The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support ExtremePSI
Please Support STM Tuned

2G GSX stalls when the fans kick on

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

#95GS-EX

Proven Member
69
49
Feb 9, 2021
Modesto, California
Hi guys,
So i recently had the heads built on my car and installed aem cam gears, my car has a aem series 2 ecu and im having an issue with the car dyeing as soon as fans kick in the car seems to be losing voltage. i have a new alternator and battery so i dont think thats the issue. before i had the heads built the car was running fine.
 
Could be a bad fan motor, or have a short or bad wiring in somewhere. Please take a log to see how much the voltage would drop while it happens. The engine runs fine until the fans get turned on, correct?
 
Last edited:
Sounds like a bad ground or other shared pathway. I would check the battery voltage right at the fans and also right at the battery at the time when the fans kick on. You're looking for some lost volts at the fans and also other things like maybe the ECU or ignition system.
 
until i start turning on electronics on the car or when the fans kick in
You have to be more specific. How and when exactly does it stall? It seems it's not only happening when the fans get turned ON. What happens if you turn ON the A/C, headlights etc? Does it stall quickly or slowly? Does engine still stall if you are opening the throttle a little bit when the fan turns ON?
Please upload a log while it is occurring.
before i had the heads built the car was running fine.
Have you changed the cams?
 
You have to be more specific. How and when exactly does it stall? It seems it's not only happening when the fans get turned ON. What happens if you turn ON the A/C, headlights etc? Does it stall quickly or slowly? Does engine still stall if you are opening the throttle a little bit when the fan turns ON?
Please upload a log while it is occurring.

Have you changed the cams?
yes the cams were changed and the car only dies out when its at idle not if I'm giving it throttle. I have also been told it could be the alternator but i just replaced it a few months ago
 
What the manufacturer of the alternator? Where did you get it?
 
yes the cams were changed and the car only dies out when its at idle not if I'm giving it throttle. I have also been told it could be the alternator but i just replaced it a few months ago
Could be the alternator, could be the cams (not cam gears), could be the tuning... Please upload a log.
As I understood, this wasn't happening before rebuilding the head with the previous cams, correct? If so, what cams did you have before and what cams do you have now?
 
Could be the alternator, could be the cams (not cam gears), could be the tuning... Please upload a log.
As I understood, this wasn't happening before rebuilding the head with the previous cams, correct? If so, what cams did you have before and what cams do you have now?
it was all stock
 
How many fans are on the car? Do you know how many amps they are rated to take from the system?
Also, be sure that the ground wire from the firewall to the intake manifold is in good shape. I think I see the firewall end of it in your picture in post #8 so it's apparently there. But it's one of the things that would be removed when doing the head and sometimes people forget.
 
Issue fixed I needed a new alternator with more amps. Thank you guys for all your help
That might not be a complete fix. On few cars will the alternator alone carry the full maximum load when idling. The battery has to pick up the difference. If your battery isn't able to do that when roughly fully charged then either the battery is weak (either old so it won't take a full charge or healthy but discharged) or something else is wrong -- most likely a wiring problem.

If you know you have a weak battery or that it was run down when fans killed the engine then you may have a complete story. If you can put the battery on charge when not driving that might help.

Otherwise I'd keep on studying the thing. Battery or wiring problems like this almost always bite you eventually.

Standard alternators tend to be a little undersized because of fuel economy and cost. Unfortunately it's tricky to upgrade the power because the pulley setup in our cars makes it hard to get enough tension to control squealing on starting with a high output unit.
 
That might not be a complete fix. On few cars will the alternator alone carry the full maximum load when idling. The battery has to pick up the difference. If your battery isn't able to do that when roughly fully charged then either the battery is weak (either old so it won't take a full charge or healthy but discharged) or something else is wrong -- most likely a wiring problem.

If you know you have a weak battery or that it was run down when fans killed the engine then you may have a complete story. If you can put the battery on charge when not driving that might help.

Otherwise I'd keep on studying the thing. Battery or wiring problems like this almost always bite you eventually.

Standard alternators tend to be a little undersized because of fuel economy and cost. Unfortunately it's tricky to upgrade the power because the pulley setup in our cars makes it hard to get enough tension to control squealing on starting with a high output unit.
Thanks and yeah the battery needed to get swapped out also. Car is running like a champ now.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top