View Full Version : Limited Power on Hills Mostly
hankallan
07-10-2010, 19:07
Hi,
My '99 Suburban cant seem to get much power up hills. Once it hits 2000-2300 RPM just hits a wall with foot to the floor. Recently have code 216 set. Could injection timing be a possible cause here? Not sure where to start troubleshooting. I changed the filter not too long ago but might have gotten some more bad fuel. Flow check is good at about 15gph at 3psi.
thanks,
Hank
What kind of boost are you getting?
AllThumbs
10-07-2010, 12:34
Hi,
My '99 Suburban cant seem to get much power up hills. Once it hits 2000-2300 RPM just hits a wall with foot to the floor. Recently have code 216 set. Could injection timing be a possible cause here? Not sure where to start troubleshooting. I changed the filter not too long ago but might have gotten some more bad fuel. Flow check is good at about 15gph at 3psi.
thanks,
Hank
I'm having the same problem towing. You can hear the turbo kick in, but the truck just goes no where. Pushing the throttle down doesn't to a thing.
A.J.Ciaccio
10-27-2010, 20:33
My 99 exspree 3500 auto runs great by it self but on a long hard pull or when towing heavy the truck will suddenly loose power the turbo shuts down and stepping on the accelerator does nothing it acts like can`t rev up. Have had the computer replaced, lift pump and fuel filter, turbo checked exhaust pulled off. the throttle motor checked (it has a long name). Map sencer replaced twice. When the truck runs right it has a lot of power, but when it fails it only runs out at about 25 to 30 mph. I hope someone knows this problem the las tgarage got me for $1250.oo in Butte Mt, and I still had to pay someone to haul my trailer to Lake havisoo Az. Thanks for readind A.J.Ciaccio
Hi,
My '99 Suburban cant seem to get much power up hills. Once it hits 2000-2300 RPM just hits a wall with foot to the floor. Recently have code 216 set. Could injection timing be a possible cause here? Not sure where to start troubleshooting. I changed the filter not too long ago but might have gotten some more bad fuel. Flow check is good at about 15gph at 3psi.
thanks,
Hank
If you have a Cat on your rig it could be getting plugged. When you are going uphill the sustained higher boost levels are building backpressure as it can't get through the cat fast enough.
My 99 exspree 3500 auto runs great by it self but on a long hard pull or when towing heavy the truck will suddenly loose power the turbo shuts down and stepping on the accelerator does nothing it acts like can`t rev up. Have had the computer replaced, lift pump and fuel filter, turbo checked exhaust pulled off. the throttle motor checked (it has a long name). Map sencer replaced twice. When the truck runs right it has a lot of power, but when it fails it only runs out at about 25 to 30 mph. I hope someone knows this problem the las tgarage got me for $1250.oo in Butte Mt, and I still had to pay someone to haul my trailer to Lake havisoo Az. Thanks for readind A.J.Ciaccio
If your wastegate is not operating proper you can get to much boost which can cause the computer to to shut down your boost. Usually if you let your foot off the pedal it will reset and be good to go. Are you running a boost enhancer of sorts?
suburbanK-2500HD
10-28-2010, 10:47
Plugged cat
or fuel restrictions, measure the fule pressure when driving.
6.5 Detroit Diesel
10-29-2010, 11:18
yea, i am going to go with a plugged up cat. had a 95 that ended up not even starting because of the cat. no codes though. we threw everything but a new engine at it. finally after removing the exhaust for other work, we turned it over and it fired. after replacing the exhaust, it wouldn't light.
it may seem weird, but it is worth a try.
A.J.Ciaccio
01-22-2011, 14:43
My van has only factory equ no boost help I have let of the throotle with no change. If I shut truck off for 10 minites it will right itself until anouther hard pull, then same thing. what does the pcm do? A.J.
PCM controlls everything in your engine. I'm thinking your vacuum system is not working up to par. Check your vacuum pump and boost solenoid for proper operation. Is Your burb an S code or an F code engine.
A.J.Ciaccio
02-11-2011, 12:30
I had the for clamps replaced on the exhaust to turbo, there are 4 of them cured the power drop off, but now on a hard pull or when accelerating to hard the van starts bucking and if I let off the throttle and accelerate lightly it will not buck but will loose speed, is it possible its the fuel injector driver module? I am told because of it`s location it will get hot and fail. And thank you Dave for all of you advise A.J.Ciaccio
Do you have a catalytic converter on your exhaust system?
A.J.Ciaccio
02-11-2011, 19:22
No the converter was the first thing to go when I first had trouble
on a hard pull or when accelerating to hard the van starts bucking and if I let off the throttle and accelerate lightly it will not buck
That sounds like fuel filter or lift pump problems.
A.J.Ciaccio
02-13-2011, 19:35
Both have been replaced lately maybe its the oil sending unit or fuel injector drive module? Don`t know what could be the cause, But thanks for the help. A.J.Ciaccio
Plumb a fuel pressure gauge into the water drain line and go for a ride. If it goes to vacuum under load, well, figure out why...
It makes sense that it could be your lift pump or fuel filter. If you lose power on hills it could be because your injector pump is having a harder time sucking fuel to it when the engine is higher than the tank. Check it out as this scenario adds extra wear to your I.P.
I have a 99 that does the same thing. I've been mildly troubleshooting it for the past few months. Yesterday I was looking at it again and did check over all the exhaust pipes and didn't feel any leaks, but that was at idle. Also the vacuum system seems to be working good. I didn't have a gauge to put on it, but it holds the wastegate closed tightly at idle. I've changed the fuel filter and the IP pump works good. Maybe I need to look at the cat again. I thought I had it's guts knocked out when I had the engine installed but it could have gotten missed. I did change the PMD last fall because it had failed, but there was no change in the turbo/lack of boost issue.
It's funny because the turbo works great until I hook up a trailer or start climbing hills. Both times when it would be really nice to have all the power I can get!
It's funny because the turbo works great until I hook up a trailer or start climbing hills. Both times when it would be really nice to have all the power I can get!
Do you have a boost gauge? What is it doing? Any SES light or codes?
A failing wastegate solenoid is often the cause for low or no boost under load, but you should do some more troubleshooting first. Make sure the vacuum pump and lines are healthy.
Under heavy sustained boost the IAT's get too high and the ECM will defuel the engine.Limp mode starts untill you restart the engine and the ECM is happy gain.
The turbo compresses the air and when compressed it gets hot-too hot and ECM says "back er down".
WMI injection would help with that problem.
An aftercooler would help as well but I have been told that the ones available are too restrictive and hurt performance more than help?
Do you have a boost gauge? What is it doing? Any SES light or codes?
A failing wastegate solenoid is often the cause for low or no boost under load, but you should do some more troubleshooting first. Make sure the vacuum pump and lines are healthy.
I do have a boost gauge and it will drop to zero right after the transmission shifts. I don't believe there are any codes but my scan program is acting up, so I'm not definite on that. Usually if I step on the pedal enough to get the trans to downshift the boost with jump to 10-12 and things will start working again. I haven't hooked up a vacuum gauge yet to test the pump, but that will be my next step. What I don't understand is that everything works great under normal driving, even if I am stepping on it to get up to speed quicker. But as soon as I hook my small 5x8 trailer up and put some camping gear or landscaping materials in it, the turbo doesn't want to perform. Where does the ECM get the temperature from to adjust the boost pressure? I'm guessing the intake?
[QUOTE=racer55;281244]Under heavy sustained boost the IAT's get too high and the ECM will defuel the engine.Limp mode starts untill you restart the engine and the ECM is happy gain.
QUOTE]
It seems like it happens more with the rpm change when the trans shifts, not so much that there had been a sustained boost. How long and how high of boost pressure would cause the ecm to go to limp? Also, I can usually get the turbo back online if I get the trans to downshift, but then the boost spikes to 10-12 at least!
I do not know the IAT temp that sets the defuel,sustained boost of 13psi for more than about 5 seconds or so will cause a defuel also but usually throw a code.
When the boost drops try backing out of the throttle and coming back slowly. If you get boost, even briefly, my money is on the wastegate solenoid. What boost levels are you seeing right before it drops out? If they're much more than 8, again, the solenoid is indicated.
When the boost drops try backing out of the throttle and coming back slowly. If you get boost, even briefly, my money is on the wastegate solenoid. What boost levels are you seeing right before it drops out? If they're much more than 8, again, the solenoid is indicated.
Thanks. I'll try this and also keep a closer eye on the boost to note where it is at prior to drop off. I'm pretty sure it's around 8, if memory serves correctly.
My next delimna, do I start changing parts or just go for the TurboMaster? If it's just the solenoid, I can handle that, but once I get into vacuum pump, and so forth, I think I'm probably better off visiting the Kennedy site.
My next delimna, do I start changing parts or just go for the TurboMaster?
Figure out the cause first, otherwise the Turbomaster is just another part you're "changing".
For anyone with similar issues, here is a bit more troubleshooting info. I put a vacuum gauge on the waste gate actuator and have 21 or so at idle. 25-26 at the solenoid. I have to get a tee and some line before I can test it on the road but I'll post those results when I do.
I put a vacuum gauge on the waste gate actuator and have 21 or so at idle.
That's too high. It should be more like 15". Either the solenoid is plumbed backwards or it is not working properly. The line to the vacuum pump should go the solenoid port with the restricter in it.
jonflies
04-30-2011, 15:16
Guys, my 99 was doing the same thing before I went through all the troubles I did. See my other posts. Turbo was spinning, but the power just wasn't there. Cannot recommend all of the changes I did, but read my other posts.
I'm now getting a code indicating a bad wastegate solenoid circuit problem. I've changed the solenoid and now I'm going for the pigtail connector. I'd like to know if anyone knows if this circuit shares a common ground with another sensor in the ECM.
Looked into things a bit more and the solenoid is plumbed correctly with the restrictor port going to the pump. I actually removed the solenoid from the truck and inspected it as well as put a few drops of wd-40 into each port. It seems to be working good since then.
Prior to that, it did lose boost at 7 psi and higher for anything over 8-10 seconds. Sometimes the boost was even below 5 psi and it would still drop off. When it does drop off it goes straight to 0. Not like when you let off the pedal and it smoothly goes down. So it does seem to indicate the solenoid is closing abruptly. I'm not sure if the solenoid is being commanded closed or failing closed, but it seems to snap shut. Then if I let off the pedal and back on the boost will come back on. But if I'm under any load, like a stiff wind, or pulling anything, it seems to be very finicky.
I'm going to keep my eye on everything for the next few weeks and if it seems to stay healthy after lubing the soleniod I'm going to put one in the glove box for the next time it acts up.
Are yoiu Guys that are experiancing this problem also getting excessive black smoke when the drop in power happens along with a dull sound like the engine is missing slightly and being held back?
Also what coolant temperatures are you all getting when the reduction in power happens and do you get the "CHECK GAGES'' warning appear on the instrument panel?
I was hauling a load of hay yesterday, trailer plus hay was around 3.5 tons, on about a 200 mile return trip when I started to get the above problem which showed itself near the end of the return trip when the coolant temerature was around 230 to 235 and we were pulling hard up a long gradient.
If I moved the transmission manually down a gear the problem would reduce or dissappear and usually the coolant temperature would return to more acceptable levels. As soon as we were over the gradiant and on the level everything returned to normal.
I suspect the high coolant temperature temperature may be caused by a sticking coolant temperature regulator (My Suburban is a 96 with the twin temperature regulators).
I will order two new regulators tomorrow.
Since I installed a 4 inch exhaust system about 3 years ago I have had no trouble with high coolant temperatures when pulling trailers as the exhaust gases are getting out easier along with the heat.
Regards
Jim
Are yoiu Guys that are experiancing this problem also getting excessive black smoke when the drop in power happens along with a dull sound like the engine is missing slightly and being held back?
Also what coolant temperatures are you all getting when the reduction in power happens and do you get the "CHECK GAGES'' warning appear on the instrument panel?
I was hauling a load of hay yesterday, trailer plus hay was around 3.5 tons, on about a 200 mile return trip when I started to get the above problem which showed itself near the end of the return trip when the coolant temerature was around 230 to 235 and we were pulling hard up a long gradient.
If I moved the transmission manually down a gear the problem would reduce or dissappear and usually the coolant temperature would return to more acceptable levels. As soon as we were over the gradiant and on the level everything returned to normal.
I suspect the high coolant temperature temperature may be caused by a sticking coolant temperature regulator (My Suburban is a 96 with the twin temperature regulators).
I will order two new regulators tomorrow.
Since I installed a 4 inch exhaust system about 3 years ago I have had no trouble with high coolant temperatures when pulling trailers as the exhaust gases are getting out easier along with the heat.
Regards
Jim
I get a ton of black smoke, but coolant temps didn't seem bad. They do rise as the problem occurs as does my egt. It seems since I fiddled with the waste gate solenoid the problem hasn't reoccured but I haven't tested it with a load yet.
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