Sudden loss of power- inconsistent symptoms - Page 2

bet on black · 03-26-2018, 03:07 PM

sounds like it could be hitting the de-fueling point in the tune potentially...many use a "boost fooler" mod, which is just a regulator in line with the map sensor boost line to bleed off boost so the map sensor never sees over 20 psi, and never triggers de-fueling.

clark · 03-26-2018, 04:08 PM

I had a similar issue last summer. Would run fine and then just totally lose power. Tried a bunch of stuff, even took my DP tuner out on the side of the road as a last ditch. Then I noticed that my EGT's were dropping at the same time as I was losing power. Lack of fuel. I had installed an in line small fuel filter from RiffRaff as a temporary pre-pump filter when I dropped the fuel tank to do the Hutch mod. Turned out this was clogged after only a few thousand miles. Took the filter out and solved the problem.

I now have a spin on pre-pump filter and a fuel pressure gauge. Side note, I took on about 80 gallons of B20 in AZ. The tank looked clean when I dropped it but I wonder if the B20 cleaned some gunk out of the tank that clogged the filter...???

Bbasso · 03-26-2018, 04:11 PM

Isn't the stock boost limited to 17psi or lower?
Which means if his rig is over boosting and cutting out at 20psi he has a problem other than fuel cut.

rallypanam · 03-26-2018, 04:33 PM

Quote:

Originally Posted by Bbasso

Isn't the stock boost limited to 17psi or lower?
Which means if his rig is over boosting and cutting out at 20psi he has a problem other than fuel cut.

I believe so.. I never see more than mid teens on my stock '01.

Jeffrey · 03-26-2018, 04:54 PM

Does that engine have a FICM like the 6.0L? I had power loss recently and that was the problem.

Bbasso · 03-26-2018, 05:26 PM

Now that you mention FICM, the 7.3 doesn't But the IDM could also be the culprit.
After you check the trans oil and see it's ok, take the IDM out (inner D.side fender) and see if it's water logged by shaking it.the IDM has been known to collect water and fail.

bet on black · 03-26-2018, 05:39 PM

Quote:

Originally Posted by Bbasso

Isn't the stock boost limited to 17psi or lower?
Which means if his rig is over boosting and cutting out at 20psi he has a problem other than fuel cut.

In the vans, Boost is controlled by the amount of fuel injected, and measured by the map sensor. From my understanding, if over 22 PSI of manifold pressure is detected, it will cut fueling way back to slow down the turbo.

tortorelli · 03-27-2018, 12:17 PM

Make sure your uptake fuel screens in the tank are clear. Mine were clogged and I had no power. Removed those screens and "straight piped" out of the tank, bringing fuel to and through the filter on the frame rail now, pre-pump... still change that filter out 2-3 times a year...

djbonsu · 03-27-2018, 03:28 PM

Definitely sounds like a fuel or electrical problem(due to the loss of power inconsistency). Your filter for the lift pump in the tank could be clogged OR your fuel pump (on the frame rail) could be dying or BOTH. Check your fuel pressure while driving and at idle. Depending on your fuel pressure regulator you should be seeing 50-65 psi at the heads. Also check your IDM for water inside of it or hook a scanner up to it to see if it is failing. My IDM went out randomly (i think due to age and heat as there was no water in it) which cause me to lose power to the left bank of injectors basically having the van run on 4 cylinders. Also ohm the injectors UVCH to check if you have any cut/exposed wires. Troubleshooting this can get overwheling but one thing at a time. Good Luck and let us know what you find out.

Wire89 · 03-27-2018, 07:58 PM

Thanks all for the replies and suggestions.

Picked up a Scangauge and no codes were reporting, no pending codes either. I've not had a chance to drive a grade so can't say what some of the other gauges are reading.
The transmission fluid was just recently replaced so it may not give me much of a clue. I still give a check on current condition.
Mileage is 206,000 or so.
Not running a fuel pressure gauge so not sure on that one. I'll have to set up some test points to check. Fuel filter was replaced about 7,000 miles ago. I typically fill up before 1/4 tank but did have to run it to the low fuel light about 3,000 miles ago. Symptoms have been within the last 1,000 miles.

Is there a way to inspect or test the CPS?
Is there a good way to test the torque converter?