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3800 Swap - Fuel Pump Won't Prime by Jfrost
Started on: 04-09-2015 11:03 PM
Replies: 8 (332 views)
Last post by: Jfrost on 04-12-2015 04:29 PM
Jfrost
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Report this Post04-09-2015 11:03 PM Click Here to See the Profile for JfrostSend a Private Message to JfrostEdit/Delete MessageReply w/QuoteDirect Link to This Post
Starting the L67 engine for the first time in 2 years and it turns over just fine but I don't hear the fuel pump priming with key on and it won't actually start. The car is an 87 GT that I swapped an 86 GT cabin harness into for various reasons. Before I pulled the old 2.8 (with 86 GT cabin harness installed) I started the engine and it ran for a few seconds but I didn't hear the fuel pump priming at all. I believe the engine ran due to fuel being left in the rails (it died due to vacuum lines being disconnected). Not sure if the issue is related to the different cabin harness or not as the 2.8 ran fine before I puled the original harness and engine.

Is there a difference in the way the 87 and 86 GT's were set up for fueling? I'm not sure why the pump isn't priming, everything worked great when installed in my 86. I haven't had a chance to check voltages on the fuel wires yet but I did check the fuse and it is OK. The harness is from Phonedawgz and I do believe I have everything set up correctly.

Any help would be appreciated figuring this out.

------------------
Project L67 Fiero

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Mike Gonzalez
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Report this Post04-10-2015 01:19 AM Click Here to See the Profile for Mike GonzalezClick Here to Email Mike GonzalezSend a Private Message to Mike GonzalezEdit/Delete MessageReply w/QuoteDirect Link to This Post
Does the SES light come on when you turn the key on? If not the PCM may not be getting power. Check for power on one of the large wires of the FP relay, if there is power jump it to the other large wire bypassing the relay and see if the pump runs. If no power at the relay check for power at the fuse and check the fuse with a meter.
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Jfrost
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Report this Post04-10-2015 10:19 AM Click Here to See the Profile for JfrostSend a Private Message to JfrostEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Mike Gonzalez:

Does the SES light come on when you turn the key on? If not the PCM may not be getting power. Check for power on one of the large wires of the FP relay, if there is power jump it to the other large wire bypassing the relay and see if the pump runs. If no power at the relay check for power at the fuse and check the fuse with a meter.


No lights are on the dash with the key on. I swapped fuses and checked them again and still no luck, ECM fuse looks good too. I'll test wires later on today after work. I did just remember I swapped in a junkyard steering column in unkown working condition, that could be an item of concern as well. With that in mind, I rewatched the video of the 2.8 running before I pulled it and no lights lit up on the dash then either (thats also when I first noticed the fuel pump not priming). Can the 2.8 even start without the PCM powered up (assuming the dash lights not being on indicate no power to the PCM)?

[This message has been edited by Jfrost (edited 04-10-2015).]

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Mike Gonzalez
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Report this Post04-10-2015 10:34 AM Click Here to See the Profile for Mike GonzalezClick Here to Email Mike GonzalezSend a Private Message to Mike GonzalezEdit/Delete MessageReply w/QuoteDirect Link to This Post
No the 2.8 wouldn't star without power to the PCM. If your dash lights are not working for another reason you can check yout PCM pins 19 and 20 on C1 for power, 19 is switched, 20 is constant.
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Jfrost
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Report this Post04-10-2015 06:20 PM Click Here to See the Profile for JfrostSend a Private Message to JfrostEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have power at the relay but nothing coming out of it so I tested it off car with a battery and I don't hear it clicking. Thinking the relay is bad I tried jumping power on the connector but all it did was blow the fuel pump fuse, tried it again with a new fuse and nothing happened again. I'll track down a new relay and hopefully get the pump working.
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Mike Gonzalez
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Report this Post04-10-2015 09:33 PM Click Here to See the Profile for Mike GonzalezClick Here to Email Mike GonzalezSend a Private Message to Mike GonzalezEdit/Delete MessageReply w/QuoteDirect Link to This Post
If your relay has power to it, just unplug the connector and use a jumper wire or something to connect the two large wires together (tan/wht-org/blk) the FP should run if its working. The Green and white (if its factory color) wire should get 12v for 3 seconds when you turn the key on, if the PCM is working.

[This message has been edited by Mike Gonzalez (edited 04-10-2015).]

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Jfrost
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Report this Post04-12-2015 12:42 PM Click Here to See the Profile for JfrostSend a Private Message to JfrostEdit/Delete MessageReply w/QuoteDirect Link to This Post
Retested the relay with different wire leads and turns out it's functioning. I have power to the relay for the both the control and switched side. I was originally jumping the wrong leads which was blowing the fuse, I tested the correct ones and still no fuel pump operation. I know my PCM functions as my scan gauge hooked up to the OBDII connector displays engine sensor readings. The fuel pump is new and worked when last started a few years back. I'll test for power at the fuel pump connector but am stumped as to what else may be causing the issue.

Is there anything on the steering column sensor/connector wise that could cause an issue? As previously mentioned the column was pulled from a junkyard Fiero in unknown working condition.

It's a gorgeous day here and I'd love to get this thing running again today!
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Scott2scott
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Report this Post04-12-2015 04:24 PM Click Here to See the Profile for Scott2scottClick Here to Email Scott2scottSend a Private Message to Scott2scottEdit/Delete MessageReply w/QuoteDirect Link to This Post
i had the same ploblem for weeks.. make sure u have power on computer at pins 19 and 20 . and or just run a hot wire off the battery to pump plug and see if u hear it prime then . that's what I did and it ran then. and I just tested away for days. now everything kinda works. I just replaced the starter for the 3 time and still cant get it to start once again. what a waste of time and money this swap was. still cant drive the car. goodluck.
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Jfrost
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Report this Post04-12-2015 04:29 PM Click Here to See the Profile for JfrostSend a Private Message to JfrostEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Scott2scott:

i had the same ploblem for weeks.. make sure u have power on computer at pins 19 and 20 . and or just run a hot wire off the battery to pump plug and see if u hear it prime then . that's what I did and it ran then. and I just tested away for days. now everything kinda works. I just replaced the starter for the 3 time and still cant get it to start once again. what a waste of time and money this swap was. still cant drive the car. goodluck.


Thanks for the advice!

I found the culprit: bad wire repair in the ground wire for the pump. I bypassed the wire repair connection and am able to get the pump to work. Time to properly fix the wires and then reinstall the tank.

This should fix it, thanks for all the help!
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