88 bronco 5.0 starts but wont run

Hello everyone Im new to the forum and need a little advice . My bronco will start and run for a couple of seconds and then die like its out of gas . If I feather the gas pedal I can get it to repeat that sequence . It runs for a sec or two and then tries to die . I actually got it to warm up a couple of times by doing that  and once it warmed up it ran pretty well although not 100 correctly .

So far Ive changed the fuel filter , coolant sensor, and the external fuel pump . I also cleaned the IAC  and put sea foam in the gas tank

I checked the fuel pressure and its 40lbs ,however i noticed that as soon as the engine  dies the pressure drops way down . If I spray starter fluid in the intake I runs until I stop spraying so I know its fuel related .

I didnt check codes since the check engine light did not come on  before  this problem occured

Any help greatly appreciated-

Update edit: TRUCK IS NOW RUNNING!!!!! see my final post in this thread  for info

yo fv333

WELCOME!

Here are PSI Specs for a 94 that are prob close to your 88

94 FUEL PRESSURE ENGINE RUNNING 30-45 PSI  KEY ON, ENGINE OFF 35-45 PSI  Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator

Pull that vac hose, any gas aroma or gas in line, replace the fuel pressure regulator

Here is FORD's Test;

CHECK PRESSURE REGULATOR DIAPHRAGM CONDITION  

• Key off.
• Connect Fuel Pressure Test Kit at Schrader fitting on rail. Observe Warning Instructions to avoid fuel spillage and injury.
• Start engine and run for 10 seconds.
• Stop engine and wait 10 seconds.
• Start engine and run for 10 seconds.
• Stop engine and remove vacuum hose from pressure regulator.
• Examine vacuum port in the pressure regulator for evidence of fuel leakage through the diaphragm.

-----------

--

Check for Codes anyway; hopefully batty was not disconnected

Thanks for your reply . A new FPR is 20$ at pep boys so Im just going to replace it

Well I replaced the fuel pressure regulator andddddddddd same problem . Starts and runs for a second or two and then dies . I did manage to get the engine  a bit warmed up by repeatedly starting and feathering the gas for a few seconds and  when it warmed a bit it would actually idle , although only at 500 rpm or so and with lots of misses . It would run like that for about 20-30 secs and die  .I even drove it a couple of days  when this problem first started but it got progressivly worse . Im at a loss , whats left to replace? I pulled a plug and theyre fouled so I need to replace them but does anyone have any ideas ???

Just to recap

It got progressively worse over a period of 3-4 days

It will run if I spray starting fluid in the TB

I replaced the coolant sensor,external ful pump, fuel filter,fuel presasure reg

It starts run for a sec or two and dies

It will start to run better as it warms but misses badly

yo

Did you check for Codes yet?

a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-code-reader/?&pid=74587&mode=threaded

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test 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 first.

And Post em here according to:
KOEO
&
KOER
 

This is by Ford for(94 Bronco but = to your 88

Starting Concerns

  —Stalls After Start http://www.thedieselstop.com/faq/9497faq/maint/vra/images/a16137a.gif

STARTING CONCERNS System Possible Causes Visual/Mechanical EEC Ignition

• Check distributor cap, adapter, and rotor.
• Inspect spark plugs and plug wires.
• Check ignition switch.
• Check ignition coil for voltage.
• Inspect ICM for damage.
• Check for presence of anti-theft devices.

• Ignition System: PIP circuit
• SPOUT circuit
• IGN GND circuit

Fuel

• Check IFS switch.
• Check for fuel contamination/quality.
• Check fuel filter.
• Check for correct fuel pressure.

• Fuel Pump System: FP circuit
• FPM circuit
• FP relay
• FPRC solenoid

[*]Fuel Injection:

• INJ 1, 2 (MFI)
• INJ 1, 2 .. (SFI)

Power and Grounds

• Check for low battery voltage.
• Inspect electrical connections, wires, and harnesses.

• EEC Power: VREF
• VPWR/EEC power relay

[*]EEC Grounds:

• SIG RTN
• PWR GND
• CSE GND

Air/Vacuum

• Check vacuum lines for leaks or wear.
• Check air intake system.

• TP sensor
• MAP/BARO sensor
• MAF sensor
• IAC solenoid

Other

• Check engine coolant level.
• Check thermostat for proper operation.
• Check EGR valve stuck open.
• Check for moisture entry into PCM.
• Check camshaft timing and cylinder compression.
• Check for throttle body contamination.
• Check for proper idle speed setting.

• ECT sensor
• EPC solenoid
• EGR Systems: EGRT, EVP, DPFE or PFE sensor
• EGR solenoid(s)

[*]PSP switch
[*]A/C Systems:

• ACC, ACCS, WAC, ACD or ACON

[*]TCC solenoid
[*]BLR circuit
[*]DEF circuit
[*]HDL circuit
[*]PNP switch
[*]CPP switch
[*]IAC solenoid

Ck for Vacuum Leaks

http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/

GL!  will be back Friday

how is vacuum level at idle?

Normal Engine Vacuum at Idle is 15-22 in-Hg

"rent" w/ ful refundable depsit a hand held vacuum pum w/gauge from local parts store.

Have no way to ck codes right now but I will . Ill check vacuum tom or sat

Thanks for your help

yo, All you need to check codes is a is a piece of wire, a pencil and paper, and possibly a helper to look over your shoulder and razz you if you  drop the pencil.

READ this http://broncozone.com/topic/14269-code-reader/?&pid=74587&mode=threaded

Put in a set of new plugs ,still the same . I cant check for vacuum leaks because it wont run long enough although I traced all the hoses and they look ok . I cant pull codes because the self test input wire (single wire) is missing , looked all over very carefully and its no where to be seen . I can rule out timming chain,timming and ignition because it will run perfect with starting fluid sprayed in the throttle body . So Im at a loss as to what to do next . Could it be the in tank fuel pump is bad ? When I try to start it it has no fuel pressure left in the fuel rail because it takes a bit of cranking to get it to start , then it runs perfect for a second and quits ? Hate to have to tow it to a shop .

Try checking out some of the items necessary for the engine to start as described by Ryan in his great EFI writeups  http://oldfuelinjection.com/?p=64 .  Page or read down to Start/crank.

Hope that gives you some clues.

Good luck,

>-

Thanks for the info . Im wondering if it might be the in tank pump . What do you think?

yo,

CHECK FUEL PRESSURE LEAKDOWN

• Observe the "Notes, Cautions and Warnings" to avoid fuel spillage and injury.
• Connect the Fuel Pressure Test Gauge at the fuel pressure test point.
• Connect a jumper to the FP lead of the DLC.
• Key on, engine off.
• Ground the test lead using the jumper wire to run the fuel pump(s).
• Run the fuel pump for 30 seconds minimum.
• Remove the test lead ground and note fuel pressure on the gauge.
• Verify whether the fuel pressure remains within the specified 5 psi for 1 minute after the test lead is ungrounded.
• 
• Diagnostic Link Connectors for EEC-IV processors (84-95).
  84-86 (red) located on R wheelwell near starter relay.
• 87-95 (black or gray) located under L hood hinge under EEC TEST cover. (WPT-743 & WPT-352)
  Connect FP Relay (terminal A) to any ground (like terminal E) to force the fuel pump(s) on when the key is in RUN.
   
  Consider Ford Fuel Injection and Electronic Engine Control: How to Understand, Service and Modify, 1988-1993; & Ford Fuel Injection and Electronic Engine Control: How to Understand, Service, and Modify All Ford-Lincoln-Mercury Cars and Light Trucks, 1980 to 1987 by Charles Probst
  avail @ BARNES & NOBLE, AMAZON, E BAY, ETC.

yo, For some unknown reason, many times I can not add more info to a reply bec. I can not get my cursor to go to the end on the last sentence,  I try moving cursor manually to insert another C&P test ot to type in more text.  Also Ctrl End does not move cursor to End.

So..here is more;

re your

"I cant pull codes because the self test input wire (single wire) is missing"  That wire is White/ Purple & Labelled as Sef-Test Intput (STI) on diagrams

It travels back to the EEC IV (Computer /Processor Pin # 48 as shown by Ryan M

In EEC IV PIN LEGEND

http://oldfuelinjection.com/truckpinouts.html and

EEC IV Connector diagram

==== 

OK, having hand-eye issues again partly due to COMCAST Lag

In Probst's book, we can use this info to rule out certain things since you can get it to run for 20-30 seconds;

Part07.pdf

read 2.3

The Control Module (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 CRANK signal from the Ignition Switch, When receives a PIP signal from the hall effect device 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. The pump will also run when the terminals of the fuel pump test connector are jumped.  MIESK5 NOTE; this is the test I presented in previous reply.

the Control module signals the pump when it receives a CRANK signal, and when the Control module 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

Accumulator/Single (Bronco) & Dual (non-Bronco) Function Reservoir

Single-Function Reservoir Overview; "...Dual fuel pump systems must have a fuel accumulator between them. The model from BC Broncos is a multi-tasking wonder. Fuel accumulators store fuel from the low-pressure pump for the high-pressure pump. Storing fuel is a great idea for rock crawlers, as the accumulator holds a reserve of fuel, just in case gravity temporarily affects the gas tank. Accumulators also equalize fuel flow between the pumps. If one pump is pushing 72GPH and the other is only flowing 50GPH, something has to give. Once the accumulator is full, excess fuel flows out to the return fuel line, and back to the tank. This keeps the low-pressure pump from stressing the high-pressure pump. Normal accumulators stop there, but not the model from BC Broncos. They built one starting with a fuel filter. You get the accumulator and the filter all in one $70 package..."
Source: by Ryan M



Click to Enlarge

'88 Single-Function Reservoir

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 ******, 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, Fram CG3862, or equivalent filter.

To permanently eliminate the reservoir, use these Dorman fuel tubes. http://dormanproducts.com/p-12461-800-159.aspx Dorman part # 800-159 STEEL FUEL LINE ASSORTMENT. 1 EACH- 5/16 AND 3/8 IN x 12 IN DOUBLE BEAD LINES
 

Repairs are more affordable and easier with Dorman’s Fuel Repair Line. Now you can replace only the damaged section, not the entire fuel line assembly. Dorman’s Quick DisConnect label offers a complete array of connectors, slips and line repairs for fuel lines, oil and transmission lines and heating/cooling systems.

• Leak-resistant
• Easy to install
• Also available as part of Dorman’s Fuel Line Repair Kit
• Steel or nylon construction resists rust, corrosion, warping and cracking

See this caption:



http://www.supermotors.net/registry/media/477914_1

Single-Function Reservoir Fuel Flow; "...Fuel flows in through the larger tank-side supply ****** from the in-tank pump to the inlet check valve, which allows it into the reservoir. As the cup fills, fuel moves up the pickup tube & out the larger engine-side supply ******. Unused fuel enters the engine-side return ******, bypasses the blocked-off check valve ('88 revision) and exits the tank-side return ******. The only fault that would cause a noticeable problem would be for the check valve to stick closed, blocking any fuel from entering the reservoir, but this isn't likely. With the cup removed (have a replacement cup O-ring in-hand before attempting), a sharp pick can be used to pull the valve downward & open. The valve cannot be removed from the reservoir body..."

Single-Function Reservoir in 84-89; "...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; Steve deleted his post

Single-Function Reservoir in 84-89; "...were only used on the early EFIs; carbs & diesels used electrically-operated tank-select valves, and later EFIs use an in-tank fuel delivery module (FDM) that performs these functions. 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. Its (meager) function is described in the caption of the 2nd pic..."
 

Single-Function Reservoir O Ring; "The Ford engineering number on the filter is E6TZ-9365-A. 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..."
Single-Function Reservoir Overview & pics in 84-89; "The Ford engineering number on the filter is E6TZ-9365-A. 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..."
Source: by Steve83 (Steve, That dirty old truck) at Ford Bronco Zone Forums

more at http://www.supermotors.net/registry/2742/66025-4

88-90 Bronco, etx, Wiring Diagram

showing Pin 17 STO tat EEC IV to Self-Test Connector & CHECK ENGINE LIGHT (CEL)

If CEL never lights up, then this wire or ckt is defective AND IT ALSO SERVICES IGNITION RUN CIRCUIT

http://www.yunost.ru/docs/Ford-injectors-book/Part12/Part12-4/Part12-4.pdf

Probst page 395

WOW cant thank you enough . Now all I need is some time to do this

yo fv,

YW!

My prority is to;

Get the STI ckt workimg by finding sinle self-test  wire; it is White/ Purple & Labelled as Self-Test INPUT (STI) on diagrams

look in closest harness to drivers side fender behind the air filter box

 pic by Ryan M

----

-- and a pic by my PAL BRONCOJOE below

/monthly_05_2008/post-9476-1209780173.jpg">/monthly_05_2008/post-9476-1209780173_thumb.jpg

2ND priority if no codes or can't pull codes is to go over and test the components cited in Ryan Ms article as advised by SEABRONC;

MAP see my archived site @ http://web.archive.org/web/20101224145505/http://www.broncolinks.com/index.php?index=138 for Tests, etc

and read my signature about copying 2nd Http and poasting it in new Browser Window to see current site

TPS http://web.archive.org/web/20101224145551/http://www.broncolinks.com/index.php?index=137

PIP signal

& Power to EEC and fuel pump(s)
 

Seabronc said:

Try checking out some of the items necessary for the engine to start as described by Ryan in his great EFI writeups  http://oldfuelinjection.com/?p=64 .  Page or read down to Start/crank.

Hope that gives you some clues.

Good luck

Click to expand...

Regarding this article . What is ECT ?