I've got a 1988 2wd Ranger with a 2.9l v6. I just recently got it running. It has been setting for awhile. I replaced fuel tank, both pumps, fuel filter, Plugs, Wires, Cap, Rotor, TPS. It ran great for about 100 miles. Then yesterday on my way to work about 4 miles down the road it started to miss/stumble especially at about 55mph while in overdrive. When I got home I pulled the codes and I got KOEO 22 Map sensor signal out of voltage(engine off), 53 TPS signal voltage to high, 95 Thermactor Air System Problem, or Fuel Pump Monitor signal, indicates circuit problem.

KOER I got 21 ECT sensor signal voltage out of range or loss of signal during normal operation or Crank Sensor problem, doesn't have a crank sensor I believe. But I did change the ECT sensor and it still stumbles and seems like it misses. Noticed it is sluggish getting up to speed kinda surges and bogs. Im at a loss it isn't showing any more codes. Checked all plug wire connections and made sure everything was making connection. The only other thing I can think of is that the ignition module on back of distributor is going bad. Not advancing the time correctly. Anyone else have any ideas? Any help would be appreciated!! Thanks

 

You've been plenty busy on this one & done some good work to bring its scheduled maintenence up to date.

You seem to have more than one problem & a number of, or combination of them could cause your driveability problem/s

In general we're supposed to work the lowest number trouble code first & work our way up the list. So, begin with the P022 MAP sesnor code & find out whats going on with it, put it right & work your way up to the P053 TPS sensor problem & put it right, as they can be big players in the stumble problem, then move up to the P095 EGR system problem, as too much EGR can affect engine power output. Maybe refer to this web site in testing & trouble shooting sensors & their electrical ref. & rtn. voltages & let us know how your trouble shoot goes. EDIT : http://oldfuelinjection.com/

I'd also do a KOEO & KOER fuel pressure & volume over time test to see how the fuel pump pressure & flow rate over time is doing.
Edit: Fuel volume over time should be in the range of 1/2pt/15seconds. Not sure what the fuel pressure spec is for an 88, but it's probably in the range of 28-40 psi range, but maybe a member with hard fuel pressure data on an 88, will chime in & set us straight.

Have you also replaced the distributor cap & rotor & if so, was it with Ford/Motorcraft or aftermarket brand parts, the same question for the plugs & wires. Our engines are kinda persnickety about some parts like plug mfgr & design.

 

I did replace plugs, wires, cap, rotor, and coil. They were all oriellys brand and plugs where auto lite. It Is weird everything was fine and drive great for about 100 miles. Then it got cold and windy like 15 degrees and it started doig this. The tps sensor is new replaced it caused old one was bad. It is like it isn't gettig enough fuel. I have to check pressure yet will do that when I get off work tonight or in the morning. Also. Where is the egr valve located. I'm not seeing it anywhere.

If I unplug the map sensor when the truck is running or unplug the vaccum line to it it dies right away. I was going to have it tested but the guy at parts store wasn't sure how and I wasn't gonna let him screw it up!

Disregard egr location. Just found out ford didn't put them on 88-92 2.9l.

 

While your at checking the fuel pressure, also remove the fuel pressure regulator vacuum line, to see if its wet inside with fuel, if it is, replace the FPR.

 

Well I got around to testing the fuel pressure. I hooked it up on the fuel rail it didn't move. So I took it off and cycled the key a few times to pressurize the system. Pressed the little valve down and fuel came out but not at 40psi! Kinda squirted maybe an inch high. I'm thinking the regulator is bad. No fuel in vacuum line off the back. I've got a new one will be here later today. Tool my map sensor in to have it tested just to see if it could be a culprit. Well it's bad now guy hooked it up wrong when he tested it. Got a new one and will install both and post results tomorrow!

 

OK, good find on the fuel pressure being low. I'd again suggest doing a delivery/volume over time test, as that could flag a weak/worn pump, low operating voltage to the pump, clogged in tank pump fuel filter sock, crimped or otherwise restricted fuel delivery or return line, clogged fuel filter, acting out fuel pressure regulator, are some thoughts that come to mind.

EDIT: Autolite plugs if platinum design, of specified heat range, carefully gapped to spec with a wire gauge so as not to damage the platinum pad on the electrodes & torqued in to spec, were likely a good choice. Not familar enough with OReillys ignition parts to offer up an opinion on their quality, as I've only used OEM/Motorcraft replacements in my Fords & Motorcraft has proven to have been of good quality for me.

Don't replace parts on a hunch, take the time to perform a proper trouble shoot, get a positive result, Then replace the faulty part!!!!

More thouhts for consideration, keep us posted on your troubleshoot.

 

New tank, fuel pump, sending unit/pump, filter so that shouldn't be an issue. Not ruling weak high pressure pump out even though it new. Will check it out tomorrow morning when I get a few hours! Thanks for the help!

 

Ok I tested fuel pressure again today. 29-30psi running. Unhook vacuum line to regulator goes up to 40psi. Plug it back in goes back down. Figured it was bad. Put new one on same thing. Issue still there. The pumps are pumping good and will pump up to pressure. Cleaned IAC again. Tomorrow I am going to pull cap rotor and all plugs and wires and start over again and see if maybe there is something bad there. Anybody got anymore ideas? Thanks for all the help!

 

The fuel pressure numbers are in line with my 94 Taurus numbers, so I agree the fuel pressure regulator is likely ok.

Hold on, before taking everything loose, you might consider raising the hood after dark, start the engine & look for arcs & sparks. Maybe consider using a spray bottle of water & wet down each plug wire, dist cap, coil wire & coil, while looking for arcs & sparks, or a rougher running engine.

If no joy on the after dark wet down test, inspect for cracks in the dist cap, also on rotor that cause the rotor to break down to the dist post are good suspects for your list. Look for carbon tracks inside the dist cap.

The dist mounted ignition module is a known problem part, as under hood heat takes its toll on it.
Make sure the wiring to the dist is in good shape & is electrical connection is clean/ bright & tight. Same for ite ignition module.

More thoughts for consideration, keep us posted on your findings.

 

Will do that when I get home from work tonight. I've though about the ignition module but wouldn't that just quit if it was bad? Also what about the pick up coil? I don't know much about it but doesn't it act like a crank sensor but in the distributor? If it was going bad and not advancing the timing correctly that could lead to the stumbling and missfires? Just throwing things out there. I'm gonna figure it out! Thanks for the help it is much appreciated!

Also can thy distributor be pulled out without taking the upper intake off? I haven't looked at it real close to see? I thought about pulling it and checking everything on it if nothin else and cleaning all connections up.

 

When you remove the dist cap for inspection, wiggle the dist post that the rotor is on, it should be tight, no play.

The ignition module usually just quits when it goes bad, but I've heard of some that are heat sensitive & come & go.

Intermittent problems are the most difficult to run down, as you have to catch the faulty component in the act.

For instance, I recently had that kind of problem on my 94 Taurus, that would just randomally stop running. After several months of trouble shooting & head scratching that left me nearly bald, I found it was the dang computer!!!!

No trouble codes, no warning it was about to happen, just driving along & realise the engine wasn't running. Pull over, crank it, would instantly start & run like nothing had happened!!!! It was a PIA to trouble shoot, but on the way to get it inspected one day, it quit on a down hill run just before getting to the station. Drift in & hear the fuel pump still running, so with all of the other wierd happenings, like cooling fans cycling on when they shouldn't, fuel pump running when it shouldn't, CCRM relay chattering, now spark going missing, I knew it was the computer, as the ignition module doesn't control the fuel pump, nor the electric cooling fans, or the CCRM. SO, on your trouble shoot, make note of any other ususual happenings when it acts out, look to see what controls them, then after a while maybe you can by process of elimination come to a drill down conclusion, sorta like I had too, because I wasn't getting any trouble shooting trouble code clues to help out on my trouble shoot!!!!

Speaking of trouble codes, do you now have a CEL lit & if so, post up All trouble codes you now have, as they can offer up good trouble shooting clues. Don't throw any more parts at the problem until you get a positive trouble shooting result!!!!

 

No check engine light and no codes with engine running. Only ones with koeo are 21 and 53. Tps signal out of range but its new the other is ect sensor (new) or crank sensor( not applicable) to this. That's what lead me to pick up coil.

 

OK, thinking about the no fuel pressure at the rail when you tested it & the previous trouble code you posted that suggested a fuel pump power monitor problem, have a close look at the B+ power feed all the way from the under hood fuel pump power relay, through the in cabin inertia switch, to the on tank fuel pump electrical connection. Wiggle & Test these electrical connections under load for voltage drop with your multimeter. With the problem coming about suddenly after about a hundred miles of driving, maybe look to an electrical feed or ground wire connection problem, or pump electrical connection problem, since its recently been messed with.

Did you get the MAP problem resolved????

On the code 21, ECT out of range during self test, check the computer supplied ref voltage being supplied to the sensor at KOEO. Ref to the injection site I posted above, check the new ECT resistance value chart according to the ambient temp. Just because the sensor is new, doesn't automatically make it good, make it prove itself with a resistance check.

On the 53 code, do the same with the TPS sensor & computer supplied Ref voltage & let us know how it goes.

 

You know I had that inertia switch jumpered at first and then put it bad in but it ran fine after that. I thought that switch was not right when I first put it back in there. I'm gonna bypass it and see if that helps then check all the other things. Thanks again!

 

Well I got around to checking everything today. Came across my distributor rotor


Thought yes thats the problem. So I put old cap and rotor back on and took it for a drive. Same thing nothing changed. I brought it back in garage and checked all the sensor and everything and it all checks out fine. Checked a couple of the injectors and they were in spec about 15.5 ohms. Its got me fooled. When you drive it and you are gaining speed it will kinda surge and you can see the tack jump up and down alittle then it will be fine and accelerate just fine then start the stumble/miss again. I noticed that if you floor it and take off it will take off good then kinda bog and then it will take off. Im almost leaning towards the injectors being plugged. Out of curiosity would a plugged cat be causing any of this? Thanks for all the help!