1.6 TD idles poorly with AC

[Brianshayne]

My idle is super rough with AC engaged.

Bit of a backgrounder: AC was blowing warm yesterday morning. 55psi on the low side.

Dropped it down to 40, ice cold - but idle feels steps away from stalling... Stumbles, shaky etc.


Is there idle air on a diesel? Still waiting on my Bentley so was hoping for some insight as to some other diagnosis ideas. It's not over pressure AFAIK, I need a new belt - that is clear.

Any ideas?

Also. HUGE power loss... Like, can't get up a hill in second that's usually not a problem. Normal?

[CRSMP5]

  now think what na is like.... common... low power.. rough idle as no kick up for its load when on..

[Brianshayne]

now think what na is like.... common... low power.. rough idle as no kick up for its load when on..

So best solution: Turn up idle? Or just not use AC at idle

[bajacalal]

There's no provision for automatically controlling the idle on these, it's "static," and they barely make enough horsepower at idle to run the a/c. And, there's no control over air at all, it's all done by controlling fuel.

Also, as these injection pumps wear, the idle speed decreases.

Assuming there is nothing wrong with the a/c system and it is not overcharged, the idle speed may be too low and may need the necessary adjustment on the pump made. If your car vibrates a lot even with the a/c off, the idle is probably too low. It's pretty easy but you should adjust it very slowly, and keep track of what setting it was on, as it's very sensitive, go too far and it won't return to idle.

[CRSMP5]

well knowing what year it is.. some later 1.6 kick up idle when advance pulled.. that is a way... old audi 5000 has a rotating knob hooked to a cable to turn up the idle via drivers seat if it vibrated too much with ac on... it was a cable to throttle lever trick..

[Brianshayne]

There's no provision for automatically controlling the idle on these, it's "static," and they barely make enough horsepower at idle to run the a/c. And, there's no control over air at all, it's all done by controlling fuel.

Also, as these injection pumps wear, the idle speed decreases.

Assuming there is nothing wrong with the a/c system and it is not overcharged, the idle speed may be too low and may need the necessary adjustment on the pump made. If your car vibrates a lot even with the a/c off, the idle is probably too low. It's pretty easy but you should adjust it very slowly, and keep track of what setting it was on, as it's very sensitive, go too far and it won't return to idle.

My idle is fairly good without AC.... Lowers but no shaking if I full-lock with powersteering at idle. AC on, however, shake/almost stall. I'm pretty new to this -- still figuring out the screws on the pump even - don't wanna screw up/do anything till I can get my Bentley, cross reference and then cross here as well.

Power with AC on is non-existent. I'm sensing that it's STILL a bit overcharged and compressor may need some oil -- will test asap. Have to replace that belt as well, which I'm sure doesn't help one bit.

[Brianshayne]

well knowing what year it is.. some later 1.6 kick up idle when advance pulled.. that is a way... old audi 5000 has a rotating knob hooked to a cable to turn up the idle via drivers seat if it vibrated too much with ac on... it was a cable to throttle lever trick..

That's been my work around so far... Downshift, clutch in etc then cold start advance pull out, idle goes up, no shaking.

[damac]

Never had to deal with this yet, but curious for future reference.  Has anybody ever bumped up the static idle 100 rpm at a time to see how much of a hit we are talking before it maintains without rattling?  Maybe a small price to pay just for the summer

[8v-of-fury]

I like to idle them low. A small pressure on the go-go pedal is enough to remove the vibes.

I wouldn't think you'd need more than 100..

[ORCoaster]

By "HIT"  you mean in fuel economy? 

If it doesn't idle right chances are you are "revvving it" to get it going anyway and I would venture to guess that consumes more fuel than to elevate the RPMs all the time to a proper level.  Why run slow?  None of the parts work well with that kind of set up.  Water pump is slow, AC is not doing its job, oil pressure is suffering and the engine is probably hotter than it would be otherwise. 

Hand that man a 10mm wrench and a screw driver please.  He has just a tweak of work to do with it. 

2 cents less change

[bajacalal]

I like to idle them low. A small pressure on the go-go pedal is enough to remove the vibes.

I wouldn't think you'd need more than 100..

Why? Engines are happier at higher rpms than the idle speed they are usually set at. Alternator works better, water pump works more efficiently, oil pressure is higher... all good things. I firmly believe the reason a lot of manufacturers don't set the idle speed higher than what it is, was because of the EPA (or corresponding regulatory agency) and not for reasons of engine longevity. A lot of police cars came with an idle speed bump to produce enough power for all the electronics.

[8v-of-fury]

I agree that most engines are probably happier at higher RPM's, but at idle I want an IDLE not a screaming clackity clack clack. lol

I feel there is no issue idling these down under 900rpms. I have oil pressure, no issues with running hotter, and the alternator is still putting out its 13.75V.

How often does your car idle? Mine doesn't for long. My idle is still up enough to have 20psi hot oil at the head, and enough engine power to run the alternator with everything powered on. Is my idle really too low?

FWIW, these diesels couldn't give two sihts what RPM they are running, so long as it is a static one. They seem to like one set RPM very well, and the best economy comes from it too. If you still have ANY oil psi at the head then you have enough, and if she is not overheating.. what could be the issue with idling it down a little? Don't you guys like a nice slow idling DeeZull?

[CRSMP5]

he likes to ride round in 5th gear at 35mph.....................  ive given up on his lugging of the motor... just not worth it...

[8v-of-fury]

What lugging?

[ORCoaster]

OK 8V,

As long as you have the oil pressure, the volts and the smoothness you claim I will agree that what you have is good enough.  I was thinking some may have it down so far that they would be in the hurt zone rather than where you are.  I would say my idle is nearly as slow as yours as my numbers are about the same.  I don't like a racing motor at all the lights.  People do wonder about the noise as it is.

 LADY, it's a Diesel don't worry about it!  No, that engine part back there is not mine!