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89broncodude

89 bronco loss of power

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1989 Full Size Brono 5.0L E40D(Pretty sure)

 

One day my bronco started losing power when I would hit around 30-35mph. But if I hit the pedal hard it would skip pass this bog and i could keep on accelerating. When I got it home I decided maybe it was a dirty/clogged fuel filter so I changed it out . The gas out of the old fuel filter was clear and looked 6/10 at best. 

 

After changing out the fuel filter my truck bogged way down and stinks like gas. I cant even drive it anymore. IT still runs and idles(somewhat decent) it just wants to die when in drive or reverse. So I went out and bought a innova OBD1 reader.

 

 

I pulled codes KOER:

 

12

33

41

52

77

 

 

I know 52 is because i moved the steering wheel and 77 is because I didnt run the KOEO first.

 

So I went out and bought a new EGR Valve and a new sensor to go with it. I also changed out my TPS Sensor and Fuel Regulator after reading through the forums and seeing other folks with my same symptoms. My performance has not gotten much besides the idle being slightly better. I rented a Fuel Pressure Tester and with KOEO its at about 17 Psi. With KOER the needle jumps(like its having a seizure) from 20 to 30Psi consistently.

 

After all of this I ran another KOER test.

 

I pulled codes:

 

21

41

34

77

52

 

Im not sure whats going on with my PFE Sensor(CODE-34) but I made sure the oring was on correctly and its nice and snug on the EGR

I thought about running out and buying a new MAP sensor and 02 sensors but honestly funds are starting to run a little low and Im getting a feeling that this might be a pump issue or an injector issue. 

 

Can anyone help point me in the right direction? I am by no means a mechanic but Ive got a little experience. I really appreciate any help anyone has to offer :) 

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Yo,

Your fuel psi is too low.

87-89; Fuel Injected Engines - "...Two electric pumps are used on fuel injected models; 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. The externally mounted high pressure pump is capable of supplying 15.9 gallons of fuel an hour. System pressure is controlled by a fuel pressure regulator (FPR) mounted on the engine..."

Pull the FPR's vacuum line off, there SHOULDN'T be ang gas or gas aroma in it.

FPR circled in;

http://www.supermotors.net/getfile/148480/fullsize/fuel-pressure-regulator-replacement-002.jpg

someone drilled out the tank and stole the gas. I patched it up with some techsteel and it finally just started to leak so it's time to replace the tank. While I have it down though I'm wondering what the odds of the low pressure fuel pump failing are? Test Diagram at the Diagnostic Link Connector (DLC); connect DLC to any ground to force the fuel pump) on when the key is in RUN...

 

 

 

 

MIESK5 NOTE; from Ford EVTM; The PCM runs the pump{s} for one second when it receives an ignition-on signal. It also runs the pumps as long as it receives a PIP signal from the Hall-effect devices, it continues pump operation even after the key is released from START. If the PIP signals fall below 120RPM, the PCM cuts off the signal to the fuel pump relay. PCM signals the pump when it receives a CRANK signal, and when the PCM gets PIP signals that the engine is running. the pump does not run if the PIP indicates the engine is not running even with ignition ON {except for that first one second}.

Key ON Engine Running: 5.0L is 30-45 psi

 

Key ON Engine OFF: 5.0L is 35-45 psi

Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator.

 

If fuel lines/systems have been drained or evacuated, it may take up to 15 seconds to obtain the pressure specified.

For low pressure pump diagnosis :

 

-attach test lead to FP lead on VP test connector. Make sure test lead is long enough to reach work area under vehicle

-Turn key to RUN position

-Raise vehicle on hoist and bring test lead to a convenient point for grounding

-Ground test lead and listen at fuel tank for low pressure pump operation. (it may help to disconnect high pressure pump electrical connections)

-Is pump running? If yes read C1, if no read C2

 

C1

Remove ground from test lead

-Disconnect pressure line from pump at reservoir inlet fitting

-obtain a 1 quart or more container

-place fuel line is reservoir and operate pump for 5 seconds

-Is fuel level at least 6 ounces?

If yes then the pump is good.

If no then attmpt to restrict lines to build up pressure and also check for line blockage,

 

 

C2

-If no check all electrical locations related to fuel pumps (they are on same circuit

-Make sure HP pump is running

-any electrical problem found?

-If no then replace pump

 

On top of this, run a long the jumper wire straight from the battery to the fuel pump(s). use correct wire awg.

 

 

Single-Function Fuel Reservoir in 89; "...The PN for the filter is given, but you shouldn't actually have a filter in there. It should be an external inline filter further up the frame rail - you only buy the reservoir filter to get the O-ring, and only then if you have some reason to open the reservoir bowl. Unless you're having fuel delivery problems that you've isolated to the reservoir, you should never open it..." Miesk5 NOTE; be wary of fire!

 

Single-Function Reservoir in 89 . The single-function reservoir (SFR) is used on vehicles with ONE gas tank, like Broncos, vans, & low-trim pickups. The reservoir is always inside the L frame rail beneath the driver's floorpan about 10" behind the frame fuel pump. The 10mm bolt heads are easy to access on the outer face of the frame rail, but some vehicles have a large heat shield that must also be removed...There's not much to the SFR (which is what ALL Broncos of those years have): the '88 version just has the cup & 1 check valve (earlier versions have 2), but it's almost foolproof.

Single-Function Reservoir Overview, Location & O Ring Installation in an 86; "Mine is under the T-Case skid plate on the drivers frame rail, it's black plastic with a screw style thread top & bottom which uses an O ring and a hockey puck style filter with a hole on one side, hole side goes up to the nipple inside the cap, both about $9.00 at any autochain. The "O" ring doesn't want to cooperate when putting it in place so use something tacky to keep it in place when you go to thread it back on otherwise you'll squish it and it will piss gas all over, also the bottom part needs to be threaded all the up without any gap at the top also will piss gas if incorrect. used a small model paint brush almost DRY with Permatex for the inside "O" ring track just to get it to set up to keep the "O" ring in place when screwing it back together and it worked fine, the amount of Permatex was insignificant with no potenial to impead anything, but use what ever you like. IIRC the Reservoir was designed to keep the fuel pumps supplied from starving when the vehicle is at different positions, cornering, off road driving etc..."

Source: by JKossarides

Single-Function Reservoir Testing in 88-89; "...Used on '88-89 Broncos & F-series/E-series/Rangers/others with single tank dual-pump EFI. In this version, the only moving part is the tank-side inlet check valve. The return ports flow freely and are NOT connected to the reservoir. The engine-side supply port is open to the reservoir. To test it, unplug the frame fuel pump, disconnect the engine-side supply (large) line, and cycle the key. If fuel flows out of the reservoir nipple, the reservoir is working normally. If not, disconnect the tank-side supply (large) line, and cycle the key. If fuel flows out of the line, the reservoir check valve is probably stuck, or its internal filter is clogged. A reservoir marked "DO NOT REMOVE CUP" does not contain a filter. For a replacement O-ring for the cup, buy a NAPA 3268 (or equivalent) filter..."

...

DTC 21 ECT out of self test range 0.3 to 3.7 volts; "... ECT is bad, bad thermostat, low coolant.,

Coolant is less than 50 deg F for KOEO, or less than 180 deg F for KOER, or greater than 250 deg F for either. If coolant temp is in proper range, suspect ECT sensor or it's connector/wiring..." read more

Source: by miesk5 here a few centuries ago.

...

DTC 41, 42, 85 OR THREE DIGIT CODES 171, 172, 173, 179, 181, 182, 183 & 565 are received.

O2 Sensor Ground in 89 5.0 is through it's threads to it's bung to Y pipe

bronco-1989-eec--pg-41.gif

by Seattle FSB

 

If the HEGO ground is good, the following areas may be at fault:

* Ignition Coil

* Distributor Cap

* Distributor Rotor

* Fouled Spark Plug

* Spark Plug Wires

* Air Filter

* Stuck Open Injector

* Fuel Contamination Engine OIL

* Manifold Leaks Intake/Exhaust

* Fuel Pressure

* Poor Power Ground

 

* Engine Not At Normal Operating Temperature

 

...

DTC 34 - EGR voltage above closed limit - Failed sensor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. the egr is not closing properly which can cause detonation. remove the egr and clean off any carbon built up on it with carb cleaner and a brush if necessary.

 

DTC 34 "...in Key On Engine Off (KOEO) or Engine Running (KOER) Self-Test indicates that the EGR valve and/or EGR Valve Position (EVP) sensor may not be fully seated in the closed position. The EVP sensor voltage is greater than the closed limit voltage of 0.67 volt. Because of the preload on the installed EVP sensor, it is very difficult to determine whether the EGR valve is seated or the EVP sensor is in contact with the EGR valve stem..."

Source: by rla2005 (Randy)

 

EVP Test;

DTC 34 - EGR voltage above closed limit - Failed sensor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. the egr is not closing properly which can cause detonation. remove the egr and clean off any carbon built up on it with carb cleaner and a brush if necessary.

 

DTC 34 "...in Key On Engine Off (KOEO) or Engine Running (KOER) Self-Test indicates that the EGR valve and/or EGR Valve Position (EVP) sensor may not be fully seated in the closed position. The EVP sensor voltage is greater than the closed limit voltage of 0.67 volt. Because of the preload on the installed EVP sensor, it is very difficult to determine whether the EGR valve is seated or the EVP sensor is in contact with the EGR valve stem..."

Source: by rla2005 (Randy) via miesk5 at http://broncozone.com/topic/22091-th...ensor-trouble/

 

 

DTC 31, 32. 33. 34. 35. 38 or 84 - EGR Valve Position (EVP)

will give you a test in next post

...

DTC 77 system failed to recognize brief WOT dynamic resistance test.

...

52 As you know, power steering pressure switch always open or closed. KOER, Code 52 means after you get four flashes, or sweeps (three flashes or sweeps for a 6 cyl) you depressed and released the brake pedal, then DID NOT turn the steering wheel 1/2 turn.

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Yo,

I kept getting error messages about an image nit allowed here, but it didn't  cite which image!!!!!  I had 7 images.

Overview: Fuel Pressure Regulator is attached to the fuel supply manifold assembly downstream of the fuel injectors. It regulates the fuel pressure supplied to the injectors. The regulator is a diaphragm-operated relief valve. One side of the diaphragm senses fuel pressure and the other side is connected to the intake manifold vacuum. Nominal fuel pressure is established by a spring preload applied to the diaphragm. Balancing one side of the diaphragm with manifold vacuum maintains a constant fuel pressure drop across the injectors. Fuel in excess of that used by the engine is bypassed through the regulator and returns to the fuel tank. pressure test point with a Schrader fitting is in the engine fuel rail to relieve pressure in the fuel system and to measure the injector supply pressure for service and diagnostic work.

Check vacuum;

See  my vacuum leak test in post #20 @ http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/?p=125535

 

One way to do a quick check is to grab a vacuum gauge. Bring the engine to normal operating temperature. Connect gauge to the intake manifold tee. BEWARE OF FAN, BELT, PULLEYS & HIT ENGINE. 
The vacuum gauge should read between 15 and 22 in-Hg depending upon the engine condition and the altitude at which the test is performed. SUBTRACT ONE INCH FROM THE SPECIFIED READING FOR EVERY 1,000 FEET OF ELEVATION ABOVE SEA LEVEL.
The reading should be quite steady. .

When engine is rapidly accelerated (dotted needle), needle will drop to a low (not to zero) reading. When throttle is suddenly released, the needle will snap back up to a higher than normal figure.

When vacuum leaks are indicated, search out and correct the condition. Excess air leaking into the system will upset the fuel mixture and cause conditions such as rough idle, missing on acceleration, or burned valves. If the leak exists in an accessory unit, such as the power brake, the unit will not function correctly. Or Air Conditioning when in MAX mode may switch to Defrost.

...

EVP TEST @ http://broncozone.com/topic/25304-check-engine-light/

Wiring Diagram in an 89 

bronco-1989-eec--pg-42.gif
Source: by SeattleFSB (Seattle FSB)

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I kept having similar issues. It mostly only showed up when going uphill. First time my truck ever went to a "real" mechanic. They told me my cam shafts were bent. 
With a lil more research and finally deciding to inspect the one part I assumed was good all along, I replaced the O2 sensor. I just replaced it too but I messed up installing it and seems that caused a problem. Replaced it and truck has never had that issue since and that was almost 10 years ago. I had replaced my EGR valve and the TPS sensor as you did too with a lil bit of improvement particularly at idle thanks to the TPS sensor but the O2 sensor was the true fix.

A final fix to my idle and some other running problems was replacing all the rotted hard plastic lines some of which are part of your emissions. I just snapped em near the connections leaving a lil bit left over then put appropriate size breather tubing with some heat shrink wrap to hold em on the connections. 10 years later no issues there either.

If you ever pull your battery, your truck will run like crap for a bit. You gotta drive it around a bit. Seems like 10-30 minutes with 2-3 restarts gets it in tune.

Looking over Miesks response and your sorta low fuel pressure a pump is sounding to be a good suspect. If you have to drop the gas tank, I recommend considering making yourself a hatch bay door just above the fuel pump in the bed so you'll never have to drop that tank again (cuz it's always full when you have to) :) If it's the one under the driver side, well that'll be one of the easiest fixes you'll ever do on the Bronco. Since you have fuel with pressure but it's low, then it sounds like if I had to suspect either pump, it'd be driver side which I recall is the high pressure. Usually you've got zero fuel if it's the rear.

Fun fact, your electrical wires for the pump are in direct contact with the fuel in the tank which keeps the pump cool :D

Edited by entity-unknown

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