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Vehicle speed correlating to idle speed

I

iHateVolvoPeople

Active member
Joined
Feb 1, 2014
Location
Midwest
Ah, weird title. Sorry. 1993 245 m47 lh2.4

Pretty much stage 0. This isn?t a huge deal, but I?ve noticed that every 240 I?ve ever owned doesn?t really idle above 1,000 even on cold starts. My old Toyota?s would shoot up to 1,500+.

Anyway, on my wagon on really cold days if i accelerate, the rpms will shoot up to 1,500 or so whether I?m in first gear idling or not. But the EXACT SECOND the car stops, rpms drop to normal warmup rpms. So essentially, it seems like this car kicks up the idle when the car is moving forward, but kicks it down at a stop. It does not have a cold start injector and this is the only 240 I?ve ever seen do this. It almost seems like it?s hunting a bit.

Any clues?
 
No, but if it makes you feel better I SWEAR that my 240 idle chases the rhythm of my LEFT turn signal. Like when only the left signal is on, the motor goes up and down a couple of RPM with the cadence of the clicker.

Get out the foil hats!
 
EivlEvo said:
No, but if it makes you feel better I SWEAR that my 240 idle chases the rhythm of my LEFT turn signal. Like when only the left signal is on, the motor goes up and down a couple of RPM with the cadence of the clicker.

Get out the foil hats!
Click to expand...

That could actually make sense. Maybe a voltage drop issue? Or something being tapped in to that shouldn?t be tapped in to? Idk
 
Not of particular help here but my 940 does this too.
When I'm slowly rolling to a traffic light, even in neutral, the rpms are around 1.300 or so, as long as I'm moving. When I come to a full stop, the rpms immediately drop to the usual idle below 1.000. I've always wondered about it myself and thought it's a bit weird, but didn't really care about it. I just thought it's normal.
My 240 did this as well.
 
Is it possible that there's some wiring weirdness between the speedo/ecu? My 240 idles at about 700 regardless of temperature or speed.
 
Cwazywazy said:
Is it possible that there's some wiring weirdness between the speedo/ecu? My 240 idles at about 700 regardless of temperature or speed.
Click to expand...

No idea. My other 240 idles 700-800 regardless as well. But this car also has an intermittent odometer even though i replaced the gear and cleaned everything. It seems to only work after driving on the highway for a bit, or if i pull the cluster and shove the connector into the back of the speedo. Weird thing is, i know it’s a tight connection on the back of the speedo because i bent the little fingers inwards to grip the speedo. So it’s like it’s tight enough, but not deep enough? Difficult to explain.
 
I've noticed lh2.4 do this. Not really anything that seems wrong to me. The idle regulation is tied to vehicle speed. So it would seem proper that the engine idle could wander a bit especially with a cold engine and the vehicle is for example rolling along at five mph.
 
dl242gt said:
I've noticed lh2.4 do this. Not really anything that seems wrong to me. The idle regulation is tied to vehicle speed. So it would seem proper that the engine idle could wander a bit especially with a cold engine and the vehicle is for example rolling along at five mph.
Click to expand...

It’s just weird because it’s the only 240 I’ve seen this happen on. And it’ll stay at 1500rpm from 5 mph rolling speed all the way down to .5 mph or so, so it’s definitely not *correct*. Oh well guess I’ll ignore it.
 
I have had two LH2.4 240s and they both did/do this but it is with a cold engine in my experience. Once you've been driving and the engine is fully warm I don't notice it. One was an 89 244 that had a 561 ecu. I don't remember the ezk. My present 93 wagon does this with a 951 fuel and 169 ezk. Actually, I just put a chipped 146 ezk in there now. Runs great.
 
dl242gt said:
I have had two LH2.4 240s and they both did/do this but it is with a cold engine in my experience. Once you've been driving and the engine is fully warm I don't notice it. One was an 89 244 that had a 561 ecu. I don't remember the ezk. My present 93 wagon does this with a 951 fuel and 169 ezk. Actually, I just put a chipped 146 ezk in there now. Runs great.
Click to expand...

So it doesn?t do it with the chipped ezk or it still does? Cold electronics/engines are kinda just weird IME.
 
You know with the distraction of a heavy pedal enjoying the new found power with what little I drive. I haven't thought to look for that weirdness. I'm hardly driving as much as I used to and not on cold mornings for many months now. That's when I used to notice that weird idle stuff.
 
dl242gt said:
You know with the distraction of a heavy pedal enjoying the new found power with what little I drive. I haven't thought to look for that weirdness. I'm hardly driving as much as I used to and not on cold mornings for many months now. That's when I used to notice that weird idle stuff.
Click to expand...

Hm so you installed a chipped ezk on an otherwise stock na 240 and had good results? I may have to try that to get my mind off of the weird idling stuff.
 
Well I have had an enem V15 n/a cam in there for about five years. Didn't know how poorly setup the stock timing curve was for my cam. But the chipped ezk is only a month ago and it completely made the car run and drive like it should have from Volvo. Power and torque at all rpms. Heavy flywheel not an issue. I'm sure an A or B cam in there would be similar. It added so much from about 3k rpms and up it's wonderful.
 
That's related to 2.4. 2.4 will close the idle motor once the vehicle is stationary, leaves it partially open on decel once it's out of fuel cut mode. With it staying that high, I'd suspect the minimum airflow isn't set correctly. Make sure the throttle cable is set correctly, linkage from the spool to the throttle plate is set correctly, and the throttle stop screw should be set to 1/4 turn after it contacts the lever, so set the minimum airflow, assuming a stock-ish setup. That can actually play a pretty big difference.

I've been dealing with idle issues a lot lately since I tweaked cam timing a bit.
 
dl242gt said:
Well I have had an enem V15 n/a cam in there for about five years. Didn't know how poorly setup the stock timing curve was for my cam. But the chipped ezk is only a month ago and it completely made the car run and drive like it should have from Volvo. Power and torque at all rpms. Heavy flywheel not an issue. I'm sure an A or B cam in there would be similar. It added so much from about 3k rpms and up it's wonderful.
Click to expand...
Good, because i just ordered 2 B cams! Maybe a chipped ezk will be on the fhrusymas list if it makes it that much more driveable.
gsellstr said:
That's related to 2.4. 2.4 will close the idle motor once the vehicle is stationary, leaves it partially open on decel once it's out of fuel cut mode. With it staying that high, I'd suspect the minimum airflow isn't set correctly. Make sure the throttle cable is set correctly, linkage from the spool to the throttle plate is set correctly, and the throttle stop screw should be set to 1/4 turn after it contacts the lever, so set the minimum airflow, assuming a stock-ish setup. That can actually play a pretty big difference.

I've been dealing with idle issues a lot lately since I tweaked cam timing a bit.
Click to expand...
Ah so idle motor is open when moving (even in neutral coasting)? Weird. I remember adjust the tps on this car to click at the slightest throttle movement, as well as taking up any slack in the cable. I have also cleaned/swapped IAC valves before. I will check the other things as well.
 
I think the take home message here is that the Idle Air Control valve (Essentially it is a choke... ), really is causing high RPM problems with our old volvos: most noticeable when we come to a stop but also when we start the cars when it is cold out. This issue may or may not be related to the throttle linkage but more than likely is a LH2.4 fuel injection problem/limitation I am learning

( I have noticed on my 89 244 with a 940t ECU that when I cold start the car (10-20degrees), I am at 2000-2500RPM before the car warms up, this problem was not there before I did a +T, also have the "coming to a stop RPM problem" you describe... )
 
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