Okay so heres whats going on, my car was driving great then out of no where the temp gauge jumped up right under where it would be fully maxed, but right when i took my foot off the gas it would go back down, but if i accelerated more, the temp gauge would go back up. So i managed to make it home. And to my surprise the car wouldnt even turn over, click nothing. Battery is brand new dura last with a full charge. If i turn the key i get power to all my ACCYs but the weird thing is the fuel pump doesnt prime, and while my seatbelt, handbrake and door light all light up, the Check engine, oil,temp warning lights are all very dim. So naturally i replaced the master relay, thermostat, tested the starter, it was bad bought a brand new one, installed that, checked EVERY single fuse, and still nothing. Anytime i turn the key my accys work, but if i even try to crank it i just hear one simple click. and it doesnt even come from the starter. Could this be a bad ECU? Like i said ALL my warning lights are very faint. But the really percular thing is after i installed the master relay the warning lights worked again and the fuel pump primed, but this morning i come back out to try to work on it and im back to square one. PLEASE HELP. PS i am the 2nd owner of my 1990 CRX Si, so it has not been messed with at all.

 

This would NOT be ECU.

How are you battery connections as well as all your grounds?
Have you done any work in the engine compartment recently?
Make sure you put the two ground lugs back on correctly after the thermostat change.

 

Make sure the fuses are good and the main relay works then see if the starters geti g signal when the key is turned to start. Anyways the over heating almost soundalike you blew your head gasket.if it did and you drive it for a bit and now it dosent start, and your starters doin what is soposed to the. You might have a seized motor.this is just worst case scenario

 

Ground the starter.

 

Check EVERY earth. I welded some rust in my boot up in my old Honda and afterwards had the same thing. Turned out it was the earth on the radiator support that had come loose.
Had the same issues as you, temp gauge was at full, no fuel pump, no crank etc

 

Yea check grounds crazy stuff happens when they are loose

 

U didn't put the battery in backwards did u?

 

That will cause a car to act the way u are explaining it will fry the ecu.

 

I went back and checked grounds again, cleaned them and still nothing. We had a huge snow storm and i know a lot of snow hit the bottom of my car and ice maybe that could have knocked something loose?

Could some one please explain why my warning lights like the check engine oil and those lights come on but are DIM? Also, i pulled the carpet back and turned the key to see if i could see the light come on the ecu and NOTHING came one. No light whatsoever. The car is literally completely stock never been messed with i bought it from a 80 year old women.

So even with the ecu light not blinking its still not the ecu? And i check the grounds on the thermostat and radiator ect, what else could this be?

 

ECU will not light up at all if it doesn't have correct power or ground.
ECU will light up solid if it's in failure mode (or sometimes if ground is not present).

 

I know the ECU is grounded at the thermostat.. are there any other grounds besides the radiator i should be aware of to check?

 

The ground from battery to chassis.
The ground from chassis to transmission near the air filter box.

To test out grounds, you can take a jumper cable and clip it only to the NEG post on the battery.
Clip the other end to the transmission.


Do you know how to use a multimeter or voltmeter?
I can tell you what pins to check on the ECU for power/ground.

 

I was taking the dash out of my '90 EF yesterday and I found a ground behind the cluster. Can't remember if you can see it easily with the dash still in. Anyway, pull the cluster, look for the ground from the cluster's dash wiring harness to the chassis ground. Loosen it, clean it, check for improvement. It's in the immediate area and seems like a reasonable possibility.

 

Sure sounds like a grounding issue...

 

transmission ground. EXACT same thing happened to me.

 

damn that sucks, but ya check all grounds, make sure u can still rotate the crank too! just go grab pulley and see if it will turn in any direction by hand if not, its swap time.

 

GROUNDS GROUNDS GROUNDS. Check those things. All of them. Pull them off, clean the crap out of them.

 

cant say it enough. i bought a new battery, starter, alternator to chase an electrical problem and all it took to fix the problem was a new ground connector to my battery... check small stupid stuff

 

GROUNDS!!! My CEL was dim too and had the same symptoms and the ground by the thermostat was not hooked up

 

I once bought a CRX with a B16 and JDM front end ( 8 or 9 years ago). The car ran like total crap and nobody could figure out why. New everything and still the car could not be driven safely. The owner got tired of it and sold it for scrap money.
I had the CRX towed home and it was dark by the time I got it home. I started the CRX in the driveway and ran like crap. As I was looking around the engine bay I say a tiny blue light by the transmission. I thought, there are no bulbs there, why is there a bluish light there? The transmission ground was almost all the way out and the electricity was making a constant spark trying to make a gound.
I tightened the 10mm bolt and the car ran like new after that.

So yeah, it's a gound.