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  #11  
Old 09-23-2018, 02:12 AM
Lofgren__ Lofgren__ is offline
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Quote:
Originally Posted by ngoma View Post
Forum Member volvo-dennis recently had a problem where a broken turbo wastegate was limiting boost, therefore power. Probably wouldn't limit the ability to rev.

http://www2.d24t.com/showthread.php?t=1847
Yes I've been thinking that I could be something with the wastegate. Im on 0.9 bar of boost usually. Obviously I can't reach that when it decides to only let me rev to 3k. But as I said the problem goes away now and then but comes back after every time I've let the car sit. So might it be that it's getting stuck at random
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  #12  
Old 09-23-2018, 11:11 AM
ngoma ngoma is offline
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So the problem can go away while you're driving it but comes back again after letting the car sit?
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  #13  
Old 09-24-2018, 01:45 PM
Lofgren__ Lofgren__ is offline
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Originally Posted by ngoma View Post
So the problem can go away while you're driving it but comes back again after letting the car sit?

Seems to be a bit random, but mostly yes. I often get the problem on my way home from work.
I'll try to explain like this;

• I wake up. Start the car, drive to work. Car works fine, drives like a champ.
• finished work. Start the car. Can't rev over 3k. can't hold full throttle, because then it will only rev to Max 1,5k (sort of bogs?) half throttle lets me go to 3k. If I finnes the throttle just under half throttle hold it for some seconds the problem goes away and then it will work fine for a period of time. (This fix I just sorta found out while driving. Before knowing this the problem wouldn't go away)
• come home, park the car.
• next morning still works (most of the time)

It starts just fine. One crank and it's on.
I have a new filter.
I just now blew out the fuel lines so see if it helps tomorrow.

Only problem I have more than the rev thing is that when the car is working normally and I accelerate hard and go into netrual it'll have very bad idle for a couple of seconds
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  #14  
Old 09-26-2018, 10:32 AM
v8volvo v8volvo is offline
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Still sounds like a possible inlet restriction or air leak but a sticky governor or intermittent sticking vane in the suction pump in the IP could be a possibility also.

Installing a clear section in the fuel return circuit as ngoma suggested is the best first step. If there is air present then that will cause these intermittent issues and then you just need to locate the source. For air ingress issues while running the only possibilities would be the driveshaft seal or between the fuel filter and the IP inlet. All other areas including the injector return circuit do not see suction when running and would not cause these issues so you can rule them out.

Just so that we are sure we are starting off with a correctly assembled fuel system, can you confirm these things also:

Fuel pump was installed using a dial indicator to set injection timing to correct spec including disengagement of cold start device while timing was being set? Any unusual engine noise or smoke when the power loss issues are occurring?

Fuel pump inlet and outlet banjo bolts are in their correct locations and not reversed? (Outlet banjo should be stamped "OUT")

New fuel filter was installed tightly and you are certain the old fuel filter's inner O-ring was removed prior to installing the new filter? The filters like to leave the inner O-ring on the filter head nipple and then when you install the new filter, it bottoms on the extra O-ring and the outer O-ring does not seal correctly. This can cause an intermittent air leak.


If these things are confirmed and you install a clear section in the return line and see no air in the return fuel during the problem episodes, here are steps to try next that will help find the issue:

1) Install a vacuum gauge inline between the fuel filter and the injection pump inlet. It is best to get some extra banjo fittings and fuel hose to do this rather than cutting the hard clear plastic line from the filter since that clear inlet line can be helpful. Run the gauge up onto the windshield or inside the car so you can watch the vacuum in the inlet line while driving. See what the vacuum measures when everything is running normally, then watch it closely when the problems are happening. If the vacuum reads much higher when the engine is malfunctioning, then you are dealing with an intermittent fuel inlet restriction somewhere. If the vacuum reading drops down when it malfunctions then that may indicate an intermittent issue with the IP's transfer pump. If the vacuum reading doesn't change then it would probably be another issue inside the pump. In any case this information will give you a direction to go.

2) If you can't get your hands on a gauge and fittings to do the above measurements easily, a quick alternative is to temporarily install a low pressure electric fuel pump (<10psi) inline before the fuel filter. If being fed fuel under positive pressure makes all the problems go away then you are most likely looking at an intermittent problem with the IP transfer pump. Unfortunately if the problems don't change by adding fuel pressure then you still will have the same list of other possibilities and will need to make measurements to figure out the next step. But with injection pumps that have sat unused for long periods of time, issues with the transfer pump are fairly common and can be intermittent. Fortunately if happens an intermittent problem can sometimes be resolved with ongoing use and letting the pump soak in some lubricant such as ATF.

3) Replace the fuel shutoff solenoid and plunger with known good parts or temporarily remove the plunger and spring to test. Problems with the solenoid are rare but if it gets weak or has intermittent poor contact then the plunger might not retract fully and create a restriction at the high pressure pump head. On rare occasions the rubber tip of the plunger can also come off and partially or intermittently plug the opening, but I have only had this happen once. As mentioned this is not a common trouble area so probably not worth looking at unless you do all the other diagnostic steps and still are not seeing the source of the problem.


Restrictions in the air intake, turbo, or exhaust could cause an inability to rev up but would be accompanied by a large amount of black exhaust smoke if they were bad enough to limit RPM this much. I would focus on the fuel system for now.

Good luck and let us know what you find out.
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  #15  
Old 09-27-2018, 01:54 PM
Lofgren__ Lofgren__ is offline
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Quote:
Originally Posted by v8volvo View Post
Still sounds like a possible inlet restriction or air leak but a sticky governor or intermittent sticking vane in the suction pump in the IP could be a possibility also.

Installing a clear section in the fuel return circuit as ngoma suggested is the best first step. If there is air present then that will cause these intermittent issues and then you just need to locate the source. For air ingress issues while running the only possibilities would be the driveshaft seal or between the fuel filter and the IP inlet. All other areas including the injector return circuit do not see suction when running and would not cause these issues so you can rule them out.

Just so that we are sure we are starting off with a correctly assembled fuel system, can you confirm these things also:

Fuel pump was installed using a dial indicator to set injection timing to correct spec including disengagement of cold start device while timing was being set? Any unusual engine noise or smoke when the power loss issues are occurring?

Fuel pump inlet and outlet banjo bolts are in their correct locations and not reversed? (Outlet banjo should be stamped "OUT")

New fuel filter was installed tightly and you are certain the old fuel filter's inner O-ring was removed prior to installing the new filter? The filters like to leave the inner O-ring on the filter head nipple and then when you install the new filter, it bottoms on the extra O-ring and the outer O-ring does not seal correctly. This can cause an intermittent air leak.


If these things are confirmed and you install a clear section in the return line and see no air in the return fuel during the problem episodes, here are steps to try next that will help find the issue:

1) Install a vacuum gauge inline between the fuel filter and the injection pump inlet. It is best to get some extra banjo fittings and fuel hose to do this rather than cutting the hard clear plastic line from the filter since that clear inlet line can be helpful. Run the gauge up onto the windshield or inside the car so you can watch the vacuum in the inlet line while driving. See what the vacuum measures when everything is running normally, then watch it closely when the problems are happening. If the vacuum reads much higher when the engine is malfunctioning, then you are dealing with an intermittent fuel inlet restriction somewhere. If the vacuum reading drops down when it malfunctions then that may indicate an intermittent issue with the IP's transfer pump. If the vacuum reading doesn't change then it would probably be another issue inside the pump. In any case this information will give you a direction to go.

2) If you can't get your hands on a gauge and fittings to do the above measurements easily, a quick alternative is to temporarily install a low pressure electric fuel pump (<10psi) inline before the fuel filter. If being fed fuel under positive pressure makes all the problems go away then you are most likely looking at an intermittent problem with the IP transfer pump. Unfortunately if the problems don't change by adding fuel pressure then you still will have the same list of other possibilities and will need to make measurements to figure out the next step. But with injection pumps that have sat unused for long periods of time, issues with the transfer pump are fairly common and can be intermittent. Fortunately if happens an intermittent problem can sometimes be resolved with ongoing use and letting the pump soak in some lubricant such as ATF.

3) Replace the fuel shutoff solenoid and plunger with known good parts or temporarily remove the plunger and spring to test. Problems with the solenoid are rare but if it gets weak or has intermittent poor contact then the plunger might not retract fully and create a restriction at the high pressure pump head. On rare occasions the rubber tip of the plunger can also come off and partially or intermittently plug the opening, but I have only had this happen once. As mentioned this is not a common trouble area so probably not worth looking at unless you do all the other diagnostic steps and still are not seeing the source of the problem.


Restrictions in the air intake, turbo, or exhaust could cause an inability to rev up but would be accompanied by a large amount of black exhaust smoke if they were bad enough to limit RPM this much. I would focus on the fuel system for now.

Good luck and let us know what you find out.

Hey, thanks for the answer. This will help alot!
You typed so much that I can't really answer everything haha.
But now I know what to look for. I'm peacing together my other d24 so I can get it of my lift and out of my garage. So when that's done I'll start looking at this problem car of mine!

• What I can say this far is when the problem starts it comes quite a lot for gray smoke. Sounds normal but of course it cuts out on 3000rpm other than that no weird sounds.
• The banjos are correctly fitted.
• I have not installed the pump with a timer but I've done pump installs many times before the same way. Not the correct no but should still be working I think?
• I do not have a clear line on the fuel inlet since it's hard to find clear fuel line in sweden apparently.. I'll order some!
• no bubbles in the return line (return line is a clear line)
• it's a new seal on the driveshaft. My father installed it for me I can't really say. Maybe it could be damaged but he has done it loads of times.


The cold start device is unknown to me.. don't know how it works at all? The problem obviously occurs mostly on cold start.. should I try to re time the engine without the coldstart then?

This is as much as I know right now.. I'll check some more this weekend I hope


EDIT;

I havent done the vacuum test youre talking about, and I didn't really understand how to do it. Could you explain I another way? haha

Last edited by Lofgren__; 09-27-2018 at 02:02 PM.
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  #16  
Old 09-27-2018, 11:19 PM
ngoma ngoma is offline
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Quote:
Originally Posted by Lofgren__ View Post
• I have not installed the pump with a timer but I've done pump installs many times before the same way. Not the correct no but should still be working I think?
It could work, but might not be the best setting for the engine health, or best fuel economy, or performance. I consider the dial gauge mandatory when setting the IP timing.
Quote:
Originally Posted by Lofgren__ View Post
• no bubbles in the return line (return line is a clear line)
That is a good sign. If the return line remains bubble-free at all times we can rule out air intrusion and move on to other suspect areas.
Quote:
Originally Posted by Lofgren__ View Post
• it's a new seal on the driveshaft. My father installed it for me I can't really say. Maybe it could be damaged but he has done it loads of times.
If it is not letting air in (proved by no bubbles in the IP return line) or leaking fuel out, we can say the seal replacement was a success!


Quote:
Originally Posted by Lofgren__ View Post
The cold start device is unknown to me.. don't know how it works at all? The problem obviously occurs mostly on cold start.. should I try to re time the engine without the coldstart then?
IP needs to be timed with the cold start cable slackened. Slacken the cold start cable NOT by loosening the pinch nut at the end of the cable, but yes by loosening the flathead screw and rotating the U-shaped barrel so the cable end can retract. Here is a diagram:
http://www2.d24t.com/attachment.php?...8&d=1391853478
Between 2 and 3 is the cable. The flathead screw is the one I am talking about. Here is a photo:
http://i1295.photobucket.com/albums/...ps1knxbpu8.jpg

Quote:
Originally Posted by Lofgren__ View Post

I havent done the vacuum test youre talking about, and I didn't really understand how to do it. Could you explain I another way? haha
Similar to a fuel pressure gauge installed on a gasser, to read fuel pressure from the fuel pump, or fuel rail. Temporarily splice in a "Tee" fitting into the fuel hose between the fuel filter and IP. One of the legs of the Tee goes to a long vacuum line connected to a vacuum gauge positioned where you can see it while driving. Vacuum gauge instead of pressure gauge.

Here is a representative diagram:
http://www.minimopar.net/images/quickfpg.gif
NOTE: The sizes listed might not be correct for our application. We want a vacuum gauge instead of pressure gauge.
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  #17  
Old 10-04-2018, 08:27 PM
v8volvo v8volvo is offline
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No bubbles in the return line is good but did you see that when the engine was running well or when it was malfunctioning? Since you have an intermittent problem you want to watch for things changing when the engine changes how it runs.

If you saw no bubbles in the clear return line when it was running properly there still might be an intermittent air leak or restriction that would be visible when the engine is acting up but not when it runs correctly. Did you check to make sure the new fuel filter didn't get installed on top of an extra O-ring from the old filter?

On some engines replacing the IP without timing tools can work out OK but because there are so many variables that affect timing on these engines, you are less likely to get lucky on one of these. The dial indicator tools are cheap to get online and are probably common in shops where you are. Why not check the timing and make sure it's right? Even if it isn't the cause of the particular problem you are dealing with, incorrect timing can cause many other problems including hard starting, excess smoke, bad fuel economy, overheating, or blowing the headgasket or causing other serious engine damage if too far advanced. It's easy to check it and worth doing.

You can post a picture of what you are dealing with and that will let folks here help you more.
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  #18  
Old 10-23-2018, 10:43 AM
Lofgren__ Lofgren__ is offline
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First of all I'd like to thank everyone for the help this far. I haven't done much with the car the last month, i simply haven't got the time and the middle part of the driveshaft, the rubber thing with a bearing inside it. Broke so I just now orderd a new one..
Although I did retime the IP and changed almost all fuel lines a couple of weeks ago and since then started it every couple of days and it has worked good at idle, no rev "limit" at 3k anymore. But maybe I'll have to drive it alittle to see if it comes back.

(Iknow you shouldn't rev a old diesel alot) but if I rev it to like 4-5k on idle then letting it go down to idle again it will lose idle speed a couple of seconds then back to normal. (Normally have it on 7-800rpm) also have a bit of a missfire somewhere between 4-5k rpm sound like it's just on one cylinder.

I'll get on to looking more at it and driving it next week
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