I need help, ASAP

[AdamDude04]

89 EFI 302 w/ 319,739 miles with 4 speed auto

Okay, so I go campin a lot. My main problem is at high elevations the truck starvs for air. Now I'm not sure if this is a power issue, or an oxygen issue.. but going up a 6% grade up the pass at roughly 11k ft..well max I can do is 35 mph. I pass semi-trucks at a snails pace.

Anyone have any ideas if this can be fixed? Or is my motor just tired, or do I lack a MAF sensor? I didn't see one, so I assume I don't have one? They are usually from what I've seen, located on the intake tube from the airbox..

I've been spoiled as my new truck will do 75mph up the pass and still quickly pop over 100 if I want it too. Which leads me to think it's a MAF job as that's what measures the oxygen levels and makes the proper adjustments.

This rolls over into my question about a beasted motor..if I rebuild my motor to the 300-400hp range, will I still have this issue because I lack a MAF sensor? (assuming I don't have one..)

 

[Xxxyank]

I'm not sure what your vehicle has injection wise... But my 95 XL with a 302 has a MAP (manifold Absolute Pressure) sensor.

It has a rubber vacuum line that comes off the intake and attaches to a little box, which has 3 wires running to it... one is the power supply from the PCM, 2nd wire is the output, 3rd is Ground...

wish i could be more specific & have pictures, I'm sure someone more enlightened will fill in the gaps of what you have...

 

[Rons beast]

*** is right with the MAP sensor. It should be mounted to the firewall next to the evaporator housing, and have a vacuume hose attached to it. You are thinking of MAF (Mass Air Flow) That would be inline with the intake tube.

Don't you get any codes when this happens?

If the engine is strong at lower altitudes, it must be healthy internally.

I am amazed you got no cel with codes. Is it the original engine?

 

[AdamDude04]

Yep no codes. I noticed when down in Cali in December, it had a bit more pep in its step but nothing too major. I know naturally living at 5,200ft it's not going to be as powerful as a truck at or near sea level with more oxygen. But going up to 11k ft is just plain weird on the power difference. It seems like anything higher than 8k ft it looses a bit of power. Enough to notice and make me question.

It is sound, with 319k orig miles. It does have a lil bit of blow-by but that is expexted with worn rings 21yrs old..

I'll have to check the MAP sensor.

It runs fine..it just doesn't have any power. When camping, our camp site is roughly 9,*** ft and the truck will idle fine. Sometimes if idling at a normal 600rpm it'll bump up to 1000-1,100 rpm for a minute or so, then slowly work its way back down to 600rpm. Kinda rare for this to happen but it does happen from time to time..

Sometimes we do idle the truck for 4-6hrs at night for warm air while at our camp site if temps are near 30ish degrees. Has no problem like I said, but when traveling, esp going up hills it bogs down more than I think it should..

 

[miesk5]

yo,

Bad Ford MAP Sensor

This bad ford digital map sensor was captured using the digital MAF/MAP autometer. This vehicle was experiencing an extreme rough running condition as well as stalling out at times. Notice the autometer shows the current frequency reading plus the minimum and maximum reading recorded, a histograph of the frequency, and a labscope display of the waveform: by omitec.com

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MAP sensors measure engine load and provide a barometric pressure value to many PCMs when the ignition is first switched on, before the engine is started. MAP sensors detect changes in engine load by measuring the amount of pressure inside the intake manifold. Manifold pressure is relatively low at idle and increases during acceleration. MAP sensor voltage or frequency (Ford) also increases as load increases. DonÕt confuse manifold vacuum with manifold pressure. Compare MAP voltage to vacuum in the chart below. Mirror images aren't they?; Slide # 2 shows 90 Lincoln Town Car Reading

Waveform in Good Condition; MAP sensors are only used in Speed Density systems Source: by wrenchead.ca

MAP Testing, Symptoms & Overview; "...a multimeter that can read frequency is normally required to check the sensor’s output. But you can also use an ordinary tachometer because a tach can display a frequency signal. Here’s the procedure: Connect the two jumper cables the same as before, (see diagram in site) attaching each end terminal on the sensor to its respective wire in the wiring connector. If you want to measure engine vacuum so you can correlate it to a specific frequency reading, connect a vacuum gauge to a source of manifold vacuum on the engine, or tee the gauge into the MAP sensor hose. Turn the ignition ON and note the initial reading. The reading on the tachometer should be about 454 to 464 at sea level, which corresponds to a frequency output of 152 to 155 Hz. Start the engine and check the reading again. If the MAP sensor is functioning properly, the reading should drop to about 290 to 330 on the tachometer, which corresponds to a frequency output of about 93 to 98 Hz. No change would indicate a defective sensor or leaky or plugged vacuum hose..." a vacuum gauge to a source of manifold vacuum on the engine, or tee the gauge into the MAP sensor hose.

Source: by wellsmfgcorp.com http://www.wellsmfgcorp.com/pdf/Counterpoint1_1.pdf

 

[AdamDude04]

Could it really be the MAP sensor?

I don't seem to have any issues other than lack of power at high elevations. No idle issues..

 

[miesk5]

yo

...lol

who knows?

Why not read what the symptoms are of a faulty MAP (hmm, looks like you are experiencing) or it's vac line, connector/wires, etc. and do the test?

Why Guess?

I know people who tune sensors by using that wellsmfgcorp test and installing the vac gauge in-dash



(as Steve83 did)

with a scope/or freq counting w/display MM mtd in a console

You don't have a MAF sensor unless a prev owner converted it over.

 

[AdamDude04]

Yeah I figured I didn't have a MAF sensor..being there wasn't one located on the intake tube.

I just hate doing those kinds of tests. So I try to find symtoms of such before doing the test to see if it fits into what problems I'm experincing.

I know I have a vaccume issue of some sort. Some days my brakes work like a brand new car..other days, like an old truck. No change in conditions..just start it up and drive. Sometimes they touchy, sometimes they require a lil space.

 

[miesk5]

Yeah I figured I didn't have a MAF sensor..being there wasn't one located on the intake tube.

I just hate doing those kinds of tests. So I try to find symtoms of such before doing the test to see if it fits into what problems I'm experincing.

I know I have a vaccume issue of some sort. Some days my brakes work like a brand new car..other days, like an old truck. No change in conditions..just start it up and drive. Sometimes they touchy, sometimes they require a lil space.

ok, but the testing is what saves $$$ vs parts buys and all the associated problms w/bad sensors.

Did you do KOER portion too w/eng at norm op temp?

ck vac hoses esp at MC Booster, intake manifold; Broncojoe posted vac leak testing here many times.

 

[AdamDude04]

ok, but the testing is what saves $$$ vs parts buys and all the associated problms w/bad sensors.

Did you do KOER portion too w/eng at norm op temp?

ck vac hoses esp at MC Booster, intake manifold; Broncojoe posted vac leak testing here many times.

True testing does save money. However at 319k miles I have no problem replacing sensors because I have no idea how old they are. I am planning on testing the MAP sensor though. It looks newer than some of the sensors I've already replaced in the past. Plus at $60 somethin bucks that's a lot of ammo cash :-"

Did the tests cold an at op temp. Nothin unfortantly

Vaccume test soon on the way. I'm actually going to buy a new brake booster first, then do my vaccume test. Mine is pretty crappy looking an rather replace it than wait for it to rust a hole through it and leave me without brakes..

 

[BroncoJoe19]

MAP sensors measure engine load and provide a barometric pressure value to many PCMs when the ignition is first switched on, before the engine is started

See that? You learn something every-day!

I thought it gave constant updates.

I wonder if you get part way up the hill, and turned the engine off, would the MAP give a new barometric pressure to the PCM when you re-started it?

Had you niticed that your power returned once you were at the site, after you restarted it?

 

[AdamDude04]

See that? You learn something every-day!

I thought it gave constant updates.

I wonder if you get part way up the hill, and turned the engine off, would the MAP give a new barometric pressure to the PCM when you re-started it?

Had you niticed that your power returned once you were at the site, after you restarted it?

I havn't noticed..but I tell you what! I'm going to try it!

 

[miesk5]

yo Adam,

My man, you're killing me man.

Now why didn't you do the KOER portion w/engine @ normal op temp?

I mentioned this a few times to you in other posts for other issues you asked about & you didn't get back with a reply.

run it around to heat the engine up and shift thru all gears incl Reverse.

then; turn off all accesories/lights, etc.

Do KOEO portion first

For Key On Engine Running (KOER) portion, the engine has to be @ normal operating temp. so do that test while engine is still warm.

Post any codes found here or look em up in my broncolinks.com site.

Self Tests by buddy, by BroncoJoe @ http://broncozone.com/topic/14269-code-reader/page__p__74587entry74587

--

and as for replacing parts; ask BigAls87 (ign. cylinder) & a few others here how their parts didn't fit or work or failed after a week becaause of POOR QUALITYY from China... how about 3 returns to get one to fit?

 

[Seabronc]

Adam, if you won't take the advice given, you may as well not come and ask for help. People will stop responding to you after a while.

Good luck,

>-

 

[AdamDude04]

EDIT: Wrong button

 

[AdamDude04]

yo Adam,

My man, you're killing me man.

 

Now why didn't you do the KOER portion w/engine @ normal op temp?

I mentioned this a few times to you in other posts for other issues you asked about & you didn't get back with a reply.

run it around to heat the engine up and shift thru all gears incl Reverse.

then; turn off all accesories/lights, etc.

Do KOEO portion first

For Key On Engine Running (KOER) portion, the engine has to be @ normal operating temp. so do that test while engine is still warm.

Post any codes found here or look em up in my broncolinks.com site.

Self Tests by buddy, by BroncoJoe @ http://broncozone.com/topic/14269-code-reader/page__p__74587entry74587

--

and as for replacing parts; ask BigAls87 (ign. cylinder) & a few others here how their parts didn't fit or work or failed after a week becaause of POOR QUALITYY from China... how about 3 returns to get one to fit?

What the ****! lol I did do the tests! read last post.. I did it at cold, and at op temps. First was done prior to leaving to work (truck sat in driveway for at least 12hrs) then right when I got home that night (roughly a 15mile drive) so this way it has got up to operating temp and all sensors balanced at normal driving conditions.

The testing of the MAP sensor I'll have to get to on my day off in a few days unfortantly. But again I do have a month until my next camp trip.. And gotta slap some new shocks on, hopefully some new tires, tune up, an oil change.

 

[miesk5]

yo Adam,

OK, thanks for clarifying that; I didn't see the KOER specifically stated as done. I've seen a few other folks follow Ryan M's self-test instructions, but he just shows the KOEO portion in the main section of his site; his KOER portion is shown elsewhere in his site.