What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Camaro overheating

Problem started one day. Hadn't made any changes to that point. Was a hot day out and bam boiling.

The tune is from a PO.

I don't drive this often and it's kinda been shelved for the last couple of years. Needed to do the clutch on it and try to figure out an oil leak. Got the clutch done, think I know where the oil's coming from, but that's another project for another day. So looking at this heat problem as the next on the list.
 
I know we've talked about the tune on this. I'm not a tuner, and don't know HP Tuners that well. But I pulled the tune out of it, and found a 'factory' tune from hpt website and compared them.

A couple of curious things I noticed.

1. They LOWERED the idle speed. Not a ton, but a little in part of the coolant temp range - even though the cam is a little bit larger than factory.
2. They changed the spark fairly significantly in the idle range - which could be a problem.. But again, I may need to post up some screenshots for someone smarter than myself.
3. They change the LTFT boundary's.. And I'm not sure what effect that would have any why someone would do that. The ECM in this is a bit more basic - the tables are smaller than the 0411's but yeah.
 
That's what I was thinking. Not sure if it will idle or not. Some people said it would some wouldn't with this cam. Was borderline
 
It could be that this cam/tune is making more heat than the stock setup. With a bigger cam, you usually raise idle to smooth out the loping. The fact they lowered it may just be personal preference, but it also means the water pump is turning slower. It's hard to comment on the changes without actually seeing them, but the more ignition advance you run, the more heat is in the head and block. With less ignition timing, you transfer more of that heat to the exhaust. Typically these engines idle at stoich, but adding fuel keeps it cooler, assuming you won't hurt the cat(s) or O2s. The changes are probably there for a reason and seeking cooler temps may result in degraded idle quality. I'd say it's definitely worth looking through, as there could be a mistake, or at least room for improvement.

Have you scanned it to know AFR/LTFT/Advance at idle?
 
How about a smaller water pump pulley or a pump with higher flow? It should be easy to adjust the idle up (even something stuck on the throttle linkage) for experimentation. Being on the highway gives more airflow, but also higher pump speed.
 
All good thoughts. The idle was dropped between 50-100 rpm depending on the coolant temps. Not a huge amt but maybe just enough. I may play w/ the cable and see if bumping the idle slightly has any effect - I'd like to keep the writes down on this ecm as its getting on in age and they're getting a little rare. If it fails I'd have to repin for a 0411.

The cam is a comp 212/218 high lift - 54-424-11


If anyone is versed in hptuners I can upload the tune that's in there and a factory tune to compare. - if the forum will allow. Otherwise, I can upload some screenshots.

Did some more looking today and I was looking at the idle spark tables and the main spark tables (high and low octane) the high is barely touched, the low has been punched up in quite a few areas.
The idle tables have been changed, but with it being a manual, I'm not sure if the effect would even take, as they're labeled for park/neut and drive...

I dont have any afr gauge or sensor. I can log, and I'm not sure why the ltft's boundary tables were modified and what effect that would have on them.

I also noticed a small change in the cylinder volume, not sure if that's actually making any effect or not.
 
It doesn't really know AFR, but you should be able to log O2 voltage or something comparable. For any car with an old standard/narrowband sensor(s) you never really know the AFR, just how often you're crossing stoich on the up/down dance. I wish it wasn't so, but normally you can't read LTFT or STFT out as a table for review. You pretty much have to log it by having the engine under the relevant operating conditions. The point is just to see if the engine is in the range of stoich while it's idling.
 
Did some logging, and got some results. Not sure what to make of them.

On initial start, the ltft's were up at +10/8 I think. After a min or so they started dropping and basically 0'd out. Then slowly started rising again think they were +6/8

The map.. Was saying it was in the low 40s kpa which is like 12" of vacuum. So kinda low.

The timing, not sure what to make of it. If I'm reading the log right I'm only seeing 5deg of timing... which matches the 'idle spark advance" - 'in drive' table. Which would be no bueno. Anyone know how that table relates w/ manuals?
 
I'm not familiar with that era ECM, but usually there are several things that feed into a final timing value. If you have a timing tab, it's good to check with a light and verify it's hitting where it should.

If you want to post/send the 2 files I can thumb through them in HP Tuners.
 
Looks like the forum allowed me to upload in a zip. The one labeled emissions is the current tune. the one w/o is the hpt 'base' and the 2 log files are there because the initial one had an interesting timing number. So the 2nd one I pulled up all of the timing fields. and it seems to jive with ea other. base and one slightly modifying...

If that really is my timing that would explain the low vacuum.
 

Attachments

  • 1998 Camaro Stock tune downloaded hptuners 1196783970.zip
    1.1 MB · Views: 1
Went through and made some changes to the tune file but had to do some actual work, for work last night so didn't have a chance to actually put it on the pcm. Hopefully,
I'll get to that tonight.
 
Well, I got the changes written to the car and some interesting observations.

The car does seem a little cooler. I'm not gonna say it's fixed but improved. It was hot in the garage and I couldn't stay in longer to test things further. But it ran a bunch longer both with the a/c on and off. And it seemed to only rise about 10 deg in about 20 mins the the a/c on. Opening the hood dropped the temp about 6 deg fairly quick. (and the IAT about 50deg..) but in 45 mins I didn't feel the temp was on the spiral up.

How much temp change is normal, or is any normal hood up vs down? Fans would prob help that I imagine.

I wasn't able to stay in there any longer but I dropped the voltage on the fan down to what the car would be producing and it seemed to hold temp w/ the a/c off. Wasnt able to test on.

The exhaust note is a lot mellower

The engine now idles a bit lumpier, not a lot, just a little.

I LOST vacuum... figure that out. went from 5deg timing to 22deg. And lost vacuum 12 to 10...

ltft's are pretty consistently adding fuel. 8ish % +- 1 or so. One of the banks is consistently higher than the other so I may need to look for an exhaust leak.

The throttle response is actually a little softer maybe..

I think at this point I need to take it to the gas station and see how it behaves. Driving is going to change things over just idling in the garage.

At some point I may bump the idle speed another 50 and add a smidge more timing at idle to see what it does, but that's maybe down the road a hair. It need a real tune.
 
I still say load the stock tune and see how it goes. Otherwise there’s plenty of quality remote tuners for the ls platform that can help you out.
 
Took it out for a low speed test through the neighborhood. Slow speeds, were the problematic area. I'll say it's improved, but not fixed. Pretty much if it was moving it could mostly hold temp, at least at that ambient, but it was only about 100 outside and kinda cloudy.

But at idle it would slowly climb, and once it crests 220ish it almost seems to start to run away. Gaining temp, faster. Which is similar to what it was doing before I started this journey.

Gonna take a look at the tune again, to see if maybe there's something temp related that I can find at around 220 ish.

Otherwise, I may be into some new fans.

These fans factory, I keep seeing are something like 2700ish cfm. Found some that are 4000cfm. Pricey though.

--

New clutch is kinda grabby, and w/ the lighter weight flywheel I'm having to reprogram my leg.

And I've got an oil leak that isn't fantastic, and I'm hearing an exhaust leak... :-(
 
I don't know that they'd fit w/o some serious hackery. The core on the 4th gen is about 17h by 25w. Height be about perfect, The width would be an issue. I'll have to do some noodling on that.

99-03 windstar dimensions
1753158417625.png

Funnily enough, I did find someone local on ls1tech having an almost identical problem. He went to some aftermarket fans, but not quite as much air flow as the ones I was looking at or the windstar.
 
Last edited:
I was just out there checking my measurements and yeah.. There's no fitting the windstar fans in there w/o some serious riggery.

I need to make friends w/ someone that has a sheetmetal brake.. lol
 
You must log in or register to reply here.

Latest Posts

Top Bottom