240 ugh so many issues

suener · 03-08-2021, 01:08 PM

1992 240 wagon m47 5 speed 3.1 lh no egr nonturbo

First good morning,

Ok where to start? I am only going to post 1 issue at a time although they may be all related or unrelated. so hard to tell.

My car is getting up there and I have been neglectful in the past, but now I feel bad and am trying to do right by her.

The biggest issue right now is no/delayed responsive via accelerator or throttle manipulation at normal operating temp. This is relatively new symptom

There are no issues with response while cold.*
There zero starting issues

*rpms SEEM high - no tach but I did order one and will test asap.

I have checked and replaced the IAC, cleaned the throttle body, replaced the air intake boot between MAF and throttle, checked throttle cable and pulley, Checked ignition codes (ok), check ODB codes - rich/lean at cruise and idle, fault at fuel injectors (ordered) Checked MFA with multi-meter (read 110 omhs) and car immediately died when I unplugged the MAF, checked fuel pressure regulator (no leaks), checked hoses for air leaks but as of yet found none. Tested the TPS at cold (test results ok) but I did not test at operating temp (sadly I just thought of that now)

HOWEVER none of that is the question I want to post today it is just for background.

I know that because this is a system and all components must work together I am merely trying to narrow the issues down through elimination.

So what I want to identify is this:

Currently the idle seems high and is definitely erratic. the longer it runs the lower and more erratic idle becomes- but she doesn't stall out unless I press the gas. It feels as though the car is bumping- that is how erratic it can be-almost as if she fits and starts like sporadic gurgles (idk how else to describe it) in addition to the erratic idle

Any suggestions about would be greatly appreciated and I thank you for your time

dl242gt · 03-08-2021, 02:05 PM

Start with a full tune up. New plugs, wires, cap and rotor. The bumping you are describing seems like the engine missing. Worn out plug with too wide a gap can do weird things. I'd also replace the fuel filter if it hasn't been done in a long time.

Is the speedometer working? No speedometer means a high idle after you get done driving on the highway as the computer wants to see a vehicle speed signal. If it doesn't see that signal you get a high idle after driving.

2manyturbos · 03-10-2021, 03:02 PM

The issues you describe point to a bad air mass meter. The surging idle, no throttle response and sudden stall when the throttle is applied are all classic symptoms of a bad AMM.

dalek · 04-03-2021, 08:42 AM

Quote:

Originally Posted by dl242gt

Is the speedometer working? No speedometer means a high idle after you get done driving on the highway as the computer wants to see a vehicle speed signal. If it doesn't see that signal you get a high idle after driving.

I myself have that issue.

Quote:

Originally Posted by 2manyturbos

The issues you describe point to a bad air mass meter. The surging idle, no throttle response and sudden stall when the throttle is applied are all classic symptoms of a bad AMM.

If that is the case, can't he do the "disconnect AMM plug and see how it behaves" test?

dl242gt · 04-03-2021, 03:40 PM

He did. The engine stalled which may not be the AMM fault. Check out the cleanflametrap web site for help with diagnosing a bad AMM. I do agree that the running symptoms are typical of a bad AMM. A clogged fuel filter can also cause this running issue.

03-08-2021, 01:08 PM	#1
suener Newbie Join Date: Apr 2018	ugh so many issues 1992 240 wagon m47 5 speed 3.1 lh no egr nonturbo First good morning, Ok where to start? I am only going to post 1 issue at a time although they may be all related or unrelated. so hard to tell. My car is getting up there and I have been neglectful in the past, but now I feel bad and am trying to do right by her. The biggest issue right now is no/delayed responsive via accelerator or throttle manipulation at normal operating temp. This is relatively new symptom There are no issues with response while cold.* There zero starting issues *rpms SEEM high - no tach but I did order one and will test asap. I have checked and replaced the IAC, cleaned the throttle body, replaced the air intake boot between MAF and throttle, checked throttle cable and pulley, Checked ignition codes (ok), check ODB codes - rich/lean at cruise and idle, fault at fuel injectors (ordered) Checked MFA with multi-meter (read 110 omhs) and car immediately died when I unplugged the MAF, checked fuel pressure regulator (no leaks), checked hoses for air leaks but as of yet found none. Tested the TPS at cold (test results ok) but I did not test at operating temp (sadly I just thought of that now) HOWEVER none of that is the question I want to post today it is just for background. I know that because this is a system and all components must work together I am merely trying to narrow the issues down through elimination. So what I want to identify is this: Currently the idle seems high and is definitely erratic. the longer it runs the lower and more erratic idle becomes- but she doesn't stall out unless I press the gas. It feels as though the car is bumping- that is how erratic it can be-almost as if she fits and starts like sporadic gurgles (idk how else to describe it) in addition to the erratic idle Any suggestions about would be greatly appreciated and I thank you for your time

03-08-2021, 02:05 PM	#2
dl242gt Happy playing the blues Join Date: Jun 2002 Location: S NJ, a suburb of Phila.	Start with a full tune up. New plugs, wires, cap and rotor. The bumping you are describing seems like the engine missing. Worn out plug with too wide a gap can do weird things. I'd also replace the fuel filter if it hasn't been done in a long time. Is the speedometer working? No speedometer means a high idle after you get done driving on the highway as the computer wants to see a vehicle speed signal. If it doesn't see that signal you get a high idle after driving. __________________ Dave, 1982 242 turbo. 338k miles. MVP coilovers and 3" exhaust. Flowed 405 with a V15. Cossie turbine housing with upgraded compressor housing. 90+, IPD remote oil filter. Some other goodness, too. Been lots of fun over 25 years. Restored in 2k. Now ready for a 2nd restoration. 1993 245 Classic, 430k miles, enem V15. IPD bars and chassis braces. Simons sport exhaust from Scandix. sbabbs ezk chip. Been a good road warrior. Genuine Volvo rebuilt leaky M47.

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03-10-2021, 03:02 PM	#3
2manyturbos Moderator Join Date: Mar 2003 Location: Monroe, OR USA	The issues you describe point to a bad air mass meter. The surging idle, no throttle response and sudden stall when the throttle is applied are all classic symptoms of a bad AMM.

04-03-2021, 03:40 PM	#5
dl242gt Happy playing the blues Join Date: Jun 2002 Location: S NJ, a suburb of Phila.	He did. The engine stalled which may not be the AMM fault. Check out the cleanflametrap web site for help with diagnosing a bad AMM. I do agree that the running symptoms are typical of a bad AMM. A clogged fuel filter can also cause this running issue.