Got a bunch of new stuff in the truck and know I need an HPOP soon but want to troubleshoot the problem and see the failure in the data, rather than just throw parts at it. Pic below is a 2-3 gear pull and as soon as the truck hits 3rd, it falls on it's face. I'm new to diesels but it feels like an LS motor bouncing off the rev limiter. Power comes in and out and in and out, etc.... about 5 times a second.

This is the 1st time I'm running > 30psi and some have mentioned a boost leak but I thought that would clip high end power and not cause it to come in and out so rapidly.

If it were a weak HPOP, I would have though the IPR% would just increase and ICP would just sit there and not climb with it but both seem pretty steady when it happens (see pic) but the IPW goes crazy and bounces at the same rate as I feel the power coming in and out so can this be a condition where I need a boost fooler? Again, this is new to me and I thought that was only a problem on SD and not OBS. I have the logfile but can't send it here,
Thanks



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the engine typically defuels between 21 and 25 psi boost. maybe there is a boost fooler in the truck that is not set properly?

 

Time for a boost fooler or a tune that dont use it

The PCM defuels when you exceed 22 PSI and 2500 RPM

https://www.riffraffdiesel.com/ocr-o...egulator-94-97

 

Straight hose right into the map. That was the 80hp PHP tune, I'll just run a lower tune till I get under 30....for noiw

 

I was looking at that exact one but not going to run it this hard till the new motor is ready.
Was just going to bolt the heads but will stud it after seeing these numbers. cheap insurance.
Thanks man

 

Phil, i used a little harbor freight pressure regulator like this one:
https://www.harborfreight.com/14-in-...uge-68223.html
set at 18-19 psi with a few hose clamps and hooked it into the map sensor line on my 02.
it has worked great for the past 20 years i have had the truck.

 

Looks easy enough, I'll pick one of those up today,Thanks
I'm building another motor and should be done over the summer/fall and wasn't planning on pushing this one hard but you know how that goes.
The last thing I want to do is blow a head gasket on this one and be forced to rush the other build or have the truck down but it's hard knowing there's more power available and not occasionally use it.

That 30psi came in quick since it's only a stage 1 and not sure where it will max out or what is considered "reasonable" safe and what the danger point is considering the block and heads are stock and I don't want to find out the hard way

 

Boost fooler wont protect your engine, only the MAP sensor.

OEM 7.3 can handle up to 40 PSI then studs are needed

 

my stock 02 will make rite around 34-35 psi with a DP tuner set at 80 econo tune

 

Not going to lift a head at 30psi, defueling is almost certainly to drop EGTs.

Those injectors are pretty oil hungry as I recall you did 180/30s. Stuff wears, a new HPOP is not a bad idea. Mine runs far better with one. The bucking may be the thing not keeping up, mine did that with the old 15° pump

Pretty sure I have seen far north of 30psi on mine, been a while since I checked.

 

Connecting rods....

 

My take on this is...the factory map was meant to see around 20psi max. Cramming 30-40-50 psi makes it go out of range.

Add in that they are mostly 30+ years old..

Boost fooler and tunes that are set to know your max boost signal psi so they figure full boost as that number are needed.

 

Did the $10 Harbor Freight regulator but changed the spring so the adjustment wasn't so sensitive. Best 10 bucks I ever spent.
Set it to 20 psi. Runs like a dream and spools up to 35psi @ 3000 RPM on the PHP 80hp DD tune and nice to have the power available if needed. Not that I typically run it that hard often, just makes the trips to the hardware store for sheetrock screws a lot more fun,
Seeing HPOP starting to top out above 3000 RPM so might go with a T500

Thanks for the knowledge and assistance guys.