Truck won't start

[KEVIND]

Cant seem to narrow down my problem...bought my 89 bronco a couple of months ago. It had been sitting for a couple of years. The truck wont start when I turn the key. I changed the fuel tank, fuel lines, fuel pump, relay's, ignition switch. I can turn the motor over by jumping the solonoid, but no fuel pressure. The truck will start with starting fluid, but that last only a few seconds. I cant figure out why I cant start it with the key and/or why no fuel pressure. I haven't replaced the neutral safety switch until I figure out why no fuel pressure....dont want to spend the money unless it's necessary. Im guessing a bad NSS wont have any effect on the fuel pump. Any help would be greatly appreciated..

Thanks!

Kevin

 

[chris the redneck]

Cant seem to narrow down my problem...bought my 89 bronco a couple of months ago. It had been sitting for a couple of years. The truck wont start when I turn the key. I changed the fuel tank, fuel lines, fuel pump, relay's, ignition switch. I can turn the motor over by jumping the solonoid, but no fuel pressure. The truck will start with starting fluid, but that last only a few seconds. I cant figure out why I cant start it with the key and/or why no fuel pressure. I haven't replaced the neutral safety switch until I figure out why no fuel pressure....dont want to spend the money unless it's necessary. Im guessing a bad NSS wont have any effect on the fuel pump. Any help would be greatly appreciated..

Thanks!

Kevin

when u turn the key can u hear the fuel pump in the tank run for bout a second before u start it? if so try rplacin the fuel pressure regulator. its mounted at the back end of the fuel rail by the firewall. fuel pressure regulators aint that expensive... shouldnt b more than 6 bucks. if that aint the problem then there is also a high pressure fuel pump mounted on the frame on the drivers side of the truck. if it aint one of those three things it could be an electrical problem. i bought an 89 bronco custom about a month ago and i replaced all three of those parts just to find out that it was a bad wire in the fuel pump relay. if the in tank pump runswen u turn the key then try replacin the fuel prssure regulator... that aint fun to replace at all. i had to lay on the engine to get at it and ya gotta use an allen wrench to get that thing out... not fun at all.

 

[michael1989]

If you can't hear the fuel pump when the key is in the 'RUN' position. Check the fuel relay under the hood behind the air cleaner. If you can hear it check the fuel filter. Those are the two things that are easiest and could keep you from replacing a healthy fuel pump.

If you do decide to change the fuel filter, LET THE PRESSURE OUT OF THE SYSTEM, relief valve is along the fuel rail, looks like a tire valve stem

Good Luck

 

[Wild-Will]

I'm not certain what you mean by "it won't start". Is it turning over without catching or is it doing nothing at all when you engage start?

Some of these vehicles may have a crash fuel stop switch that will prevent the fuel pump from operating if the vehicle sustained a serious enough hit. Not positive about location but I've found it behind the passenger side cover in the footwell in many Ford vans and trucks.

If nothing is happening, I'd check to see if the solenoid is getting a signal from the key switch and trace from there, there may be a switch or relay that has failed and will not allow the engine to turn to start.

 

[Krafty]

we need to know a couple more things but this is how you can narrow it down.

1- When you turn the Key to ON do you hear TWO PUMPS?

you need another set of hands so you can be under the gas tank to listen for the two pumps when the key is turned.

the Loud one is the high pressure pump on the frame rail under the drivers seat ( easy to hear) the second is the low pressure pump INSIDE the tank.

YES go to #2 NO go to #3

2- you can hear your pumps, but you still have little or no pressure on your fuel rail. Replace your fuel filter and your fuel pressure regulator on the fuel rail and check for pressure. turn the key on to run the pumps while the filter is off to flush out the fuel line,

Do you have pressure now?

Yes- it should run NO- you may have a dirty pickup in the tank ( rare).

3- If you dont hear both pumps then you need to do some testing, with a volt meter check for voltage at the pumps in the first 2 seconds after the key is turned on, check it a couple of times to ensure a consistent reading.

Do You Have Voltage at Both pumps but one or both are still not working?

Yes- #4 No - #5

4- if the pump or pumps are not working but there is voltage then replace the pump(s)

5- First check the inertia switch on the driver side, up aginst the fire wall to the left of the brake pedal or behind the right kick pedal.Push the reset button on the top of the switch to compete the circuit.

re check for voltage, if its a no then you need to test for power before and after the relay. no power before = no signal from eec, no power after = relay or relay plug.

run through this and tell us whats going on.

good luck

 

[BroncoJoe19]

Krafty,

Nice post! /emoticons/[email protected] 2x" width="20" height="20" />

You might want to save it, cuase it may come in handy again.

 

[Krafty]

thanks broncojoe, i put alot of effort into that,

I must clarify that only on the 87-91 efi vehicles (including F series and E series) these systems have the low pressure pump in the tank with the high pressure pump on the frame rail with the fuel reservoir with vapor recovery systems between the low pressure pump and high pressure pump, the fuel filter on these models is typically found after the high pressure pump just below the firewall.

now the 92-96 (and up)efi systems only use ONE pump which is a high pressure pump in the gas tank, the fuel filter is also on the frame rail but closer to the fuel tank. these vehicles have a vapor or excess fuel line that runs right back into the tank instead of having a fragile plastic reservoir on the frame rail.

adjust your diagnostics accordingly

 

[Krafty]

hint hint a moderator could copy my diagnosic how to into another post and pin it somewhere handy.

 

[Seabronc]

hint hint a moderator could copy my diagnosic how to into another post and pin it somewhere handy.

Go to your profile under settings select Notification Options and enable PMs. You can copy your procedure and additional comments to a new post and submit to the "How To" forum.

 

[miesk5]

yo Krafty,

GOOD STUFF,

May I add this too?

Check Battery voltage - must be at least 12.4 volts.

Cranking voltage at the starter is at least 9.6 volts.

and to "3- If you dont hear both pump"

The Control Module (PCM) runs the pump(s) for one second when it receives an ignition-on signal. It also runs the pump(s) as long as it receives a PIP signal from the Hall-effect devices (inside the Distributor), it continues pump operation even after the key is released from START. If the PIP signals fall below 120RPM, the control module cuts off the signal to the fuel pump relay.

"Check the fuel pump relay when cranking the engine over. Not the 2 second run after the key is turned on, but while cranking the engine. If the fuel pump relay kicks on when cranking, the TFI & Stator are good..."

Source: by Ryan M (Fireguy50) at oldfuelinjection.com

The pump(s) will also run when the terminals of the fuel pump test connector are jumped. the Control module signals the pump(s) when it receives a CRANK signal, and when the Control module gets PIP signals that the engine is running. the pump(s) do not run if the PIP indicates the engine is not running even with ignition ON {except for that first one second}.

In the Diagnostic Link Connectors for EEC-IV processors (84-95);

Connect Fuel Pump Test terminal to any ground (such as Signal Return) to force the fuel pump(s) on when the key is in RUN.

Diagram by my pal, BroncoJoe19

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If pump(s) run, then diagnose the ignition ckt to the FP Relay.

Wiring Diagram in an 89 5.0, 5.8 & 7.5 (partial at FP relay); miesk5 Note; G801 is located on the LH inner fender behind the headlamp & both pumps Grounds join @ Splices S155 & S903

Source: by Seabronc (Rosie, Fred W) at http://broncozone.com/topic/20547-fuel-pump-wont-shut-off/

& Such as in; No Start Troubleshooting but Starter Cranks Engine in 4.9, 5.0, or 5.8L; "....TIP 1: Since a lot of folks confuse a No Crank Condition with a No Start Condition... I'll clear it up right now: In a No Start Condition means your vehicle's Starter Motor is cranking the Engine but the Engine is not starting. In a No Crank Condition, the Engine is not cranking when you turn the key to crank the Engine. This article only deals with a No Start Condition..." read more

Source: by easyautodiagnostics.com @ http://troubleshootmyvehicle.com/ford_no_start_4.9L_5.0L_5.8L/diagnose_no_start_1.php

Two electric pumps are used on fuel injected models to 1989; a low pressure boost pump mounted in the fuel tank and a high pressure pump mounted on the vehicle frame. The low pressure pump is used to provide pressurized fuel to the inlet of the high pressure pump and helps prevent noise and heating problems.

And it won't take much time to do a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test

Later, if you get it running; and greater than 180° F for the Key On Engine Running (KOER) Self-Test.

Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion

Some typical DTCS are;

DTC 87 - FP relay circuit failure- suspect inertia switch, fusible link, FP relay

Source: by miesk5 at Ford Bronco Zone Forums

DTC 87, 95 & 96; "...These codes relate to low or no power reaching the fuel pump. Start testing at the fuel pump relay. The relay must respond to the EEC processor and the relay contacts must be a low resistance path for fuel pump power. Relay testing can be done in a couple minutes with the fuel pump test table. Fuel pump relay testing;1. Use solenoid test at EEC pin 22 to check relay coil current draw. 2. Voltage at pump power terminal must be within .5v of battery power when relay is turned on with amp meter at pin 22. Check power from battery if voltage is low. Check the inertia switch and fuse if battery voltage is missing. Pin 22- (light blue-orange) Grounded to turn "on". Voltage will drop to about 1v when "on". Current draw will be 160 to 270mA Pin 8- fuel pump monitor (dark green-yellow) 0v engine off, battery voltage with engine running..."

Source: by Dustin S (Dustball, Mellow Yellow, Mr. Laser Boy)

 

[jake23]

my 1994 ford bronco has trouble starting the first start of day,after that it will satrt all day long.when i turn key to start check engine light comes on as it should but if light does not go out while cranking it wont start, when this happens i checked and there is no spark, any suggestions

 

[Krafty]

jake I would recommend starting a new thread about your problem, but I would pull your stored codes before looking at anything else.

 

[92bronco_in_progress]

i would suspect one of the fuel pumps not running. Most likely the one on the frame since you said you replaced the one in the tank. there is a ton of good info here as far as diagnosing. the other thing you can do to test the pump is to put 12 volts directly to it to see if it runs. if it does try and start the truck, if she fires you now have to find where you voltage breakdown is. could be a bad or tripped inertia switch or a bad wire, or a bad ground, or even a bad PCM.