FG649 down on power, slow

unkamonkey

Explorer
My neighbor thought I was nuts when I mentioned a loss of power in hotter temps. He thought I was deluded until he paid attention to his Ford Powerstroke. He looses boost as well.
On a pass West of home, I can pull the East side in the early morning or in the winter, 5th gear. Summer, in the middle of the day, I'm down a gear or 2.
It's the big whatever, I have the AC going and tunes on for the drive and I have lot's of gears to go to.
 

kerry

Expedition Leader
Seems like you should have more boost than that. Is your wastegate operating correctly? Are you getting adequate air thru the air filter? I haven't put a boost gauge on mine.
 

CropDuster

Observer
Its winter here unkamonkey, the sky should be the boost limit :)

Seems like you should have more boost than that. Is your wastegate operating correctly? Are you getting adequate air thru the air filter? I haven't put a boost gauge on mine.
I believe it should hit 15-16psi then the pop off valve on the intake manifold will open.
The wastegate is closed and i am running no hose to it
Ive driven with the air box removed, next chance i get to work on it i might just take the hose off the front of the turbo and eliminate that section of piping altogether.

It's going to be something simple i bet, just have to find it!
 

gait

Explorer
the fuel consumption is way too high ------> perhaps something absorbing the power rather than engine not providing it ----> are all the brakes free, not binding, brake cylinders working, wheels free to rotate, free wheel hubs free, handbrake free, anything getting hot that shouldn't, etc. ????????

just some thoughts ....
 

CropDuster

Observer
It revs, drives and does everything fine its just noticeably slower than it was.

Wastegate connected = 10psi
Boost controller on and dialled up = 10psi
Wastegate hose disconnected and blocked on compressor cover = 10psi although it hit 12psi in 5th gear a few times but goes back to 10 once it gets to 3000rpm.

Im going to put a camera on the exhaust and see what smoke its blowing then i will connect EGT and AFR gauges that i have when i get time [its my daily work truck]

The fuel comsumption is probably partly me, the pedal is like a light switch :victory:
 

unkamonkey

Explorer
Obviously there are a few things to look at but this is a 1992 so I'm not to sure how the numbers swap over for power and boost ranges. Other engines? If I head out to Moab I have to use the happy pedal so I'm not going down the pass at 35 MPH in 5th gear. (5.714 gears?) Brakes aren't hot. Pretty much 11 MPG regardless of what it hooked to the rear of it.
I suppose that is why I have a 50 Gal fuel tank on it now. After about 250 miles, I just need to get out for a walk and add some fuel.
There is only about 88,000 K on the thing.
 

boostin

Adventurer
I would take the waste gate right off and wire it shut to rule it out, also I would take the turbo outlet hose off and make sure the turbo spins freely, and no damage to the compressor wheel.

Also I think you need to do a compression test, maybe valves are sticking open and need a adjustment
 

CropDuster

Observer
I would take the waste gate right off and wire it shut to rule it out, also I would take the turbo outlet hose off and make sure the turbo spins freely, and no damage to the compressor wheel.
Thats where im at right now, have done just that.

Compression test will be next :)
 

CropDuster

Observer
Does anyone know if it should have a high idle on cold start?
It starts up right away without the engine even needing to do a rotation and idles at ~900 rpm from stone cold even with the current temp of 0-2 degrees celsius here at the moment.

TIA
 

gait

Explorer
Hope this bit helps .... I've never noticed mine do anything else. Managed electronically I suspect. If battery has good volts it usually starts within a second or two and just runs. I've only seen glow plug light on once in 100,000 km, I think -10 centigrade.
 

CropDuster

Observer
Hope this bit helps .... I've never noticed mine do anything else. Managed electronically I suspect. If battery has good volts it usually starts within a second or two and just runs. I've only seen glow plug light on once in 100,000 km, I think -10 centigrade.
Thanks gait, I guess that part is working fine then :)
Going to test coolant temp sensor next, once i get a chance to stick my head in the engine bay and find it.
 

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