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Discussion Starter #1
Hi guys, me again. Still working on my 89 E350 ambulance with the 7.3 idi.

Replaced the injection pump, water pump, new glow plugs, injectors all work well, new fuel, fuel filter, fresh oil and filter change, new antifreeze, air filter and two new batteries.

Before the injection pump gave up she ran great, didn't smoke at all.
Now, at idle, on the gas, all the time it smokes a lot, black smoke. I haven't had it professionally timed, I have tried the timing right on the mark, and the thickness of a dime & 2 dimes both advanced and retarded, makes no difference.

The IJ pump is a Stanadyne D7 DB2 831 4812 from my searching that appears to be the correct one.

Anyone have any thoughts? Would sure love to drive this thing but it's rolling coal all the time.

And, one other odd issue, the alternator has two belts, the inner belt rubs on the air pump pulley below, I have the alternator belt tension plenty tight. Any ideas?

Thanks, Patrick in Nashville.
 

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First question- Where did you get the pump from?

Second question- when you changed it, did you remove the IP gear cover?

Third question- Did you mark the steel lines so they are in the original positions?
 

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Discussion Starter #3
First question- Where did you get the pump from? ***I'm not 100% sure, the shop I took it too for this repair took off the old pump and put the new pump in place, then they couldn't seem to finish the job so I did. I know it's a rebuilt pump, was $430.00

Second question- when you changed it, did you remove the IP gear cover? ***Yes the cover was off, mechanic said he was sure it's correct and not 180 degrees off. BUT anything is possible, what could be the issue?

Third question- Did you mark the steel lines so they are in the original positions?
***No, I didn't take it apart, but it seems to me the lines only fit one way each is so unique in it's bends you couldn't get one wrong. I did have the full line install instructions from alldata which made it easy, just tedious.

Thanks, Patrick
 

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Not knowing where the pump came from could be a problem. Can you find out where the shop got it from?
If the Gear cover was removed odds are the timing is off. Even one tooth will make a huge difference.

Yes the steel lines are preformed and meant to only fit the way they should, but I've seen weirder things. Plenty of pics on the WWW showing correct lines.

odds are the IP gear is out of time....Fix is to re set the IP gear timing, NOT an easy task in a van ( ambulance)
 

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Discussion Starter #5
OK, I'll tear into it. Was hoping it wasn't that but oh well. At least it's not my daily driver and I can work on it a little at a time in the evenings.

Question, can the top gear be off too, the gear that connects to the pump? Meaning the pump is not set correct to the top gear?
 

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The pump is dowled to the top gear. you can't put it in any other way than the way it goes...BUT the gear itself CAN be put in wrong, and usually is if the gear cover is removed with the pump.
 

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If you decide the IP gear is out of time in relation to the cam gear, post back because there's a method of retiming it correctly rather than pulling the entire front cover to see the marks.
 

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Discussion Starter #8 (Edited)
Hi, are you talking about the small mirror method to see the Y mark ?

Also, rethinking this. I talked to the mechanic that put the pump on, he just put the pump on, I finished it from there, he was suppose to do the whole job but he's lazy, so I finished it. Anyways, he swears 99.99% that the timing is correct. And he also thinks its correct because it does start easy and runs really good, aside from the black smoke issue. He thinks if it was off a tooth it would start very hard and not run well at all, or as good as it does.

Here is what he thinks and more of the whole story; he thinks the smoking is because it sat for 12-14 months not running before I bought it in Feb 2017. During it's life it spent a lot of time idling. I got it running with old pump, changed fuel filter, drained all old fuel and put in new, and an oil change, then drove it home 50 miles with 1/2 bottle of lucas fuel injector cleaner in it, over the next 3-4 weeks it got harder and harder to start, I tried putting a can of SeaFoam into the fuel filter and getting it started to run again thinking maybe multiple injectors were plugged, that didn't work, the IJ pump was dead. Note, it barely smoked, only on very hard acceleration, wondering if old pump was lean at this phase as it was dieing a slow death.

Took to "mechanic" sat for 5 months during the new pump install, so now that it's running he thinks it's likely an injector or two is squirting and not misting the fuel. All the injectors are working, verified by cracking lines while running and the engine stumbles each time.

So, he suggested I add one more bottle of Lucas fuel injector cleaner in 1/2 tank plus a qt of ATF and go run it up and down the interstate to see if that cleans up the injector spray patterns and cleans up built up carbon etc before tearing into it to see if timing is off. It does start well, runs good. The engine has the same power but it does perform weird, seems to take more to get it to wind up than it did, sort of inconsistent. Then again I've never had an idi so i don't know what to expect and most of the driving I did do was on the interstate home with it.

It smokes at idle, it smokes on acceleration, black smoke. Moving the timing didn't change it much at all.

I do have the front two injectors seeping a little on the drivers side. Does that have any impact on this? And, when I start it, it runs for 3-4 seconds and dies, then I crank it again and it starts so I know i have a small air leak somewhere.

So, any new opinions on what could be wrong?? And would you do the adding more Lucas Fuel injector cleaner and ATF and run it up and down the interstate a while, like 50 miles ???

Totally open to all suggestions guys!
Thanks much!
 

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DON'T put any ATF in the fuel system. If he says it may be "old" fuel, he needs to quit being a diesel mechanic.

I'm leaning towards a bad pump. If he can't say where he got it, odds are he got a CHEAP ( bad) one.
 

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Discussion Starter #10
he's not saying it's old fuel. He thinks the injectors are dirty and squirting instead of misting the fuel, the spray pattern is bad. The injectors have a small sticker that says 2002 remanufactured on them. Another data point, I'm really believing this thing has 48,000 miles on it and not 148,000 based on how little wear there is all around the rig. So it's had a lot of sitting time.

Ok, I'll leave the ATF out, any thoughts on taking it out and running it with Injector cleaner in it? I'm thinking it couldn't hurt, spend an hour stretching her legs and see if anything changes. If not then I'll tear into it.
@LMJD, I'd like to hear more about the technique to check timing without tearing the whole thing apart again. I have seen a Youtube video on using a small mirror to see the Y mark on the lower gear so you don't have to take water pump and more off. Curious if there is another way?

Thanks,
 

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You can put Diesel rated injector cleaner in it and run it on the highway, not going to hurt anything. Based on the statement you made that didn't smoke at all before, points to the IP, either bad rebuild or out of time in my opinion.
 

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I'd like to hear more about the technique to check timing without tearing the whole thing apart again. I have seen a Youtube video on using a small mirror to see the Y mark on the lower gear so you don't have to take water pump and more off. Curious if there is another way?
First make sure the crank pulley timing mark is on #1 TDC firing/compression stroke, NOT TDC #1 exhaust stroke. Then remove the pump from its gear, remove the gear housing, lift the gear out, count up an equal amount of teeth 1/2 way up the gear on both sides from its timing mark and scribe a line across the gear from counted tooth to tooth one side to the other. Then center the gear on the cam gear so the scribed line is level with the timing cover top edge, that way both cam and gear marks have to be meshed correctly. If you can use a mirror and bright light, better yet. One guy years ago said he used a shiny butter knife. I've never suffered through having to do this, so I can't say.
 

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Took to "mechanic" sat for 5 months during the new pump install, so now that it's running he thinks it's likely an injector or two is squirting and not misting the fuel. All the injectors are working, verified by cracking lines while running and the engine stumbles each time.
An injector squirting or misting spray pattern means very little or nothing on an IDI, because the fuel is injected into a precup as opposed to direct injection, then the spray (misting pattern) does have an effect on engine efficiency.
If an injector needle is stuck open (could be only a couple of thousandth) then fuel is constantly being "leaking overloading" into that particular cylinder. One bad injector will cause a light Black smoking, two or more will cause really Black smoke, specially if they are firing in sequence (like 6 & 8).
Cracking each injector line will verify an injector is working if the engine stumbles, but it won't tell if it's stuck open.
 

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Discussion Starter #14
First make sure the crank pulley timing mark is on #1 TDC firing/compression stroke, NOT TDC #1 exhaust stroke. Then remove the pump from its gear, remove the gear housing, lift the gear out, count up an equal amount of teeth 1/2 way up the gear on both sides from its timing mark and scribe a line across the gear from counted tooth to tooth one side to the other. Then center the gear on the cam gear so the scribed line is level with the timing cover top edge, that way both cam and gear marks have to be meshed correctly. If you can use a mirror and bright light, better yet. One guy years ago said he used a shiny butter knife. I've never suffered through having to do this, so I can't say.
Ok, I understand what you are saying, I have no idea how to determine when crank pulley timing mark is on #1 TDC firing/compression stroke. Can you help with the best way to do that? I know how to do it on a gas engine... but not diesel...

THANKS!
 

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Take the GP out and you'll know when compression stroke starts. These engine produce 400+ PSI so just have someone hold thier finger over the hole. Or use a compression tester, just make sure it can handle that much pressure.
 

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In post #13 I failed to note, some times feeling each injector line fuel return cap, a stuck open injector the cap or line will be hotter than others, the blow back from compression/firing will make it so. I've seen the plastic cap melt or blow a hole in it.
 

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Discussion Starter #17
I've got one of those temp guns, after I run it up and down the interstate a few times with injector cleaner in it I'll take some temps and see if that tells me anything.

Thanks for the info, I do appreciate it!
 
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