Mopar1973Man

Like I had a conversation with ISX one evening about this... Like we all know that everything has a operation range to it... So like for example you take your laptop with you on a hot summer day and place it in the back seat. So now your truck is parked out in the sun baking away. The cab temperatures can rise to 140*F really easy on hot summers day. so even that laptop is baking in that heat. But now try and operate that laptop in that kind of heat at 100% CPU load I'm sure it would die in a short order. But just leave the laptop sitting there in the heat it will survive... But now looking at the VP44 yeah it might operate at 80-100*F of fuel temp while going down the road. But now turned off its getting heat soak sure so is the ECM hanging on the side of the block. But it not like you firing up the engine and going to 100% load from a dead stop. If your lift pump is doing its job and pumping high volume flow by the time you roll out of your yard and get to highway speed the VP44 is sheding a huge amount of heat in the fuel. So I think most of the P1688 failures are cause from low fuel pressure and poor return flow which in turn does a poor job of removing the heat soak on the VP44 electronics. As for the electronics they have been revised several times over the years to improve the performance of the electronics due to heat soak. Like my own VP44 its going just fine as long at the fuel pressure is kept up above 14 PSI I know the fuel is flowing past the electronics and cooling them.

I was allowing this thread to continue hoping JKidd would show up and explain/deal with this issue but out of respect for vendors and people I'm closing this thread... I hope you all understand...

No kidding... I think he's mastered how to work a wrench in on hand and hold the camera in the other... --- Update to the previous post... In you pics there I've never seen that can before??? Ok... So 1 line from the vane pump drives the vacuum brake booster. There should be another line that is smaller that passes through the firewall... Then somewhere there is a tee and a another line should head down for the CAD switch (transfer case). As for my numbers they have no bearing... (Sorry)

Like I got a thread on this... But the simple way to look at this is the fact there is only ONE inlet and 2 OUTLETS for fuel to travel. The INLET is from the lift pump to the injection pump... The 2 OUTLETS... 1. The first outlet is the injectors.2. The second outlet is the overflow valve which only open at 14 PSI of pressure. When the pressure falls below 14 PSI the valve starts to shut till its completely closed by 10 PSI. So now as long as you giving throttle there is fuel flow to the injectors. But if you coast the pump bypasses the injectors and suppose to route it towards the overflow valve. But of the pressure is to low in the pump (internal vane pump wore out) then the overflow valve will not open enough to keep the electronic cool. So like on my truck I maintain a MIN pressure of 15 at WOT and 17 PSI at a idle and I know I'm flowing plenty of fuel through the VP44 during my cool down.

Doing brakes don't require any special tools to do. Just standard sockets and wrenches. As for bleeding you can do that yourself too. http://mopar.mopar1973man.com/cummins/general/brakes/brakes.htm The 2 wire plug into the ABS module under the edge... You'll have to feel for the socket under the edge of the module. As for the vacuum line I would replace the section with a proper size piece of rubber vacuum hose which should withstand the acid a bit better than the plastic tubing. As for that vacuum line at the firewall... 1. First goes to the vacuum res. under the cowling. 2. Second line takes off and heads into the cab for the HVAC controls. 3. Might be one that leaves this point for the CAD system.

Thanks for the tip on the vacuum test... As for the oil... I learn my leason long ago about buying freon with a oil charge over time it will flood the system with oil and like you said decrease the performance. So very true... To empty the system of oil might be a bigger PITA that most think...

So far the second ride out and about 4 days after the repair and still holding good cold A/C. So now I change all O-ring except 1 at the condenser and the 2 on the back of the compressor. The evaporator is new this spring. So I think I got it all covered for now...

Hmmm... Wow! I better go voer and do some reading... Well I'm fresh out of other web sites. Let me ask around locally and find out...

Can you possibly get a phot of this separation spot your talking about... Oh yeah get the wife to do it...

Interresting video there... It explains how the the AC compressor functions for the most part...

Well I stopped in the local NAPA sotre and order a set of O-rings for $10 and proceeded to replace all the o-rings in the system. Be aware there is 1 O-ring missing in the kit for the condenser up front so remember to pul it and take it with you for size. Re-assembled everything and place a vacuum on it and it held for at least 20-30 minutes while I did other things like straightening all the condenser fins. So since it held a good vacuum I figure its time to toss my last 3 cans of freon at it and hope for the best.

Well get it fixed now before it get worse... Like my motorhome its a wonderful rig but the coach needs new skin... :banghead:

Well now your down to just a injection pump error codes... So replace the Vp44 and lift pump and you should be heading in the right direction now...

Here you go so you don't have to dig everywhere... http://www.tstproducts.com/j-hookassembly.aspx

Hmmm... I've got another site that is right up your alley... http://letsplow.com/index.php The owner of the site is a member here of the name SnoFarmer... He's really knowledgeable about plows and such...

Another tidbit I forget the last post is the 0-14 PSIa is a vacuum so like using a SGII on Mom's 96 Gasser will read about 1.1 PSIa to 14 PSIa at WOT.

Interesting...

Is the vent control for the recirulation vacuum driven or cable? If its cable driven you should be fine doing that to keep the 4 legged suckers out. But vacuum driven the system will lose vacuum and the door might sag open again...

Cool. I'm still very greeen to the PHP programming and learning as we speak... I've been reading "PHP & MySQL for Dummies" to bone up. It simular to older BASIC programming back in the day... But then add the MySQL server tosses a monkey wrench in things... So I've been playing with smaller programs to get boned up and then start playing with the idea of a maintenance database of the members...

Yeap that right its PSIa is the measurement... So do all your reading with a 14 PSI offset.

Hmmm... It got the dye pack in it... It looks like the freon lines were leaking for sure. The seal kit is $10.29 at NAPA it supplies the full kit of o-rings and seals for the freon lines... But the housing leaking... I don't think you can get that seal can you?

At least it was a easy fix...

Any programmer or any box that plugs in to the MAP sensor line...

Yeap you need a boost fooler of some sort so the ECM doesn't see the boost rise above 20 PSI. Other than that the P0234 code is triped and the engine defuels heavily to get it way down below 20 PSI... Because at this point the ECM assumes the wastegate is rusted shut.

That's not to bad for a tire of that size... I paid $1300 for my Cooper STT's 2 years ago...