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What are the symptoms of a bad map sensor


Old 01-10-2011, 11:25 AM
robinhood is offline
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Originally Posted by HeyYou View Post
Try swapping out the ASD, and fuel pump relays, with some others under the hood. See if anything changes.
yes hi i have tryed that too but thanks
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Old 01-10-2011, 12:42 PM
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CPTAFW163 is offline
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Location: Ft Campbell, KY/TN
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you need to get the PCM for your year, make model, engine, tranny, even Off road package. Also, if your truck is a cali truck, you need the cali emissions flash.

Could be the camshaft position sensor. But I think it is still the relays. They differ from year to year (What slot they use). If you got a used PCM, you need to also take the PDC cover and relays to ensure that you can put them in the right spot.

Have you done a fuel pressure test? Get a fuel pressure gauge, put it into the test port and do a bleed down test:
1. COnnect to port
2. Turn key to on position, but do not crank
3. Read pressure at the rail.
4. Take out key
5. look at fuel pressure after about 5-15 minutes. if it foes down, you have a leak.

Then a running fuel pressure test:
1. connect gauge
2. Start truck
3. Get out and look at the fuel pressure. Should read 49 (it will be bouncy between 49-50, because you lose slight pressure every time an injector fires.)

As far as checking the electrical system. Cmckenna can help with some PMs. If he has not already PMed you.
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Old 01-11-2011, 11:37 AM
robinhood is offline
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H i thanks ok yes i used a use pcm but did get it flashed with my vin and mil wen it dose it runns like brand new so fuel i think is out but but i did give them my vin so that should take care of if from cali and tranny i hope
i did put in new crank and cam sensers cap and rotor
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Old 01-11-2011, 02:21 PM
98ramowner is offline
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Location: everett, wa.
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Originally Posted by robinhood View Post
ok now what it is doing it starts then dies right away

Will it stay running if you push on the accelerator pedal?
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Old 01-11-2011, 03:13 PM
cmckenna is offline
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Originally Posted by robinhood View Post
Hi everyone i need help i have a 98 durando i bought it cuz good price and iam a fairly good mech or least i thought i was till this can into my life lol
my 98 had starting problems the old owner took to dodge the said after hours of testing the the think it needs a pcm ( but cant garintee it it is that ) so the 500 plus 800 for pcm with no garintee she says no way tows it home puts it for sell i buy thinking iam this great mech il fix it lmfao this dodge is winning. wen i first got it home no start at all this is a list of what i have done
#1 used pcm
#2new crank sen
#3 new can cap and rotor
#4 got oringenle pcm reflashed
#5 picked up anoth used pcm ( that a totle of 3 ) now
#6 i get two more reflashed
ok now what it is doing it starts then dies right away
please if there is any body out there that can piont me it the right way i dont like dealer ships there just part replacers not mech and i know they know this a reacureing problem they dont care as long as you need them i think we as dodge owner get to gether as one grope and solfe this problem i think with all our knolage we could my email is [email protected] or robert steffen on face book iam the one with the two dogs in pic look me up lets chat about the durango and solf this thing
So, after looking into this, let me say that this one may a tough one due to one reason: the PCM has been swapped out. Not that this is an issue (I don't run OEM PCMs and have no issues) but, it could be either one or more areas within the system.

If it starts and dies right away, I'd be mentally thinking about what or why this would be doing this. Someone mentioned fuel pressure and, I will say that again -one of the more common failures when cold is the fuel pump going out.

Testing is everything and, it's quick to get to the root of the problem rather quickly. In order to steer you in the right direction, I would at the very least, verify fuel pressure as instructed in this thread. IN fact, his instructions look very similar to what I recommend.


Again, get a fuel pressure gauge connected to the Schrader Valve.

Turn KEY <ON>

Note reading.

Reading should be ~50 psi cold.

SPEC SAYS: Pressure is to hold @30 psi for 5 minutes.


Start Vehicle and have someone watch pressure gauge and note results.

<IF> pressure fails to meet the above pec, there's a problem with the fuel delivery system.

<IF> pressure drops like a rock or, no pressure exists: you've got a few different possible failures to choose from..

a. leaking fuel injector
b. pressure relief valve at fuel pump fault thus allowing fuel to pour back into fuel pump.
c. gross leak in the fuel delivery lines and / or fuel rails
d. FUEL PUMP failure
e. loss of supply TO FUEL PUMP due to clogged inlet filter.

Now, while all of that is fine, you may not even have a fuel system related issue at all. You may be experiencing a failsafe event. Let me ask you this: when turning the KEY to <RUN>, how long does the vehicle RUN for in duration?

If the vehicle is killed within 2-3 seconds, there's a fairly good chance that the PCM is putting the vehicle into what is called AUTOMATIC SHUTDOWN MODE due an ERROR with one of the two MASTER sensors that were just replaced OR, there is a PRE-existing error or, a compatibility issue with the ABS MODULE and the new PCM.

These TWO MASTER Sensors are: CKPS and CPS. The afore mentioned is for the CRANK and the latter is the CAM. Whenever changing those out: it is imperative to go with OEM on those. WHY do I need to go with OEM? A: Because, aftermarket sensors are usually rejects that DID NOT MEET OEM SPECS at time of electrical test and ESS screening. IN fact, they rarely even test them anymore to any degree let alone full testing to ensure it works 100%. While it may work at room temperature or hot temps, when cold, there may be an issue with the potting material thus leading to a thermal mismatch on the potting compound to which, when cold, starts contracting thus pulling the assembly apart thus tearing the coil wire up thus, an open condition results.

The other thing when replacing any one of those is, sometimes FUEL SYNC needs to be reset with a DRBIII scan tool to get the firing line lined / timed up with the fuel delivery system again.

But, before going over every possible cause and affect here, I highly recommend running a pressure test first.

Start there and report back the results.

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Old 06-13-2011, 01:46 AM
kingnadda999 is offline
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Default Think my map sensor is going out

Think my map sensor is going out on my 98 ram, however did the steps to see if I could get any engine codes but nothing happens not even the p-done code any ideas on what I am missing or something else you have to do for that model year?
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Old 06-13-2011, 11:28 AM
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HeyYou is offline
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Take it to your local neighborhood parts store, and they should have plug-in code readers, and will scan the truck for free. You might even be able to take a guy for a ride around the parking lot, and have a look at map values.

Question here becomes, what leads you to believe the map sensor is failing?
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Old 11-27-2011, 05:37 AM
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graythang is offline
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I wonder is this the cause of the famous 4.7 & 3.7 hard acceleration stumble. I mean if it is measuring load then under load could cause engine stumble. Any chime ins
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Old 02-14-2012, 07:47 PM
Dadof3girls is offline
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Default Puzzled

Still having issues, 2001 dodge ram 5.9 start fine idles fine runs great until you put a slight load on it ( going up hill at highway speeds) the rpms pulse up and down not much 50-100.Replaced TP sensor cleaned IAC checked grounds and checked for vacuum leaks still no change. Also ran a can of sea foam through engine, changed tranny fluid and filter. I'm out of ideas could it be a MAP sensor, o2 sensor etc. Plugs and wires aren't that old, pellium looks fine. Any help would be nice.
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Old 02-14-2012, 08:18 PM
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Unplug the O2 sensor, and test drive it again. Just to eliminate that as a possible cause.
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