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Car wouldn't start today...fuel system questions


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#1 hawkandhorn

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Posted 14 December 2018 - 08:43 PM

Hey Guys,

Finally got my quest smogged and was running well...then today I parked it, ran inside, ran back out, and it wouldn't start :(

The engine turns over...it has spark at the coil for sure...so i'm assuming it's not getting fuel..

Excuse my naivety with these questions..

I should be able to unscrew the fuel feed into the Throttle body, turn the key on so the pump primes (but not start the car) and gas should come out of that line correct? Hoping I can use this as a quick test to see if the fuel is making it into the TBI





#2 markhansenconquest

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Posted 14 December 2018 - 09:30 PM

take off Intake pipe and look inside TBI to see if injectors are spraying while u turn car over ....... U.need 2 people

Edited by markhansenconquest, 14 December 2018 - 09:33 PM.


#3 mikec

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Posted 14 December 2018 - 10:08 PM

StarQuests do not "prime" the fuel lines like some cars when the key is just turned to the ON position.  The fuel injectors and check valve at the fuel pump should "trap" the fuel pressure in the fuel line when the engine is turned off... that pressure is used next time the engine is started.  Since the pressure was trapped, the fuel pump should not have to work hard to re-pressurize the system on start-up so no "priming" is required.  That pressure though will bleed off after some time (days hopefully) as parts age.  If the injectors bleed off the pressure that means they are leaking and need to be cleaned; the car won't run properly if they leak significantly.

When the key is turned to the START position the fuel pump is energized... then when the ECU sees ignition pulses (same pulses that drive the tachometer) it "knows the engine is still running" and the ECU maintains power to the fuel pump.

So for your test just turning the key to the ON/RUN position won't prove squat.  Instead, reach down and unplug the smaller wire feeding the starter solenoid to disable the solenoid.  Then undo the fuel RETURN hose from the fuel pressure regulator - the half-inch hose clamped to the regulator at the top/front of the throttle body.  Run a spare hose from the regulator to a bucket or gas can (and tape it or zip-tie it because it'll try to flair about) and turn the key to the START position.  See if you have fuel flow.

There is also a fuel pump test connector in the wire bundle by the air filter canister and passenger side fender.  Look for a wire and connector hanging from that bundle, or taped to the bundle.  It'll be a single black+white wire... there's also a 2 or 3 wire "dead-end" connector there too but that's something else - ignore it.  Run a beefy jumper wire from the battery positive post to that black+white wire to "hot wire" the fuel pump.  The pump will run regardless of the ignition key position.  Expect a few sparks when you make this connection... which is also why I suggest connecting the battery end first so that the sparks happen away from the battery and the hydrogen gas (think Hindenburg) that accumulate around lead acid car batteries being charged/recharged.

One thing about leaking fuel injectors: as they leak they flood the engine.  The car will be hard to start 20 minutes or so after a shutdown... but wait a day or two (that flooding evaporates) and it'll start and run decently again.  While doing the black+white jumper wire test, remove the fat air hose feeding the throttle body... shine a flashlight in there and look at the injector tips.  If you see ANY gas spraying or dribbling from either injector tip you've found a bad injector.  Maybe cleaning it (spray carb cleaner through the injector while using a small 9 volt battery to open it - once you remove it from the car... and don't use the car battery to power the injector as that WILL fry it) will save it... or you may have to send it to an injector cleaning/repair company.

Usually fuel pump issues manifest themselves as a car that will start and run normally at first but after a bit of driving it'll buck or run poorly when you try to accelerate... and the longer it is driven the worse and worse it gets.  Basically, worn fuel pumps get hot and that heat causes internal thermal expansion until the pump starts jamming... fuel flow and fuel pressure drop and the engine struggles to run on less and less fuel... eventually the pump jams completely.  If you can hear a nasty sound when doing the black+white wire jumper trick (especially with the gas cap off) that's a warning sign of a near-death fuel pump.

mike c.

#4 croquest87

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Posted 14 December 2018 - 10:17 PM

Agreed w all of the above. Just for the hell of it. Do you have a fuel pressure gage? If not yet? Get one  What's it reading while cranking?  If 36 psi cool.   Take the clips off the injectors. Get in the car hold the gas pedal to the floor and crank it till it starts and clears all the fuel out. Reconnect injector clips and start the car while giving some throttle till smooth again. This will pretty much tell you if your injectors are leaking after you turn the engine off. Fuel gage that is permanent or just for testing is one of the first things needed for troubleshooting on any fuel injected gasoline powered engine.

Edited by croquest87, 14 December 2018 - 10:44 PM.


#5 Indiana

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Posted 16 December 2018 - 08:47 PM

Maybe they messed with or just bumped the ECI fuse link and you're making this too complicated.

#6 croquest87

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Posted 17 December 2018 - 06:27 AM

View PostIndiana, on 16 December 2018 - 08:47 PM, said:

Maybe they messed with or just bumped the ECI fuse link and you're making this too complicated.
Very true   it's the simple things that will make you run circles.

#7 hawkandhorn

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Posted 17 December 2018 - 05:38 PM

ECI fuse link.... guess i'll look at that. How would I know if it's gone bad? voltmeter?

#8 hawkandhorn

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Posted 17 December 2018 - 07:07 PM

Where is the ECI fuse link located?

#9 hawkandhorn

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Posted 17 December 2018 - 07:36 PM

IF the fusible link was bad per se for the ECI....wouldn't other stuff be out too? what else is on that link?

#10 croquest87

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Posted 17 December 2018 - 08:51 PM

ECI link is brown in color link located to the right of the battery along w other color links in that little distribution box.

Here you go
Fuse links https://imgur.com/a/mEBoRGM

Third one from left(brown)

You can swap in let's just say  red one in and see if your car starts. Note: do not leave it in permanently you must replace it w brown one.

Edited by croquest87, 17 December 2018 - 08:56 PM.


#11 pcristquester

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Posted 18 December 2018 - 09:03 AM

Get new ones here http://www.enginemac.../electrical.php
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#12 cowdough

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Posted 03 August 2019 - 09:39 PM

This is exactly what i needed to know. Most excellent




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