Well I spent the better part of the day today working on the van.I replaced the spark plugs,cap rotor,wires,air filter,and cleaned the IAC valve per Stev's instructions.At first the van didn't want to stay running,and the check engine light was on. I think this was due to me starting the van after changing the plugs,and wires while the IAC valve wiring was unplugged.This may have caused the engine computer to turn on the check engine light.I never noticed the idle being off before,but then again I wasn't really paying attention to it.The van does however seem to have a better idle now,and the power seems to be better as well with the new plugs.I could not find the Fram crankcase air filter thing for the breather mod that Stev wrote up at the local parts places,and I bet they have it at Wal-Mart,but I can't go in there.Does anyone have the part number for the crankcase air filter from Fram?Working on the van wasn't as bad as I anticipated,but the front two plugs on the drivers sdie were a real chore to remove,and install.Even with the front drivers side wheel off it wasn't easy due to the tranny lines,and cooling lines for the rear heat being in the way.I ended up using a swivel,and various extensions to get the front two on that side through the doghouse.Hopefully I will get the coolant flushed soon,and flush the tranny,and replace the fluid with synthetic.Maybe if the funds allow I will get the Roadmaster suspension as well.Thanks for all the help,guys.


Chris
2001 Ram Wagon 2500 5.2 litre
2001 Jayco Kiwi 23B Hybrid travel trailer
1979 Mazda RX-7 GS
1974 Mazda RE/PU

 

Chris,

It sounds as if our two vans are very much identical in nearly every way except mine is a 12-passenger with cloth seats and upgraded interior package.

Let me relay a problem I had not too long ago with the van. To fix the problem, I had to give the van the finger! Well, not that kind of a finger. It may help your van too.

-- clip in from another forum --

Here's the problem ...

The DW calls me at work saying, the engine light came on and the van is very difficult to keep at 55mph. I told her to pull the van over. Next she calls back. The van will not go faster than 40mph. I told her again to pull over. Finally, she calls back. She pull the van over, I told her to do the on-off key trick. The code of P0121 was given.

P0121 (M) TPS Voltage Does Not Agree With MAP TPS signal does not correlate to MAP sensor signal.

P0121 (M) Accelerator Position Sensor (APPS) Signal Voltage Too Low APPS voltage input below the minimum acceptable voltage.

OK, so I know a little about this after searching the forums. It could be anything from a bad connection, damaged wires, bad TPS or MAP, A/C clutch relay or .... worst case needing a new PCM.

Without those sensors functioning properly, the PCM is going to default to a "limp-home" mode, which is running very rich and low mph down the road.

The van is sitting some 50 miles away from home right now.

Anyone else had this code in the past?

Stev

--- clip to solved answer ... ---

P0121 shows up in engine tech as MAP and TPS dissagree. The ASTG manual said if the TPS sensor fails the computer will use the MAP sensor in limp-home mode. In so doing the engine may not run well and OD/lock-up will by controlied by MAP and will be more sensitive to shifting OD/lock-up.
It's also possibly the 5 volt supply from the PCM to the MAP, TPS, IAT and coolant temp has a broken wire at the MAP or TPS area.
If there was a short or no 5 volts from the PCM to these sensors there wouldn't be any voltage for the PCM to compare.
Quick test. Test for 5 volts at the sensors. This will tell if the wiring and ECU are OK.

--- clip in to resolve the MAP and TPS dissagreement ...

Good work. However, I managed to poke though my Haynes Repair Manual and followed all of the steps involved for testing out the TPS, MAP and IAC. All of these sensors were operating in their correct ranges. Bummer. Now what is the issue? A bad PCM ?!?

I did find that the TPS is like a potentiometer. As the gas pedal is pressed, the cable moves, the TB valves open and the TPS sensor rotates via the shaft axis. I took off the TPS, cleaned the contacts and carefully shook the sensor. I heard a little noise of something rattling around inside, but then it stopped. So, I place the TPS back onto the TB. I then restarted the van and the problem was still there. Bummer again.

Next, I visited the IAC. There was this gut feeling I had that this part could be the problem even though the TPS and MAP were reported being out of voltage range with each other. Per the advise of another Dodge forum on the internet to me, a DCX service tech, to give the TB the finger. After that all the problems went away. Well, this is a finger treatment you give to the IAC with the engine running at idle. Placing your index finger over the air-inlet port to the IAC on the TB, carefully and slowly choke off the air going into the port until the engine nearly stalls out. I did this several times since the IAC was pulsating. At the last time, I totally choked off the IAC until the engine stalled. This made the IAC to draw all the way back within it’s sensor housing. (NOTE: this is done only with the IAC mounted on the TB.)

The next step is critical. Take the negative battery terminal off for 2 mins. DO NOT touch the key until the 2 mins have passed.!!!! Now, turn the key off and reconnect the negative battery cable. This resets not only the PCM, but the other sensors for the TB.

Now, the final step was to turn the key back on for 5 seconds prior to a full start crank over. The IAC when it had stalled the engine from running drew all the way back in travel. Upon restarting, and waiting for the five seconds, I heard two distinct cracking noises from the IAC in movement as it went into it's position. Did this fix a sticky IAC or what was the finger trick suppose to do???

At first, I thought the advice was a little crasy! BUT, with nothing to loose, I tried it. Not only did this wacky procedure work, but the engine behaves far better than when I had originally purchased it. It worked so well, that stomping on the pedal from a dead stop now lays a 15 foot streak of rubber on the street! The van NEVER did that before since I’ve owned it! I thought, what did this finger thing do ?!?!?

The last thing I did was to replace the air filter. It wasn't totally bad, but I didn't get to it when I changed the oil last.

Now, my next step is to try the finger trick on the V6 B1500 since it's running like a dog with it's tail between the legs.

--- clip out ---

So, that's what I ran into with the van back in January of this year. It sure had my brain rattled for a time.

Peace!

Stev

 

These are the cross references I've found for the filter. However, when I did the mod, I forgot to write the filter number down! So, measure the hose fitting ID and tweak it to fit into the new crankcase breather housing in the air-cleaner canister. https://dodgeforum.com/m_525412/tm.htm

Fram BA3525 or BA3554
Purolator B43127 or B23125
NAPA FIL2992

 

Hey Stev,

Thanks for the help on this.Where is the air intake port for the IAC on the TB?When you say disconnect the negative abttery cable,and don't touch the key,do you mean the key is in the run position with the engine off,and then disconnect the battery terminal?I think this is what you are saying as the next step is to turn the key off,and then back on,and wait for 5 seconds befor cranking.Would this be a smart thing for me to do even though the van is running fine,and the check engine light is off now?Also it seems to me that the elbow on my air cleaner where the crankcase airfilter would go looks different than the one in your post about the crankcase mod.Mine doesn't have the clip thing,and such.It is just a molded elbow that has a barb on it to accept the hose from the breather.

Thanks again,

Chris

 

Well I drained the coolant today,and did like you said Stev,and put a mix of 50% distilled water,and 50% distilled vinegar,and let it run for a few minutes.I think I may have screwed up though,as while it was running I walked away for a few minutes,and when I came back it seems the engine was at operating temp,and the thermostat was more than likely open as the radiator was warm.I drained it again at the radiator,and refilled it with fresh pre-mixed coolant.

I was wondering though,did I get most of the stuff out by only draining the coolant at the radiator,and removing the lower hose from the engine to the radiator?If not how bad is it to run with some vinegar,and distilled water mixed with the 50/50 coolant mix?What about the rear heat?I took the van for a ride after I filled it up,and ran the heat both front,and rear,and they blew hot air.When I got back I had to add some coolant to the overflow bottle,and it was at the ADD mark.Any help on this would be appreciated?

I also bought the crankcase breather filter thing,and plan on doing that soon.While I am in there I may try the finger trick you spoke of with the IAC valve,and see if the van responds to that by running better than it already is.Thanks again.

Chris

 

Chris,

If you look at this thread, you'll understand how to clean the IAC, the port it fits into in the TB and the slot under the port. https://dodgeforum.com/m_525409/tm.htm

You are 100% correct on the key turned to on, but not starting the van.

The elbow fitting in the air-cleaner housing is correct. When the crankcase breather cup and filter element is purchased, the FRAM part comes with the clip. The clip is very handy in the setup.

As for the coolant flush, everything seems to be well. A little vinegar will not hurt the cooling loop. Since you have rear heat like my B2500, you can drain the rear heater by crawling under the van along the drivers side. Look up just before the rear wheel well. You will see the pumping to the rear HVAC unit. Two lines are for the AC and the other two are for heat. You will need to drain the heater line the next time your due for a flush..

When you did the flush, how did the coolant color look?

Good work so far!

Stev

 

Thanks for the reply Stev.I have cleaned the IAC valve,and I know where it is,but what I didn't understand was your fix taht involved choking the air inlet port to the IAC until the engine dies,and then disconnecting the battery to reset the system.I was just wondering if the air inlet to the IAC was inside the throttle body like I think it is(spot where the brass cone looking piece if the IAC fits into),or if it was somewhere else?

I bought a NAPA crankcase air filter setup,as I couldn't find the Fram unit,and it didn't come with the clip,just the plastic housing and a filter element.I have yet to try this fix,but I will be soon.Hopefully the part I bought will work.

I knew of the plumbing for the rear heat,but it must have slipped my mind on draining it,or maybe I didn't want to do it with the worry that it would get air-bound,and be tough to bleed.The coolant that came out was pretty dark,and not som happy looking,and I am glad I replaced it,but I have seen worse.My biggest concern was that I didn't get all the vinegar out,but if you think it is okay I won't worry about.I put just over two gallons of coolant in the van after I drained it out,so I am guessing that if there is Vinegar in it still it probably isn't much.

The van seems to be running better now with the new plugs,cap,rotor,and such,but it doesn't seem to have the power my company van has which is a mostly neglected 98 3500 cargo van with the same motor,axle ratio,and wheelbase(length as well).The company van seems to down shift,and get-up,and go much better than the 2001.Any idea what it could be?Extra weight of the fully finished van complared to the stripped down work van.Mileage on the 98 is 75k,and the 2001 is 102k.Maybe I will try to clean the Throttle position sensor,and do the IAC reset method you wrote up.What should I use to clean the TPS?Electronic contact ceaner,carb cleaner,brake cleaner,other?

Thanks again.I will be in contact I am sure.

Chris

 

Yes, the spot is the IAC port hole. With the air-cleaner housing off and only the TB to be seen atop of the engine, you can start the van and let it idle. Next, use your index or middle finger and choke off the back side of that IAC port hole. As the pintle part of the IAC moves, you'll get a touch on your finger the more the air flow is choked off. Try choking the air flow off until the engine almost dies. Then at that moment open the IAC port wide open for the engine to return to a normal idle. Doing this several times excersizes the IAC pintle and allows the PCM to calibrate then entire pintle length of travel.

I must say, you do bring up good questions. It's better to ask them if you're not fully sure. I may assume or forget a step in writing up a process. So, keep asking the questions.

When you changed out the cap-n-rotor, did your get the parts thathave copper/brass contacts? This will make a big difference in performance and longer durability life of the ignition system.

My 2001, 12-passenger 5.2L/318cid, 3.92 rear was sluggish until I did the finger trick and cleaned the contacts of the TPS and IAC. The engine seemed peppier and I can lay down a burnout from the tires over 21 feet long. Prior to that, I would only chirp the rear wheel.

As for cleaning the electrical contacts of the IAC or TPS, NAPA sells the CRC QC electrical cleaner. It comes in either a red can or a blue/green can for marine use. Either can will work since it's the same formula.

 

Thanks stev,

I used plain old CRC carb cleaner for the AIC when I had it out last week.I hope that is okay.I will try the finger method this weekend if I get the chance.Do I run the risk of causing a check engine light by doing this "FIX"?

Chris

 

Chris,

Nope, no check engine light came on either time I did this.

Stev