just installed gauges and took the truck for a ride. When i get on the pedal the boost will rise to 10psi and then immediatly drop off to about 6psi. If I let off and get right back into it it will go back to 10 then drop to 6 is this normal or should I check out some kind of boost control. Thanks

Welcome DWBJRB,

That's the stock boost levels. You might find the FAQ area informative.
Can you put your truck's description in your signature with all it's mods?

thank you. have been reading faq's but so far hadnot found my condition maybe haven't read enough.

What do you have in mind to increase the boost? A boost controller that tricks the PCM into allowing >15 psi from the vacuum pump or a spring controlled WG?

no I'm thinking more in the line of just staying smooth and steady at 10psi or do you think this is to much to ask of the motor?

was checking out the turbo master control from heath diesel, will this hold the boost more steady? Don't really want to mess with pcm.

Turbo Master holds boost, but set too far it can set overboost codes, fooler lies to the PCM so it does not know you are making big boost & does not clip it, drawback it depends on fully functioning vac system ad aslo if set too far will put you above 10 psi, which is where you start to need post turbo cooling

Is a reprogrammed pcm the ticket or should i just try pulling my rv the way it is? Also getting new hi-pop injectors installed on tuesday can't wait to see if it makes a difference.

Reprogrammed PCM will probably do more for you than Hi pops , together they are a good match, the TM works well with a reflash, just remember to keep boost to about 10 psi sustained max without post turbo cooling, if you run with a temp sender for IAT you can limit your boost to max that IAT allows, 15 psi on cold days probably 11 would be your limit on a hot day. How heavy is your RV?

Had already purchased the new injectors from advice from someone else so I'm kinda bound to use them,know what I mean. RV is 7300pound fifth wheel, pulled great with my gasser, first diesel that I've ever had. My truck has L56 motor 3.73 gears auto trans. On the interstate tonight I was watching my gauges and was running about 5psi boost and 550EGT at 65 mph is this alright, and also adding a new pcm, will it hurt to have the hi-pops and ecm?

Not at all, something you can do cheap in interim is get a junkyard L65 PCM wntil you can afford the reflash, you will need a core for flashing anyway assuming you want to keep stock one for troubleshooting, the L65 delivery is higher than the 56 PCM, you then can also bypass the EGR, MAF, then you can boost fool PCM or Turbo Master, where is your EGT probe, that will determine some your EGT limit. 7300# is on the heavy side for mostly stock when combined with sail area of a 5th wheel.

To keep the engine cool more boost helps to a point if you don't have post turbo cooling to far with boost adds heat. Something to consider is a recalibrated fan clutch, bypass filtration adds more oil to heat up & some passive cooling by getting filter away from engine, deep trans pan adds extra fluid, additional remote trans cooler is a good deal, and 97+ water pump & dual thermostat.

the water pump upgrade was going to be my next investment.My exhaust probe is after the turbo.when you say a junkyard L65 pcm is this from a 3/4 or 1 ton truck if not how will I know. I also am looking for a deep trans pan to add extra fluid and to mount my sensor for the temp. probe in. would really like to add intercooling but the budget wont allow right now.so though. Picked truck up from dealer today and seemed to run very well on the way home.Dealer said ignition timing was 7 degrees positive and should be 7 negative he told me this wouldn't pose a problem. Its all greek to me I'm still learning.

.Dealer said ignition timing was 7 degrees positive and should be 7 negative he told me this wouldn't pose a problem. :eek: :eek: :eek: .Don't use that dealer, he hasn't a clue, during time set command time desired goes to 0, and actual is supposed to be + 3.5 avg, if not pump needs adjusting, +8.5 degree at idle is a good number, maybe he said it is a little negative, at -7 deg., I don't even think it will run.

Yes 3/4 or 1 Ton HD truck PCM is what you are after, 8th digit in VIN will be the clue to what is what. 3/4T LD truck S or 1/2T is same PCM you have.

Thanks alot. Any good brand pans out there for a fair price?

I forgot that, www.yourcovers.com