2007 Chevy sorta goes into Limp

[TWoodford]

HI guys,

2007 2500HD, work truck with various drivers, towing and climbing a hill and goes into "limp" then seems to recover without any problem. Dealer says oil pressure switch or the pump itself, so we replace the pressure switch, still did it but not often, when loaded and pulling a longer hill (all second hand info so not a whole lot of exact specifics to go on) from what I read this is sort of common, is the oil getting hot and putting this truck into "limp"

 

[Robby05]

Codes?

 

[TWoodford]

I don't know, I was told no dash lights

 

[roxyfever]

How many miles on the truck?

 

[TWoodford]

About 150,000 and when it was at the dealer they wrote;
found code P0087-fuel rail pressure low and P0674-glow plug control circuit tested for P0087 all pressure and fuel vacuum perfect at this time, vehicle has evidence of new fuel filter (box on floor and looks new) customer obviously fixed this concern, testd glow plug and found excessive resistance recommend all glow plugs on that side

etc etc of other misc recommendations (but then)
After speaking with customer and finding out more info on check engine light tech advised that problem is most likely oil sending unit of the oil pump spoke with owner of company and he decided to replace oil pressure sending unit only, first

 

[TWoodford]

so that was 2 weeks ago, the truck is worked hard daily and only yesterday on the way home pulling a grade and towing a mini track loader it "went into limp again" or lost power and the driver just took it easy to get home, no one has driven since but I have every expectation that if I drive it again right now it would be 100% fine again until these conditions were repeated, this is a recurring issue but only under these conditions

Note track loader is not heavy maybe the whole trailer and load is 12,000, I worked it harder than that when I drove it but it was newer too, and IDK if there using the tow mode, allowing it to lug etctera

 

[Mike L.]

Welcome

 

[TheBac]

Do you have a lift pump installed? I dont mean the engine's injection pump -- I mean an aftermarket pump installed in the feed line.

 

[ikeG]

Does fuel filter life go to 0% when this "limp" happens?

 

[Dkatubi06]

My 06 used to do it when I first got it. all filter percentages were at 100%. Until I physically looked at them. Turns out, the DIC percentages were reset before I bought it. The fuel filter probably hadn't been changed in 15k. After i changed it my Limp never happened again I'd start there

 

[TWoodford]

no lift pump installed,
IDK about the filter percentages when it happens as I was not the driver
But the fuel filter was just changed in our shop
Alot of other stuff I have read leads me to think the oil temp is getting too high and causing this

 

[Robby05]

Does the truck loose oil pressure? Verified this by a mechanical gauge. Your description of the issue is really vague. Have you drove the truck when it sorta goes into limp mode

 

[TWoodford]

I'm not the driver so its hard to be more specific
They said the truck just looses all power and then they also note that it looses oil pressure, if they wait awhile it starts back up and the power is restored
Someplace on this site I have see guys talking about the ECM shutting off fuel when the Oil Temp reaches 250 F, is it getting hot, how many of you guy have had overheating issues? This truck is 100% stock so its not as though is been all tuned up either?

 

[clrussell]

Oil temp should not cause a truck to limp. They have no way of knowing the oil temp.


Id be looking on the fuel side of things

 

[TeaBagger2006]

Fuel temperature sensor

 

[TWoodford]

TeaBagger2006 - please explain,,,, Is there a fuel temperature sensor? You think it is bad?
Does anyone here give any merit to the dealer telling me the oil pump itself is bad? I see many comments about oil pumps and nuts loosening and having to pull the motor to replace them but as a novice I just have trouble believing that the oil pump is fine 90% of the time and then once every 2 weeks decides to perform so poorly that the truck looses power like this

 

[TheBac]

I guess you'd have to actally drive the truck and see. Is your oil pressure dropping off? Corbin is right.....oil temp wouldnt cause a limp.

If you are throwing an 87 code when the engine is under stress, then chances are its in the fuel system somewhere. Worn injectors returning too much fuel, the CP3 weakening and cant maintain psi under duress, fuel lines collapsing under vacuum.....there's a ton of things that can cause it.

Keep in mind, you're asking us to guess at something that even you havent even seen first hand yourself. How the heck are we supposed to do that?

 

[TWoodford]

Teabagger, Clrussell, please clarify So the truck has a Fuel Temperature sensor but no Oil Temperature Sensor?, Are you saying the Fuel temperature sensor might be bad or somehow to blame? I've seen in other treads guys talking about the oil pumps nut loosening or how you have to pull the motor to change them but no one here has jumped on that explanation. Do you guys think the oil pump itself can be to blame? I just have trouble with that explanation because the problem is so infrequent, 98% of the time its fine and then once in 2 weeks this issue pops up and then just goes away again, I don't get it.

 

[TWoodford]

TheBac, sorry I didn't mean to ignore you, I thought my last post didn't stick and was only attempting to repeat myself on purpose, I guess I will have to get the truck and trailer (heavy) and go for a road trip,,,,, I think I know where to go because twice this has happened on 81 South out of Syracuse, there is a kind of sneaky easy but long grade there that makes a truck work and it has happened 2x on that stretch of road, Thanks I'll report back after I do that maybe tomorrow

 

[TWoodford]

I drove the truck today the dash engine light was already on and the truck had codes P0087 and P0674, I'm a novice at this and was unable to clear them (can you clear them?) it was about 74-75 degrees out, with trailer of about 14,000, back roaded it to delivered some parts to a job around finger lakes, plenty of hills, did not use tow mode and lugged on hills trying to stay below 2000 to make heat (I was thinking this was a heat related issue) at one point and only for a very short time I got the coolant to about 250 the tranny to 240 and the oil pressure was 30, bottom line in 114 miles the truck did nothing wrong, it has 170,000 miles on it, using the site to see if I should have been able to get rid of the codes I found this link which seems to be talking pretty near to what we have seen, some of you guys implied injectors and lines and I'm starting to question why the dealer even got started on oil pressure, there hasn't even been a code for oil pressure, I expect what happened is our drivers (construction company) were not even really paying attention till the truck went into limp and then saw pressures of about 28 and got concerned, (is that a concern? I'm told it's okay but seems low to me too, usually runs right around 30 and 45 and 50 seem to be the high numbers and only when revving the motor

here is the link, your thoughts are appreciated

http://www.kennedydiesel.com/docs/Duramax LBZ and LMM P0087 Low Fuel Pressure code.htm