EGI relay clicking, car wont start....Electrical experts please read....

[amolao]

Ok, Im still working on this and collecting data in order to find a fix for my dilemma. Lately, my 1989 240sx refuses to start in hot days. This is always in the evening. I know I have spark, air and fuel. I can also hear the fuel pump running during the initial priming. When the car refuses to start (it cranks fine...)I can hear the EGI relay and the AIV control solenoid valve clicking loudly at the same tempo. THis is only with the ignition ON. If I take the key out and walk away and try to start the car half an hour or so later the car starts fine.

Questions:What does the EGI relay does??? is it the same as E.C.C.S relay, engine control relay, EFI relay??? The Nissan manual seem to use diferrent names for the same relay....

Im using a multimeter and FSM to trace the circuits, but having intermittent problems makes it worse.

thanks


Modified by amolao at 12:37 AM 7/18/2006

[vancouverbc]

egi=electronic gas injection=efi=elec. fuel injection

your fuel pump relay and aiv solenoid will click when you turn the key. relays and solenoids are supposed to click when you give them power.

[vancouverbc]

hard starting when engine is hot.

zerothread/160219

[amolao]

thanks for the info....

When I said they clicked, they are actually clicking and stay clicking. Kind of sound like when you have your warning flashers on. In perfect rhythm, as long as the ignition is on. Something is making the relay "bounce" on and off......In order for a relay to click, the coil needs to be energized/turned on. I just dont see a common cause to make this two act up the way they are.....

[SlowBack]

I'm having the same problem. I thought maybe the relay was fried, but I swapped it out and the other one did the same thing.

[vancouverbc]

.

The aiv solenoid and the fuel pump relay have a lot in common as both are in the same circuit. When you turn key to "on", power goes to the relay box under hood to two 10 amp fuses for fuel pump and aiv solenoid. The ignition coil and ignition relay are also in this circuit. I would guess the ignition relay (by fuse block inside car) is also chattering.

I would guess bad ground, short or bad ignition coil. I'm only guessing.
Modified by vancouverbc at 3:45 PM 7/18/2006

[vancouverbc]

Circuit that is powered by turning key to "on" postion.

[NISTECH]

Check your connections at the battery. Both the terminals for the battery posts and on the positive cable check the plug in connections for corrosion or poor fit.

[amolao]

thanks for the diagrams and tips guys, I have more data to add for future search reference. I will find a solution whatever it takes...Yesterday happened again, hot day, time to go home and the car will not start until cranking on/off for about 15 minutes. I also found out that more relays and solenoid valves are clicking in unison. These are all the stuff that clicks at the same rhtym which tells me is a common cause to this behavior.

FICD solenoid valveEGI relayAIV control solenoid valveACC2 relayA/C relay and others in relay box if the A/C is on....My car starts fine everyday at lunch time. Is until later (time to go home...)during the day that acts up. I will double check the grounds and look into getting another ignition coil to try....Are the ignition coil of the SOHC and DOHC the same ??? Maybe I can swap with my coupe's one....

Modified by amolao at 4:16 PM 7/19/2006
Modified by amolao at 4:17 PM 7/19/2006

[amolao]

Instead of updating my post, I will continue adding to it, I think it will be easier to follow and serve as a step by step process....Basic electronics says that to trigger a relay, you need to energize the coil inside with a ground and +....The EGI relay clicks (energizing), and going by the diagram the + and - potentials are independent of any other valve or relay...weird....I will wait unit it happens again today and concentrate on that area and forget about the other relays for now. The clicking is timed and syncronize (like a clock signal)something tells me it migh be coming from control section at the ECSS (computer). And the fact that it happens at certain temperature also makes think that the ECSS is the culprit. More to follow....Feel free to add or comment on this.....

[vancouverbc]

Make sure you jump start car to eliminate possibiltity of weak battery.

Not sure whether ignition coils are interchangeable. the fsm says the primaray resistance is .7 ohms for primary but it doesnt have the secondary resistance.

for 1991-1994: the primary resistance is 1 and the secondary resistance is 10000 ohms.

[Amybirds]

Amolao,

Any luck troubleshooting?

My Q45 is doing a similar thing...

zer...40207

Thanks, Amy

[amolao]

Quick update: Im still having problems, I have checked and reviewed the schematics for a logical explanation but no luck. The only thing I can come up with is the battery. Even mine is not over a year old, I think that the heat might be getting to it, therefore not allowing the EGI/computer to get a good enough charge to activate. I known of cold weather affecting batteries, but never of heat actually changing battery charging properties. I'm switching batteries and run another test, lately it had been very hot and humid around here.....
Modified by amolao at 2:39 PM 8/4/2006

[amolao]

FIXED!!!!

zer...74447
Modified by amolao at 3:57 AM 8/12/2006

[vancouverbc]

What was wrong? that link doesnt work.

[amolao]

EPILOGUE:The battery was the problem, with the high temperatures affecting the crank and amps in the battery, the car and starter cranks fine but do not send enough charge to activate the ECU/relays...this was a fairly new battery. But a cheap economy one. The battery seems to work and crank fine, but is not sending enough amps to energized the ECU and relays. Hopefully this helps somebody......I went and got a new better battery, and it works fine.

[vancouverbc]

Interesting. Thanks. My understanding is that batteries have higher amps during warm weather but the heat can damage the plates and other physical structures.

[amolao]

I have experienced cold weather issues with batteries in the past, never heat issues.... The funny thing is that always happened at around 95 degrees or higher.....