Engine/Transmission (1998.5 - 2002) Engine swap need help

[Bulldog80]

I like a dumb azz thought it would be a piece of cake putting an 01 motor in friend's 99. A year and a half later I've finally got it running good except for one thing that I cannot figure out. I've got no power from idle to about 1700 rpm. It's not a dead petal, but it's not normal power either until the revs come up and the boost comes on. It's just enough of a problem to get you killed entering an intersection.



Last time I had it hooked up to a scanner the only thing that appeared out of the ordinary was that it showed 6 pounds of boost no matter what. I thought great, it must be a map sensor. So I replaced it and the IAT sensor just to be safe but no difference. I've already replaced the apps also with no change. Any other ideas on where to go from here would really be appreciated, I'm stumped. Thanks guys.

 

[johncameron]

I think the map sensor voltages are different between the 2 trucks. I know they have different part #'s?

 

[Bulldog80]

Thanks John, I'll look into that. Anything else anybody?

 

[jhoughton]

Which ECM are you using? I believe that you need the one from the 01 engine. Just another thought. Jim

 

[justinp20012500]

I would first start with a map sensor.

 

[Bulldog80]

I'm using the 01 ecm and I've replaced the map sensor.

 

[AFarmer]

I'm guessing it's not running any better right??

 

[CSnyder]

You may have a bad VP???

 

[onestackdram]

Bulldog80, do you have an injection pump shop near by that has VP pump stand? If so pull the pump and run it to them to be run. I am willing to bet you have a pump issue. Atleast thats the way it sounds. I would get the pump tested and see where your at.

 

[GTrent]

Well, having just done the MAP sensor replacement on my '01 Suburban conversion, and finding that it was the problem... you might want to double check that sensor too. Having dealt with this sort of crap in years past, I've had new sensors that were bad.....



My symptoms were exactly the same as yours are, and I drove about 300 miles that way on a trip back from Baja. That sucked. I now have a backup sensor on board



IAC, something else to look at.

 

[Bulldog80]

That's a good idea GT. How did you diagnose it? Did you just get another one and try it or is there a way to test it?

 

[jmy]

BD80,

Have you pulled the codes with an ODBII scanner to to see what is stored in the ECM?

 

[Bulldog80]

The only code that's been stored through this is the 0121 APPS code. After I adjusted the APPS and then ultimately replaced it that went away too. Should a bad MAP sensor send a code? I need to get it back on the scanner and see if it's still reading that constant boost. I really thought the new MAP would do the trick but now GT has got me wondering if it's bad too.

 

[GTrent]

Well, the MAP that I pulled out was loaded with crap, and I know the previous owner had cleaned it several times. Taking a look at the common problems, it almost looks like the MAP is a consumable item - so I figured it wouldn't hurt to replace it and the IAT. I haven't gotten to the IAT yet, but the MAP cured the issue. There's a link here https://www.turbodieselregister.com/forums/showthread.php?goto=newpost&t=139057 to the top of the 24V forum FAQ that gives the sensor specs if you want to hook it up. Where you at Bulldog? If you're local to me - SoCal - I could swing by and swap a known good MAP sensor for you to try... ...

 

[Trashdawg]

Depending on the year, the map should read 0 psi or 12-14 psi reading atmospheric pressure. You will need to replace it with model year of ECM. They can also be bad and not set code. I had a 24v last month would not make boost til 2800 rpm and no codes.

 

[jmy]

BD80,



The boost related codes are as follows;



P0234 Turbocharger Overboost Condition

P0236 Turbocharger Boost Pressure Sensor Performance / Rationality

P0237 Turbocharger Boost Pressure Sensor Low

P0238 Turbocharger Boost Pressure Sensor High



Normally when the map sensor fails completly the 237 code is set. However as Trashdawg mentioned, you can have a bad map sensor and not set a code at all.



You may need to hook a DRB scanner up to see whats happening. Sounds like map sensor low voltage. This will signel ECM that map sensor doesn't see boost and ECM will not add fuel.

You can see whats happening with boost and fueling using the DRB scanner. Some upper end shops have a DRB. If you need to go to a dealer they charge about $60 to $80 around here to do a scan.

 

[Bulldog80]

Thanks for the info guys. GTrent, I'm in Idaho. I wish I was closer to try that. I got a feeling that would save me a lot of time. I'll get it on the scaner and check the map on my next day off and then get back and update.

 

[Bulldog80]

One more thing guys. Trashdawg you said to match the map with the ecm. I put the map on that matched the plug for the 99 harness. Do any of you know if there is a voltage reading difference between the model years? I'm wondering if the map part number differences are just reflecting changes in the plug design. Cummins seems to make what appears to be the same map sensor with numerous plugs. Do you guys know if there is actually a difference in the sensor itself? No problem to change the harness to accomadate a different sensor, but I don't want to if there's no difference with the sensor. Thanks again.

 

[jmy]

There is a difference in the 2001 map sensor and and the 1999 map sensor. Boost level sensing inside the 01 ECM is calibrated for the 01 sensor. Youi should use the 01 sensor. It's adifferent plug and cost about $40 more then the 1999.

 

[Bulldog80]

Well you might have just given me the answer jmy. I'll get one by engine/ecm number this time. Thanks