4 runner starts but cuts off quickly
#1
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4 runner starts but cuts off quickly
- 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
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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.
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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.
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.
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#8
Probably Issue with AFM or Second COR Coil
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.
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.
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.
Last edited by RAD4Runner; 12-07-2012 at 03:04 PM.
#9
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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?
Last edited by r1v3rrat86; 12-09-2012 at 09:53 AM.
#11
This still does not rule out your AFM (Like Terry mentions above, nor your COR)
Could it be the ecu?
Gotta test using the fuel pump test connector like I mentioned above.
#12
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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
#14
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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'.
Make sure your ignition switch is still good. It could be providing power when in 'start' position but not in 'on'.
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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.
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.
Last edited by Dras16; 12-11-2012 at 05:59 PM.
#18
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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.
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#20
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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.
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