I'm stumped, stalling and low power - Diesel Truck Forum - TheDieselGarage.com
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post #1 of 6 (permalink) Old 05-15-2007, 04:00 PM Thread Starter
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I'm stumped, stalling and low power

Sorry this is long, but Iím trying to give as much detail as possible.

Iím having 2 problems with my truck. It stalls randomly, and itís lacking power. Iíve been trying every diagnosis I can think of, and I need some new ideas of where to look.

First the stalling. The truck will die and/or have a no start situation that is exactly like a CPS issue. When it wonít start back up, there is no smoke whatsoever while cranking. First thing Iíve tried is CPS. Iíve replaced it 4 times in the past month, and still having the same issue. 3 times I replaced the CPS, the truck started up. However just yesterday I put a brand new one in and the truck just cranked and cranked. Iíve also tried unplugging the ICP sensor to get the truck to start with no luck.

So, Iíve had no start issues with new CPSís, and also with the ICP sensor unplugged. I think Iíve ruled both of them out as potential problems. Iíve checked the wiring harness at the PCM and also checked to see if the chip came loose, and no luck. All other wiring harnesses look fine. I canít find any chaffed or loose clips, harnesses, or wires anywhere. Iíve wiggled around every wire and harness I can think of when itís stalled out, and nothing changes.

Oil level in the HPOP is good. Sits about half an inch from the top, and thatís when itís not starting.

As for codes, there arenít any except for the usual ones associated with my mods. Only once did I get a P1212 after a no-start, but that was one time out of countless stalls this past month. It has never popped up again. Iíve tried to keep my laptop with me as much as possible, but the damn truck has never stalled when I had AE with me. I was at the drag strip last Wednesday when the truck stalled driving around the water box. Another PSD owner had his laptop, and by the time we got it hooked up the truck started. So again no diagnostics to go by. Every test that I have run with AE the truck has passed with flying colors.

Now for the loss of power. As I mentioned I was at the drag strip on Wednesday (Bandimere near Denver). This year I was slower at the same track than last year. Here is the difference, last yearís mods were:
- DP-Tuner
- 4Ē exhaust
- Homemade Intake with the Napa 6637 filter
- HPX
- 36Ē tires w/ stock 3.73 gears
- Stock tranny with Sonnax valve and spring kit
- Hutch and Harpoon mods
- Best time of 16.1 @83 MPH in the 120 race setting

This yearís additional mods are:
- Same DP-Tuner and settings
- Regulated fuel return
- GTP38R ball bearing turbo
- BTS transmission
- 4.30 gears
- 6.0L intercooler
- AFE Stage II intake
- LL #8 injector replaced with a stock AD
- Non ebpv plate and pedistal
- Best time of 16.2 @ 80 MPH in the 80 econo setting

The 120 race setting gave me a worse time of 16.4 @ 80 mph, and that run on the race setting had the best launch of the night. Hereís what I know, my stock HPOP is weak, and can only maintain just over 2100 psi of oil pressure at WOT on the 80 econo tune, and around 2000 psi on the 120 race setting. However, this is nothing new, and itís been like this for a long time (including last yearís races). I figured this year I should have shaved off a tenth or maybe two with the help of the BTS tranny, gears, and possibly the turbo. Iím running higher boost and lower EGTís than last year. Last year I maxed out at 28 lbs of boost at the track on the stock turbo compared to 32 lbs on Wednesday with the ball bearing. EGTís last year were 1450 at the end of the strip, with this year never even reaching 1300. 60 ft times last year were 2.3ís, and this year was 2.1ís.

So, Iím at my wits end here. Iíve checked for boost and exhaust leaks and found nothing. Fuel pressure is bumped up to 70 psi, and no fuel leaks or problems. Fuel filter is new, oil is synthetic and pretty fresh. This truck has been very well maintained, and the stalling issues only started up a month ago. Daily driving is normal, other than the stalling which is suddenly getting much worse this week. Started off stalling once or twice a week, and yesterday it stalled 3 times in a row then ran fine for the rest of the day. I canít drive my truck anymore for fear of getting stuck somewhere bad (like an intersection). Can anyone give me any other advise on what I should be looking for? I will again drive around this week with my laptop in hopes of catching it when it stalls and reply back here with what, if anything, that I find. In the mean time, Iíll be seriously looking at your responses.

Thanks!
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post #2 of 6 (permalink) Old 05-15-2007, 05:19 PM
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Have you pulled the valve covers and checked the injector harnesses. The sympotms of stalling sound a lot like UVC harnesses to me.

As for the "less power" than last year. Yes you did uprgrade several things on the truck but are not going any faster. But to say the truck is making less power is probably not accurate. More than likely the new mods are making the lack of ICP more evident. I recently added an IC and changed the exhaust housing on my OBS and I did notice an incrase in power but on the other hand the "flat line" of power due to low ICP is way more pronounced. Seeings how your 60' time increased but your ET remains the same means you are making MORE power (torque) at the low end but are running out at the top end (low ICP).

I was originally thinking that you may have a dirty or sticky IPR causing the non-increase in ET/MPH in the 120 setting but since you have ICP info from last year and this year that match that wouldn't really make sence.

If you think ICP of 2000 is low you ought to see my truck. It will hold like 15 or 1600 in my Extreme burn

Eric
96 F-350 CC Dually My TDG Gallery
B codes, head studs, Comp 910 valve springs, stock turbo w/ 1.00 turbine housing
6.0 IC, NAPA 6637 air filter, AeroTurbine 4040XL, ITP Overboost Annihilator,
Quadzilla Commander, electric fuel system w/ regulated return
coolant filter, 203* thermostat
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346.7HP, 852.1TQ 12/15/07 Greeley, CO w/ stage 1 injectors and Wildman tunes
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post #3 of 6 (permalink) Old 05-15-2007, 07:41 PM
 
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The big thing that jumps out at me here is fuel pressure.

My uncle had the same exact issue, symptoms just like a CPS but it wasn't.

Ended up being the fuel pump. I would check your fuel pressure at idle, normal cruising, normal accleration, and WOT.
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post #4 of 6 (permalink) Old 05-15-2007, 08:18 PM Thread Starter
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Well it finally stalled on me with my laptop in hand. Looks like it's a stuck IPR after all. Kinda weird that the engine never has issues with rough running or anything like that, it either runs fine or not at all. Thought for sure an IPR would cause a rough running engine along with the other problems I'm having.

Anyway, cranking it's only able to push 100 - 130 psi of oil pressure, and the DC climbs all the way up to 65%. ICP voltage also climbs as I keep cranking.

Looks like it's time to get that HPOS that I've been wanting and take care of ALL my troubles.
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post #5 of 6 (permalink) Old 05-15-2007, 08:30 PM
 
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Quote:
Originally Posted by LocoMotion
The big thing that jumps out at me here is fuel pressure.

My uncle had the same exact issue, symptoms just like a CPS but it wasn't.

Ended up being the fuel pump. I would check your fuel pressure at idle, normal cruising, normal accleration, and WOT.
Same deal here. Mine is the mechanical pump however. It would pass pressure tests. Just couldn't pump the volume needed.

Gas will do the same with electric pumps. Resistance builds in the pumps internal wiring. Intermittenly it can't deliver, eventually fails.

You could check for restrictions by breaking the line at differant points as well. Some have reported clogs at the pump inlet from the gauge arm stop desolving. Looks like black bits of debris.

Well I see while I typed, you found it. This might help someone so I'll leave it as is.
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post #6 of 6 (permalink) Old 05-15-2007, 08:34 PM
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Quote:
Originally Posted by Pocket
Well it finally stalled on me with my laptop in hand. Looks like it's a stuck IPR after all. Kinda weird that the engine never has issues with rough running or anything like that, it either runs fine or not at all. Thought for sure an IPR would cause a rough running engine along with the other problems I'm having.

Anyway, cranking it's only able to push 100 - 130 psi of oil pressure, and the DC climbs all the way up to 65%. ICP voltage also climbs as I keep cranking.

Looks like it's time to get that HPOS that I've been wanting and take care of ALL my troubles.
You could just pull the IPR and rebuild it yourself for cheap. On the other hand if the down time and cost isn't a problem you might as well get the oil system coming :Thumbup:

Eric
96 F-350 CC Dually My TDG Gallery
B codes, head studs, Comp 910 valve springs, stock turbo w/ 1.00 turbine housing
6.0 IC, NAPA 6637 air filter, AeroTurbine 4040XL, ITP Overboost Annihilator,
Quadzilla Commander, electric fuel system w/ regulated return
coolant filter, 203* thermostat
Dually Club Member #53

346.7HP, 852.1TQ 12/15/07 Greeley, CO w/ stage 1 injectors and Wildman tunes
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