phineascage

Hi, to everyone. I'm new to this forum. I have an 89 Civic DX manual transmission that I'm having some problems with it intermittently not cranking(starter not turning over). The only common thing with the problem is that it does this in very hot weather only occasionally. The instrument lights come on. All other electrical in the car is functional. The main relay and fuel pump work, although I don't think either are related to this problem. The starter works when jumped to 12V. My question is, is there a "Starting Relay" in series with the ignition switch, clutch switch and the starter solenoid? I can't seem to find a wiring diagram for this particular trim. If someone knows where this alleged starting relay may be located, any help would be appreciated.

Thanks.

4drEF

First, how old is the battery?
I experienced this issue before with a 5 year old battery - only on hot days or after long drives.
After the battery cooled down it would start right up.
Batteries usually have a life of just 3 years.

Starter relay;


Also, there is a little plastic bumper on the top of the clutch pedal that you might want to have a look at.
If this breaks, the car will not start.


And if that all looks good, maybe try turning the key slowly.
The ignition switches wear out to the point where the key needs to be in a certain position to make good electrical contact.
This might be the onset of that.

Opening up the main relay and resoldering the contact is always recommended, but you are probably right in thinking that isn't the problem since you hear the fuel pump.

fcm

Next time it will not crank... https://honda-tech.com/forums/tech-m...mp%5d-2961164/ 94

phineascage

I'm not precisely sure how old the battery is but it probably is 3+ years. I would tend to agree about the battery being a culprit however the cranking (when working) is never sluggish. When this problem is occurring the starter does nothing. I can't detect any activity at the starter solenoid either. I've suspected poor grounding as a possibility. I haven't yet contorted my way to the clutch switch but I do hear it clicking when actuated. I will test it with a multi-meter though. I have considered the ignition switch. The funny thing though this problem so far has been during the hottest part of the day, when its happening that is. We've been having days of 95F+ with heat indexes much higher. So far what I've experienced is that if the car is sitting in direct sun when it's this hot that's typically when I can expect it to not crank. Now when it finally takes a notion to crank and I'm able to get home, I cannot immediately replicate the problem and believe me I've tried.

I really appreciate the diagrams. I'm not finding a lot of minor technical details in my Haynes or maybe they're just not in there. I'm trying to gather an arsenal to fight this thing this coming weekend.

Would the TW or ECT sensor have any affect on not cranking? I know when it's flaking out weird things can happen. If you have any other ideas, please let me know.

Thanks again.

4drEF

No engine sensors that I'm aware of would prevent the engine from cranking.
They might prevent it from actually starting -yes-, but not cranking.

fcm

Ditto the above ^^^, the only way to narrow the problem down is to try the bypass jump when engine is not cranking, if the bypass jump works, you know the problem is not the starter motor or solenoid ansd is either the ign. switch, starter relay or wiring/connections in-between the ign. switch and solenoid, all are susceptible to heat failure.

If on the other hand the bypass jump does not work, the problem is the starter motor or solenoid, replace or repair. 94