I have an 89 manual 240. Recently check engine light came on and right now im getting 231and 113. I just changed the oxy sensor and it seems to run fine but the idle is on the high side it will idle from 1000 to 1500 rpm when warm. In the past it had a slight high idle at 1000then would go back to around 800. I am stumped the tps seems to click when u first move the accelarator. What can i do to remedy this???

 

a cold engine idles at about 1000rpm, and as it warms up it should drop to 600 rpm and stay steady.

rather than 'seems to click', disconnect the cable to the throttle position switch, and put a ohm meter across it, and verify that its 0 ohms at idle, and open circuit as soon as you give it any throttle.

verify there's no air leaks in the intake manifold, obvious leaks can be found by a careful visual inspection, but better is a 'smoke test'

a gummed up throttle body might not close completely.

a gummed up idle air controller might stick open and allow too much idle air in.

procedure for properly adjusting idle on a LH 2.4 car
Engine Tune and Performance:

cracked idle air controller rubber hoses are high on the suspect list, too.

re: your OBD errors, you should clear them and see if they come back. see Engine and OBD Diagnostic Codes

to test your o2 sensor, get a inch or two of THIN copper wire (I'll split some lamp cord, and take a single strand). unplug the round single wire O2 sensor harness connector, wrap one end of htis copper wire around the pin, and snap the connector closed. set a digital volt meter for DC Volts and the low volts range (like > 10 volts), connect the red plus lead to that copper wire and the black ground lead to an engine block ground. start the engine, let it warm up. the volt meter should swing back and forth from a low value like 0.1 to 0.3 volts to a higher value like 0.7 to 0.9 volts. these swings are every couple seconds. if it stays high, you're running too lean (air leaks?) if it stays low, you're too rich (leaky injector?). OR your 'new' o2 sensor is bad. was it a real Bosch one with Volvo connectors?

 

Thanks pierce. Yes is a bosch sensor i put on. I cleared codes last night then check engine light came back on way home from work today.. I will have to get my hands on voltmeter this weekend this is driving me nuts.. it seems idle will be good when first started but then is erratically high right above 1000..also first thing i looked for was vacuum leaks but all my hoses and connections look ok.

 

so both codes came back, or only one?

probably doesn't matter, both those codes meant pretty much the same thing, and I dunno why there's 2.

does your car have a 5th 'cold start' injector, or just the main injectors? some lh2.4 systems have a cold start, others don't and just use the main injectors to give an extra squirt when cold. a leaky injector could cause all kinda nasty too-rich-at-idle behavior

 

Ok so heres a bit of an update. I went to jumpstart my old 6v truck with the wagon and had the jumpers hooked.to my car running. When putting them on the truck battery idle dropped and it seemed the problem cured itself., i drove it with no issues it would idle right around 800 when warmed up. Check engine light was still on. Today i made the mistake of disconnecting the battery to reset the check emgine light. When i started it back up it started idling real low like 500 and was stuttering slowly idle went up now it stays up.above 1000 like before.. i Am at a loss what should i start checking first?
I decided.to try to jumpstart my truck to see if that would.slow it back down again, this time i hooked up the cables and my car died and would not start back up. I ad to unhook battery and reset whatver went wrong and it started back up. And pierce there is no cold start injector. Does this seem to be some electrical issue? Could i have fried a sensor? I dont know where to start..

 

When you disconnect the battery the ECU resets and it will have to relearn idle and mixture and idle can change. Especially if things aren't right.

This one could be tough. You should do the greenbook tests with a multimeter and make sure the ECU input parameters are all correct.

http://www.volvowiringdiagrams.com/v...20Complete.pdf

Please actually TRY to do the above tests in the link. Otherwise you will just be chasing your tail .

 

ok i checked engine codes im getting 3 now the sre 113 221 and 231. I am going to biy an ohmmeter hope to figure this out.

 

https://www.volvoclub.org.uk/faq/Eng...InjectionFault

those codes all suggest mixture too lean or rich at partial engine load. one of them is specifically too lean. this is measured by the O2 sensor, so doing the volt meter test of said sensor is a good idea. common cause of too lean is air leaks anywhere in the intake path between the head and the AMM/MAF sensor, or bad AMM/MAF.

also, see https://www.volvoclub.org.uk/faq/Eng...ReferenceChart

if you have the 'pink label' -561 ECU, that could be problematic. these were found on some 1989 LH2.4 cars...

 

Ok so i found some things that i should have long ago. Two clamps were not secured the first was the rear behind air mass meter. The other was the one on the hose that hooks to throttle body from top of flame trap. I had did some work on car thos winter and never secured them.
Yesterday i made the mistake f screwing with the connection on the amm. I had taken it off with car running a few times,.
Also this past fall i had donesome weldi.g on exhaust and disconnected battery but not the ecu.
So this morning i unhooked battery again to reset everything and it wanted to idle lower but a little rough. Let it warm up a few minutes and it ran better. Drove it a bit and all seems well althoaybe a bit sluggisg in low end. It would.idle right around 800 tho. But when car is shut off and restarted then the idle acts all screwy again and wants to idle over 1000. I am thinking this has to be an ecu issue not mechanical at this point.. i plan to dig a bit deeper with ohmmeter this weekend.

 

Pierce just looked at my ecu it is the pink labeled type. It seems like now when i reset everything by disconecting battery it will idle lower. It will.smooth out and idle at 800 .,,

 

High idle can be air leaks too. Air leaks on a non turbo car will make the car run lean. Unmetered air getting in the engine.

Bad MAF will make your car run lean, but they are expensive so look elsewhere first.

Like I suggested, download that manual and go thru the tests. It starts from top to bottom with what you need to check for. FIRST you check for air leaks.

The way I test for air leaks is with a tube in my ear then I listen around. All I found last time for a tube was a 3 foot vacuum cleaner tube! It worked well enough for me to find a torn EGR pipe rubber elbow at intake mani. It's still torn though. Gotta change. SMALL airleaks wont cause too much of a change.

I would remove your intake hose and inspect carefully. If somebody installed it where it is touching the strut tower, it will wear thru. Inspect and reinstall so that it doesnt rub.

 

pink label LH2.4 -561 ECUs are highly suspect. ideally find a compatible one, see that table I linked for candidates.

 

lets give that poor pink label a chance before firing the parts cannon at it!

 

Would a small exhaust leak ahead of o2 sensor be an issue? I noticed a small leak on upper part of pipe running into the cat. This is where i could not reach my mig nozzle because no room. Could this throw off sensor casing all this ?

 

small leaks at low throttle settings suck air in, causing the O2 to think the burn is leaner than it is, causing the ECU to enrich the mixture.

 

lets start over, this is a high idle problem, which that exhaust air leak couldn't affect.

1) remove and clean the throttle body using a throttle body cleaner spray and old toothbrush to remove crusty deposits. make sure any vent holes are clear.

2) use a digital multimeter in 'ohms' mode to verify that the idle position switch actually closes when the throttle is at idle, and opens as soon as you give it any throttle. adjust the screw stop on the throttle plate so the plate is just barely completely closed at rest and adjust the switch so its closed.

3) remove and clean the idle air controller (IAC) with the same cleaner spray. if you jumper 12V to the pins, it should clack open, and as soon as you disconnect, it should clink closed.

4) inspect the IAC hoses carefully before installing, if they are at all cracked or hardening, replace them.

5) reinstall all of the above. start and warm up the engine, verify the idle speed.

if the high idle persists... when the engine is fully warmed up, and all accessories, A/C, lights, etc switched off, use a heater-hose pincher to pinch off one of idle air hoses, the idle should drop to ~ 500 rpm, which will be on the edge of stumbling and stalling. if its higher than that, there is an air bypass screw on the side of the throttle body, adjust this so the idle is in the 500-600 RPM range. now unclamp the idle air controller, and it should speed up the idle to about 750 RPM if everything is working right. unplug the electrical connection to the IAC and it should drop back to 500-600 RPM. plug it back in.

with it plugged in and everything normal, the idle should stay around 700RPM as you switch on the headlights, A/C, etc. each thing you turn on, you'll hear the engine work just a bit harder to maintain that 700 rpm idle.

OH, if you can borrow an automotive meter, it might be a good idea to use IT as a tach rather than the dashboard tach for these tests... you'd clip the meter to the battery, and to the "1" terminal on the ignition coil. you can also use a multimeter that has a 'Hz' frequency mode, clip it to the coil '1' pin and ground, and multiply the Hz (Cycles/second) reading by 30 to get RPM, so 600 RPM should read 20Hz. 700 RPM is 23Hz, etc.

 

Don't fill your IAC with solvent.

There is no idle screw on lh2.4.

Test o2 sensor for voltage swinging between 0 and 1 volt once its hot.

Do tests in link.

 

Paid a visit to the junkyard and found a couple untouched 2.4 240s. Pulled iac and amm off one of them. Swapped out iac solved problem. Put the amm on for good measure. Car runs like a top again and no more check engine light. I now have a very good idea how the fi system works thanks to link with the manual. I printed it out for ref. Thanks alot for the help everyone. Scored big time on those.parts.cant believe what.they want for those parts otherwise. Im thinking of going back to pilfer parts off other car to set aside in my stash of spares..

 

Parts cannon:1 point

Pink label ECU: 1 point

Albert: 5000 pts

nothing but win!