xaine

Ok , so i thought i had a main relay issue. but i do NOT!!! replaced it with several working ones!!

i have 1990 crx si with obd1 ls swap.
its all stock wiring,no cut up slaughtered wires, bought swap harness, rywire i think

any way, the car will just dies while driving it. I have noticed when it wont run, the fuel pump does not come on when switch is turned, also the fuel injectors dont pulse when turn over.

what other common things can cause this?
i have replaced ignition switch like 1.5 years ago so dont think its that.
plus everythign else seems to work except fo fuel pump cut on and no fuel pulse.
any help would be greatful

xaine

just want to add, seems like th hotter it is the more it does it.

but when it dies i can wait 5-10 minutes it'll start.
wierd. i had thought maybe wiring issue but i jiggle all the wires and it wont make a difference.
also messed with wires while car was running and cant make it die.
IDK need help.
i was thinking maybe there is another relay that controls fuel.
i was thinking maybe ecu, but i just bought a rebuilt/chipped ecu 1.5 years ago.
IIDK

89jdmcrxDOHCzc

Yea thats what I was about to say the ignition switch because of those symptoms. So when you turn the key to the run position (II) do you have any lights, cel, no fuel pump, battery? If you have lights and a good main relay then I would think that its the fuel pump itself.

dohc_star

main relay is my vote!

xaine

switch to on position all lights are on the dash that are supposed to be. but no fuelpump activation. And it cant be just the fuelpump because it does not pulse the injectors either!!
It is not the main relay!!! checked and replaced!!
i dont think igntion switch. but i have never had it die close enough to the house to test anything.
I spent all day in the back yard with the car running and messing with everything, could not get it to die on me.

Im at a lose here. And im a master tech. but anytime i was able to test anything it all test good cause the car is running.
if it broke down by the time i make it tools and make it back to the car it runs again.

thanks for all the suggestions. I still need help though
is there nothing else that controls the fuel pump in on position and fuel inj pulse when trying to turn over?
that what i need to know.

xaine

i think i need wiring diagrams for a 1990 crx si

4drEF

Hook a test lead to the power input on the main relay that comes down from your ignition switch. Tape off the open end and tuck it someplace safe.
When the car dies, pull down the test lead and hook up a volt meter to make sure your ignition switch is sending power to the main relay.

simplest way I can think of checking your input to the main to rule out the possibility that it is the culprit.

xaine

The main relay clicks when i turn the switch on everytime.
so just an educated guess that it is getting power from switch to relay.
I have had a lot of honda switched go out , so i dont think that is the issue

i assumed there would be another relay after the main for ecu or fuel ijectors or fuel pump
but if not then i do need to start testing wires from the main relay to the ecu circuit
or for that matter out of the ecu if eveything else looks good

but i need wiring diagrams for 1990 crx si and i will trace it down

4drEF

The main relay is the only relay for the circuits you just listed.

xaine

i have five relays. one brand new!!
when the car is running fine all five relays work
when the car is not running no relay makes a difference
so Not the relay.
ignition switch seems more likely but the relay clicks when key is turned on
i can feel it clicking.
so why would it click if it wasnt getting power
next time it messes up im testing all these things
thanks for the diagram!!!
im keeping a test light in my car so next time ill stop and test these wires

but i know there has got to be something between the main relay and the fuel pump at least because, what makes it kick on the pump then kick it back off when the key is put in on position?
something has to control that.
im guessing its the ecu

but i need a full wiring harness diagram for the engine related stuff

jlicrx

could be a bad ground connection at the thermostat housing - it is the ground for the main relay, the ECU and most of the sensors

gringo7718

Here is a great website

http://techauto.awardspace.com/mainr...l#Troubleshoot

SlobberGoat

Try swapping out the ignition loom for another one (short loom between the ignition barrel & the fuse box under the dash). Sometimes the points inside the white connector (on the barrel side) get worn.

xaine

ok guys. It broke down on me today and i was ready!!! had all wiring diagrams and test light, noid lights spark tester, ect.......

anyways, it wasnt ignititon all things good there
it wasnt relay all good there
it wasnt any grounds, although i noticed i needed to re-do my ground on t-housing
I had no fuelpump activation, no pulse to the injectors, no spark, and when i grounded my wire to get engine code the light did nothing!!!!!

ne ways
everything check out to the computer but did not check out coming out of computer
so its the dang ecm!!!!
it also wouldnt start while i was messing with it.
then i let it sit for 10-15 min cranked right up and made it home.
and it going to stay there till i get a new pcm
ANY BODY GOT A 92-93 ls computer? for FREE lol

also another note, it seems to mess up more on really hot day and not so much when it was cooler outside

ne ways glads i got it nailed down now!!!
hopefully this thread might help some one else out one day!!
and some advice dont buy your computer chipped off ebay!!!!!
from now on stock pcm and a hondata for me

slipyoke

I am almost 100% sure this same thing is happening to my car. Thank you so much for this thread.

If i may ask, i bought the car for a guy who put a td04h turbo in it and injectors from an eclipse he then tuned it on crome.

If i through a ne brain in it i am going to need to tune it again for it to run correctly wont I? that's prolly a stupid question. anyway where is a good place to buy a brain?

jdmboyef9

I understand that you say it's not the relay but all signs still point to this or the relay ground wire on the thermo housing. To test, turn key into on position so that the check engine light comes on (do not start) when the light turns off you should hear the relay click. No click=bad relay, bad relay=no fuel pump.
Are you sure that you are changing the ignition relay? I used to carry around 5-6 used ones and all would go bad mostly on hot days. I bought a bnib honda one and never had another problem

Mr. Fuel Pump

These symptoms really point to a cavitation/vapor lock issue in my opinion.
Were you running at less than 1/4 tank?
On a hot day especially, your fuel pump needs to be cooled by a constant supply of fuel, preferably submerged at all times. On return systems you are constantly flowing fuel up to the hot engine and back into the tank, this coupled with low fuel situation=hot fuel pump that will vaporize the fuel as it hits the pumping section.
If you sit around for 15 mins, everything cools down and the pump will pump liquid again, until....

slipyoke

How do you test/fix vapor lock? replace fuel pump?

jlicrx

been working on these Hondas for close to 15 years - never seen a vapor lock problem - usually, when it won't run when it is hot, it needs either a new main relay or a new igniter in the distributor, but most of the time it is the main relay

slipyoke

Yeah vapor lock is a problem more common in carburetor style cars.

So i listened for the main relay when the car was nice and cold and it sounded fine. then i drove a few miles got it all warmed up and turned it off, put the key in accessory position and i could barley hear the relay click when the check engine light went off.

think i found the problem. YES

slipyoke

Hey man sorry for jacking your thread!

Ok this is such a newb question. I can hear the main relay but i cant find it, anyone got a pic? and if you send me a fuse box diagram plz point it out or give me the number because ive been looking at the one in the faq i cant figure it out.

slipyoke

slipyoke

http://www.google.com/imgres?imgurl=...:0&tx=90&ty=44

slipyoke

google image, im a jack ***

xaine

I AGREE THAT 98 PERCENT OF THE TIME IT IS THE MAIN RELAY OR THE IGNITION SWITCH.
MY PROBLEM ISNT THAT. I WISH IT WAS.
I WORK AT HONDA. I HAD PRINT OUT OF ALL THE WIRING DIAGRAMS.
I TESTED RVERYTHING RIGHT THERE ON THE SIDE OF THE ROAD.
MY CHECK ENGINE LIGHT COMES ON AND WILL NOT GO OFF.
JUMP THE WIRE TO PULL CODES AND IT DOES NOT BLINK OR ANYTHING BUT STAY ON.
GOT POWER AND GROUND INTO ECU AND NO SIGNALS COMING OUT TO TURN OF FUEL PUMP. OR THE PULSE INJECTOR OR TO SEND SPARK .

I AM GOING TO BUY A NEW ONE FROM ACURA