Fuel deliver troubleshooting for an 88 2.9L?

[BillRod]

Hi All

I have the issue from a few threads ago regarding stumbling trying to maintain 75mph on the highway with partial throttle.
The check engine light never came on but to start the diagnostics I bought an OBD1 code reader(21.99 at Checker) and the KOEO, Stored Memory and KOER test all came back with No errors. Now I think I should focus on Fuel.

Question for this thread:
Where do I find Fuel delivery troubleshooting tips?
I have researched what I can but don't seem to find much on Fuel troubleshooting.

Can anyone point me to where I need to go to find this?

Thanks in advance for any help on this.
Bill

Here's the history:
1988 Ranger 2.9L 5spdMitsubishi, 4x4, Manual Tcase and hubs, ext cab, at least 175K miles, owned about 6 months.
Last week I cut off the stupid 1foot long cherry bomb and replaced with an oem style muffler to quiet it down, and new air filter. Today I pulled the all of the spark plugs and they looked great and consistent to eachother so I put them back in without replacing any of them. Fuel filter replaced (again) yesterday.
Traced through as much of the wiring that I could get to looking for a worn spot for potential short but found nothing.
Thanks again.
Bill

[BillRod]

I just checked the Fuel pressure using a fuel pressure gauge I just bought and the instructions in the Chiltons manual.
Every test came out OK.

Engine off and pump running = 39 psi.
Turned pump off and it only dropped 1 psi and held there for the 3 minutes stated in the manual.

Vacuum removed from the regulator and plugged, Engine running 39 psi, Accelerated the throttle a bunch of times and the pressure never moved.

"Fuel Pump OK" was the next statement on the Chiltons chart.

I guess my next steps are:
1 - Pull the pump electrical connector and see if it's dirty or anything.
2 - Hook up my shiny new Fuel pressure gauge and road test it on the hiway to see if it drops pressure under the same conditions that make it stumble.


Anyone have any other thoughts or ideas?

Thanks
Bill

[tiemann66]

I might be having the same problem as you. I have an 89 with 2.9 5speed manual 4wd. As long as i baby it it seems to drive fine or if i drive it hard starting off in 1st grear and keep the rpms up seems to run fine but inbetween it hiccups pretty good. Or if i try to accelirate in a higher geer it hiccups pretty good too. I have done ignition checks fule checks and everything I can think of and still no idea. I can say it stoped for about 15 miles worth of driving after i replaced a fuel filter but i can't find any fuel problems. I even ohmed my fuel injectors and all are with in spec. No KOEO or KOER codes other than one for the TP sensor when i was doing a wiggle test.

I have done:
New wires
new cap & rotor
spark plugs are good and at gap
fuel presure test 38 psi
high speed fuel pressure test did not move gauge with regulator discnected from vaccume. Also tested while driving.
Injectors all right at about 15 ohms
new fuel filter
new TP sensor and also new tp sensore plug

[ovie]

Does anyone know how to convert a 1988 Ranger from dual fuel pumps to a single pump?

[thomas2132]

Had same problem and I replaced throttle position sensor and problem solved

[terry G]

Tiemann66, did you have any luck troubleshooting ?

[newarkman43055]

FIX FOR RUNNING OUT OF FUEL SENSATION WHILE ON THE HIGHWAY.I had the problem with what seemed like running out of fuel (some people thinks it's loading up) while driving down the road. It got worse over time and I parked the truck. This summer while changing fuel pumps and fuel tank, I found that the fuel sump, behind the fuel pump on the frame was the problem. There is a check valve inside and it apparently goes bad over time. I replaced the sump with two pipes that I got from Advance Auto Parts. They are sold as a pair, cost about $18.00 and are perfect for the job. One is 3/8" and the other is 5/16" and slip in the hoses which snap onto the sump. It no longer runs out of fuel while in motion.

NOW, if someone could tell me why my '87, 2.9 is sucking too much fuel. It used to get 28mpg and dropped to 20mpg while on a trip. We're talking from one tank to the next. Everything has been checked and replaced by two dealers (one even made it worse and had to undo what they did) and several garages. One garage owner was a Ford factory trained tech with many years in the field. It just barely has 17 inches of vacuum and won't idle below 900rpm without wanting to stall. Now the distrubuter, ALL sensors, egr valve & solenoid, O2 sensor and a whole lot more has been replaced. The passage between the egr valve and throttle body opening has been cleaned out. The compression is fantastic. The vacuum lines have been checked or replaced. Fuel pressure regulator has been replaced. Fuel filter replaced - Twice this summer. MAP sensor will hold 5 lbs till hell freezes over. It's been checked for manifold leaks. And like everyone else who has experienced this problem, and they are numerous, it started well over 100,000 miles.

Other than that, it runs great.

[art47]

Might some sensor be telling the computer that it is running cold and the computer is therefore dictating a rich mixture and ruining your mileage?

Is your coolant temp sensor and your temp gauge ok.
Thermostat?

[newarkman43055]

[B][COLOR="Red"]Repaired my rich running problem....


My 87 Ranger 2.9, 5 speed had been running rich for a number of years - 14 to be exact. As I stated earlier, several garages and 2 dealers could not correct this problem. EEK4 is really "Guess 4". This thing threw so many codes that it was joke. No one really knew where to start. Recently, a Ford master tech told me that there is a temp sensor on the 2.9, but he couldn't remember where it was located. He thought it was on the side of the block. For the '87, 2.9 I could find no reference to a temp sensor. I checked books and the parts locator on my NAPA parts locator program, at work - Nothing. However, there was a temp sensor listed in the parts catalogue for the '87, 2.9. I checked the '88, 2.9 locator and found it under the throttle body on the intake manifold, above the thermostat, on the opposite side of the temp switch. And wouldn't you know it, the '87 has one in the very same place. I replaced the sensor, and after a several miles, my mileage improved, dramatically.


By the way, the temp guages on the Rangers were notorious for going bad and giving a false indication of overheating. I screwed in a mechanical guage and my overheating problem went away.


For the first time since October of 1996 this truck is finally running as it should.

[Earlyboomer]

Why would you want to do this? The pump in the tank is not that big and is the low pressure pump which feeds the much larger frame mounted pump. I just changed both of them on my Ranger and after seeing the fuel system all apart, I doubt that one pump would be able to do the job without a lot of re-engineering.

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Are you aware that there is probably a second fuel filter after the frame mounted fuel pump. The filter before the frame mounted pump is plastic and takes a replacement cartridge, and if you follow the line out of the frame mounted pump, I think you will find a can type fuel filter.

[Earlyboomer]

Besides a temperature sensor being out of calibration and lying to the computer and killing the MPG, the O2 sensor can do the same thing. Also, the fuel pressure regulator's diaphram could have developed a leak. Pull the fuel regulator vacuum line off at the intake manifold, and there should be no smell of gasoline in that line, if you smell gas, the regulator is bad. A bad regulator allows extra fuel right into the intake.

[tiemann66]

BillRod,
I had a similar issue but couldn't go faster then 75mph and only got 15 mpg. Turned out the integral filter in the injectors was clogging with rust. The fule rail can rust up if it gets water in it. Hope this helps.