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-   -   1990 240 Rough Idle/Cannot hold idle/throttle is unresponsive (https://forums.turbobricks.com/showthread.php?t=359874)

ryanvstheworld 04-09-2021 10:20 PM

1990 240 Rough Idle/Cannot hold idle/throttle is unresponsive
 
Hi all,
Back in December of 2020, I parked my 1990 240 (B230F, LH2.4, AW70) and swapped out the auto box for a M47 manual box. The swap is complete now, and I went to start the car today for the first time in about 4.5 months. I left about half a tank of gas in it without any stabilizer, but when my dad smelled it today he swears it smells fine. When the neutral safety switch was set to neutral, and the car was started, the car gave me a rough idle and sometimes would die out on me, although most of the time it would maintain the rough idle. Additionally, when I gave the car gas, the throttle pedal seemed to increase the throttle very little for the first 10% of travel, and then not increase throttle at all for the rest of the pedal travel. The car also throws a check engine light but the check engine light seems to go away with a touch of the throttle. I used the test probe underneath the hood and it came back showing no stored codes on 2 and 6. I checked for fuel pressure, and it seems I'm getting enough, as the car will idle. I'm at a complete loss here. My only thoughts are maybe bad gas, or that when I had the exhaust apart, the O2 sensor went bad because I left it dangling and a little ATF got on it. My dad seems to think that this wouldn't be a problem but I'm not a technician so I really have no clue. Any and all help would be appreciated.

shoestring 04-10-2021 11:37 AM

#1 error here is usually flywheel oriented correctly for crank sensor pickup. Are you certain you positioned the manual trans flywheel properly when you installed it? The gap in the holes should have pointed toward the starter provision.

2manyturbos 04-10-2021 03:53 PM

^^

Unfortunately, there is a very good chance this is the problem.

ryanvstheworld 04-10-2021 04:34 PM

I didn't even know that was a thing. I guess I'll see you all in 6-8 hours. That's seriously embarrassing. When I orient the flywheel, should the motor be set to top dead center? :oops:

Edit: I read my manual, it should be set to TDC #1. I should add that I have a STS Flywheel, not sure if that makes any difference.

2manyturbos 04-10-2021 04:45 PM

With the crank shaft at TDC cylinder # 1 the skip in the windows of the flywheel should be about in the middle of the starter drive.

KwikBrik245 04-11-2021 09:18 AM

Quote:

Originally Posted by shoestring (Post 6174481)
#1 error here is usually flywheel oriented correctly for crank sensor pickup. Are you certain you positioned the manual trans flywheel properly when you installed it? The gap in the holes should have pointed toward the starter provision.

I made this mistake on my first Volvo swap back in '08. Definitely a mistake that people don't make a 2nd time haha.

90volvo 04-11-2021 09:21 AM

Dont feel bad, I did the same thing. What was crazy is I had the tranny out twice swapping flywheels. I guess, I got lucky but not on the 3rd time.

KwikBrik245 04-11-2021 09:44 AM

Was this car running normally before the 4mo. rest? I only ask because if it did, the flywheel isn't you problem.

ryanvstheworld 04-12-2021 06:05 PM

KwikBrik245, The car was running normally when I parked it. I took the trans off, repositioned the flywheel as stated above, and the car runs a lot better and takes throttle, but now will not idle well, and the timing (when checked with a timing light) is completely off.

KwikBrik245 04-12-2021 06:09 PM

Quote:

Originally Posted by ryanvstheworld (Post 6174893)
KwikBrik245, The car was running normally when I parked it. I took the trans off, repositioned the flywheel as stated above, and the car runs a lot better and takes throttle, but now will not idle well, and the timing (when checked with a timing light) is completely off.

LH2.4 controls timing to a certain extent. However, I'm not sure it can compensate for the distributor being off a tooth or more. Possibly your issue? If you haven't changed anything else, I'd just swap known good spare parts like IAC

ryanvstheworld 04-12-2021 06:18 PM

Quote:

Originally Posted by KwikBrik245 (Post 6174897)
LH2.4 controls timing to a certain extent. However, I'm not sure it can compensate for the distributor being off a tooth or more. Possibly your issue? If you haven't changed anything else, I'd just swap known good spare parts like IAC

Wouldn't surprise me. My dad and I tried to adjust the distributor but It didn't change anything. We didn't move it over a tooth, we just used the built in adjustment in the car.

esmth 04-12-2021 06:25 PM

some ezks will set the cel temporarily when the idle is too low for too long. it won't actually store a code ime.

KwikBrik245 04-12-2021 06:26 PM

Quote:

Originally Posted by ryanvstheworld (Post 6174902)
Wouldn't surprise me. My dad and I tried to adjust the distributor but It didn't change anything. We didn't move it over a tooth, we just used the built in adjustment in the car.

Unplug your MAF sensor and see if that clears it up.

KwikBrik245 04-12-2021 06:29 PM

This link not only lists all the codes, it also shows how to run the various test modes of the diagnostic ports

https://www.volvoclub.org.uk/faq/EngineOBDCodes.html

ryanvstheworld 04-12-2021 10:59 PM

No dice with the MAF. Gonna take a break for a couple of days and come back to it with a clean frame of mind. :grrr:

Otto Mattik 04-13-2021 02:36 AM

Quote:

Originally Posted by KwikBrik245 (Post 6174897)
LH2.4 controls timing to a certain extent. However, I'm not sure it can compensate for the distributor being off a tooth or more. Possibly your issue? If you haven't changed anything else, I'd just swap known good spare parts like IAC

LH 2.4 cannot compensate enough for the distributor being off by a tooth


;-)

shoestring 04-15-2021 11:17 AM

Don't be embarrassed. I'm pretty sure anyone who's done this swap has made this mistake. No harm, no foul.

Timing at idle for 2.4 is fixed by the EZ116K at 12 degrees.

I'm assuming that when you say it won't idle well, that it idles at lower than spec rpm and is rough. Spec is 750.

Following Occam's Razor, I would:

1) If you did other mods at the same time, let us know. To use an STS flywheel, especially with a first time swap, is not common. I leads me to believe there may be other changes in play here.

2) Make sure the idle air bypass is plugged in

3) Make sure the idle air bypass is functioning

4) Check for wicked big vacuum leaks (vacuum lines, caps, etc) or cracks in the air intake tubing AFTER the MAF.

5) Check for significant exhaust leaks BEFORE the O2 sensor. They may introduce oxygen that the O2 will try to compensate for by throwing a bunch of fuel at it. This is, however unlikely. An aural check is probably sufficient to rule it out.

6) Set the engine to TDC not based on the balancer but based on the timing belt guide washer and front crank seal plate. I say that because perhaps the outer ring on the balancer has slipped and is giving a false TDC reading. Make sure that all your cam belt timing marks line up, and that your distributor is oriented correctly. The rotor should point at a little square cutout in the housing.

Report back with what you find. These are pretty simple, robust systems that will reward you with a systemic, methodical approach.


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