car doesnt start good when its hot out
06-15-2006, 04:36 AM
#1
3.0 BAR
Thread Starter
Join Date: Jan 2006
Posts: 2,057
car doesnt start good when its hot out
when my car sits all night and then i go out when its hot outside at like 1pm my car will start shitty, like bareley runs and or i have to start it a few times, then after a few seconds of it running at like 100rpms it finally idles normal
if my car sits all day and i go start it at night when its cooler outside, it starts fine. makes no sence to me.
car is a 96 civic. also is it normal in the summer for my car to still idle at like 2200rpms when its cold and just started? shouldnt it be like 1500?
if my car sits all day and i go start it at night when its cooler outside, it starts fine. makes no sence to me.
car is a 96 civic. also is it normal in the summer for my car to still idle at like 2200rpms when its cold and just started? shouldnt it be like 1500?
06-21-2006, 02:44 PM
#2
1.0 BAR
Join Date: Dec 2002
Posts: 479
Re: car doesnt start good when its hot out
Yeah that isn't normal for it to shoot up to 2200rpm. Check your vacuum lines for leaks, could possibly be the PCV valve is bad. I would just do the basic testing of all sorts of things like timing, compression, vacuum leaks(which eradic idle can be cause by vacuum leaks and what not ), and sensors. Are you throwing any codes when this happens, next time you do it see if you are throwing any codes.
06-21-2006, 11:36 PM
#3
1.0 BAR
Join Date: Dec 2002
Posts: 479
Re: car doesnt start good when its hot out
Hey I just thought of an idea what might be wrong with your car while helping another guy with his car bogging problem. Check your PGM-FI Main Relay. Here's a little article to see if this is what's wrong.
Symtoms Of Bad Main Relay (Outside)
Getting symptoms of a bad main relay means usually, that on very hot days, say 90 °F +, sometimes our cars are difficult to start. Sometimes it seems to be very random. You notice that during the engine turns over with no problem, but will not start. It sounds like it's not firing. After 5-10 min's, it will eventually fire and the engines starts. The other reason could be, if the starter cranks but does not start, then in most cases, you may have a bad main relay! I suspect the main relay is temperature sensitive. Another common problem also caused by the main relay is, that our car starts fine, but stalls as soon as you release the key. In this situation, it may take many attempts at starting before the car will continue to run with the key released.
Symtoms Of Bad Main Relay (Inside)
Bad Dry Joins
The first cause could be the well known "Hairline Cracks". A bad main relay is a common fault like "Possible Hairline Cracks" or "Bad Dry Joints". The last item is sometimes possible through any vibrations and changes in temperature cracking the solder around a joint. This can cause intermittent failures, which are especially likely to happen when the car has been parked in the sun on hot days.
Hot Main Relay
Another cause could be a Hot Main Relay. That means, that this relay should not get hot even if the pump is drawing too much current - until the excess current starts to kill the contacts. There are 3 possible reasons for a hot relay:
- Cold Solder Point
- Bad Crimp Joint
- Bad Relay Contacts
Over time these bad joint gets worse due to the heat (heat cool cycles), the resistance goes immediately up, the joint gets hotter, the voltage at the pump goes rapidly down. So then it needs more current to do the same work so the joint gets hotter, it gets worse.
How To Check
Sometimes it helps to see what's going on in this relay. Our Main Relay will click 3 times during the starting process. If problems arise, one of those clicks (usually the third) is missing. If you can hear all 3 clicks, the Relay is fine. You don't need to replace it.
Turn ignition to ON: Click 1
CEL light goes off: Click 2
Turn the key to start: Click 3
Click 1
When you turn on the ignition switch to "ON" => Position II (don't turn to start) you should hear a click and a hum sound at the fuel filter. That means that the fuel pump gets energized. If you don't hear it, it's probably the main relay.
Inside The Main Relay
A relay is an electromagnetic switch. Anytime you want to switch a device which draws more current than is provided by an output of a switch or component you'll need to use a relay.
When power or ground is applied to a coil, the relay clicks on or off. The result is, that a power wire to a function is either closed (connected) or opened (disconnected). When the line is connected, the function is turned on and works. When the line is disconnected, the function is turned off and will not work. A relay can be used on alarm systems, things like to disable a starter, to flash the parking lights, and so many other things.
Check out this article to help you out: http://www.marklamond.co.uk/tech-hon...main-relay.htm
Symtoms Of Bad Main Relay (Outside)
Getting symptoms of a bad main relay means usually, that on very hot days, say 90 °F +, sometimes our cars are difficult to start. Sometimes it seems to be very random. You notice that during the engine turns over with no problem, but will not start. It sounds like it's not firing. After 5-10 min's, it will eventually fire and the engines starts. The other reason could be, if the starter cranks but does not start, then in most cases, you may have a bad main relay! I suspect the main relay is temperature sensitive. Another common problem also caused by the main relay is, that our car starts fine, but stalls as soon as you release the key. In this situation, it may take many attempts at starting before the car will continue to run with the key released.
Symtoms Of Bad Main Relay (Inside)
Bad Dry Joins
The first cause could be the well known "Hairline Cracks". A bad main relay is a common fault like "Possible Hairline Cracks" or "Bad Dry Joints". The last item is sometimes possible through any vibrations and changes in temperature cracking the solder around a joint. This can cause intermittent failures, which are especially likely to happen when the car has been parked in the sun on hot days.
Hot Main Relay
Another cause could be a Hot Main Relay. That means, that this relay should not get hot even if the pump is drawing too much current - until the excess current starts to kill the contacts. There are 3 possible reasons for a hot relay:
- Cold Solder Point
- Bad Crimp Joint
- Bad Relay Contacts
Over time these bad joint gets worse due to the heat (heat cool cycles), the resistance goes immediately up, the joint gets hotter, the voltage at the pump goes rapidly down. So then it needs more current to do the same work so the joint gets hotter, it gets worse.
How To Check
Sometimes it helps to see what's going on in this relay. Our Main Relay will click 3 times during the starting process. If problems arise, one of those clicks (usually the third) is missing. If you can hear all 3 clicks, the Relay is fine. You don't need to replace it.
Turn ignition to ON: Click 1
CEL light goes off: Click 2
Turn the key to start: Click 3
Click 1
When you turn on the ignition switch to "ON" => Position II (don't turn to start) you should hear a click and a hum sound at the fuel filter. That means that the fuel pump gets energized. If you don't hear it, it's probably the main relay.
Inside The Main Relay
A relay is an electromagnetic switch. Anytime you want to switch a device which draws more current than is provided by an output of a switch or component you'll need to use a relay.
When power or ground is applied to a coil, the relay clicks on or off. The result is, that a power wire to a function is either closed (connected) or opened (disconnected). When the line is connected, the function is turned on and works. When the line is disconnected, the function is turned off and will not work. A relay can be used on alarm systems, things like to disable a starter, to flash the parking lights, and so many other things.
Check out this article to help you out: http://www.marklamond.co.uk/tech-hon...main-relay.htm
06-22-2006, 07:43 AM
#4
3.0 BAR
Join Date: Feb 2003
Posts: 9,089
Re: car doesnt start good when its hot out
if you had a 88-91 i would tell you to go out and buy a main relay, but you dont hear it happening to newer civics/tegs very often.
that 'could' be it... but i would also check the iacv.
that 'could' be it... but i would also check the iacv.
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