My '87 240 wagon has a mystery problem ---

Symptoms:
Runs on 3 when cold started
After warmup, accelerates normally. Idles rough. When maintaining a steady speed, engine surges or misses. Mileage had dropped to about 20 mpg. Odd kind of a rattling noise from left front on acceleration.

Good news:
Always starts right up, warm or cold

What I've Tried:
Disconnecting Air Mass Meter makes no difference
Fuel regulator appears clean and dry at vacumn hose to manifold. I don't have the gear to pressure check it.

What I Am Not Sure About:
On the bottom of the throtle body there's a hollow, knurled "bolt" about 3/4" in diameter. I can't find any mention of this anywhere. It is loose with some fuel around it. Is this how it should be?

Any help will be appreciated!

Scott

 

Here's the leaky bolt I mentioned. I can't imagine it's supposed to be loose and leaky, but hey - what do I know? Anyone have insight on this?


[IMG]local://upfiles/13501/4428CF3AF57F490C80BD62080C27CAA5.jpg[/IMG]

 

Looks like the throttle stop screw. And it should have a locking nut. With the throttle linkage disconnected, the screw should just touch the throttle lever, then another 1/4 turn in to just open the throttle slightly. Then lock it down with the locking nut and reconnect the linkage.

 

The Black **** is to adjust the idle.
Try cleaning the throttle body and Vent sheild and see if that helps.

 

It sounds similar to the issue that I experienced, and it turned out to be my fuel pressure regulator. I didn't notice any moisture in there until I pulled off the vac hose while it was running and had a bunch of fuel spray out. After changing it, my car runs like a top.I did have to leave the battery disconnected for an hour after changing it and all is good.
The issues that I had were almost exactly the same, one difference was that mine didn't want to start when warm and had been sitting for a few mins. It always started but didn't really want to.
I wish you luck!
Scott

 

If the regulator is bad, you should normally have black smoke out the exhaust and you won't always get fuel through the vac. line. Of course, checking pressure or replacing it is the way to find out.

I'm a big believer in performing a throttle body service, even if there is another problem. This can cause more idling problems than any other service item on your car (e.g. fuel filter/spark plugs/air filter etc.)

If you need detailed instructions, let me know. It takes awhile to write it up, so I'll take the time if you are going to do it.

Check the hose from the MAF to the throttle body for holes rubbed through, and check that the fresh air flap in the air filter housing isn't stuck open.

Make sure the wire terminal on terminal 15 of the coil is not loose, tighten if it is.

B

 

First, thank you all for your input. I haven't worked on a car since Chevy added those extra 2 cylinders and you've been a lot of help in working out the mystery.

Today the light bulb came on and I did something I should have done a week ago - new plugs. They reeked of gas and, well, see below. Now it ran well enough that I could get some results.

Disconnecting thefuel pressure regulator vacumn line made no difference in the way it ran, and I didn't get any fuel from the line. I've gotten posts both ways on this; fuel or no fuel - that is the question.

The Air Mass Meter is a different story however. With new plugs and the AMM connected it lopes significantly at idle. WithAMM disconnected,no miss AT ALL from idle to about 3,000 RPM.. However, it did starve out and die climbing a hill at fairly low RPM - say 1,500 RPM in 2nd gear. I restarted it and let it warm up a bit more and got home under it's own power.

Those of youwho have experienced "Limp Home", is this descriptive of how that would be? Is it time to plunk down the money for am AMM? And if so, VLV has REMANUFACTURED Bosch at under $300. What experiences has anyone had on this?

Finally, the throttle stop screw. The screw that the throttle "leg" rests on goes vertically through the throttle body. THIS this goes in almost horizontally. And it does not have a lock nut on it. I just want to make sure we're talking about the same thing.

Thanks again for your patience!

Scott





[IMG]local://upfiles/13501/4AF0C0F3A86D409EA826F22A53DC8D71.jpg[/IMG]

 

Scott,

Looks like your running rich.

As far as the regulator, it can be either way, leaking or not. What I do find is that if the regulator is bad, the fuel pump can make some strange noise, because it is working extra hard.

As far as the MAF sensor, I was just at a "pick'n pull" wrecking yard and I must've seen 10 LH 2.2 MAF sensors in cars. I bet there were tons of regulators, but I didn't notice.

The stop screw is the stop for the arm, and it has a nut on it. The black knurled **** is the air bypass screw to adjust idle speed.

 

did you ever think that your timing could be off. That can cause your engine to miss. Just an Idea though.

 

My previous 240 would do the same where the idle would get rough when accelerating and would eventually die. You then get it restarted and then limp home. It would act like it was running out of gas really. My pressure regulator was dry when I checked it and I did not reallt think it was the problem. After changing and cleaning various other things I did change the regulator. Guess what? Fixed it! I did not think that was it because it seemed like it was not really getting to it and it was'nt. The regulator was clogged and it was not pulling fuel into it. I hope this helps. Regulator from Napa $68.