Stalling in hot weather

[pceh]

Hi, I have a 2002 CC and on the weekend I made a 1/2 run on the highway in 32 degrees (celsius) heat. After that run, the truck started stalling after idling at a light for a few minutes. It would always stall just as I was taking off from the light. It would stall and then I would put into neutral while coasting and it would start right back up again. This has never happened before. I checked the rotor and cap and replaced as the Cap appeared to be quite corroded and the rotor was a bit worn. With the replacement, the truck idles a bit lower than before, just above 500rpm - before it was a bit above 600rpm. The weather has now cooled off again and there is no issue with stalling. Hotter weather seems to cause it but not sure why. After the cap and rotor replacement, I am thinking that the cause is something else. Could the Ignition Control Module be the culprit? or could the fuel sending unit be the issue? Any thoughts? I really do not want to start replacing parts without narrowing the possibilities. Any ideas you can provide would be appreciated. Thanks.

[WileyHunter]

Sound's like when my old S-10 was with bad O2 sensor... Until it was almost completely gone there was no code but similar to your symptoms.

WH

[pceh]

How would o2 sensors cause an engine to stall? I thought they only determined air/fuel mixture?

[roadrunner]

Ses light on? Any codes even though light may not be on (not all driveability problems will turn light on)? Ethanol blend fuel (fuel boil in lines, possible though not very likely)? Tps sensor bad? Fuel filter changed lately? Recent fuel fill-up (possible water contamination)? Done a fuel pressure and leakdown test? Engine temp running normal? Iat sensor bad? And yes module could cause this problem but is less likely than some of the afore-mentioned items. The list goes on to more obscure items from there. More information and diagnostics needed to help narrow search for your problem. Possibly this list will give you ideas where to start looking. Hope it helps you.

[pceh]

- no SES light
- no blended fuel
- fuel filter changed 1 month ago
- have not done fuel pressure test
- Engine temp was higher on that day than previous by 10-15 degress celsious (sorry, Canadian eh!). I did notice that the fan was engaged a lot more on that day than any other this year.
- IAT - not sure what failure symptoms would be - assuming stalling?


Thanks for your input. Since the cooler weather over the past 3 days, no issues. It is supposed to warm up again so I will see on the weekend. Also, I noticed that my truck still has Dex, but changed 1 year ago. I am going tonight to have it flushed and install Green. This might explain why the truck was running hotter.

[HenryJ]

Check and clean your battery cables.

[roadrunner]

Check and clean your battery cables.

Excellent suggestion Brule. Had trouble with that one myself. Noticed dash light flickering with it and guage erratic operation and fluctuations also.
IAT sensor is a stretch for this problem but possible. Other than stalling the only other noticeable symptom of that sensor failing would be likely reduction in performance or fuel economy or both. Hope you can make use of any of this advice.

[pceh]

Thanks for the great suggestions. I looked through the forum and also perfomed the following:

- Flushed Dex and replaced with Prestone
- Cleaned Idle control - truck idles very steady, no burps.
- Inspected MAP - clean, no issues
- New Cap/Rotor
-Cleaned batter connections - the were practically spotless on the battery.

All works great. NO stalling, reached 28 Celsius this weekend and no issues. I noticed that while flushing Dex, there was quite alot of gummy gunk in the coolant, so I flushed several times to clean it out. I will flush again in a few months. Truck runs cooler, never above 100 degress celsius on the gauge.

One question I did have is the grounds. Grounds usually corrode the most and I am wondering where all of the grounds are located. Thanks.

[pceh]

We have had hot weather for the past week and I went on a long trip in 35 celsius weather. 4 hours in, the truck started stalling again. What I noticed is when it stalled the fuel pump was off. When you pulled over, cycled the switch a few times, the fuel pump would start up and truck would start. I was a half a tank of gas so I went and fuelled up and no problems for the next two hours. My guess on this was the fuel pump was overheating and stopping, thus putting in some cool gas was enough to keep it going. I changed the pump yesterday and no issues. The new pump is 10x's quieter and the idle is more smooth. Hopefully, this puts an end to the stalling issues. Since I have 150K, changing the pump regardless makes good sense.

[roadrunner]

My 90 Buick did the same routine you are talking about. Replaced pump there also and no more problems.