Hey guys,

I just finished a bunch of work on my truck and dealing with some issues I’m not sure are related or not. For background I Pulled engine and trans, resealed engine, new poly motor mounts, new RV275 injectors, new VP and alternator, rebuilt the 47re w Goerend VB and rebuilt transfer case, head studs, resealed AC, rebuilt turbo, new fuel lines, intake and exhaust gaskets, basically went through the whole powertrain.  
 

What’s happening now is I’m not getting a tach signal and the truck sounds like it’s missing at idle and there’s a sharp hiss/tick in the exhaust like a misfire. I’m wondering where the sensor is for the tach signal because I’ve checked all around the motor and can’t find anything not plugged in. I assume it’s the sensor in the back of the timing case between the VP and the block but I’m not positive. I am positive the VP key way is in correctly. Would not having a tach signal cause issues with injector timing or does it sound like I have a mechanical issue inside the head causing this? If the sensor for the tech is correctly plugged in is there a way to test if it’s the sensor itself or an issue in the wiring? 
 

Any advice appreciated as always.

My tach recently stopped working but after about 5 min or so it started back working again. I was told the cam sensor, so Im pulling that tomorrow. There's an injector install article in here Ive read several times that has helped me just by reading and going over what Ive done it might be helpful for you. 

On my 99 it was the Crankshaft Position sensor that went out that caused a no tach issue.  It is located behind the starter.  Its a simple job.  I had it go bad twice so far.  The first time I replaced it with a cheap Autozone part, the second time (about a year later) I got a NAPA part and no issues since.

I also have a 99.  I had the pleasant experience of having a piece of the crank tone ring come off.  It’s a two piece deal and the screws broke.  When I pulled my crank sensor, the end was broken off.  After replacing the crank sensor with a new one, my tach still didn’t work.  An inspection camera in the hole revealed one of the pieces was missing.  The hardest part of the job was getting the oil pan out.  I had to order the tone ring from Cummins.

After doing a oil pan gasket I know exactly how to remove a oil pan the easy way. You need a cherry picker and let the axle hang fully extended. It will nearly fall out. Yeah I've had crank sensors break off at the o-ring. I've drove a drywall screw in and attempted to pull it out nope... Then I continued to break off bits and piece till it came out. 

1 hour ago, Mopar1973Man said:

After doing a oil pan gasket I know exactly how to remove a oil pan the easy way. You need a cherry picker and let the axle hang fully extended. It will nearly fall out. Yeah I've had crank sensors break off at the o-ring. I've drove a drywall screw in and attempted to pull it out nope... Then I continued to break off bits and piece till it came out. 

I’m not seeing why I would need to pull the pan, a broken tone ring seems very unlikely especially since the tach worked perfect before the engine was pulled. Any ideas on testing the sensor? 

If memory serves right, it’s 5 volts supply.  Backprobe the connector for the crank sensor for the signal and ground wire.  Spin the crank by hand and watch the voltage.  It should read 5 volts or 0 volts, showing the peaks and valleys in the tone ring. 
 

 

OK, good news today. I cleaned out the sensor and plug with brake cleaner after seeing some diesel near it and I got my tach back. Bad news is the truck still doesn’t idle right. The injectors I put in are RV275s. No diesel in the oil, no blow by, tuner makes no difference plugged in or not. I’ve been reading these RVs aren’t pop tested and balanced from factory so I’m thinking they are what’s causing the uneven lope at idle. Anyone else heard about this issue with RV275s? I wish I had the stock sticks to put back in and see if they solve it but I don’t. 
 

On a sad note, have to say I’m kind of disappointed with this Goerend valvebody. For the price point far above anyone else and the assurances I got from talking with them I really expected more. Shifts don’t feel much firmer than stock, it shifts late and I triple checked the TV adjustment per their instruction. Going to have to give them a call about that this week…

On 1/12/2023 at 10:44 PM, Reaper22 said:

For background I Pulled engine and trans, resealed engine, new poly motor mounts, new RV275 injectors, new VP

 

On 1/12/2023 at 10:44 PM, Reaper22 said:

head studs, resealed AC, rebuilt turbo, new fuel lines, intake and exhaust gaskets,

 

Did you perform all of this work in one time frame?  In other words, did you pull the engine, do all of the work, and never run the engine until the work was completed?  If so, that leaves a lot of possibilities as where the problem lies.  If you performed the work differently, break it down into events and let us know how you proceeded.

 

On 1/12/2023 at 10:44 PM, Reaper22 said:

and there’s a sharp hiss/tick in the exhaust like a misfire

 

Is this symptom still present?

 

If you purchased Bosch RV275 injectors (ending in part number  635, not knock-offs),  I really doubt the injectors are the problem.  By the way, I installed RV275 injectors in my engine over 65,000 miles ago.  They idle very smooth. 

 

@hdpwipmonkey and @weissguy01, when your crank position sensor failed (no tach signal), did it affect the engine idle?  If it did, were the symptoms the same as @Reaper22's?

 

- John

 

 

 

 

@Tractorman The VP had been in the truck for about a month before I pulled the engine and it was running great, no uneven idle. Same with the turbo rebuild. I did the injectors, gaskets and seals, trans work, motor mounts, new fuel lines, and new batteries at the same time. The only thing I’m seeing there that could cause this is the injectors.Also, I have tach signal again. No change. 

44 minutes ago, Tractorman said:

 

 

 

@hdpwipmonkey and @weissguy01, when your crank position sensor failed (no tach signal), did it affect the engine idle?  If it did, were the symptoms the same as @Reaper22's?

 

- John

 

 

 

 

The first time it went out there was no difference in the way it ran, in fact I drove it like that for about a week till I could change it out.  The second time it did have a bad miss.  Not sure why it was different.    

@Tractorman, it was a little uneven, but I could still drive it.  I also went a week or two like that, waiting on time to do the repair.

I'm guessing you checked for fuel/air leaks at the fuel lines and at the intake boots after the injector install?  Simple things like that can mess with how it runs.