Jump to content

Recommended Posts

Timing sensor, or pump advance.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

Link to post
Share on other sites

Timing sensor on the side of the pump and the drivers side of the engine, the rack may be stuck in the pump or the advance diaphram may have gone bad in the back section of the pump. Ask STAXX for specifics he knows those engines well I only had two.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

Link to post
Share on other sites

The rpm/tdc sensor is most common problem location is drivers side flywheel housing close to the starter . adjustment in all the way in bottom out and back out one turn .Resistance check pin a to pin b of sensor 200-300 ohms . Sometimes these sensors get debris on end of sensor causing intermitant issues can remove and clean end off and recheck also if crankshaft end play is excessive the gap between sensor and flywheel will be too much so may need to look into that if rpm/tdc sensor is the issue.

  • Like 1
Link to post
Share on other sites
The rpm/tdc sensor is most common problem location is drivers side flywheel housing close to the starter . adjustment in all the way in bottom out and back out one turn .Resistance check pin a to pin b of sensor 200-300 ohms . Sometimes these sensors get debris on end of sensor causing intermitant issues can remove and clean end off and recheck also if crankshaft end play is excessive the gap between sensor and flywheel will be too much so may need to look into that if rpm/tdc sensor is the issue.

You may know what i am trying to ask and may not have any thing to do with this problem. My son changed a engine out yesterday and today. It was 95 VMAC and he pulled a cap plug off of a adjusting screw on the side of the pump mis ways back on pump and i would say against the rack. He screwed on it not thinking and when he started it it was jacking off at idle. It was ok in the other truck so i pull the cap and adjust the loping out of it. I would say not knowing that its a rack tension spring, right? any way its good to go now.

glenn akers

Link to post
Share on other sites

Funny thing went down to start the truck and see if i fixed the problem and it wouldn't start I have fuel to the pump just not coming outta the injection lines. Could this be the plug that goes into the pump or computer issue if I check it with a test light g is the only one with power and it's not constant it's on off on off I'm thinking this could be the reason I have a miss at high rpm?

Link to post
Share on other sites
If you run the rack buffing screw in too far you might have bent the rack also.
Yes i think so but he only back the nut off and the jam nut back out some and that when he said dad come her.He has been away from mack for about 10 years and i done think like i should any more when i told him to pull the timing sensor so we could install the A B light.Yes i am glad he did nt go in with it and i said we will stat it first with a choke plate and then try to adjust.I guess my prolink cartage for VMAC 2 is bad cause all it would say is in the programing mode and would not go no futher than that.

glenn akers

Link to post
Share on other sites

Buff srew adjustment turn adjusting screw in until it contacts rack note the amount of rotation use a small lite screwdriver for this, back the adjusting srew out until it contacts the other side of the rack note how many rotations then turn srew halfway back into housing to center it by turning it back in exactly one half of the total distance from fully in to fully out. the tighten jam nut . Be carefull the rack is thin and easy to bend when it makes contact its a very lite touch .....to much in it bends rack to much out bends rack .

Link to post
Share on other sites
  • 7 years later...
47 minutes ago, kaybee710 said:

my 1994 Mack e7 blows white smoke, misses and runs rough when the rpm gauge stops working but it runs fine when the rpm gauge come on.   Any body know where to start look for this problem.

You have a code coming up? Probably the engine RPM/TDC sensor involved so a 3-2 code or 3-1. 200-300 ohms is the range for that sensor. Remove it from the flywheel, check it over, ohm it, clean the tip of clutch metal, run it in and back it out one turn and jam the nut lightly to about 15ftlbs.

  • Like 1
Link to post
Share on other sites
On 1/25/2013 at 4:51 PM, dusty0791 said:

The truck is a 1996 e7 427 at about 1600 rpm the truck will start to surge like its not getting fuel or the timing is off. New filters new lift pump any suggestions??

If that doesn't work It's probably one of the wires on the deutsch plug (9 pin connector going into the gov housing) J1939, possibly timing event marker. Check for continuity in all the wires. I know it's tedious but that will give you piece of mind it's not that. That's another issue. How does it start? If it's starting like normal, evens out after the oil psi picks up you can probably rule out the econovance going bad. 

 

When it stumbles/studders does it throw out white smoke or smell raw unburnt fuel?

 

I'm betting its deutsch plug we had same issue before. I could very well be wrong but we had the surge your talking about.

 

You could get long hose to go into the cab and tee of a fuel gauge and see it's getting right psi. Don't remember what it's supposed to be. 

 

 

  • Like 1
Link to post
Share on other sites

part show up today and i replaced the RPM/TDC sensor  the truck started right up no smoke no miss run like brand new engine. thank you very much!! I've been  dealing with problem about a year of a on.

Link to post
Share on other sites
  • 8 months later...

1995 CH613 Mack. Throwing code intermittently when pulling hills of three five which is #1 engine brake. I disconnnected both wires to engine brake #1 and #2. Still throws the code. Now looking at engine speed sensor adjustment because this all began after I replaced my clutch, flywheel and tranny.

Link to post
Share on other sites

First Check your crank end play ! if it's OK Say between 7/11 Thou  ( Rough guidline ) then  Tri running the Fly wheel sensor a little closer Back a 1/3 turn instead of 1/2 turn see if it improves you situation!

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...