zeitghaist

I'm battling with my engine running hot for around a year now and can't find the issue. (I had the original gauge until then so the issue may have always been there and I just didn't notice it --> water is neither bubbling nor overflowing)

1989 Trans Am 305 LB9

Thats what I've done so far:

-New Coolant (will add water wetter next week)
-New Aluminium 3 Row Radiator
-Two new Fans (one runs constantly, the other is manually triggered)
-New Temp Gauge (just to be sure, cross-checked with infrared gun)
-New Coolant Overflow reservoir with new cap
-New lower Radiator Hose
-New Thermostat (180)
-New Highflow water pump
-Airdam is fine

Car runs great and has passed an emissions test a few weeks ago so I would think that the engine should be running as good as it feels?


Tried two tests today (after I've changed the water pump):

Parked about 15 Minutes running, ran up to 230 (Outside temp around 95)

Driving around outside town (around 60 mph) ran up to 235

During both tests I manually switched on the second fan at around 200

Next thing I will check is:
-Ignition timing (if it would be so lean that it runs hot it should not have passed the emissions test?)

One known issue: The block is bored out to 0.060 over (maximum) but runs fine --> Is it maybe time for a new block and just drive it till it gives out? (wanted to get a new block anyway as a backup)

I'm really at a loss here and have absolutely no idea where the issue may be --> would be really grateful if I got some tipps and/or opinion

mantaguy

iTrader: (5)

Get yourself one of these,
https://www.harborfreight.com/non-co...ing-61894.html
Sounds like your temp gauge is off (very common on these cars)
You don't say if your fan kicked in at 235??

zeitghaist

Hi,

Sorry for the late reply!

Temp Gauge is definitely on point and both fans are running

Could someone with ALDL Experience take a look at my log file? (already converted to excel for better readability)

It's from today after I removed my Thermostat (wasn't the solution)

https://ufile.io/c2jug

zeitghaist

No one's got any tips what could cause the issue?

System was also pressure tested now and is ok! (therefore the head gasket should be ok I suppose)

Tootie Pang

iTrader: (2)

Don't bother with any more little things like "water wetter." Your system should easily hold 200 degrees parked.

Have you made sure the lower radiator hose isn't collapsing? And you did buy the reverse flow pump? Have you verified the fans are running in the correct direction? I highly recommend one of these:

https://www.summitracing.com/parts/m...BoCt18QAvD_BwE

zeitghaist

Hi,

I bought a new lower Radiator Hose just to be sure (no change, old one was fine as far as I can tell)

This is the waterpump I've now installed: https://www.rockauto.com/en/moreinfo...=1251537&jsn=1
(old one also worked fine it seems, no change with the new one)

Fans are pushing air through the Radiator to the engine (should be correct?)

I've crosschecked the temp with my temp gun (thermostat housing) + via the aldl log

My guess now is that my engine runs really lean even though I passed emissions?? (see BLM value of the log file, which is all over the place?)

The previous owner told me he changed the injector's for corvette ones (stupid) --> that would maybe mean I have the 22lbs injectors instead of the 19lbs injectors, but that should not lead to a lean condition, correct?? (don't want to spend 150$ unnecessary on a set of reman injectors)

Tootie Pang

iTrader: (2)

Looks to be the correct one. A diagnostic tool should tell you what your O2 sensor is seeing and if you are running lean. And check that lower hose collapse- just look and see if it is collapsed when it heats up and revved.

zeitghaist

From what I see with WinAldl it is running extremely lean since the BLM is like crazy high with >200 sometimes?? (please correct me if I'm wrong!)

I've ordered a fuel pressure gauge (checked the injectors today for their resistance and they are all in perfect condition) --> maybe something is wrong with the fuel pressure regulator and/or pump?

Is there something else which could cause it to run so lean that the car runs hot??

Tootie Pang

iTrader: (2)

You are in closed loop correct? And your Integrator should be close to 128.

zeitghaist

Correct,INT is around 128 (sometimes a little more and sometimes a little less)

Tootie Pang

iTrader: (2)

Check for that collapsing hose. Warm it it, park and idle. Rev the engine sharply with the throttle lever and observe the lower hose.

zeitghaist

I've already replaced the lower hose with a new one, so that should not be the issue? (btw how could this be connected to the BLM?)

Tootie Pang

iTrader: (2)

No connection. Just observe the hose and make sure it isn't sucking flat.

Cheerio

iTrader: (1)

ummm. i believe its supposed to kick on at around 235- 240 degrees. if its not bubling or overflowing you should be good.