hello???? With the MAP plugged in and the truck running: 5 volts coming to the map, ground, and 1.3-1.4 volts out of the map on the signal. Are these values correct? I just don't want to replace it if its not bad as I have already done that with the AIT sensor. After resetting the codes by taking off the neg. terminals and leaving the swith on overnight I am still getting 0236 and 0237 codes.

 

ANY COMMENTS?

 

Texas Pride,, what part of South Texas are you in?

Phox,, the MAP sensor doesn't create voltage, it actually recieves it from the ECM

That is the correct voltage WHITEY, 5volts reference, 1.4-1.5 at 14.7PSI (atmospheric), and the 3rd wire is ground.

COULD be a dead injection pump... Is the truck ever hard to start?

It's starting to sound like a stuck wastegate. Do you have EGT/Boost gauges? Knowing your EGT, and Boost at different speeds, and throttle positions would really help us out.

As far as gauges,, call Doug at Advanced Diesel Technology, he's great with gauge stuff,, I envy him, LOL. (304) 864-3399, tell him Merrick sent you


Merrick

 

I wasn't meaning it "creates" voltage, I was assuming it changed resistance depending on the manifold pressure.
Thinking it was like a thermocouple, but reacted to pressure instead of temperature.

Brings up a question, how exactly does the MAP sensor work?


phox

 

never hard to start

i tested the wastegate this weekend with 20 psi it works properly from an external view

still trying to get gauges on order. i emailed rod at wildcat on monday but no reply yet. i'll try doug in the morning.

i ordered a MAP sensor from Cummins South yesterday ($72.00) dealer wanted ($188). i went ahead with ordering the MAP due to the 236 and 237 codes. was this a waste?

 

Like an oil pressure sensor... ?

Phox, I'm sorry, HOHN, was the one that said the MAP sensor "generates" voltage...

Technicly, 12V to ECM, 5V to all sensors, then the sensors send back a resisted voltage, and the ECM interpretes that. The grounds are for pokes and giggles when the truck gets to be 10 yrs old, and has lived in the slat belts. just kiddin'


Whitey,, no, it's not a waste. It's good to carry a spare, or you could sell your used one on e-bay if it doesn't fix the problem.

It could be a cracked exhaust manifold... Check the bottom of the exhaust manifold where cylinders 1,2,3 and 4,5,6 meet up. You probably won't be able to feel a crack, but if your hand gets all sooty, then there is a crack, and that would definatly hurt performance.

Merrick

 

Put in my new MAP sesor with no change in my problem.

Merrick, I got my gauges ordered through Doug yesterday and your right he was very personable and great to deal with. Just one of those people that you talk to for 5 mins and you think you have known them forever. We will be doing more business together in the future.

However my problem still is the same with the new MAP installed.

Next????

 

would it be safe for a few minute test to " turnbuckle the wastegate " to see if the problem is boost? should know in a matter of mashing the pedal if that gate is opening early on you.

 

i have the elbow at the wastegate tapped with a setscrew in it as a bypass. the other day i pulled the line off and tested it with 20 psi of air to make sure the spring was functioning still and it was returning to position just like it should.

 

I don't remember the answer to this one, but, Did you look for signs of an exhaust leak, or a cracked exhaust manifold?

Merrick

 

I did go over the exhaust manifold again completely with my hand as best as I could but did not have any soot.

My gauges from Doug should be here tommorrow so I will be getting them installed this week.

Could wastegate itself be damaged internally forming a blockage before the turbo? just a brainstorm

 

I this point I would take it to Cummins and let them run it on the dyno and they can monitor your user fueling state , and all other parameters and get you an answer for less than a hundred buck.

 

Got my gauges installed and all hooked up (except pyro) fuel press stays at 11-12 psi but never goes below 8. However my boost stays around 5 psi cruising around and alot of 10 psi just going through the gears shifting at 2000-2300. I have the old 3 step comp and at wot on the highest setting i can only get 32 psi. I think the boost values are low but need confirmation. Sounds like a boost leak right? But where? I can hold 25-30 psi from the 1st boot out of the turbo to the last boot at the intake horn. Coffee and ideas please.

 

has anyone ever had a boost leak anywhere besides the boots and intercooler?

 

Your boost numbers sound okee dokey. Not too bad.

Do you ahve aftermarket injectors? Exhaust Brake?
Might not be getting FULL Throttle?

Reading back to your first post,, it really doesn't seem like there is a problem. ??

I'm starting to lean closer to "Operating as designed w/BOMBs" diagnosis.

Merrick