Engine/Transmission (1994 - 1998) First test run on the 12V after bombs, got some trouble....need help

[JBlackwell]

Well, after a few months of getting the head off and cleaned up with valve job, new seals, shaved . 010, and then back on with . 020 marine gasket. Had a unmolested pump and changed out to a #10 plate, 4K GSK, and 370's, I went on its first test run.



I was having problems with it "popping" at around 1500-2000 rpms when I put it to the floor in neutral, I checked the timing... . had slipped to 11*, bumped it up to 18*, but slipped back to 16. 5* when tightened. Good enough for me, so I readjusted the govener (sp) to . 046 an the other to . 050. Fired her back up and idled much much better from 450rpms to 750rpms after. Fixed a fuel leak or two, cleaned out the fuel bowl thats between the started and motor mount on the drivers side. Wasn't bad at all. Still had some popping after that at high rpms. Could rev it up to 2500 real easy, but after holding it there after a second and then flooring it in neutral, would pop some more and rev up slowly from there.



I also got the guages wired up to so I can see whats happening.



Decided to take it down the road finally. After a second gear start and floored it the boost went to 32# went to third and only went to 22#. Drove it through a few more hard shifts and the boost only went to 22#. The pyro never hit 1000*+ expect for the first time I took off and went to 32# it hit 1200* pre-turbo.



After 2400 rpms or so it would climb slowly, but would rev quick before then. Never could hit 80mph with it to the floor.



I hope someone can tell me where to check first. I hope I gave enough data for someone to help me with this scenerio. I don't have a fuel pressure guage, so I don't know where I was on fuel pressure during the test run.



Can someone give me a place to start checking?

I guess I need to check the fuel pressure?

Check the timing again to see if it slipped?

Check govenor springs again?

Anything else?



HELP,

JD





P. S. Also after the test run the truck idled at 450rpms and before the test run it wa at like 750rpms.

 

[onestackdram]

Well the first question I have is, did you pop test the inj. prior to installation? To check for pop pressures, and spray patterns? This can hurt you sometimes if not done. Secondly did you use the proper shims with the inj. ? You should have recieved a bag with atleast three different sized shims, one on the inj already and two in the bag itself.

Then check your throttle cable, idle adjustment. Then begin checking each individual injector, do this by loosening the lines (I prefer at the pump, to keep myself away from the heat of the exhaust, but thats just my preference) one at a time, as you cut fuel off to each inj. you should here a difference in the engine. What I am wondering is if you might have a few small proplems showing themselfes as one larger one. Those are just where I would start to check. Also not that this seems to be a contributing factor, but I always run the overhead after having done such mods to a truck, I had one that I didn't and at some point I threw the valve lash off (don't ask, I still haven't figured it out... LOL) but I since then run it everytime just to be sure.



Hope that puts you in the right direction.



Russell

 

[MDW]

Recheck your timing.

 

[JBlackwell]

onestackdram:



How do I pop test the injectors?



On the shims, I got the install kit and took the shims off that came with the injectors and put the thinnest shim on that came with the kit.



Yes, I opened the injector lines at the injectors when the truck was at idle. All of them made a miss when I cracked them open. The engine seems to run fine at idle. Just sounds like it isn't getting enough fuel when I floor it though.







MDW:



Yes, I guess I need to recheck my timing.

 

[mikel]

After you recheck your timing, find a way to check your fuel pressure. If it's not a timing issue then it might be a bad overflow valve or lift pump.

 

[Ben Rumson]

Originally posted by onestackdram

Well the first question I have is, did you pop test the inj. prior to installation? To check for pop pressures, and spray patterns? This can hurt you sometimes if not done. Secondly did you use the proper shims with the inj. ? You should have recieved a bag with atleast three different sized shims, one on the inj already and two in the bag itself.

Then check your throttle cable, idle adjustment. Then begin checking each individual injector, do this by loosening the lines (I prefer at the pump, to keep myself away from the heat of the exhaust, but thats just my preference) one at a time, as you cut fuel off to each inj. you should here a difference in the engine. What I am wondering is if you might have a few small proplems showing themselfes as one larger one. Those are just where I would start to check. Also not that this seems to be a contributing factor, but I always run the overhead after having done such mods to a truck, I had one that I didn't and at some point I threw the valve lash off (don't ask, I still haven't figured it out... LOL) but I since then run it everytime just to be sure.



Hope that puts you in the right direction.



Russell

I concur. You haven't touched your lift pump or overflow valve so I doubt they suddenly quit working - but it's possible. I would look at the injector shims and timing. It doesn't sound like anything major... just a few minor tweeks here and there and you should be able to iron it out.



Best -

- Ben

 

[JGheen]

Why would the injector shims cause a miss or pop? Forgive me for I did not know that injectors require shims for proper depth setting, but how would the depth of them affect the performance of the engine? I guess it just screws with the angle of the spray pattern and where it sprays, correct?

 

[DavidGardner]

I know this sounds simplistic, but have you changed the fuel filter and checked the throttle cable for stretch or wear? Have found two now that wouldnt rev up like they should. both had the old throttle cable ( before the recall) that were worn and badly stretched not allowing for full opening travel on the fuel pump and one had a badly clogged fuel filter. Just something to check for. Sometimes the simple things are what is wrong.



Good luck and let us all know what you find.



Dave Gardner.

 

[Scot]

The rev slow and then run sounds like possible governor lever misadjustment.



Go to Piers website, he has a good article on how to do it.

 

[JBlackwell]

Originally posted by David Gardner

I know this sounds simplistic, but have you changed the fuel filter and checked the throttle cable for stretch or wear?

Yep, throttle cable looks good and I already put a new filter on when I put the head back on. I am going to pull it back off though to see if there is any trash in it. The fuel tank may have trash in it.

 

[JGheen]

Originally posted by JGheen

Why would the injector shims cause a miss or pop? Forgive me for I did not know that injectors require shims for proper depth setting, but how would the depth of them affect the performance of the engine? I guess it just screws with the angle of the spray pattern and where it sprays, correct?

Anyone have any answers to my above questions about the injector shims, etc. ?

Thanks, Joe

 

[1dslram]

You need at least 181 DV's to feed the 370's, upgrade the DV's first. With your little pump you could use 191's but if it was me I would call Piers and talk to Harry or someone there.

Bruce

 

[Ben Rumson]

Originally posted by JGheen

Anyone have any answers to my above questions about the injector shims, etc. ?

Thanks, Joe



... I guess it just screws with the angle of the spray pattern and where it sprays, correct?

Sorry Joe, I've been away for a few days... 320 branded, casterated, injected, ear-cut, de-horned calves would have rather I stayed near the computer and away from their future plans...



You're correct about the angle of spray.



The thickness (in thousands of an inch) of the spacers/shims beneath the injectors can significantly affect the spray pattern, and can also affect the compression and timing - to a much lesser degree. A lot depends and the spray pattern and pressure point of any particular injector to PLUS your specific timing - in combination. This in turn can also affect the efficiency, heat buidl-up, and overall performance. IE JBlackwell may need a different spacer for his new injectors - given his current timing and delivery valve capability. A pressure test at the injectors will help indicate whether a thicker or thinner spacer will help. This is part of the "fine tuning" that can make your engine purr like a lion or sputter and cough like a cat choaking on a fur ball.



My understanding is that if you want to "heat things up" go thinner - momre responsive and hiher pressures. If you want a plush, easile tuned, day in/day out driver, go thicker.



... but the actual "poping" is probably a result of insufficient fuel at the higher end IE weak delivery valves and pump - If the timing is set ok. The lack of top-end power would also suggest insufficient fuel or weak dv's and pump.

 

[JBlackwell]

Originally posted by Ben Rumson



My understanding is that if you want to "heat things up" go thinner - momre responsive and hiher pressures. If you want a plush, easile tuned, day in/day out driver, go thicker.



... but the actual "poping" is probably a result of insufficient fuel at the higher end IE weak delivery valves and pump - If the timing is set ok. The lack of top-end power would also suggest insufficient fuel or weak dv's and pump.

I was thinking the same thing about not enough fuel.

Don't know if I said it or not but I have a . 010 shaved head with a . 020+ marine gasket. The 370's have the thin washer that I got in the install kit. I replaced the washers on the injectors with the thin ones. I think they were . 020 thick.



Also with 210K miles on this truck and I believe nothing has been touched on it, I ordered a new overflow valve and also a new lift pump. Even if thats not the problem, I plan on keeping it anyways and it is good insurance for me. The lift pump was only $92 and the overflow valve was only $24-25 or so.



I guess if that doesn't cure the problem I will either pull the pump and have it sent off and checked or put in a set of bigger DV's. Everything else on the truck that would be problem related I have changed.



JD

 

[JBlackwell]

double post

 

[JGheen]

Thanks Ben,



Sounds like quite a trial and error kind of thing that could take a lot of tuning. How many different size washers are available for the injectors? I would think there would be an infinate amount and finding the right ones can be a PITFA. How do you know when you have the right size washers installed? I see you mentioned pressure testing, but how is that performed and how do you read the results to determine what size is needed?



Thanks, Joe

 

[Ben Rumson]

Originally posted by JGheen

Thanks Ben,



Sounds like quite a trial and error kind of thing that could take a lot of tuning. How many different size washers are available for the injectors? I would think there would be an infinate amount and finding the right ones can be a PITFA. How do you know when you have the right size washers installed? I see you mentioned pressure testing, but how is that performed and how do you read the results to determine what size is needed?



Thanks, Joe

True. Many different thicknesses. Bosch would have a comprehensive list - or - check your local Diesel repair shop (for big rigs). They will know all sizes and what thickness to recommend for your particular fine tuning needs. You may end up buying a few different sizes and then trial and error each size to see how each performs with your particular set-up, internal pump settings, etc. IE PITFA is correct. The Diesel shop can get you started in the right direction and that will save some trial and error.



I've always had a shop (trusted mechanic) do my pressure testing and washer selection IE Dialing everything into perfect syncronicity. I'll do the basic stuff, but actual fine tuning can be again, as you appropriately remarked, a PITFA. That's why I choose to hand it over to a trained technician - with all the right equipment.



I'm not sure what pressure equipment is used or what size washers cause what result - but it does make a difference.



Joe Donnelly would be able to point you in the right direction.



Good luck.

- Ben

 

[Ben Rumson]

Originally posted by JBlackwell

... I guess if that doesn't cure the problem I will either pull the pump and have it sent off and checked or put in a set of bigger DV's. JD

Pull your pump as a LAST RESORT. This is major. Go with larger DV's and work your way up the ladder of severity slowly.



Also, having machined your head and aftermarket head gasket is an important note. This WILL affect (ie "dictate") what size washer is best.

 

[JBlackwell]

I GOT IT!!!!!!!!

It was the freakin overflow valve!!!

Boy, this truck just pours the smoke out the exhaust!!!



I pulled the AFC housing back off and checked to see if the lever arm was hitting the plate right. I thought that it might be hitting under it. It was just fine. I went ahead and slid the plate up about . 040 or so. I backed the Air/fuel screw almost all the way back. Put everything back together and put in a new $25 overflow valve. I was hoping that it would run better. MAN... . that thing rocks. It's building 37# boost. It's slipping my clutch in 4th & 5th. The EGT's climb nearly as fast as the tach does, I let off when I hit 1300*pre. Now I am going to slide the plate back a bit, til I get a clutch, Scotty II, HX40, and exhaust.





Later,

JD

 

[Jim Fulmer]

Remember, the truck will talk to you if you listen, I still learn this from time to time with mine and we are talking very good together now



Jim