yaj15

iTrader: (3)

Charlie did you figure out how to get your temp gauge working? Mine is stuck in the same position as yours is in some of the interior pics.

chazman

iTrader: (4)

Let's see......

Just driving it back this morning, I noticed my right rear turn signal doesn't work, probably has something to do with removing the tail lights a couple of times last week.

My right front tire has a leak.

Need an alignment and the steering wheel centered.

Need to check out the fuel return line - smells like gas.

This car runs hot. I hate that. It's okay on the highway or with air on, but the temp climbs quickly in traffic. Time for a 160* t-stat and fan switch/chip.

Below 1/3 tank, the fuel pump screams enough for me to want to drive it into the lake.

Hate my tires. They are old and are mud and snows.

The oil pressure gauge annoys me. It's fine when I'm driving, but when I'm idling the needle gets into the lower half of the gauge.

Probably some other stuff too......

chazman

iTrader: (4)

The needle was stuck in the bezel. Motown clued me in earlier in the thread...

yaj15

iTrader: (3)

Thanks for the tip. I'll have to work on that next time I get the chance.

eseibel67

All problems those can be fixed in time, but the only one to worry about is the overheating. Good news is that at least one fan and relay works because it runs cool in traffic with the A/C on. There are some really good diagnostic tips on cooling fans in the "cooling section".

And don't worry about the oil pressure guage, it's supposed to be in the lower half when idling.

1MeanZ

iTrader: (9)

Charlie's 85 only has one fan. It's the big single that early TPI can all TBI cars have. Charlie, the factory fan enable temp is 227* Yes it's hot, the only way to fix it is to modify the chip or add a manual switch. A cooler 'stat won't help you a bit, if you replace it go with a 180, 160 is too cold. If you end up bringing this car to TGF I may be able to throw a chip in it for you, but I gotta be honest I've never tuned an '85 and they are different, but I think I can work with it. I may be able to play with my buddy's '85 Z28 here locally before TGF if I know for sure I'll be working on your car. I have an extra adapter and chips I can sell you cheap. I'll have my laptop and equipment with me. I tuned a guy's car back in '10 and it was a new machine after I was done! LOL

burnout88

I run a 160 t-stat and hypertech automatic fan control switch. Turns the fan on and off without any tuning in the chip. http://www.jegs.com/i/Hypertech/533/4026/10002/-1

chazman

iTrader: (4)

Okay, that makes me feel better. My other two never go under the midline (30 psi).

chazman

iTrader: (4)

Yeah, I remember. It only took you a couple of minutes, too.

chazman

iTrader: (4)

Seems like the simplest appraoch.

1MeanZ

iTrader: (9)

no it isn't because what he is talking about only works for dual fan cars which your '85 isn't.

I know you guys are trying to help but you need to get your facts straight first.

eseibel67

170*F or 180*F thermostat is good. Sounds like that car might have missed some scheduled maintenence in it's life, a really good cooling system flush and fill is always a good idea on a 27 year old used car.

I checked the wiring diagram for 85 TPI Camaro, and the single fan is controlled by either A/C, or by thermo switch in the passenger side head. Since the fan in Chazman's car runs when A/C is on, the relay is good and the switch is suspect.

If you are going to run a cooler than stock thermostat with single fan, the simplest fix is to replace that switch with one that comes on at a temp that is lower then stock. At the parts store, ask for a radiator fan switch for a 1987 Buick Regal V6 turbo. Part # will be Standard Motor Products TS136 or AC Delco D1882D. I tested these switches in a pot of boiling water, they will turn the fan on at 210*F, and turn if off at 195*F. When installed in the car, that means the fan will come on in traffic, and it will shut off shortly after you get underway, so it's perfect.

1MeanZ

iTrader: (9)

that is great info. Sounds like the 85 TPI stuff is like the TBI setups, fan control is not in the chip at all, I was wrong about assuming the 85 TPI stuff was like the 86-87 stuff. Guess I gotta get my facts straight. Sounds like the other temp switch is the ideal route unless you want to convert the car over to 86 and later electronics which is not all that hard either.

burnout88

Easy does it my friend. It should work just fine. 85 TPI should also still have a fan switch screwed into the pass. side head just like the single fan setups on TBI cars and early HO cars.

I have not looked at an 85 TPI car wiring in awhile but if I recall the factory ecm control is 220 and then the pass side cyclinder head fan switch is 238 degrees (kind of a "O S-h-i-t switch").

You just use that pass. side switch to turn on the single fan earlier then the ecm does. Very simple.

1MeanZ

iTrader: (9)

I apologize for being rude. I felt like Charlie was getting led astray and I wanted to make sure that didn't happen. In the end it was me leading him astray because I'm not intimately familiar with the '85 setup. I ASSummed that the 85 cars were like the 86-87 TPI cars.

One point to clarify however, you seem to state that the '85 ECM has a fan temp in the program. Are you sure of that? I know for a fact TBI cars DON'T have a fan enable temp in the .bin. If I ASSume that the HO cars and the 85 TPI is like the TBI cars then the ECM has no control over the fan, it's only the AC pressure switch and the temp switch in the head and that's it.

If I can change the enable temp in the tune then that is easiest, but at this point I'm doubting that we can do that. In that case the lower temp fan switch makes more sense.

chazman

iTrader: (4)

Thanks all of you guys for your help. You're all my 3rd gen bros!


Anyways, tonight I took the car out for it's first longish ride. My son and I went to a cruise night about 20 miles away. On the way back home, my check engine light went off and my speedo stopped working. I came home and whipped out my paper clip and got code 24. That's my vehicle speed sensor circuit. Makes sense. Probably the trans guys didn't secure the cable.

Tonygxp

my 84 ho Z28 had that problem. big radiator = same problem idling and in traffic without AC on. changed all coolant related switches on the car and one in the head = same problem. I ended up giving up and installing a manual switch for low speed and idling inno AC situations (like a "panic" button). One alternative is to buy an aftermarket radiator fan switch. probe goes into the radiator fins and it uses a relay to turn the fan on and off, also has a jumper wire for the AC compressor. I've isde them in the past without issue (if you cannot ID the problem) If it's done properly nobody would ever spot it or be the wiser and there's nothing wrong with it.

burnout88

The 85 TPI single fan DOES have ECM control of the fan. I am sure of it. And you should be able to reset the fan temp in the chip. This guy has an 85 TPI BIN posted on his site that you can look at to verify. http://www.eecis.udel.edu/~davis/z28/index.html

And even if there was no secondary switch in the head you could still use the Hypertech fan temp switch to turn the fan on early. It's just a thermo switch instead of a manual switch. A switch is a switch. You would just wire it in place of using a manual override switch. Still very simple and the hole for it should still be in the head. Because right now I am starting to question myself if the "o-s-h-i-t switch" is really in the head of an 85 TPI. It's been so long since I looked at my dad's 85 TPI car.

Charlie, would you be willing to jack up your car and take a look at the passanger side head between cylinders 6 & 8 and tell us if you have a brass looking sensor screwed into the head. You will have to look from below because the exhaust manifold is in the way to see it from the top.

1MeanZ

iTrader: (9)

good info in that link. I'm going to pull a few of those 85 .bins into tunerpro and see what i can do with them. A good friend locally has an 85 Z28. I may ask him to bring it over and see if I can play with it. I'll keep you guys posted.

Charlie, if I can change the fan temp in the chip, we're golden.

On your speedo issue, the speedo cable may have come loose from the trans or it may be broken. NAPA can get new ones that are of decent quality, I have one on my IROC. You may know this, but the speedo cable should be in 2 sections, either section could have failed, the union between the cables should be around where the driver side frame rail goes into the firewall.

yaj15

iTrader: (3)

I had a question about the brakes on the '85 IROC's. I was looking at one online that was for sale and it didn't have disc brakes on the rear. I know with the L98's the disc brake rear was a mandatory option. Were disc brake rears mandatory for the '85 IROC's?

chazman

iTrader: (4)

Took it to work today and purposely left the AC off so I could watch the temp. It ran a little hotter than my other two do, but never hit 220. I also didn't get a gas smell today. The trans shop drilled out the broken bolt on my cat and replaced it. Last night, I was getting an exhaust drone at idle, that seems to be gone today as well. Strange. Maybe it's healing itself.

I removed the airbox baffles last night - I'm sure I'm up about a 1/8 hp.

It does move through traffic with more authority than my Crossfire. Trans shifts great. Exactly what I wanted from it.

Brian, I'll either get it jacked up, or get a look at it when I take it back to the trans shop for the speedo.


yaj: My car has Al drums. Those were the standard fare brakes for that year. I actually don't mind them, in fact they may even work better than the cast iron rear discs. Just wish this car had a posi. The motor with a 3.42 simply outpowers the right rear tire.

yo soy el warg

Was your car built in April, May, or June of '85? All the California Irocs came with everything but posi which didn't make much sense! All 502 were built from April 1, 1985 and later. They might have ran out of posi units at the end of the production year in 1985. Just a guess. Also, all the Cali Irocs had 3.42 gears.

chazman

iTrader: (4)

May.

yaj15

iTrader: (3)

Hmm thats kind of strange. I know I would want disk brakes. I am looking to upgrad my brakes to the 1LE style on the front and '89 up PBR rear disk brakes. I have the J65 4-wheel disk with the single piston calipers.

You have to get a posi on that rear end when you get it rebuilt. 3.42 gears with all the low and mid range torque on a TPI ha ha I can understand your traction issues. I don't get why GM didn't put in a posi in that car especially since you have 3.42 gears. I guess we can thank the bean counters for that. I am sure that a non-posi rear end was cheaper to make than one with a posi. I still think for a long runner TPI car that 3.42 gears are the equivalent of 3.73 gears for cars with shorter runner intakes.

I have 2.77 gears with a posi with my L98, full exhaust, and stalled converter I can easily spin the tires any time I want, especially in first gear. I have to be careful in the rain to. Downshifts can also break the tires loose.

Motown

Wow mine always sits on 220 while cruising and climbs enough for the fan to kick on in traffic. This is with ambient temp above 60 degrees.

Thanks for that little note Charlie. I think its time I flush and fill my system! I also want to do that Regal temp sensor mod that was noted a while back too...

KMK454

I've searched the forum numerous times but can't determine what is "right" on this... I know these cars were designed to run hot from an emissions standpoint. That being said, what is right? Here's what mine does, and the car is completely stock:

Highway cruising - 180-190.

Traffic, stop and go driving - 190 and it will creep up. It keeps creeping up until it passes 12 O'Clock (220). Around 220 to 230 you can hear the fan switch on. It may drift a degree or two higher before it comes back down slowly but surely.

The first time this happened, I worried thinking the car had a cooling problem. The coolant was recently flushed and cleaned, but that temp range didn't seem right. I searched TGO and can't find anything conclusive, but can't find anything saying this is wrong online or in the car's documentation. Regardless, if I could keep it south of 220 all the time I'd be happy.

Aside from where the needle points and the fan switching on or off, there isn't really any change in the car's driving behavior.

chazman

iTrader: (4)

I think that is correct - but it makes me nervous. I seem to remember my black car doing that when new, (loooong time ago), and I installed a colder t-stat and Hypertech chip which turned the fans on sooner. It never approached 220 ever again. Nor does my white car.

KMK454

Yeah, I am gradually concluding that this is factory correct behavior. Of all the old and new cars I've toyed around with, none have ever had cooling behavior like my thirdgen. But this is also the only 80s/90s GM I've owned. I looked at some Monte Carlo forums as well as some C4 'vette forums and their motors tend to run a little warm from the factory.

I get worried when I put it in the garage. It's a few stop and go roads to get to the house, followed by a slight incline driveway that is tough to get in to. And of course, I have to back the car in as parallel as possible to the garage wall, so this may require some adjusting. By the time I shut it off it's crept up to 220.

Looks like a 180 Tstat and chip are in the future...

chazman

iTrader: (4)

I am and have always been a third pedal guy. I've driven a stick virtually every day for 30 + years. With that said, I have an appreciation for an automatic trans which works nicely.

Saturday night, on the way home, I turned onto a 4 lane road and was going around 15-20 mph. Ahead, was a huge gap before any other traffic. I floored it and the trans quicky and smoothly down shifted into 1st, revved to 5500 RPM, delivered a high quality firm shift into second, and then revved to 5000 RPM before shifting smoothly and quickly into third. This tranny rebuild was an unexpected expense. But....there is no way that I could have been happy with the sloppy shifts I had before.

If this car had traction, I'm convinced that it is a mid 14 second car.

yaj15

iTrader: (3)

I've heard a lot of different theories as to why our cars run hot from the factory. Most of the theories that I have heard centered around fuel economy and emissions. I would like to see some real science / engineering evidence to back this up though.

I have heard that at the higher temps that our cars run stock, the fuel burns more efficiently. This may lead to better fuel economy and emissions results.

With that said, I know there has to be a sweet spot between the extremes of too hot and too cold in terms of operating temperature with respect to fuel economy and emissions.

When you guys installed lower temperature thermostats did you notice an increase in power and fuel economy? Did you notice a change in your emissions test results?

chazman

iTrader: (4)

I've been running a 160* t-stat, (with chip), in my '89 for well over 20 years. It's emission exempt because of it's age now, but while it was being tested, there were no changes in emissions, I didn't see any changes in fuel economy, but the throttle did feel snappier.

For a while I was getting worried about the so called effects of "super cooling" and not going into close loop, but we know now that those were false claims.

If someone drives their car in the winter, maybe a 170 or 180 degree thermostat might work better, as far as having your heat work. But I don't drive it in the winter - in fact, I've probably only had the heat on once or twice in 23 years.

yaj15

iTrader: (3)

Ahh I see. I didn't think it would change the emissions but I wasn't sure. I'm still running the stock thermostat. Well it still would be intresting to see if there was a good performance gain though. I don't think it would be all that much. There is just so much information about changing the engine operating temp without too much scientific data to back it up on a lot of these websites.

1MeanZ

iTrader: (9)

My buddy brought his 85 Z28 over yesterday. There is NO switch in the passenger cylinder head. The fan is ultimately controlled by the ECM which can also get a signal from the AC pressure switch. I also opened up his ECM and it does not have a replaceable MEMCAL like the 86 and up cars do.

Charlie if I were in your shoes, I'd put a temp switch in the passenger head and wire it inline with the AC pressure switch. That way either the temp switch in the head or the AC pressure switch can go to ground and tell the ECM to turn the fan on. This eliminates any horsing around with the chip. As long as you can get the plug out of the head to make way for the temp switch, you'll be home free and this would be the cheapest and easiest solution to your temp issue.

chazman

iTrader: (4)

Hypertech has this older style chip available for use with a 160* t-stat on my car.

http://www.summitracing.com/parts/HY...RO&prefilter=1

burnout88

Interesting, no high temp switch in the head. Only ECM control. I agree it would be very simple to just pull the plug out of the head and throw in the thermo switch and wire it up.

Also, the chip is removeable from the board. It's just a different style chip then the 86 and up. Looks like it will not come out but it is removeable. Just give it a good pull and it pops right out. No release tabs like the later chips.

chazman

iTrader: (4)

Hey Brian, I saw your dad and met your brother, (with his insane 1000+ hp Mustang), at a cruise night Saturday.

burnout88

Funny, I think my Dad goes to every cruise night in the Chicago area. It's always a good place to find him. My brothers car is scary fast. I think it runs low 9's in the quarter mile. He is not exaggerating about the 1,000 hp. Did you get a chance to have my brother look at the door dings on your 85?

chazman

iTrader: (4)

No, I didn't even think to ask him. He just happened to be parked right next to me too.

When he pulled in, I thought it was just another SN95 GT with wheels and exhaust, until he popped his hood. Holy smokes!

White93z34

iTrader: (1)

Do the dual fan cars run that much cooler?

my old 87' SC with a LG4 and single fan ran hot everywhere, no matter what it always seemed to want to overheat. However my 87 IROC LB9 runs very cool overall. Only thing done to it is a 180* tstat. In traffic it will climb a little but the fans will keep it in check no problem. Maybe a PO installed a cooler temp switch, I really don't know but AFIK its bone stock outside the 180* tstat..

chazman

iTrader: (4)

Stopped by the trans shop first thing this morning to see what the story is with my speedo. Apparently a speedo gear clip walked it's way out, and the gear ate up it's driven gear. They put in a temporary gear until they can locate the correct one. My speedo now indicates about 10% slower than actual speed.

While they were doing that, out of the corner of my eye, about a block away I saw a car which interested me. I walked over to an apartment building parking lot, and checked out someone's daily driver - a '77-'79, Nova Rally, 4 speed. It was beat and rusty. The paint was so faded, that I couldn't tell if it was black or dark blue. But somehow, I was smitten by that POS.

chazman

iTrader: (4)

Went back to Ace Transmissions for the new speedo gear.

I did put a note on the windshield of that rusted out, p.o.s. Rally Nova, in case the owner wants to sell it. Lord help me! It is in fact blue, now that a couple days of rain have given it a good bath.

The IROC, BTW, shifts superbly. Just what I wanted.

burnout88

Is that the Ace over in Hanover Park/Streamwood on Irving Park Rd?

chazman

iTrader: (4)

That's the one.

burnout88

Good shop, that is where I would have gone.

chazman

iTrader: (4)

Good to know, Brian.

chazman

iTrader: (4)

Hey Brian, (burnout88), I saw your dad last night and he took his '85 out of storage. He said that seeing my '85 a couple of weeks ago inspired him to get his '85 out.

burnout88

Funny, I just taked to him today before you posted this and he told me seeing yours made him want to take his out of storage. Take a few pics of that car and post them up in the forum. I am sure everyone here would like to see another low mileage original car. My Dad is not good with computers and does not have a digital camera. The car is also that unique off-white color. A shot of the rpo codes would be cool also.

chazman

iTrader: (4)

Next time I see him, I'll snap some pics. It's kind of a unique car. For the rest of you guys, it's an '85 Z/28, beige, (yes, beige), with gold ground effects and wheels. It's got an LB9/700R4 with what I assume is a 3.23 rear.

It would be interesting to get a shot of the SPID sticker........

yaj15

iTrader: (3)

Hey Chaz,

I'm thinking of doing a gear swap in my car. Right now I have 2.77 gears and I was thinking of swapping to 3.27 gears or 3.45 gears.

I have only drove one TPI car that had steeper gears than mine and that was 11 years ago. It was a 91 L98 Z28 that was all stock. I've made some mods to my car now so I can't use that car as a good reference point anymore.

Have you driven a TPI car with the highway gears like mine? How much did the performance increase compaired to your cars that have 3.4x gears?

chazman

iTrader: (4)

Sure, I've driven virtually every combo, but it's been a long time.

On the 5.7 the 3.27 definitely feels faster than the 2.77, obviously.