diesel return line and idle speed

[gropar]

After aving (lots of) problems with my 1.6td diesel filter, I switched to the old 1.6 NA filter (fuel return straight to the tank).

I had a problem with the return valve located on top of filter and decided it would not happen again.

Now, when it is cold outside, idle speed goes up about 200rpms until the whole thank warmed up (might take 30 minutes to 1 our depending on temperature).

Is it normal? (i would say so)

Could it cause any damage? (I do not think so but want to make shure)

[QuickTD]

I would say this is pretty normal. Every diesel I've ever had has behaved this way to some extent. The fuel density changes with temperature, this causes the idle speed changes that you're seeing.

I hated that stupid, leaking recirculation valve too, so I removed it and replaced it with a custom cummins filter setup. Mine now behaves the same way as yours. I don't think anything bad will come of it. You might have problems with the filter plugging in the extreme cold, I've never had it happen though...

[andy2]

I too am also using the old style no return filter on my 1.6td, its an easy fix to get the plastic leaker out of there.I would recomend the switch to anyone who has any issues with the plastic return valve/fitting. I,ve used this filter deal for a little over a year now without any problems.

[gropar]

worst is : I just replaced it with the filter "to make shure would be no problem".

I had all the problems (in fact, only one...) imaginable : since there was a huge vacuum in the filter (enough to stop the engine), I would have tough that something was cloged between the pump and the thank.

So I changed the filter. Again.
Few days latter : same problem. So I figured the thank was full of crap (bad, very bad fuel or childish prank). Changed the thank, cleaned the hoses.

Again : big vacuum. This day, on vacation, 700km from home.

Went to Canadian Tire (only one open on sunday, drove by CAA), asked to change the lines -- the only thing still original.

Did it again two days later.

Then I tought : each time the weather was cool (morning), and the fix came around mid-day. Only thing different : the damn valve.

So I came home (from Prince-Edward-Island to Montréal) with an land-mower inline  filter I got from the guy cutting the grass at the camping!


I still did not figure out how a clogged return could cause a vacuum in tje filer, though...


(By the way : the generic injection line I got gave me A LOT MORE fuel. Because it is a little bigger and has curves instead od corners. I had lots more smoke coming out of the exhaust with it. Eazy, inexpensive upgrade).

Quick TD : no problem with cold -> works fine by -25°C

[jtanguay]

vaccuum in the fuel tank?  I had that happen when I owned an audi 5k.  On a hot day I would have to open the gas cap and hear a nice big woosh of air get sucked in  (i just lived with it... annoying as heck tho)  I still didn't figure out what was wrong... car is long gone.

your vaccuum problem seems similar I think.

[gropar]

not vacuum in the fuel THANK but in the fuel FILTER (bubbles all along the clear lines between filter and pump and lots of succion when removing the return valve from filter).