93 cummins wont boost past 14 psi
 

Ok well. I want to start a project thread here but I've not had the time to do a full write up as I've been working past 1am everynight after work at 5 to get this beast running. Which it does now.

First off ill start by saying im not a complete newb at turning wrenchs I've done many crazy engine swaps but this is my first ctd. What I have is a 94 bronco on all f350 drivetrain with a cummins 93 ve engine swap.

Here is my problem I messed up somewere not sure were. Current mode are the 3200 rpm governer spring, dennyt stage2 fuel pin, and a hx40 6 blade(figured it was still a improvement), 215 injector nozzels, full 4 inch exhaust. Got it running tonight and filled it up let it warm up went out and jumped on the throttle. 14psi that's it.

I thought maybe it was because the pump star wheel, full fuel enrichment screw,and smoke screw were never modified. I was thinking not enough fuel = not much boost.

I turned the smoke screw 2 full rotations clockwise, turned fuel rod 2 turns(by the way the tamper clip was a pita and turned star wheel 8 clicks. Lights up alot faster but still 14psi.

I thought maybe wastegate was only set for that so I temporarily pinched the line closed, 14psi still, wired the gate closed 14psi still!

The only thing I can figure tho I don't think its the problem is when I did the spring install I didn't mark or write down the indexing.... :-( so I moved the throttle to just were it idled normally and tightened it all down.

I also probably made a mistake by doing this all at once not in steps. Any help would be amazing thank you in advance.

---AutoMerged DoublePost---

Also egt never gets past 7-800

93 cummins wont boost past 14 psi
 

Obviously not getting fuel. Does it run right for 14psi- no sputtering or miss?

if its a factory hx 40, I believe they have a 16mm clearance exhaust housing, you need alot of fuel or a smaller exhaust housing

where are you measuring your egts?

It is a 6 blade hx40 from a 8L cummins.

The egts are measured from the front runner on the manifold.

It seems to spudder/miss a little since a turned the power screw in. But I was kind of thinking it was just high idle. Which I've yet to adjust back down


Under wot runs great no spuddering. Not sure what else to check.

I would try indexing the throttle shaft 1 spline counterclockwise and check your fuel supply/pressure/filter. You should have plenty of fuel with those injectors.

Counter clockwise raised the idle pretty high. But on that note I never ran it since I did the fuel pin install, not sure if they raise idle too?

Is there any adjustment to turn it down with the stop screw? Also, make sure the throttle is getting full travel. Sometimes they will stop on the fuel inlet line if you don't clearance it a little, or possibly the linkage/cable is not tight.

The throttle goes all the way both directions. Had to pit a assist spring to help pull it down tight against the idle screw tho.

Ill try to index it again after work. Thanks again for all the help

---AutoMerged DoublePost---

Well went ahead and tried to move it CCW and CW on the splines, No diffrence, CW won't run, CCW idles extremely high and still only 14psi boost.

Fuel filter is brand new, fuel lines are all brand new..... More ideas?

Does the throttle go all the way from the accelerator pedal?

Double check the wastegate and make absolutely sure it is closed tight.

Fuel pressure? Idle and WOT....

I'm just about out of ideas.

Lever goes alllll the way on the pump from the pedal, checked that first thing.

I've gone as far as completely REMOVING the wastegate and tieing it closed. (closed off the port on the compressor housing also)

I've not yet checked fuel pressure from the lift pump, I kinda figured it would be working just fine seeing as it had no problems in the 1993 dodge, BUT then again, that was also a stock truck with over 200k on it. So maybe the lift pump is weak? I don't assume a helper electric pump is needed on these things.

---AutoMerged DoublePost---

I thought even maybe the aftermarket air filter was to small and went as far as taking it off and running it down the street thought maybe it was to restrictive. But that wasn't it either, I'm LOST..

When I first jump on the throttle it get a nice puff of black smoke, then CLEAR... Like no fuel which is i'm sure why the turbo isn't spooling...

Do people typically just close the wastegates on these turbos or just run a straight line from the compressor to the waste gate (wastegate boost)

I've build a few DSM's and a couple 4ktq and other turbo cars in the past which obviously use a boost controler of some short.

What should the lift pump PSI be? I'll check that in a hour or so. Maybe its not pumping enough anymore... I'm sure its original.

I would be wiling to bet that is your problem if it is the stock pump with 200k miles on it. You need a better pump for those injectors, even it is good. They were barely adequate for stock fuel on a 160hp stock truck. Go with a LP piston pump (NOT 2ndGen 94-98 12V, but the low pressure model - 15psi) or good electric, regardless of what you find there. Max inlet pressure on the VE will be around 18psi, or you blow out the front seal. Then it gets complicated.

Ill start there then any recommendations on pumps? Really don't wanna go electric

Low Press (15psi) LP: Cummins Part# 3936320

You also need a fuel line (3914753), 2 gaskets (3931348) 2 seals (3918191) and a spacer (3914284). That would be for a proper professional replacement/upgrade. If you are doing your own plumbing then all you really need is the pump, spacer and some RTV and whatever you use for fuel line.

I've heard you can get them cheaper from Case if you can cross the part#

You can get the 2nd Gen pumps for $40 off eBag now, but you'd have to modify the relief spring or regulate it down to 15psi:

http://cgi.ebay.com/ebaymotors/NEW-D...#ht_1539wt_939

Ill look into it thanks again ill keep you posted

No prob - you got lucky, I'm sitting at work with nothing to do today. :pca1:

I got about 18 psi now with the new pump. I got the dephi one cummins wanted damn near 300 for just the pump!!!! Im at a loss!!!!

---AutoMerged DoublePost---

I also tried pinching the waste gate again. No more then 18. Im pretty stumped!

I cannot figure out why the cost of LP piston pumps went through the roof. The main difference between them and the 2nd Gen pumps is just the pressure. There are other variances like the bore size and some oddball AG pumps, but they are all basically the same pumps. I am also at a loss as to why they made those 1st Gen engines with the crappy diaphragm pumps in the first place.

Just took it for a drive... Put a fuel pressure guage BEFORE the filter. It idles about 10psi... Took it for a spin, hammered the throttle, even at its 14-18 psi it still shows 8psi was the LOWEST it got....

I heard they used the crappy pumps because they never planned on them ever being built like we do :-)

I'm woundering if its got a boost leak somewhere?!?! I only did 8 clicks on the starwheel which should be enough and 2 turns on the fuel screw... Do i need to just go further in on the fuel screw? hmm.... I'm about out of idea's...

---AutoMerged DoublePost---

I just tried to screw the power screw in more because I realized I only got about a turn in. And its actually bottomed out!!! Maybe this is part of the problem?

I would plumb the gauge after the filter. Makes a nice filter-monitoring device that way.

So the fuel supply is good and still not getting alot of boost, even with the fuel screw in and bigger injectors? Still something wrong. Boost leak, tired injection pump? What's the turbo look like, where'd it come from? Does it smoke black at low boost load? It should.

Probably the VE, would be my best guess. They don't last as long as they used to running on ULSD. Fuel lube adds help. Just a guess.

Turbo is a reman from holset no problems there. Boost leak maybe. Im thinking maybe because I can't screw the fuel screw in enough? Would that make sence?