r1v3rrat86

1. I have an 87 toyota 4 runner that while driving to work last week the starter stuck open and i didnt know it and drained the battery. Well the truck cut off so i charged that battery and got a new starter and now the truck will run for about 3 seconds and cut off. I jumped the fp and B+ terminals and it still does the same thing. I also changed the fuel pump and still nothing any help as to what to look at next would be greatly appreciated.
   Thanks in advance
   Billy Mac

vital22re

iTrader: (2)

if you jumper the fuel pump, do you get 12v at the pump? can you hear the fp humming? hook up a timing light and after the motor dies, turn it over by hand and see if you still have spark.

r1v3rrat86

ill give it a shot when i get off work

r1v3rrat86

still no go someone said that if the alternator was back feeding it would cause the same problems is that true

Terrys87

iTrader: (1)

You havent by chance disconnected your AFM connector have you? It is the one on top of your air filter. That is a typical of what happens when it is disconnected. It will start then die after a few seconds.

scope103

Make sure you have 12v at the B+ terminal with key on; otherwise, jumpering to FP won't do any good. With key-off, test the resistance to ground on FP. It should be pretty close to zero (less than 10 ohms). If it's open (very high ohms) you have a wiring problem to the pump.

Don't have a multimeter? Then you're wasting your time trying to fix an electrical problem. It's not like they cost anything.

Jumpering FP to B+ bypasses the VAF and the COR, so if those have anything to do with your problem running the fuel pump with the jumper will show it.

r1v3rrat86

going to try and rewire the fuel pump to see what i can get out of that any more suggestions would be greatly appreciated im stumped

RAD4Runner

r1v3rrat86
IF engine consistently runs while ignition switch is in "start" position AND dies a few seconds after you release the switch, then your FP is most likely good, but as Terry87 and Scope103 suggest, problem is probably in your COR-Air Flow Meter system, as explained here.

While you are in "Start" position first coil of COR is energized and COR powers FP. Once there is airflow, AFM contacts stay closed and energize second coil of COR, maintaining power to FP. When you release ignition switch, first coil de-energizes but AFM contacts and hence COR contacts stay closed. Seems like this second coil is not being powered.
Jumping FP test connector here will make COR click and power FP. IF this does not make COR click:
second COR coil is bad or it is not getting power or ground.

Do not mess with wiring until you have verified things with volt-meter. (Harbor Freight could be your best friend=D) Connector to FP is easily accessible under carpet along right-side door threshold.

r1v3rrat86

when i jump the b+ and fp i can hear the fuel pump running and im getting good voltage at the fuel pump. I checked to see if there were any codes and the check engine light flashed once which means that every thing is normal. Could it be the ecu?

r1v3rrat86

could the distributor be bad causing it to lose spark? and why did a comment get deleted?

RAD4Runner

This proves that your FP is goo.
This still does not rule out your AFM (Like Terry mentions above, nor your COR)

Keep it simple and look in the area closest to the problem first, before you start looking elsewhere.
Gotta test using the fuel pump test connector like I mentioned above.

r1v3rrat86

i get good voltage at the fuel pump and like i said i can hear it run when the fb is jumped could it be a ground on the injectors making it do this

r1v3rrat86

checked the grounds on the injectors and they all checked out good

SPARKS89

iTrader: (1)

Your fuel pump is working. If your AFM isn't unplugged then I would say it is working too. It doesn't sound like it's suck closed because the truck wouldn't start at all then.

Make sure your ignition switch is still good. It could be providing power when in 'start' position but not in 'on'.

Dras16

If you try to give it gas while running, does it stay running or die immediately?
Also, check not only the AFM itself but also all the intake hoses, if they are cracked they will suck air and throw off your air-fuel mixture. My friends truck had this problem. A duct tape quick fix got him by until he got a new hose.

r1v3rrat86

giving it gas does nothing different the intake hose is in good shape im still at a loss

jason in tn

Not sure of the procedure but check your ignitor sounds to me like the injectors arent getting signal.

combatcarl

So you still haven't said whether or not you tested to see if COR or AFM were working. We know that your fuel pump is probably ok, but these guys are trying to help you, and you're off checking injectors and thinking about distributors.

Sent from my LG-P505 using YotaTech

SPARKS89

iTrader: (1)

Is everything working (lights on the dash, radio, etc.) when your ignition switch is in the 'on' position before you try and start it? Thats a pretty good quick check of your ignition switch.

r1v3rrat86

when i push open the afm i can hear the fuel pump running and bypassing the cor the fuel pump runs all the time. i did the ohm check on the afm how else am i suposed to check the stuff