Engine/Transmission (1994 - 1998) EGTs too high and poor mileage towing

[TORQUED TAYLOR]

I came back from the river last week towing a 7500# boat. The temp was 105 outside but my egt problem is regardless of the outside temp. Up any grade my EGTs were hitting 1450+ super quick, so of course I would back off the throttle and take it out of overdrive. I would then see a drop and poke up the rest of the hill and keep it pegged at 1300-1400(for no more 3-4 mins).

My mileage was 9mpg this trip. I used to tow a 12,000# trailer with a much higher profile and get 12mpg.



???What is the difference between sliding my 10 plate back or just backing off the throttle a bit???



I do not want to spend a bunch of money on a crazy turbo set up.

It's been suggested that a water injection might help.



1. I bought the truck with 88k on it and she now has 145k miles.

2. The valve adj and fuel filter replacement were last done at 118k miles (I just realized this was 3 years ago).

3. I have never been able to get the timing advanced or even checked because when I bring it to a dealer they can't seem to get this "nut" off (that's going to be another thread) because it's on too tight.

4) The truck has to turn over 5-8 times before starting unless I put my foot on the pedal then it's immediate. ( I mention this because I know that hard starting is a result of advanced timing and I have no idea what the previous owner did to this truck) I think he may have done something because the dealer says there's a lock tite on the "nut" for the timing thingy.



Any sugestions?



Thanks in advance,

JT

 

[tgrfan2]

#4 should be pretty easy. Usually increasing the idle speed 50-100rpm will solve that problem. I didn't have any EGT problems with my #6 plate in the stock position until I added a 3K GSK. After that EGTs would go high quick with or without a load at high rpm. Adding a BHAF helped me some. Increasing air in and exhaust out helps lower EGTs. Since EGTs and mileage have changed considerably on your truck, I would check the intake and exhaust carefully. Good luck!

 

[Howard Durand]

It sounds to me like the engine is not getting enough air for complete combustion. Have you checked the intake air and boost system? Replace your air filter and make sure all the intercooler hose clamps are tight and there are no holes or cracks in the intercooler boots.

As to the tight nut, are the mechanics referring to the nut that holds the timing gear to the pump? Timing can be checked without messing with that. It will have to be loosened to be able to change it.

 

[NHays]

What are your boost numbers. I just went through this with my truck, had the exact same problems and little low power and slower acceleration. turns out I had a plugged oil cooling jet on the #6 piston, which over time got worse and I stuck the piston. Had to rebuild the engine. Check the amount of blow-by you have. Or it could be as simple as a ripped intake boot. Sorry to elaborate. just my . 02





Edit... Also, DONT run at those egt levels at all, you will damage your engine severely. 1250* MAX

 

[TORQUED TAYLOR]

I checkd for boost leaks and couldn't find any. I'm running new boots and clamps. I just cleaned my BHAF... and still no difference.



My max boost is about 32 lbs.



What is the difference between sliding my 10 plate back or just backing off the throttle a bit?

 

[RDelissen]

something seems to be not right (duh). I'd check the air intake indeed and have the timing checked to see if it might have slipped ...

 

[TORQUED TAYLOR]

Update

Ok, last night I slid the 10 plate back about an 1/8" and it sure seemed to knock down how fast the egts get high. I did notice the governor lever is hitting the plate maybe about 1/4" above the bottom (just before the biggest indententation/fuel increase) on the plate.



I couldn't find any leaks in the intake and the filter was just cleaned this weekend. I did notice that the downpipe from the turbo to the 4" Jardine exhaust "chokes down to 2. 5-3" and then expands back to the 4"... I don't think this is helping but I think this is common... right???



Here's what I think I'm feeling after the plate sliding:

Before - I could get the truck to accelerate a little faster but then had to back off becasue of the egts rose so quickly

Now - the truck seems to pour on the speed more continuiously and I don't have to back off so fast, I don't feel much slower though.



Here are my numbers cruising as lightly as possible and empty (remember my issues are when I tow, not empty)

72mph 850* 5lbs 1900rpm flat ground

72mph 1050* 13lbs 1900rpm 6%ish grade

56mph 1150* 10lbs 1600rpm steep grade



Now when I'm towing a 7500lb boat it's a whole different story. I don't have those numbers yet.



I'm really seeing the high egts when the rpms are low and there's a lot of fuel. Part of my problem is tires,315/75-16 (35"+/-) and gearing, which I will not change. But I notice when the rpms are over 2050 the egts drop and are more controllable.



I think I may need a bigger turbo to get the air through.



Any input?

 

[JSharp]

When I pull my 9,000 lb 5er I try to keep the rpm up in the 1900 to 2500 range. Any less than that and she will get hot quick. Of course with the 5 speed I can use 4th gear for the highway and 5th for the interstate. Seems to keep me in the sweet spot. I am not sure how to do that with an auto.

Hope you can fix it.

Jason

 

[TORQUED TAYLOR]

Jsharp,



The only way I can control the egts is by taking it out of overdrive and keep the rpms up. Fortunately the big tires make being out of overdrive a little more bearable... I still need to chill the egts.

 

[Matthug]

Sounds to me like the timing has slipped, that would explain the fuel mileage drop and high EGT's. With a 180 pump and 215 injectors you should have no problems running a 10 plate with the stock HX35. I would turn the boost up to about 35 PSI though, and get your timing bumped to 15 or 15. 5 degrees. Never take it too the dealer for engine work, find a local diesel shop. I drove about an hour to get my timing done, well worth it.

 

[TORQUED TAYLOR]

Sounds to me like the timing has slipped, that would explain the fuel mileage drop and high EGT's. With a 180 pump and 215 injectors you should have no problems running a 10 plate with the stock HX35. QUOTE]



I'm thinking the same thing too. I'm looking for a timing shop in So Cal right now.