mattn124

Hey, having some problems with my truck.

Getting code P0236

I'm just using a standard, cheap OBD-II reader. the definition for the codes it's book gave me was " turbo/superboost sensor A CKT range/performance"

The truck starts within a few second of turning the key although it does seem to take a little more cranking than it used to to fire it up just a week ago(2 brand new batteries 4 months ago)

I also have had what can be best described as "dead pedal",, lack of power, cutting in/out now and then. but it doesn't last long. The truck idles just fine.

My first fear was that the VP44 was taking a dump... But I'm hoping maybe it's just a sensor or something much cheaper.

Here's a rundown of my truck:
1999 Quad Cab, 4x4 5.9CTD, 5 speed, 13" Valair clutch, 4" Magnaflow exhaust, AFE workhorse airbox/filter, RV275 injectors, Vulcan Big Line/Relocation kit for the LP with an Airtex pump(2 months old), Isspro fuel pressure gauge routed to stock fuel filter canister.
252,xxx miles

I do not know if it's the original VP or not, Is there a way to tell if it's the original or a replacement? The sticker on the pump says: Made In Germany, R5013925AA, MO22304

My FP gauge shows good pressure from the LP (17-19 idle, 11-12 WOT)

I do have some mods on the truck but I have never had any programmers, boxes, chips or any type of computer-type mod on it.

Any insight or tips for me? I will clean off the map sensor tomorrow, I have already reset the codes. I need to get a boost gauge...

About 3 months ago I was forced to drive about 200 miles with only 3 psi reading out of my LP. I was running empty and it was all highway and I kept it easy at 50 mph, but have been worried that I may have damaged my VP44 on that trip.

Thanks for any help

J Lent

Have you erased the code to see if it comes back?

graphitecumnz

Are you using a boost fooler or a boost elbow with those injectors?

mattn124

Yes, I erased the code yesterday, but I haven't started driving it again.

Would that fix it? I understand that sometimes codes can just show up un-explained,, but I had real-world symptoms of dead pedal and harder to start

Thanks for your reply

Barry Smith

I've been having the same hard starting problem. It just started about 2 weeks ago. I have new batteries. I also have had the "dead pedal" on and off for the last year or so. I'm thinking VP 44?

mattn124

no boost fooler at all, stock intake manifold,,

I've been running the rv275's for over a year now no problems,, the original ones were going south at about 205,000 miles and I replaced them with the rv275's then.

The only other underhood mod I have is an AFE Dryflow Workhorse intake, but thats just the airbox and filter pre-turbo.

Anybody know how to tell if your VP44 is the original one from the factory?

I didn't get to my truck today to clean off those sensors, it's about 15 miles away at my in-laws garage, maybe tomorrow. I'm also going to use a multimeter to check both the MPA and IAT sensors.

Speaking of Map sensors, called my local Napa, O'Rielly's and Autozone, nobody carries them, are the a dealer item only? I hope not.

Thanks for the replies

mattn124

Ok, new info.. Took out both my MAP and IAT sensors today and cleaned them off with carb cleaner. Neither of them was very dirty though.

Hooked up the obd-II scanner thing, cleared the codes, then went for a test drive. I didn't have any "dead pedal" per say,, but the truck was seriously lacking in power. It ran smoothly, started quickly, idled fine,, just was way low on power. The check engine light never came on either.

I only drove about 3 miles, and it was not a hot day out today. When I got back to the shop I checked the codes, same code was there, P0236 Pd.

Before the test drive, I used a digital multi-meter to check a couple things, the resistance value for my IAT sensor after cleaning it was 9.33 K Ohms, this was at 88 degree Farenheight. I checked the temp of the sensor with an infared temp gun so I am sure that is correct

According to this website : http://dodgeram.org/tech/dsl/sensors/IAT/clean.htm
Those values are a little bit off according to the chart on that page.

Also, I remember reading on a thread here somewhere about checking voltage of the orange wire that goes to the MAP to ground and it should be between 4.75-5.25 Volts. So I checked it, I had 4.98 Volts with the key on as well as with the engine running.

I wish I had a boost gauge,,, I could hear the whistle of the turbo as I was driving.

Any suggestions? ANything else I could check?

Thanks for any help

Dieseldude4x4

If you were a little closer, I would hook up my very expensive VP44 tester on the 44 and see what it does.

AggieJustin

Check the voltage between the Gray/Red wire and the Black/Light Blue wire from the MAP. The Gray/Red is the signal line, the Black/Light Blue is the Ground. On a '99, you should see 0.5V with the key on and engine not running.

You can also check the resistance between the Black/Light Blue and a true ground to verify the ground is good for the MAP.

P0236 means that the ECM is seeing higher than ~20psi of boost. If you clear the code and it comes back after you start the truck, even without running it hard, then I would think it's a bad MAP sensor (or bad ground). If it only gets set after you make a hard run, then I'd check your wastegate to make sure it was working properly and not allowing higher than stock boost pressure.

Dieseldude4x4

If he is talking about the truck in his signature, he definately will see way more than stock boost.

AggieJustin

But if he sets the code without making a hard run, then I wouldn't expect that he was actually boosting over 20psi to set the code.

Granted, with that setup he could fuel harder than the wastegate can control and go past stock boost limits, but I wouldn't expect significantly higher levels (although I've never run 275s, smallest I had were the DD2s in my sig).

A boost gauge would make this troubleshooting much easier since the actual readings could be verified.

Dieseldude4x4

Yep, that makes sense.
Here is where I got my stuff.

http://hoeslidiesel.com/store/page5.html

mattn124

Yes, I'm talking about the truck in my sig,, but I've had this exact setup for about a year and never any codes. Also, on my test run of all of 3 miles, I wasn't driving it hard.

Thanks for the link dieseldude, hoeslie is good people,, that's where I get my filters in bulk.

I'm getting a new IAT sensor today from a dodge dealer, I dont think that will fix it but my old one tests a little bit out of spec so it cant hurt

Thanks for the info AggieJustin, I'll check those voltages today when I'm also changing the IAT. Also, I'm going to say a prayer and reset my APPS and see if that does anything.

Yes,, a boost sensor is in my future. I was actually thinkinf about one of those scangauge things. If I understand it right, they can monitor all sorts of things,, including the boost pressure at the map. So, you can use them as a boost gauge as well.

Thanks for all the help

Thanks for the help

AggieJustin

One thing to keep in mind with that setup is that if you ever put on a fueling box with a boost fooler (or boost fooler by itself), the scangauge will not show you the actual boost reading. It will only report what is seen by the computer, which is the "fooled" reading.

mattn124

That's a good point,, I'll shop around for a gauge before I buy anything.

Got new results today, in fact I think I [B]may[B] have found my problem!!

ABout 2 weeks ago I changed the heater core and did some AC work on my truck, so I had it all apart. Including taking the computer off of the firewall.. Well,, when I started nosing around under the hood today,, I noticed that I forgot to attach a big 'ol ground wire!! Also, I started having problems right after I did this work to the truck

Can somebody please take a peek under their hood and tell me exactly where it goes? It is the ground wire attached to the cowl/firewall just above and to the left(if your facing the engine) of the shorter heater hose that goes through the firewall.
I think it is supposed to get mounted by one of the 3 screws that hold that computer onto the firewall(powertrain control module?) But none of my books or schematics show any kind of case ground to this computer.
There are 2 numbers on this wire, they are: 61789A, 56040337AA.

Also, here are todays results:

1. I resetted the APPS, then noticed the loose wire so disconnected the batteries again and turned the key on. I attached this wire to the back side of the PCM on the firewall through one of it's screws

2. Installed the new IAT sensor

3. I checked the voltage between the grey/red and black/blue wires that go to the MAP sensor, I got a reading of 0.065Vdc. Pretty sure this is an accurate measurement, it's with a Fluke model 75 meter.

4. I checked for a good ground from the black/blue wire mentioned above, seems fine, nice clear loud beep from the meter when I checked this

5. Hooked the batteries back up and reset the APPS again.

6. Cleared all the codes and took a test drive

The truck ran great! I let it idle for 5 minutes before I drove it to warm it up. I drove only about 6 miles. All the power was back, it was great! Also, I could mash the gas pedal and not see any smoke in my side mirror.

Then, at the tail end of my test drive, I could feel that the boost was starting to become spotty. It still had all the power, but it would seem like there was a lot of "turbo lag", best way to describe it. I could still feel the boost kick in but it seemed delayed. Also, after this, I could notice a nice puff of dark smoke in my side mirror when I mashed the go pedal

And, my code came back. Ran the codes, got P0236 Pd (dunno why it put the Pd on the end, means it's pending?)

Thanks to anyone who takes the time to read this post. Any ideas? Should I go ahead and buy a MAP sensor too?

Thanks