95 5.8 liter MAF problems?

The Mass Air Flow sensor normally sits in between the air intake and the intake Manifold

Carb cleaner should do the job

On the 4.6 its right past the air cleaner. (I'll post a picture) The M in MAF stands for Mass. As in high speed. IME, when the MAF gets dirty it causes pinging on acceleration. Have my doubts about this being the problem. Live and learn.

Thanks, this helps. Funny thing, I paid 42 bucks to have it cleaned

2500 miles ago (part of a tune up). Looking at it now, it appears there is old resin in one of the torx screwheads. I'll have to remove the resin to get a torx bit into it. It's as if the screw had never been removed! Hmmm.

Unless you already have one you'll have to pick up one of those tamper proof torx bits. If memory serves, about 8.00 at Auto Zone.

Cleaning the MAF is an easy cheap insurance type thing. All of them in domestic Ford products are made similarly. IIRC, yours should be in the intake air pipe from the air cleaner to the throttle body. I do not recall for sure whether the

5.8L engine had gone to the MAF system in '95 or whether it was just the 5.0L They did not always treat them equally. If it has a MAF try cleaning it. You will need a set of torx security bits that are hollw if it has an MAF. You can get a whole set for about $8.00US at places like Autozone or Advance. If it still has the factory sealer on the head, it was not likely cleaned. Once the screws are removed, it is simply a matter of pulling it out. It uses an O'ring to seal it which can be tight or stuck a bit.

If that does not correct the problem, I would next check the TPS if it has not alrready been done. You can either just replace it or use an analog meter to check the voltage output by using a straight pin to penetrate the voltage wire. It should rise very smoothly with NO GLITCHES or flicker. At about 3/4 throttle, it will suddenly go well above 4.0 volts to as high as 5.0 volts.

If you do not find any problem or a replacement makes no improvement, you should check the joint between the upper and lower intake manifold. Some in that vintage had a problem sucking the gasket allowing an air leak that the ECM may not always be able to tolerate. I like to use gumout or similar carb cleaner to spray around the joint as it is combustible enough to get a response from the engine and not explosive like ether that can also damage an engins if it hits a large leak and gets sucked in. You also have a personal risk of bad burns with ether if it ignites. I would avoid the ether for this. It is bad enough to use as a starting fluid for someone who is not familiar with it's unpredictable easy ignition characteristics.

Cheers

Lugnut

Got the MAF sensor off. I couldn't believe someone or something dripped resin, or melted plastic, or glue into one of the torx screws! That crap was fused inside the head. Oh well, I got it off, and the damn sensor looked clean as a whistle. I guess the mechanic did actually clean it somehow. So, since I took it off, I cleaned in again, let it dry, and put it back on. Cranked it up, and the same goddam thing.

I waited for the idle to finally come down from 1500rpm (taking longer each time, it seems), and took it for a spin. Meanwhile the ABS light goes off and stays off. I drove it hard. Hard accelerations, and hard braking. I was pissed off, but I also wanted to see if something would go really wrong.

Nope, nothing happened. In fact, the beast is really running good (besides the mf-ing idle glitch.) It pulls very strong, winds up nice. The brakes work fantastic. And it idles normally after the intial kooky startup.

Next step is taking it in, dammit.

Thanks for all the help anyway, guys.

John

Today, I bit the bullet and took it in to a shop. Seeing how I just dropped a grand on Tuesday for dental work, I wasn't looking forward for another big bill, but waddayagonnado? I decided to go over to the next town to a foreign car shop I've been to before. These guys are intelligent and honest. I figure if I pay a few more bucks to get it right, I might as well.

The owner, Bruce, is back in S. Africa on vacation. I talk to Phillip, his stand in, and he works me into an afternoon slot. I'm there 10 minutes, and he has the Bronco in a stall, hooking it up. Meanwhile the entire place is swamped with Mercedes', Beamers, Jags, you name it.

Phillip works on it, calls me into the gararge, I tells me the ECM is clean, no error codes. In fact, the beast has idled normally the entire time. He also pulled the ABS codes and printed them out for me. Code 32, right front sensor problem.

So normal idling the whole time. We shut it down and start it up several times. No glitches. All I can think of now is maybe it's all the short driving I've been doing with the truck. All my driving for a while has been short 1-3 mile jumps. Maybe this screwed up the ECM? Possiblity, says Phillip. He says before he does more (expensive) testing I should take it out for a long run. Hour or more.

That's where I am now. I'm going to take his advice, see if it calms things down in the ECM.

You know what he charged me for 45 minutes of work? NOTHING. A big fat nothing. Unreal. Beer run is coming up for Phillip.

John

snipped

Sounds like a shop to remember. It does take some use thru several drive cycles for the ECM to completely "learn" your vehicle. The ECM incorporates an adaptive system where it learns the inputs from the sensors on your vehicle and the responses of other sensor with respect to any adjustment it makes. If it does not have this data "recorded" it resorts to a table which is nothing more than a basic database programmed by the manufacturer which are safe settings that may or may not be optimum for your particular vehicle or conditions. That is why the fault codes are usually cleared instead of resetting the ECM after repairs. It is common after some repair for the ECM to toss a fault code because something is not the way it was. If the ECM is cleared, it just assumes everything is OK as long as it is within the base table specs.

You should keep in mind that the fast idle will kick in every time the ecm senses a cold engine. If this is happening too quickly, you may want to replace the ECT if you have not already. They sometimes will act a bit flakey before totally failing and preventing the engine from starting. I replaced a dead one last night that had an occasional failure to start when warm. Checked it stone cold and found it completely open. I think they said the new replacement was under $30 at the dealer. In any case, I hope you have corrected your problem.

Cheers

Lugnut

What is the ECT, what does it do, what does it look like, and where is it?

Thanks, John

john wrote: > What is the ECT, what does it do, what does it look like, and where is

Might want to stick this partial list in a folder for future references:

ABS Anti-Lock Braking System. ACT Air Charge Temperature (intake air, after filter). ATX Automatic Trans. BAP Barometric (atmosphere) Air Pressure sensor. BPP - brake pedal position sensor.... used to be called BOO -brake on/off switch. BPS - brake pressure sensor. CC Cruise Control. CCS Cruise Controm Switch. CEL Check Engine Light. aka: MIL Malfunction Indicator Light CFI Central Fuel Inj, also called Throttle Body inj. CPS Camshaft (or Crankshaft) Position Sensor - used for ignition, injection timing. CHT - cylinder head temperature sensor. CKP - crankshaft position sensor. CMDTC - continuous memory diagnostic trouble code - a problem that the PCM has seen but may not be present now. CMP - camshaft position sensor. DPFE Differential Pressure Feedback, Exhaust - measures EGR flow. DSM - drivers seat module. EECIV The Engine/Trans Computer system used from mid-80's - mid 90's. ECM Engine control Module (before trans control > PCM). EFI Electronic fuel injection. SEFI Sequential Electronic Fuel Injection EGO Exhaust Gas Oxygen sensor, also called O2 sensor. EGR Exhaust Gas Recirculation (valve).- reduce emissions by lowering combustion temperatures.

*ECT* Engine Coolant Temperature sensor. GRVPS EGR Valve Position Sensor tells ECM/PCM how far the EGR valve is open (EGRVPS is more commonly referred to as EVP) (Non-DPFE applications). EOT - engine oil temperature. EPC - electronic pressure control solenoid (inside trans). FP Fuel Pump. FPM - fuel pump module. FPR Fuel Pressure Regulator. FPS - fuel pressure sensor. HEGO Heated Exhaust Gas Oxygen sensor, heated to reach op temp earlier, also called O2 sensor. IAC Idle Air Control (valve). Also referred to previously as ISC, IABP. IAT Intake Air Temperature (sensor). interactive vehicle dynamics. IMRC Intake Manifold Runner Control (late model, multi-valve variable induction). lighting control module. MAF Mass Air Flow (sensor). MAP Manifold Air Pressure sensor..used in engines without MAF (speed-density systems) MLP manual lever position sensor. MPLearn - misfire profile learn. MTX Manual Trans. OBDII Standardized powertrain control system from mid 90's (depend on model) ODDTC - on demand code - a problem that is present at the time of the test. OSS - output shaft speed sensor. PCM Powertrain Control Module (engine AND trans EEC). PCV Positive Crankcase Ventilation (valve). PIP Profile Ignition Pick-up - dist position pickup, ALSO the pulse sent TO the ECM power steering pressure switch. SAW - spark angle word signal. SPOUT Spark Output, the ignition timing pulse sent back to the ignition module based on PIP, engine RPM and sensor input. TB Throttle Body. TC Traction Control.transmission control switch... also known as OCS

-overdrive cancel switch. TFI Thick Film Ignition - Ignition module used with EECIV, side of dist on most models, remote on some later models. TPS Throttle Position Sensor. TSS - turbine shaft speed sensor. VCT - variable cam timing solenoid. VSM - vehicle security module. VSS Vehicle Speed sensor (with or instead of speedo cable).

*Test terms*: KOEO Key On Engine OFF, pulls memory codes KOER Key On Engine RUNNING, real time error info WOT Wide Open Throttle. Goose Test during KOER to test throttle position sensor and engine response. STI Self Test input, EEC - ground to start test STO Self Test Output some time same electrical lead as the CEL, but carries the test pulse or data.

On Fri, 13 Jul 2007 10:20:21 -0700, john wrote:

ECT = Engine Coolant Temperature sensor. It is separate and independant of the sender for the dash guage. It senses coolant temp for the ECM. This is how the ECM knows to go into cold start mode with the high idle. It is also used as part of the calculations to detemine correct ignition timing and fuel delivery. If the ECM "sees" a cold coolant condition, it will go into open loop operation as if the engine had been sitting overnite. If it is open as was the one I replaced last night or completely closed, the ECM either deliver too much or not enough fuel for the engine to run as was that one. The ECM has no way to determine that this sensor is out of range or near failing. It takes it at it's face value so to speak and goes to the table for that temperature range until it goes back to closed loop operation. It may not store a fault code as long as it is in a readable range even if grossly inaccurate. IIRC, if it stores a code, it should be either 21 or 51on that year. It has been a while since I was intinate with a 5.8L but, IIRC, it should be installed in the water tube from the intake to the throttle body. It will be much easier to find with the air intake tubes removed. The owner picked up a replacement for $24 if I heard correctly. Almost any good parts store should have them as they are pretty muck common to many of Ford's domestic cars and trucks. BTW, this sensor can be tested and compared to a chart for correct resistance values at various temperatures. The FSM (factory service manual) and many others have this chart for testing.

Good luck

Lugnut

Thanks man, I do appreciate your input. Today I bought a multi- meter. What's the trick for measuring volts and ohms on these sensors? Do you run the motor, or just have the key ON? And, obviously these connections are closed with snap-type connectors. Do you penetrate the wires with straight pins, then take readings off the pins?

John

Thank you, F.H. I copied that list, and stored it. I had looked around for a good one, but couldn't find one with ECT. Big help.

John

The ECT is a temperature sensitive resistor or what some call a thermistor. It is supplied with a nominal 5.0 VDC from the regulated side of the ECM. The resistance of the sensor caused by temperature change is sensed by the ECM as a variable voltage input. If this this is off, the ECM will be basing it's calculations on the wrong engine temperature. Modern EFI works so well, most people thinks their engines are no longer temperature sensitive. This the sensor that gives the ECM the ability to make it seem that way. If the sensor is reading on the cool side, the engine will run a bit rich all the time and may signal a false cold start condition. Reading the resistance is just a measurement across the terminals. The way it is made and usually positioned makes this job a little difficult. You may want to just penetrate the wires outside the plug to check the values. Don't try to run the engine w/o it being plugged in unless you want other problems

BTW, if you are looking to learn a lot about Ford EFI before OBD2, tyhere is a book called Ford Fuel Injection by a fellow named Probst for about $20 that has pretty much all the info you would ever need to understand, test, troubleshoot and repair the Ford EEC-IV systems. The public library here has a copy of it. You may want to check it out for a couple of days if yours has it.

Lugnut

This weekend I took it for 2 long drives. No effect on the problem. If this ECM needs to learn something, it has a serious disability. Tomorrow I'll play around with the multi-tester. I'm also going to try to pull a code(s) using a self test method I found at

I'm pretty clear on the KOEO,but will it work KOER? I guess I'll find out. To get volt and ohm readings, do you leave the sensor connected, pierce the wires with something (like a pin), then put the tester leads on the pins? Is this the normal way to do it? And would you do this KOEO or KOER? or both?

I have to believe this is something simple. The truck runs fantastic except for this high idle. I keep looking at my rifles. No, not yet.

Thanks, John

snipped

Leave the sensors connected. Use a straight pin to penetrate the insulation for reading. The engine will run poorly if at all with this sensor disconnected. Check it at seceral points beginning when the engine is cold to be sure it is responding to temp change in engine.

I also wonder if the shop just extracted the codes and ran it thru the basic diagnostics. Not all shops have the same capability to thoroughly test the system to the degree that the Ford STAR tester can. It will thoroughly test each sensor and record the values. A tech experienced with it can damn near pinpoint a problem without ever touching a wrench. Dealer diagnostic are expensive but, may be the least expensive after the dust settles.

Lugnut

Lugnut

at

I'm pretty clear on the KOEO,> but will it work KOER? I guess I'll find out.>

I had this same problem with my F150. I decided to bite the bullet and pull the intake, so I went to the cars wash to clean the engine. After I cleaned it it ran perfect. I hosed down the base of the air plenium and foud the chincy (spelcek is my freind) gasket on top the manifold was getting letting in air. It started as a long fast idle and would stop after it heated up. It eventually got so the fast idle was a perminate thing. Ricker

at

I'm pretty clear on the KOEO,> > but will it work KOER? I guess I'll find out.>

Was yours a 1995 5.8liter? Do you mean you removed the air plenum and put on a new gasket? I'm not sure what you mean about taking it to the car wash. Are you saying it ran perfectly AFTER you washed it at the car wash? I'm confused.