Replaced fuel pump relay; now timing chain guide?

[aameaa]

1990 240sx w 190k mi. all stock no mods. owned for 4yrs. (have mantein. records for last 10yr)

BOTTOM LINE: i replaced the fuel pump relay (due to not starting), Now, there is a knocking under the head that doesn't let up (timing chain guide?)

I have been knocking my head against the wall w/ it not starting, now i have an entirely new problem! I need help connecting the dots!

Please please please help this damsel in distress!

Heres the run-down as best as i remember:

1st incident of bad behavior: 8mo ago on fwy idle dropped way down, gas pedal no response; clutch in and came back after 30 sec. this happened maybe 3 more times in 2mo. period)

2nd incident- 1 mo ago: car wouldn't start after driving 2 miles home, (20 min tops) (hot weather & parked on incline driveway for 3 days) Engine would crank, but not turn over.. checked ecu (shows fine 55 ) checked coil wires (visually), fuses good, pulled fp relay (looked fine) switched egi relay w/ eccs , back again. disconnected fp harness above fuel pump, lots of white lithium grease thru out, cleaned that up a bit, back together. car starts after 2 days.

3rd incident- runs like before for about 10 days. then same thing happens-not starting (symptoms same) i remove relays again disconnect harness, put back. smack gas tank little ..car starts runs as before ..(hmmmm scratch head...research...read..read..read) (ecu shows fine 55)

4th incident- runs for another week w no noticable changes- (then 1130 at night run into pizza joint and back in 3 min & parked on slight incline) no start! do all the things mentioned above..still no so next day she gets towed home into garage. test the relay terminals (the socket the actual plug goes into right?..the 'female' end thing that is stationary) w multimeter and 2 show 12v one nothing and one weak (like 2-3) (compare it to nextdoor terminal (shows 12 12 nothing and 12) so figure its the relay? so I put in new fp relay and starts up 1st time. but instantly is running rough..WTF ? turn off...on (3x maybe)leave it alone.Next day starts up and has loud rattle under head, its consistent after starting. no matter the idle, the rattling doesn't let up :-(

I was just trying to diagnose the starting problem, thought I had it figured out with the relay when it started right up, but NO, now i have my hands full! Im convinced they are related somehow, but I cannot connect the dots.I've read the knocking noise is most likely timing chain guide but why now that ive put in a new relay?is my car is mad at the new boyfriend? (im only driving his car because you're acting up honey, i swear...) "its not you, its me"....... actually it is you.

thanks a ton for any input/help/advice anyone can give me!

[Wc240]

its way to early to give advice, but ill give you a possible start.the chain guide will give a tapping/bb in a tin can noise( i know its hard to describe sounds over interweb) make sure your good on oil.for fuel, whens the last time you checked your filter? also,go thru the fsm and check what the voltages need to be at the pump. id tell ya, but hey, its early and my coffee pot broke.dissconnect the battery for a while to refresh the ecu. it could(possible) that its running ruff becouse it got used to something and it didnt like the new relay giving the pump more juicesorry, but ill check back later,if you still need help ill give better advice. goodluck

[aameaa]

Thanks, thats a start. I did look at the sticker for oil change (i usually pass on the dirty work to jiffy) and i am way passed the 3 mo. (altho not close to mileage yet..) so i'll check oil tomorrow. I did fuel filter 2 weeks ago that should be fine. for voltages at pump, (are you referring to the pump harness in trunk above fuel pump? ) and if so am i checking pump side/body side? w key in on position right? and "it got used to something and it didnt like the new relay giving the pump more juice" Thats what i was afraid of...(.need to wear out that new relay :-) )

I appreciate you taking the time, really.

Ill find you a new coffee pot :-)

[Wc240]

still no sleep or energy.youll be checking the body side with key on engine off.

some call it the relearn procedure, but its Adaptive strategy. the ecu gets used to certain things. sensor inputs, voltages, etc. disconnecting the battery for a few min clears this and makes it relearn it. may run/ idle ruff for like2 min then should settle down

[aameaa]

Thanks that was a lot of help. I added oil (was just below normal) and disconnected the battery for 10 min. and it started w/o the horrible knocking noise.. :-) idle stayed about 1200 for a while then went down to 900 after warming up still a little rough sounding but I am so relieved that knock went away. Didn't check voltage at fuel pump yet...still a little intimidated/confused w/ multi-meter, I'll try it tomorrow! Thanks a ton for your help

[Wc240]

no problem. post up what you find/questons.where is your idle at now? you need to adjust your idle/base timing

[aameaa]

after few minutes it went down to 900. (i remember increasing idle 18 mo ago due to hesitation) and prob needs adjusting now. (there a perfect setting? or just trial/error? ) Bought a fuel pump at the start of all this , think i should return it.