumstances, I am prepared to let this post remain open.

But you should consider getting a Programmer and UV Eraser for future modifications. You will definitely find a lot of good use for it.

 

MikeT 88IROC350
I pulled the connector off the pressure switch and jumped the 2 leads and now the primary fan stops and the secondary fan starts!!!!!......What is going on here?? Please remember that this never happend with the stock programming..


[This message has been edited by BlueZ89 (edited April 21, 2001).]

 

The secondary fan runs because of the pressure switch. Your best bet is of course to get a new prom burned. BlueZ, where are you located at?

--andrew

 

Of course this does not help the person asking, but....

TunerCats 6E file does have the switch you are all talking about. You just have to scroll down to see it (one thing I dont like about TC is it does not scroll correctly when resizing a window).

Remember the ARAP was created for Y bodies, which have the correct relay (although I did hear of one Y-body with this problem after switching). Also FYI...my 86 did not require any modification to that flag in the bin, but my friends 87 & 88 did, so I guess they changed the relay in 87.



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Mike Metzler (Desert86Roc)[*] Webmaster: SpeedWorldMotorplex.com[*] Click Here For 86 IROC 305 TPI (406 build in progress) Page

ET's @ 1250 ft[*] 14.28 @ 95.461 mph (uncorrected, NOS, no headers)[*] 15.365 @ 86.785 mph (uncorrected, headers, no NOS)

 

When you say Y-bodies, you mean Corvettes, yes? But if this ARAP bin was made for magazine test cars, such as Camaros and Firebirds, then why didn't they have the correct logic for the fan control? Did the test cars not have AC?

 

Nobody wants to help me

 

BlueZ89- E-mail me off-list if noone has helped you yet with this. ae2598@wayne.edu

 

Slow 89 Iroc/Blue89Z, I would help you more if I had access to a MAF car.

Some of these problems you get lucky and someone has been there before and other times you are off in "nether netherland". Those are the challenges sometimes. I am pretty sure this one will get resolved.

[This message has been edited by Glenn91L98GTA (edited April 23, 2001).]

 

Anyone else want to lend a hand? Please read the entire post I am not begging for a custom PROM. I just need mine fixed.

 

You have already been given the answer to the problem...it is up to you to fix it.

- Get a .bin editor and chip burner
- Change the flag for fan relay
- reburn your chip with the corrected info

If you are asking for 1) someone to make a bin for you, or 2) someone to burn your chip for you...then sorry, but you are begging for a custom prom.

I know ...sounds a bit harsh, but I got slapped down for asking the same thing a while back. So I just bought the software, found a burner, and did it. Not hard to do basic modifications once you have everything you need. Read the article at the top of the page

[This message has been edited by Desert86Roc (edited April 26, 2001).]