Delayed Sputter?

Kushballz · Post by **Kushballz** » 19 Feb 2007, 12:28

Hi everybody, thanks for reading. My car (details below) starts up and runs fine until after about a mile of driving (up to 40 mph), where it sputters and doesn't accelerate. It seems like it isn't getting enough gas, and it doesn't matter how far the gas pedal is being pushed. Before it happens, I stop at a red light, then I get on the entrance ramp to the highway. It usually starts sputtering to the point where i'm not accelerating anymore, usually at about 20 mph, and then after about 10 seconds of sputtering, and a little bit of backfiring, the car suddenly accelerates, indicating that its sputtering cycle is over. After that it runs like a normal car. I have this problem every time I use it whenever it has sat for more than an hour. I had this problem during winter when i lived in northern Virginia, but now that i'm living in southern Florida, and the temperature is always warm, I don't understand why this is still occuring. I have replaced all the engine wires, plugs, rotor and rotor cap, timing is okay, fuel injectors are working well, and I have also replaced the fuel pressure regulator with no avail. The thermostat has also been replaced, and the brakes aren't dragging or anything. Any help at all would be appreciated, I would hate to retire this Volvo. Thanks in advance!

Car info-------------------
1985 Volvo 240 Wagon
B230F 153K Auto
Fuel Injection RWD
----------------------------

Post by **billofdurham** » 19 Feb 2007, 16:09

I have been shot down on previous occasions for quoting things that only apply to UK cars because of subtle differences in the build, but here goes. Does your fuel system have a cold start injector? If it does is it working correctly? Is the thermal timer working correctly?

I note that you say it seems as if it is suffering from fuel starvation but the back firing would make me think it could be getting too much fuel or the timing is out. Other things worth checking are air leak in the intake system and the auxiliary air valve not closing.

Bill.

Kushballz · Post by **Kushballz** » 20 Feb 2007, 20:07

Thanks for the quick response. No, my car does not have a cold start injector. About the thermal timer, I'm not sure where that would be located. The timing is within specified limits according to the manual, but I'm not too sure about the spark advance timing. I brought my car in to get a catalytic converter replaced a couple years ago, and they advanced the timing, and ever since then it has this subtle misfire when idling. I have checked the intake for any leaks, but i was not able to find any. Where is the auxiliary air valve? If it helps any, I ran the car without the vacuum tube connected to the fuel pressure regulator just to see if that was the culprit, and the car ran the same. I replaced both fuel filters last fall, so I doubt there is a clog from that end of the fuel system. Thanks once again!

Post by **billofdurham** » 21 Feb 2007, 12:12

Not having a cold start injector tells me the type of fuel system fitted. The change over in the UK was about '85 but I wasn't sure for US models. Without a cold start injector forget the thermal time switch. It controlled the cold start. The air control valve was also associated with this system.

With your system check for an air intake system leak and also the air control valve. This is located under the intake manifold. It is cylindrical and has two pipes attached. The pipes should be secure.

and they advanced the timing, and ever since then it has this subtle misfire when idling.

Was this the start of your present trouble? Whether or not it was I would be getting the timing checked and reset. I can see no reason why the timing should be advanced because a new cat was fitted.

Bill.

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Kushballz · Post by **Kushballz** » 21 Feb 2007, 16:53

My car was actually imported from Switzerland as far as i know. The car could be a US model made in Switzerland, but I'm not sure about that. It does have a "Assembled In Switzerland" sticker under the hood though. As for the timing advance issue, ever since the people at the shop advanced the timing, the car has a noticeable shaking feel to it (when idling and at mid-revs). The feel is like that of a person moving around in the back of the car, but that doesn't bother me as much. Today I floored the accelerator while it was sputtering, and the car hesitated more and made a pop sound similar to someone slamming a book shut, but muffled. Would a replaced flame trap assembly have anything to do with an intake leak? I have replaced it twice so far. Once, because the original one was clogged, and the other time because the hose split. Earlier today I tried disconnecting every hose connected to the air intake, and every one made a significant difference in engine speed. I also don't see why the shop advanced my timing if it was working properly. My dad (who took my car to the shop) said that the timing was out.

Post by **billofdurham** » 24 Feb 2007, 13:04

Sorry for the delay but my computer decided to die and I have been giving it the kiss of life.

My dad (who took my car to the shop) said that the timing was out.

Was that your dad's opinion or is it what he was told?

I would have the timing checked although it does not appear to be the cause of the problem.

The flame trap could cause problems if it was blocked but if it has been changed recently it should be OK. If every pipe on the system caused a drop in engine revs as it was removed it just about rules out intake leak. The only other place there could be a leak would be around the manifold gasket.

Having re-read your first post I should have asked how long is it since the fuel filter was replaced?

Bill.

Kushballz · Post by **Kushballz** » 25 Feb 2007, 12:24

I know all about computers breaking. It happens to me every other day! Thanks for responding though. According to what my dad said, the people at the shop showed my dad the timing with the gun and all, and he said, yea its off, so he let them adjust it. I just tested it earlier today with my timing gun and it is in the middle of the correct range. I checked the flame trap and all of it's connections, and it still holds tight. I tested for an air leak around all of the gaskets by spraying some WD-40 around the whole manifold, but it had no effect on the engine speed. The fuel filter was replaced in November of 2005, roughly 1 year and 4 months ago. When it was replaced I had 142K on the motor. It is now at 154K.

Post by **billofdurham** » 25 Feb 2007, 16:02

None of my books has a set of circumstances that you are experiencing, so it is now a case of check out as much as possible.

my timing gun

Not many people have one. When you used it did you disconnect the vacuum hose at the Control Unit? That is the way to get an accurate reading. 10 -14 degrees BTDC is acceptable but the correct setting is 12. Also check to see if the ignition advance is working by increasing the engine speed. The ignition should advance.

The next check is on the vacuum advance. With the vacuum hose still disconnected at the Control Unit run the engine at about 1500 RPM and reconnect the vacuum hose at that engine speed (you will need an assistant). Ensure that the timing changes as the hose goes on. If not check that vacuum hose very carefully for cracks or a bad connection.

If that is in order the next checks should be on the fuel pump, the throttle switch and the mixture adjustment. Some of the checks require an ohm-meter or a multi-meter. Do you by any chance have one of them?

Bill.

Kushballz · Post by **Kushballz** » 28 Feb 2007, 16:47

Sorry about not posting in a timely manner. I have not had time to test my car yet. I will post my results on Friday, after I test my car. Thanks for helping so far!

Kushballz · Post by **Kushballz** » 02 Mar 2007, 23:13

Ok after expecting to work this out yesterday night (friday), I couldn't seem to find my tachometer (the manual hookup one because my car doesn't have one installed on in the dash). I did check the timing with the control unit vacuum hose disconnected, but I still got the same results, not quite down to 12, but not quite 12.5 either. more like 12.25 degrees. I raised the engine speed with my hand and checked the timing at the same time but i didn't notice any change in the timing. How does the ignition timing advance work, because I talked with my father yesterday and he says it was specifically the timing advance they reset. Another thing I noticed is that it will only sputter while it has a load such as driving or having the car idle with the A.C. on. While i was driving it was sputtering and I shifted it to neutral and the engine stopped sputtering, but started once again once I put it back into gear. As for the throttle switch, (if you're talking about the same one i'm talking about) it clicks as soon as you begin turning the throttle control with the cables. It doesn't even look like the actual valve is opening or anything but it still clicks as soon as I even put force on it to turn. I do have a few multimeters, which I believe most of them can measure resistance too. Should I use my analog or digital ones? Thanks for waiting and your help this far.