Trouble Reaching Highway Speeds (1 Viewer)

[Firsttimer]

Hi, I've got a 1985 BJ70 that has been passed down to me. I have been having issues with it at highway speeds, however. At first, I thought that it was just that the vehicle was old (730,000 km--same engine ), or that it was related to driving in cold weather, but I am able to get up to highway speeds intermittently (and in the cold too). I was wondering if anybody had any opinion as to why this could be happening? When I am having trouble, I cannot get it to go any faster than 100 km/hour. There are times, though, when I can go 130 km/hour.

 

[Dauntless]

Have you checked for fuel blockages?

 

[Firsttimer]

Nope. How do I do that? I've started running an additive through it to try and improve it, but nothing has helped. The other thing is, it accelerates well at lower speeds...it's just the high speeds that are an issue.

 

[seapotato]

I've had a bj70 for 5 years now....not sure I've EVER had it over 100kph, never mind 130kph.


sure it isn't just a head wind?

 

[David*BJ70]

Check your fuel filter

I you don't know when the fuel filter was change, you should change it.

Take a look at this page https://forum.ih8mud.com/diesel-tec...umber-thread-no-chit-chat-parts-requests.html and search for the 3B fuel filter part number. There a some part number that can fit with your local part supplier. NAPA Gold and/or WIX 3393 is usualy a good choice.

I'll suggest to unscrew the old fuel filter and refill the new with some Sea Foam (Sea Foam | Motor Treatment) then put back the new filter in place.

Search for fuel filter / Sea Foam on the diesel page in this forum.... there a lot of info !

 

[jake2far]

Things to do:
Change fuel filter.
Change or clean sedimenter.
There may be a screen on the fuel pickup that needs cleaning.
Check or rebuild injectors.
There are parts that wear with that amount of mileage, timer on the front of the injection pump, injection pump, injectors, if you can check the injection timing it can be running retarded from wear.
Diaphram for fuel control can be stretched or damaged.(the clear plastic tubes at the throttle body run to where the diaphram is located).
Linkage from the EDIC to the injection pump may be worn.

Have you done a compression test?


Just some starting points



Jim

 

[Firsttimer]

Jim, that is great! Thanks, I'll start my way through the list!

 

[roscoFJ73]

At 730000 its probably on its last legs. I would happy with the fact it can reach 100klms and hour,there are some with much lower klms that cant

 

[crushers]

VERY first thing to do, check the compression.
no use sinking money into other items if the engine is caoughing it's last breath.

IF the compression is good (yah right) then attack the list Jim posted up.

 

[BobBJ74]

Check air filter as well.

 

[David*BJ70]

Guys, your ''to-do'' list is really useful. But the guy has a 3B with 720 000km... and is a rookie (no offense here... Is what I am wrong)

I think the things he must do first are the things that do not cost too much and easy to do.

A diaphragm job is painfull.
rebuild the injector not cost less than 200$
timer gear is out of price!

I still think he should change the fuel filter first. It's a 15$ job .... + $ 12 is he uses Sea-foam.

Fuel filter is on every regular maintnance list ... compression test, no (although this test is sometimes revealing). And he can do it by itself.

I smiled just thinking about a guy who falls into depression reading your list and eventually fix the problem with a 15$ filter

 

[crushers]

compression test - - no
as in:
no i won't do it
or
no, it isn't on the regular maintance list?

with a motor of that mileage it just makes too much sense not to...

 

[David*BJ70]

- no, it isn't on the regular maintance list -

I'll do a compression test if the new filter does not change the situation. I always try to think about simple thing before.... but I'm not saying you are wrong.

 

[jake2far]

Guys, your ''to-do'' list is really useful. But the guy has a 3B with 720 000km... and is a rookie (no offense here... Is what I am wrong)

I think the things he must do first are the things that do not cost too much and easy to do.

A diaphragm job is painfull.
rebuild the injector not cost less than 200$
timer gear is out of price!

I still think he should change the fuel filter first. It's a 15$ job .... + $ 12 is he uses Sea-foam.

Fuel filter is on every regular maintnance list ... compression test, no (although this test is sometimes revealing). And he can do it by itself.

I smiled just thinking about a guy who falls into depression reading your list and eventually fix the problem with a 15$ filter

I reread my list and heyyyy the first item is the fuel filter!
I suppose I could have placed numbers by each item as in 1 2 3 but if you read my list and do them in order it really is easy to hard. I suppose I could have said don't bother with the timer but if the timer is worn it can cause the problem and at least he has info on it besides if there is wear and the timing is retarded it is free to adjust the timing, Wayne is right about compression testing but the rig sometimes runs great and sometimes it doesn't I thought it would be hard for the engine to change compression, also doing the compression test is more difficult to do. The items I selected could cause the motor symptoms. I really think if the motor still has good compression the injectors could be the cause as they really should be tested/repaired/replaced about every 100-150 thousand KMs kinda like spark plugs for gassers.
Welcome to DFISPDX.com
The link is to Diesel fuel injector service in Portland Oregon they do a first class job, they will test them for free if they don't need repair they won't charge you, while the injectors are out then you can also do the compression test, an inexpensive test kit can be purchased at Harbor Freight.
The list I gave by no means is complete and someome else could argue different items in different order but hey if I was working on my rig those are what I would do.
I hope this helps clear up your smiling depression.

Jim

 

[Firsttimer]

Hey, yeah Jim that is great. I appreciate everyone's response. Yep, I'm VERY new to this. It's something I've been wanting to get into for a long time. In terms of the speed thing, I think you are right, I don't see it being plausible that the engine compression could change so drastically even over a 3 hour trip (it is my understanding that compression doesn't change––except for a depreciation slowly over time). I will try the fuel filter first and then go from there. While I don't think the engine compression is an issue, it is something I would like to test anyway, as the engine is so old. Also, one mechanic thought it could be an issue with the vacuum lines--is this possible?

If the compression is crap, do you think I would have the capacity to do a rebuild or is this something I should leave to a professional?

Anyway, I really appreciate all your guys' help!

 

[cicak]

After readign the postings several times I believe your problem is the fuel filter. GEt the correct part number and then put it it. You can do this yourself. but make sure you have a filter tool to remove it they can be tough to twist out as there is not a lot of hand room.

A rebuild is simple get a mehcanic to do it. They can push the sleeves out resleeve it and new pistons and rings and bearings all round and a rebuilt head. Oh Yeah pop a turbo (a nicer CT26) (but you will need a proper fuel pump and a new manifold) on the top and you will not believe the transformation. IF you are going that far do what I did and put a 14B -T fuel pump its rotary and not mechanical instead.

Good luck with the cruiser remember its old with 750,000k's if you are not going to rebuild it. I suspect 130k is pushing it a little hard the tacho would be showing 3600+ revs at that speed?