I have a 2005 5.9L cummins. I had a friend help me install an Autometer 5744 Pyrometer gauge. I know from prior readings on this forum that the probe should be tapped in and installed near the back of the exhaust manifold. I specifically pointed this out and he instead ended up following autometers instructions instead and put the probe post turbo in to the front pipe. I'm pretty ticked, but is this that big a deal? Will it simply result in slightly less accurate readings? Thanks for any input.

 

If you search you will find some huge debates on this. I can remeber reading a thread where a guy was going off how cummins themselves recomentds post turbo. I personally opted pre turbo. I just want to know the temps closer to the piston are safe. bottom line.

short story long if you pyro sensor failes it will damage your turbo I think this is rare though. there is also some argument that the presure in the manifold could actaully elevate temps a bit I did not care hear either because safty was my main concern. even if temps are elvated pre turbo this just mean even more safty margin in my case. to me the main reason you would go post turbo would be if you were afraid of your sensor failing and damaging your turbo.

I was thinking rule of thumb was like 200 degree difference but could be off double check that. so if 1400 was your limit pre turbo 1200 would be your limit post turbo. I think there are people on hear tha thave pre and post. I am sure they could tell you how accutrate post turbo is in relation to pre turbo. I just went pre turbo and will look at my pyro sensor ever 25k or so.

it is so easy to mount you could always just plug the hole and mount it pre turbo if you want. all you need is a pipe tap, a drill, and something to plug the hole post turbo.

 

I've got mine post turbo. I try not to let it go past 1100. I figured that it would equal about 1300 pre turbo. Pull a 16' tandem on I-65 w/ cruise on 72 or 73 it almost never goes pas 900. Even when chip is engaged.

 

to get a exact reading Pre turbo is the way to go. If you call any diesel experts they will tell you pre turbo. To me tho it doesnt matter where pre turbo, some folks say #1 cylinder runs hotter some say #6. but in my opinion watching your EGT's is for seeing what exhaust temp is entering your turbo, to make sure you dont cook your turbo or crack your manafold. Everyone has their own opinion, but i would do a search and see what you want.

 

You can plug that hole with a pipe plug and drill a new one in the exhaust manifold.

 

That may have been me! Anyway, go to Jacobs site and see what they recommend. They say to go post turbo mainly due to the fact that if your pyro probe breaks it'll munch the turbo.

 

For installing a pyro pre-turbo, do you have to take off the exhaust manifold?

 

well to me this kind of re-enforces that 200 degree rule of thumb as I have a hard time ever getting mine over 1100 even with my juice.

again though I can see both sides of this argument though. trubo's are expensive but so are engines. a person more **** about engine repair is proalby going to opt pre turbo. a person who is paranoid about turbo failer is going to go post turbo most likely.

I have a feeling in most circumstances both are going to work fine as long as you know what the max temp on the gauge should be.

 

no. I installed mine with it on. I was careful about the shavings though. you run it before the probe gets placed as well. I was a bit paranoid though. I greased the tap good and vaccumed it out when finished. then I had someone hold over the exhaust pipe to raise backpresure as well when I started it before the pyro was installed. don't know how nessesary it all was but it was piece of mine for me.

 

I'd be ticked also I run pre turbo inbetween the two casting labels 123 cylinders. I could not get to the 456 part of the manifold.

Plug the hole and do it correctly as already advised.

Rick

 

if you dont' have a 90 drill and you actually want to get close to the turbo inlet just drill in at an angle. I had this issue as I did the install at the in-laws and they have limited tools. I shot in at about a 30 degree angle so the cowl would not interfear with the drill. worked like a charm. I did hve to start drilling with a smaller bit than the 5/16. once you have a hole started then just switch to the larger bit.

you could also go right into the inlet ifyou come thrugh the fender well but then any shaving would drop right inot the turbo so I did not do that. I have seen picks of probes mounted there though.

I don't really know how much of a difference it makes I just know that they tell you to take the egt at the turbo inlet and if you go in farther up the manifold you are not really there.

 

I just stuck mine on the top of the manifold, since that was what the directions called for, and also it was easy to get to. (Photo in my gallery).

Since it is over a horizontal area of exhaust manifold, reaching in with a magnet is a good way to get any chips that escape the grease on the drill/tap.

I'm a bit leary of the plug the exhaust or turn on the jake and drill while the engine is running method.

Idling with the jake on (or exhaust plugged) can produce some soot in the intake manifold from exhaust washing back during valve overlap.

Though it seems unlikely, I sure wouldn't want a metal chip to also be washed back into the engine. If you got some metal flakes into the piston/rings it would leave you wishing you only ruined the turbo...

Lots of people have used that method with no problems, but with my luck...

 

This is the best way to tap your manafold. I found this out doing a search just before i drilled and taped mine.

Start drilling the manafold with a 90 deg drill. at first you go real slow becasue your scared and paranoid. But your manafold is 1/2" thick. Once you are a good ways down turn your truck on and let it idle. Then finish drilling the manafold with your truck at idle. This will cause all the shavings to blow out of the drill hole just as you break the manafold. Finish drilling out the manafold and then start tapping. To start tapping dont use your NPT at first, Its a pain in the *** to get it to bite. Use a regular tap of the same size (of the small end of your NPT) to just get the threads to bite. Once the threads bite and you go down about 2 turns start using your NPT and finish the job. When you are using the NPT !!DO NOT!! go all the way down with the tap, leave about 3-4 threads exposed. Remember to do this all with the engine at idle, this will keep all your shavings out of the exhaust manafold. also it will get very hot so use some gloves. And there you go, you have a tapped manafold!!!

 

mine is installed pre-turbo and when installed, my truck was started to blow any shavings out of the hole. My dealer did all the work and i think they did a very good job.

 

I think you wil find there are many different methods used with no problems. I would be interesting to hear from someone who actually garbaged a turbo if they have to see how not to do it.

I can see from this thread there is no one way. as the pic right above this post was a way that I was paranoid to try and it seemed to work. I know I did mine without the truck running the whole time and it is fine.

I am begining to think as long as you are aware shavings are bad and take care not to dump a crapload in the manifold/turbo you are porbably fine.