Hello all,

1st post; I've attempted to research this issue as much as I could on the historical threads, but... I'm a bit stumped on what to try next. So thank you in advance for any and all help you can provide.

History:
1. For about a year now, on and off the idle has gone up and down a bit, mostly when cold at startup, eventually seemed to calm down.

2. About 3 weeks ago, things changed. Check Engine Light came on. When stopped and idling, the Van occasionally died; restarted no issue. Upon cold start the Van would die upon load of being put into gear; unless I had my foot on the gas to keep the RPMs up.

3. Took the Van down to a shop - they reported the Check Engine code as a P0505. They replaced the IAC; said it was doing better - but still giving a P0505. They threw up their hands, saying they checked the wires; and the only thing to do next was to get a new computer from the dealership for $600+.

4. I called the dealer they estimated a $800+ repair, which I can't afford.

Presto! I arrive at this forum instead, looking for answers.

A. Found the - how to check and clean things up. Did the procedure as the TB was rather dirty upon inspection. https://dodgeforum.com/forum/dodge-r...n-the-iac.html - but did not solve the issue.

B. Read the several more threads like this one - https://dodgeforum.com/forum/dodge-r...505-still.html and - pulled the battery - Check Engine light clears, and about 10 minutes after driving comes back on. Also started to ponder if this was a vacuum leak.

Drove the Van around a bit, and realized - that after the IAC was replaced, there was a loud sucking sound. Also realized the behavior was totally different. Upon Cold start-up it seems to work fine, as the engine heats up however, the idle speed increases. Weird. No tach, so I don't know how high the idle speed was... but it was fast.

5. Took the van back to the shop who changed the IAC - and asked them to look for a vacuum leak - as there was the loud sucking noise now.

They told me as soon as the control wires are connected to the IAC it immediately goes to a full open condition causing the loud sucking noise and the very high idle.

They put in another IAC for me - manually adjusted the idle - and did not reconnect the electronics connector.

Thoughts on what my next step is?

I've seen the terms PCM on several threads. Is this the same as my local shop saying I need a computer?

I see this place - http://www.autocomputerexchange.com/ - that says they do reconditioned PCM's for my Van.

Is this my next step?

Thank you.

-M3


EDIT: Ended up being the computer, wiring and everything else checked out fine. Moment a new computer went in - all way well again.

 

I am reading this and thinking looking up p0505....SLOW down on condeming the computer!! AKA PCM, ECM, VCM, ECU,

Tell us is vehicle STOCK?
No other codes?

 

Check out the PCV valve for correct operation, also check to make sure the PCV hose isn't plugged.

 

Check as alloro suggested....I really like doing simple easy things first...

Can you answer the 2 questions asked?

Looked up p0505 and have some ideas ...

Are you handy with a DVOM?

GTG

 

Ack! I'm not getting email notifications on people's updates to this thread! Sorry for the slow response.

Is the vehicle stock... Well about as stock as Dodge B1500 Incomplete Van chassis is before it got sent to a conversion company named Glaval that went out of business 5+ years ago.

So... uhhmm... sure... it's stock!

And no - no other codes; although I am doing this 2nd hand - although I did ask that question of the shop - and they said it was the only code.

As I said - their textbook response to a - p0505 - was... change the IAC, check the wires, or change the computer.

TLA (three letter acronyms) and now FLA (four letter acronyms) - and I are still coming up to speed... Shall I assume DVOM = Digital Volt Ohm Meter? if so.. yes - I'm handy with them. What did you have in mind?

-M3

 

I'm mechanically inclined, but not overly knowledgable on how to test this - got a link you can toss at me, as to how to do the test?

Also as I mentioned previously... I'm a bit rusty with my automotive acronyms - so - PCV hose is... The hose from the valve cover seemingly going right into the sidewall of the intake manifold?




-M3

 

sorry about all the acronyms....BUT your intution is correct and you are understanding especially with PCV- definately one of the more interesting codes

we are thinking of reasons the computer (PCM) would command the IAC
to open full - trying to start checking easy cheap things first - some logical reason before condeming computer (pcm)- which is NOT always a bolt in.... might need reflash or reprograming etc

Laymans apporach
no big $ scanner
the IAC wiring may be shorted to ground or shortrd to voltage- unpluging the iac and checking harness with DVOM for short to ground a or a "hot" 12v shorted wire....then with eng running same testing


professional apporach
big $$$ bi directional scanner
the technician working this should investigate throughly using a scan tool the information in the pcm - maybe a clue in the FREEZE frame - pending codes- manufacturer specific codes- or if skilled mode 06 data...just reading the voltage on the IAC circuits what is PCM seeing that trips p0505...should be able to change the iac settings observing what happens

 

Not that it is your computer...but if you absolutely have to get one, check e-bay. I've bought a couple of Dodge ECM's for about $75 each which worked fine.

 

Your picture is correct, that is the PCV valve and it's hose.
PCV - Positive Crankcase Ventilation

1. Pull off it's hose and pull it out of the valve cover then shake it back and forth rapidly. You should hear a loose rattling sound.

2. Start the engine and see if you get suction from the PCV hose.

3. Reconnect everything but don't reinsert the PCV valve into the valve cover, start the engine. Use you thumb to cover and then uncover the end of the PCV valve. With your thumb off the piece inside the PCV valve will pull in. When you place your thumb over the end, the piece inside should move back out.

If either 1 or 3 aboves fails, replace the PCV valve. If you got no suction in #2 replace the hose or push something through it to clear it out.

 

First this is a big NO-NO, the mechanic did not fix anything he just broke your newest IAC motor.

Now you will need to replace the IAC motor since he adjusted the one you have. In reality it is not a user adjustable part, you can clean it but never ever move the center valve!

After you replace the IAC with a new one then also check for a vacuum leak at the Brake Power Booster. You can pull and plug the vacuum line from the booster and see if the idle speed returns to near or at normal.

A trick that might help the idle problem as well any running rough condition is what a Dodge tech called the "Give it the finger" trick. Any vacuum leakage will not allow this procedure to work. Check first for any vacuum leaks including the fitting that goes to the charcoal canister just aft of the passenger tire on the underside of the body, you will need to crawl under the van to check it.

What you do is remove the dog house and top of the air cleaner. Have the hood open and a tool ready to unhook the negative battery cable. Once you are ready start a already warmed up engine, let it idle for about 15 seconds and then slowly put your thumb over the idle air control motors opening in the throttle body (just slide your thumb over the idle air opening just aft of the back of the throttle body opening). You want to actually stall the engine but do so slowly as this will cause the IAC to open all the way up. After the engine stalls leave the key on-Do not touch the key! Now unhook the negative battery cable, have a timer and leave it off for no less then two minutes. Once the two minutes are up turn the key switch off and reconnect the negative battery cable. Now put the key in and turn to the "On" position and wait for 5 seconds (you will hear at least one maybe two click sounds from the IAC) then start the engine.