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1984 Fuel Delivery Problem by Frahlick
Started on: 03-13-2014 01:25 PM
Replies: 6 (96 views)
Last post by: theogre on 03-14-2014 09:29 AM
Frahlick
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Report this Post03-13-2014 01:25 PM Click Here to See the Profile for FrahlickSend a Private Message to FrahlickEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hey Fiero owners. I just bought my first Fiero, a 1984, for $800. The car looks great, but I'm kind of in unfamiliar territory on a GM motor as I'm a subaru tech.

Anyway, it has a fuel delivery problem. The fuel pump is fine, the injector is cleaned, and it has a new ECM. If I dump fuel into the throttle body it'll fire up and run smooth.

Has anyone else had this problem? I'd appreciate any advice!
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Gall757
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Report this Post03-13-2014 01:57 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Welcome to the Forum!

How do you know the fuel pump is fine? Fuel pressure should be about 12 lbs. Is the filter new?
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Indiana_resto_guy
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Report this Post03-13-2014 03:06 PM Click Here to See the Profile for Indiana_resto_guyClick Here to Email Indiana_resto_guySend a Private Message to Indiana_resto_guyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Getting an injector pulse?
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phonedawgz
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Report this Post03-13-2014 04:15 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
1 - Key on - engine off - does the ECM run the fuel pump for two seconds and then turn off? It should

2 - Key on engine off - does the check engine light come on? It should.

3 - Then just bumping the starter - does the ECM again turn on the fuel pump and turn it off two seconds later - It should. Note - if you crank the engine more than just a bump, you can build up oil pressure and turn on the oil pressure switch that runs the fuel pump. That's not what I am asking. This test determines if the ECM is running (if it passed 1 and 2) and now if the ECM is getting ignition pulses from the ICM in the distributor.
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Frahlick
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Report this Post03-13-2014 04:55 PM Click Here to See the Profile for FrahlickSend a Private Message to FrahlickEdit/Delete MessageReply w/QuoteDirect Link to This Post
The fuel filter is new, and the pump tested good. I just got home, I'll run a few more tests based on the suggestions and post again! Thank you all for the possibilities!

Edit: Fuel pump responds to key on.

[This message has been edited by Frahlick (edited 03-13-2014).]

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84fiero123
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Report this Post03-14-2014 07:38 AM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
I had one on an 84 that the wires going to the injector was corroded where they plugged into the harness next to the throttle body. unplug and look to see if the contacts are corroded, if so just unplugging and plugging several times might fix the problem if it does she should fire up right away. if it doesn't check the plug at the harness side for power, if there is power there sand paper the other side and plug it back together and check for power at the injector. power there still no joy, clogged/bad injector.

Steve

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[This message has been edited by 84fiero123 (edited 03-14-2014).]

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theogre
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Report this Post03-14-2014 09:29 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Check fuel pressure. Pump maybe good but could still have low/no pressure.
Need a tool...
See my Cave, TBI Test Adaptor

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