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+--- Thread: 240D turbo idle issues (/showthread.php?tid=7141)
240D turbo idle issues - Jooseppi Luna - 04-05-2016
Hey everyone,
For those of you that missed it, JB3 gave me Purple's old car this January, which I now have up & running as my DD. I'ts been a running project, and one of the main unresolved issues that I haven't diagnosed is related to the idle. Specifically, the engine refuses to return to idle or does so very slowly when warm (when you depress the clutch, the engine speed just tends to stay where it last was in gear). If you bog it down with the clutch, it does go down willingly and stays there.
It's a 1979 240D with a turbo off of a 300D and an IP tuned by Ronnie/240dodge. I've e-mail Ronnie to ask him to look at the thread, since he might still remember what he did to the IP.
What do you guys think might be the cause of the idle issues? I hesitate to touch anything in the IP (like the torque control capsule) until I've had input from people more experienced than me... I have read the IP tuning sticky and have a spare if I screw this one up.
Cheers!
-Jooseppi
RE: 240D turbo idle issues - Greazzer - 04-05-2016
Did you have someone depress the accelerator pedal and watch the movement at the pump/firewall/linkage/springs? Could be something super simple like something is sticking in the long chain of connections.
RE: 240D turbo idle issues - Jooseppi Luna - 04-05-2016
(04-05-2016, 07:13 PM)Greazzer Did you have someone depress the accelerator pedal and watch the movement at the pump/firewall/linkage/springs? Could be something super simple like something is sticking in the long chain of connections.
I'll have my sister try that with me! The engine does willingly drop to a normal idle speed if I let the clutch partway out and bog it down... and it stays there. I would think that a linkage issue would be more likely to cause the idle to spring back once I let off the clutch, but anything is worth a shot on a 37-year-old car with a custom turbo install
RE: 240D turbo idle issues - Petar - 04-06-2016
If it's not sticky linkage it's then probably too much throttle pressure at idle. Turn the minimum throttle screw out until it returns to idle fast enough . At that point it will idle too low or wont idle at all without throttle pressure, take off the back cover and turn up the internal idle screw so it idles at proper rpm.
RE: 240D turbo idle issues - swampmonkey - 04-06-2016
try getting a spring that pulls the lever "back" as near the pump as possible. (the pumps tend to autorev when they reach a certain rpm)
if that doesnt work, id say the pump is not "tuned" properly, had the same issue on a om602turbo bought, where the idle didnt go down unless forced down. and about everything was turned a bit random back at the pump, a bit tinkering got it working correct again, althou not stock-smooth.
RE: 240D turbo idle issues - barrote - 04-06-2016
what type of pump is? or better said is a rsf governor?
RE: 240D turbo idle issues - OM616 - 04-06-2016
First make sure there is a good return spring at the IP throttle lever and that the linkage is free and well lubricated.
If the above is true, then Petar is exactly correct. First back off the Vertical Throttle Stop Screw a little at a time until the return to idle happens fast enough for you, (don't worry about the actual idle speed, just how quickly it returns to idle)
If the Idle Governor is adjusted properly (that is the internal adjustment) you will be able to adjust the Vertical Throttle Stop quite a bit with out affecting the actual idle speed. (that of course depends on where you are in the adjustment window now)
If once you have the Return to Idle rate where you want it, and the Idle speed is to low, or it won't idle on its own until it is warmed up, then the Internal Idle Governor Screw needs to be turned in (CW) probably 1/2 to 3/4 of a turn. THAT BEING SAID... This is an adjustment that does not have any "Feel" to it and the screw will turn very easily, as in when you brake the locking nut loose the screw might turn with it. You have to have control of the screw and the nut independently to confidently do this adjustment. I strongly recommend that you exhaust every other possible problem before you consider opening up the Governor!!!
RE: 240D turbo idle issues - Jooseppi Luna - 04-06-2016
Linkage definitely not sticking, I'll look at adjusting the Vertical Throttle Stop Screw tomorrow... hopefully I don't have to open up the governor.
I also noticed that the accelerator linkage isn't quite going to the stop, so I'll take care of that too.
Thanks, guys!
RE: 240D turbo idle issues - Jooseppi Luna - 04-07-2016
BTW, should I adjust the Vertical Throttle Stop Screw when the engine is running or should I shut it off?
RE: 240D turbo idle issues - OM616 - 04-07-2016
(04-07-2016, 09:18 AM)Jooseppi Luna BTW, should I adjust the Vertical Throttle Stop Screw when the engine is running or should I shut it off?
With it running. Back off the Vertical Throttle Stop couple of turns and rev it and see how it comes down. Keep doing that until it returns to idle as you would like. Be careful when breaking loose the lock nut, that tab is easy to brake off, and if that happens then it gets a different level of complicated.
This is nice to be in control over as you can adjust it so that when you shift the engine speed matches the next gear making for very easy and smooth shifting.
RE: 240D turbo idle issues - MFSuper90 - 04-07-2016
Definitely the vertical throttle stop. I had to back this out on both pumps I have tweaked
RE: 240D turbo idle issues - Jooseppi Luna - 04-07-2016
Awesome!! Sounds good. Unfortunately, I haven't been able to touch it due to the rain around here today
. Maybe tomorrow...
RE: 240D turbo idle issues - MFSuper90 - 04-07-2016
You can adjust the time that it takes to return to idle with the vertical throttle stop.
RE: 240D turbo idle issues - Jooseppi Luna - 04-07-2016
(04-07-2016, 06:18 PM)MFSuper90 You can adjust the time that it takes to return to idle with the vertical throttle stop.
Yup, that's just the plan that OM616 and I were discussing up above!
RE: 240D turbo idle issues - OM616 - 04-08-2016
Just had a thought, Make sure the Dash Pot is not turned up holding the throttle up. With a properly adjusted Idle Governor one does not need to use the Idle Speed Dash Pot, and if some one turned it and forgot about it, it would not want to return to Idle like you described, it will also tend to run away as well.
Just a thought to check all the simple things before getting into the deep end. lol
RE: 240D turbo idle issues - Jooseppi Luna - 04-08-2016
(04-08-2016, 05:38 PM)OM616 Just had a thought, Make sure the Dash Pot is not turned up holding the throttle up. With a properly adjusted Idle Governor one does not need to use the Idle Speed Dash Pot, and if some one turned it and forgot about it, it would not want to return to Idle like you described, it will also tend to run away as well.
Just a thought to check all the simple things before getting into the deep end. lol
Cable is gone, shouldn't be an issue...
RE: 240D turbo idle issues - Jooseppi Luna - 04-08-2016
Did the Vertical Throttle Stop Screw adjustment... ended up turning it about one turn out and it returns to idle very well now. The only issue is that the idle is pretty lumpy now... feels kind of like a misfire or something. This was something I had already been experiencing earlier, but it's more exacerbated now (I noticed it getting worse as I turned the screw out). The car had Greazzer injectors installed pretty recently... I'm going to adjust the valves and do a diesel purge, but is there anything else I should do? Could the rough idle be something related to the pump tuning?
RE: 240D turbo idle issues - MFSuper90 - 04-08-2016
My idle is rough when it is cold, but my pumps been turned up for so long I can't remember if it use to idle like that or not. It also idles a little slow when cold, but I just deal with it cause I'm too lazy to pull the pump and readjust the idle
RE: 240D turbo idle issues - Jooseppi Luna - 04-08-2016
Mine is rough when warm, too.
RE: 240D turbo idle issues - OM616 - 04-09-2016
Aside from the obvious things being valve adjustment and chain stretch, low compression, worn injectors, and Start of Injection Timing I have found that a ruff or intermittently ruff idle is often caused by worn DVs, Specifically warn DV Seats (not to be confused with seals).
In reality, the DVs are just as susceptible to wear as the injectors and the DVs are actually very critical in the injection process. I have had a few with eroded spots in the plunger and seat and when they line up it while on the highway for example, the EGTs would go up and power would go down. Then the plunger would rotate and power came back and EGTs went down. It would even nail horribly when cold, and once I replaced the bad DVs no cold nailing, smooth consistent running and EGTs.
From what I have seen, when the Injectors are shot, so are the DVs, and I think it is a good idea to replace them as a set.
Now that being said,
There is a difference between the Idle Speed and how quickly it returns to Idle. You can have a fast Idle and a quick return to that fast Idle, the two are individual things that can be adjusted to meet your desires.
If after the Vertical Throttle Stop adjustment, the engine Idle speed (not the return to idle) is too low and if you give it just a touch of throttle it smooths out and is not idling to fast, then you need to give the Idle Governor Spring a touch more tension, which will raise the Idle speed. Note, after you turn up the Idle governor, you may have to re do the Vertical Throttle Stop adjustment to restore the return to Idle rate, it is a balance between the two adjustments, the closer they are to being in balance the less the two affect each other. Right now it sounds like the Idle Governor may be a little week, so the Throttle Pressure is still contributing to the Idle stability more than it should, when you increase the Idle Governor Strength, you will most likely have to back off the Vertical Throttle Stop a touch more to transfer more Idle Speed control to the Idle Governor. It is important to realize that the Vertical Throttle Stop does not control the Idle Speed. It is an easy crutch for the factory to set the idle speed, but as you can see the more Idle control you give to the Throttle, the less adjustment you really have because it can take off, or not want to idle well or stable.
Try the obvious first, and if that does not work, and you think raising the Idle Speed will Smooth it out ( I have my idle set at 1000 with my 4 speed cars) then it may be worth making the adjustment to the Idle Governor. If however the Idle speed is up there already, and the compression is good, then you may want to have the injectors and DVs checked. If they are in good shape, then it might be open the governor time. I caution you though, it is a simple adjustment, but a trick one, I can walk you through exactly what to do should it be necessary.
RE: 240D turbo idle issues - MFSuper90 - 04-14-2016
Thanks om616, I didnt know you were still around!
RE: 240D turbo idle issues - TKMad - 04-15-2016
Not to hijack, but where is the best place to get delivery valves? I've searched a bit and can't seem to find any...
RE: 240D turbo idle issues - OM616 - 04-15-2016
(04-14-2016, 06:30 AM)MFSuper90 Thanks om616, I didnt know you were still around!
I'm not really lol.... Just pop in now and then.
RE: 240D turbo idle issues - OM616 - 04-15-2016
(04-15-2016, 11:16 AM)TKMad Not to hijack, but where is the best place to get delivery valves? I've searched a bit and can't seem to find any...
I just get them from Bosch. I think I paid about $50 a piece last time I bought some. I have tried to find another source but no joy.
RE: 240D turbo idle issues - bricktron - 04-16-2016
jooseppi, i have had this problem caused by the throttle return spring being hooked into the nearer of the two mounting holes in a little flange on the firewall. in that position the return spring was too weak to pull the linkage back to idle, but when i stretched it a bit to reach the farther mounting hole, the IP would return to idle again.