617A- slow loss of power while on the highway! Now runs horrible
 

My first post really sucks but here goes.

Was driving for 4 hours at highway speed. Engine was great like always. Very strong. Noticed I wasn't getting as much power at the top end all the sudden. It seemed not to want to rev up all the way. Within 5 minutes, this progressed into a top speed of 40mph. 5 more minutes and I was looking for an exit with a top speed of 30mph. I had it floored in second gear to get to a parking lot at about 20 mph at this point. No weird smoke. No smells or weird noises.

I finally pulled in with what felt like about 10hp in the engine. I shut down and looked under the hood. Nothing weird or leaking. Temp gauge was normal, oil looked and smelled good. No leaks underneath. Noticed the lower part of the turbo was glowing red.

Let it cool down. Starting is much harder than it was. (it used to start almost instantly). On start up, there is a much louder "diesel rattle" noise for just a second and then idle is rough. I can floor it and it only increases maybe 500rpm over idle speed. No power really. The fuel level in the clear filter doesnt go down much at all when it is throttled up.


This 617A has: A new/Remaned IP installed when I bought it a couple years ago. Never had any issue before. New fuel filters 500 miles ago. Fuel in first filter clear and clean looking. The IP is very tight. The turbo feels smooth and tight. I usually figure things out on my own but I feel kind of screwed on this one. I don't know what to do next and I cant afford a trip to the shop. HELP! ?

Did you check your fuel tank for vacuum? Air whooshing sound when you open the cap? Vent could be clogged.

Had you just filled up or put an additive into the tank?

Check the primer pump to see if it leaks when you pump it.

Check the fuel lines for any cracks or loose clamps. Pay special attention to the short length of fuel hose under the plastic filter (where it goes into the pump body), if this cracks or comes loose it can suck in air.

If your car has a fuel tank strainer, clean or change it!!
 

I had a similar problem on my W124 that plagued me for over 2 years. The only time I really noticed a power loss though, was when I went from Atlanta to the steep hills of Va/W. VA. I originally thought it was bad diesel fuel, but later found out it was my tank strainer. It was preventing enough fuel to get to the engine when I needed to give it more fuel to go up hills.

Did you recently fill up? this sounds like bad fuel or clogged filters

Sure sounds like a fuel issue - that's where I'd focus first.

The usual suspects are, in the general order I'd consider them

- bad fuel
- primary fuel filter
- secondary fuel filter
- tank strainer
- lift pump
- pressure regulator
- cracked/leaking hose
- clogged vent
- injectors
- IP


Bad fuel could cause almost all of filter/strainer problems

It's possible that the air filter is clogged, but it would be highly unlikely to happen the way you described it.

One other thing to consider if you've got a trap cat equipped car is the turbo getting clogged with cat elements breaking down, not likely but possible.

There are a couple useful tests here.

1. Swap the supply and return lines on the hard lines, prime and start. If it runs well, this could indicate a supply line blockage, maybe a blocked tank strainer.

Another good test is to put pull the supply and return hoses off of the hard lines and stick them into a bottle of clean diesel and prime. Some people do this to run the motor off of diesel purge to clean the injectors out ( I think that's what it does).

Running well in either condition would indicate a problem aft of the firewall, or maybe a lift pump problem if the motor only runs gravity fed from a raised fuel bottle.

300 Super D, welcome to the forum. :)

I agree, sounds line a Fuel issue. It`s been covered pretty well above.

If you do decide to clean the fuel tank Strainer, you want the tank as low as you can get it before unscrewing the Strainer. or you will get a Diesel bath. jack up the R/R corner of the vehicle so any fuel will run to the low side.

I used a large plastic pan I got form Home Depot, about 3ft x 2 ft. it`s used to mix cement etc....to catch any fuel.


Charlie

Your symptom looks like fuel starvation but I am concern about the turbo glowing red. I have seem it once in a Volvo 760 turbo, turbo was glowing red hot after I changed the timing belt. I did not set the timing correctly. I reset the timing and all was well, no damage to turbo. I am not sure how the turbo in a diesel car can glow red for no apparent reasons. So I do not think fuel starvation is the root cause but I do not know.

Is this a 1985 California model? maybe he say the trap ox glowing?

Not uncommon for gas engines to have the turbo glow red and I think it's possible for diesels to do so as well, though I've never seen it. According the the chart, steel should glow red at 11-1200 degrees F. I've pulled 1250 at the inlet to the turbo on mine on a long uphill pull momentarily, so it should have been glowing at that point. I don't think you could get it to that temp though, get the car stopped, pop the hood and visually see the turbo glowing. My TIT (turbine inlet temp) drops within seconds as soon as I let off the throttle.

The turbo datapoint is the reason I included the possibility of the cat trap disintegrating if it is so equipped.

http://www.m4040.com/Knifemaking/PIC...owChart-sm.gif

Are you suggesting that a quick change in timing could be the cause? Should be easy to check by trying to tighten the IP bolts, right?

Thanks for the ideas.

There's no cat on this car.

No, I hadnt filled up recently. This same fuel was in there for over 200 miles before this happened. I did use a little bit of additive that I have used for years which has always helped with power and starting.

The pump shows no leaks or cracks in the lines near it.

The tank is actually fairly new and should be very clean. I will have to pull the pick-up soon though if nothing else works.

The IP bolts are very tight.

The air filter is new and clean.

I didnt check the tank for vacuum but it sat for a week before I tried to restart it, with the same symptoms again today, so I doubt that is the issue but I will look tomr..

My issue with any of these fuel supply problems being it, is the start-up problems I have. Usually you would have problems with power or any kind of acceleration and not idle or starting in the way I am having. I'll try the bottle test as well.

Change both filters, fill the tank, reverse the supply and return lines and let us know what you get.

Alternately change both filters and hook up a can of Diesel Purge and see what you get.

Where in SoCal are you located?

he probably meant manifolds .. inject too much fuel too late in the cycle and the slow-burning diesel will run out of air and time to burn, and enter the exhaust manifold still burning several hundred degrees hotter than it should.

this does seems to be combination of several problems,...if I were in his shoes I would start with :

secondary fuel filer change
test drive from separate tank (to resolve is it a strainer or lift pump issue)
IP timing check paired with chain stretch check

cheers

This happened over just a few minutes so how could the timing change if the IP is tight?

The chain would not stretch over this amount of time, plus the chain was replaced two years ago.

Any other way the timing could slowly change within a 5 min. period of time?

Plus, wouldn't I get a lot of smoke if the timing was that off?

Oh I'm in Ventura Co.