Hi all,

Here is the sitsuation. My truck now seems to not want to tach out in the higher gears 4 and 5th. Would it possible that my boost sensor is bad or would you think it is oil pressure regulator? It seems to run fine except it doesnt seem to respond like it used to. It has only been happening last 2 weeks. I have a 1994 powerstroke with 212,000 miles. I checked the EBPV and it seem to be functioning normally. Any ideas?

 

I would guess a weak fuel pump or weak HPOP. Don't think a bad MAP sensor would cause this.

 

It does not want to tach out? You mean in 4th gear you run the engine to the redline on your tachometer? And in 5th gear?

 

The truck is just responding slowly. It used to take right off. In 4th gear the engine wont climb above 3000 rpms. I have run it to the edge of yellow before, but never to red.

 

Could be low fuel pressure. There is a schrader valve to check it. Look on old threads to see what the optimum pressure is. Seems like the max was 80.

 

40-50lbs is normal for a stock truck@idle.

 

Thanks guys i will check fuel pressure. Just had new pump put in 10k ago.

 

I checked the fuel pressure today and it was 45lbs at idle. So sounds like i can rule my power loss due to a fuel problem out. It must be a weak HPOP. I dont have a way to test this. I will probably have to take it to the shop for some diagnosis $$$$. Hate spending money to figure out what is wrong with my truck....ugh.

 

Have you changed the fuel filter latley...If not change it and clean the FPR screen while your at it. Its a screen just inside the hole about 1/3 the way down the inside of the filter vessel(right hand side)). Use a q-tip and clean it out good.
Also you can unplug the IPR sensor and test drive your truck. See if that makes any difference.
I think (not certian)you could do the same with the map sensor just to rule it out also.
Unplugging both will cause a CEL but will send a default value to the pcm...thus telling you if the sensor is bad.

 

Thanks, I will try and repost. BTW, I did change filter and clean little screen as well with no change.

 

Low and behold it was the damn EBPV not opening all the way. It is malfunctioning, cannot afford to fix at the moment with christmas so close, so I just had the damn thing wired open. Should be a little slower to warm up in the morning, but at least I have my power back now. The mechanic said I need a pedestal, anyone have one they want to sell. 1994 Powerstroke.