I plan to install a pyrometer, fuel pressure and boost gauge in my stock 1999 5.9 24V cummins turbo truck. Question #1 I plan to install the pyrometer probe post turbo. I know the temps will be different than at the exhaust manfold, so can anyone tell me what are the working exhaust redline temps to look out for ??? Also what is the post turbo safe cool down / shut down temp. ??? Should I order the gauge with the 1/8 or 1/4 inch probe for post turbo install ??? Question #2 I have been told that the boost gauge can be installed in the intake manifold by removal of a 3/4 plug and installation of a 3/4 to 1/8 adapter for the boost gauge. Is this adapter the only thing to buy to install the boost gauge ??? Question #3 I think that I'd like to go with an electrical fuel pressure gauge rather than mechanical. Are they reliable ??? Where is the best location for the fuel pressure tap/ sending unit ??? Top of fuel filter ??? Do I have to drill and tap anything, or can I use some existing plug ??? Also what are the differences in installing a mechanical VS electric fuel pressure gauge ???

 

[quote author=jay_naz link=board=7;threadid=9844;start=0#94033 date=1043051505]<br>I plan to install a pyrometer, fuel pressure and boost gauge in my stock 1999 5.9 24V cummins turbo truck. Question #1 I plan to install the pyrometer probe post turbo. I know the temps will be different than at the exhaust manfold, so can anyone tell me what are the working exhaust redline temps to look out for ??? Also what is the post turbo safe cool down / shut down temp. ??? Should I order the gauge with the 1/8 or 1/4 inch probe for post turbo install ??? Question #2 I have been told that the boost gauge can be installed in the intake manifold by removal of a 3/4 plug and installation of a 3/4 to 1/8 adapter for the boost gauge. Is this adapter the only thing to buy to install the boost gauge ??? Question #3 I think that I'd like to go with an electrical fuel pressure gauge rather than mechanical. Are they reliable ??? Where is the best location for the fuel pressure tap/ sending unit ??? Top of fuel filter ??? Do I have to drill and tap anything, or can I use some existing plug ??? Also what are the differences in installing a mechanical VS electric fuel pressure gauge ???<br>[/quote]<br><br>I'll try and answer what I can...<br><br>1. I believe for a post-turbo install, 900-1000 is the max temp you want to see. <br>2. I believe it's 300* <br>3. Not sure.<br>4. Not sure, but I would like to know as well <br>5. I've heard both ways, some guys like mechanical and some like electric. I've heard of some guys having trouble with both..so I say go with what you think fits you best and see if you like it. I feel that mechanical is more accurate and reliable. Not to say electrical is bad, JMO.<br>6. On the 99 fuel filter housing, there are two plugs for fuel pressure readings. If you order a kit from Geno's I believe they include the fittings that replace these fittings that your sensor/hose will tap into. The BMD guys included them when I ordered my Briar Hopper FP test kit. Simply remove the bolts and replace with the fittings. No fuss <br>7. Again, i'm not sure. With a mechanical kit you'll need to run a hose into your cab as opposed to smaller wires for the electric. You'll probably want an isolator to avoid having the diesel actually in the cab, whereas the electrical units don't need these. <br><br>I'm no expert so anybody feel free to correct me if i'm wrong. Hope this helps.

 

Today I ordered Westach gauges: combo pyrometer / boost and 0-30 electrical fuel gauge. Genos Garage had these at a decent price. I was planning to install the pyrometer post turbo, but I have been hearing that the manifold install is the way to go. Any thoughts on this?

 

I know this is an issue of great debate but a post turbo pyrometer for purposes of installation ease for a close to stock truck is more than adequate. All the semi tractor engines run them post turbo to prevent exhaust manifold cracking problems and yes I have heard the pitch for the Cummins B manifold being able to accomadate it without problems. If it is placed post turbo you will find slightly lower numbers and slower reacting times for the temps. The probe is usually a 1/4&quot; in diameter and is placed 3-6&quot; downstream of the turbo unless you happen to have certain E brakes that already have the nipple in them with a plug. The temps should not exceed 1000-1050F if you can get it that high and 300F is about the warmest before shutdown. I don't have a problem with pre-turbo if during drilling and tapping they can guarrantee NO filings go down which then heads directly through turbo- post turbo installations offer filings only to your muffler and tailpipe. If not racing or engaged in extreme bombing post turbo will work fine just like the big rigs. PK

 

Thanks for the info. I plan to install it post-turbo. The cast iron L-pipe just after the turbo looks like the place. How do I remove it to drill and tap? Sounds like the exhaust sytem basically has to be cut off to be removed. Or does this fitting come off easier?

 

As gauges in my truck and another are soon to be installed, I have been doing some research on this. <br><br>1. As I plan to add power very soon, I will be installing pre-turbo. Small risk of manifold trouble, and/or having the probe fail, and take the turbo with it. Weighed against the fact that I'm ETH, and will be able to exceed egt spec., I feel that the risks are small by comparison to installing post. I plan to install another probe post after the final turbo is in place, and switch for operating and cooldown readings.<br>Told by Cummins that they would like to see no more than 900 post. It is their belief that 900 is equal to approx 1200 reading pre. Shutdown - post 300, or less.<br><br>2. That's how I understand it.<br><br>3. As stated, there are two plugs on top of your canister. One measures pre-filter, and the other post-filter. With an electric gauge you can use two senders and switch them to measure drop across filter. Or you could change your filter every 10k and not worry. <br>The mechanical gauge is accurate and reliable until it gets cold. At that time, the diaphragm can stiffen, and refuse to move, thereby indicating low or no pressure. If you decide to use mechanical, use the isolator, and do not plumb fuel into the cab! <br>I believe that, over the years, the reliability and accuracy of electrical gauges has increased. The electric f/p gauges tend to be slightly more expensive than their mech. counterparts, but they are also a bit more flexible. <br><br>If I've got something turned around here, feel free to correct me, as this is my current understanding of the gauge issue, and will be my basis for my own purchase/install.

 

Thanks for the info Big K. Do you know which tap is pre and which one is post fuel-filter?

 

Standing on the driver side looking at the filter housing, the plug on the left is post filter and the right is pre. You can get the fittings that replace those plugs with your gauges.

 

That's correct. Another way to look at it is that the pre port is furthest from center.

 

Okay, my gauges arrived UPS today. Looks like I know what I'll be doing this weekend. One last question. Does anyone know of a place to tie-in the hot lead for the gauge lights, so they only come on when I turn on my lights? Instructions from Geno's Garage says it's easier to just direct wire them so the light is always on, but I don't care for this idea. I have the fuse tap with pigtail for the mini-fuses. I would really like to tie-in the power this way, rather than cut and splice wires. I plan to tap the basic gauge power at the instrument panel or ignition fuses, but is there any fuse I can tie into that only has power when the dash lights are turned on?

 

I'm sure there is a fuse you can tap into, however I can't tell you which one. I did use a fuse tap on mine for power to the gauges, but I found it easier to tap the gauge lights power off of the wires going to the ashtray light. I figured, this way they are still fused and they also dim with your dashlights dimmer.<br>Just my $.02

 

Thanks Rattlinram, That's a great idea. I'm sure that wire is easy to locate.

 

The wire is easy to locate and it worked out good for me because I installed my Westach F/P gauge in the dash where the cubby hole used to be. ;D <br> Sorry,,, I forgot to look and see which fuse number I used the Fuse-Tap on for the gauges main power.

 

Well, I've installed and tested my fuel pressure gauge and boost portion of my boost/EGT gauge. Don't have the lights connected yet. I'm not sure that I have an ashtray light on my 99. I don't see any light. Where should it be? Also here are my Fuel pressure readings: idle 11-12 psi, cruising 8-9 psi, WOT 6-7 psi. What are the thoughts? OK or lift pump getting weak. I have 87K on my stock truck.

 

Just remember when using an electric gauge which employ stepper motors, You want to ensure you wire them with ignition power only. They need some reset time after shutoff. If they are wired to direct power you will get inaccurate readings over time.