My car has been bogging, and has hardly any power. I've replaced almost everything (swapped parts with friends cars, and replaced some of the parts with new ones). The list of things I've tried swapping includes: AMM, ECU, Ignition ECU, ECT sensor, FPR, Starter, Ignition Power Stage, Cap/Rotor/Wires, Spark Plugs, Catalytic Converter, Knock Sensor. I've also cleaned the AIC and Throttle Body, and I've verified that the TPS is working. I've also checked for vacuum leaks with propane, and checked the intake snorkel for cracks. So after all of that, it still runs like crap. I do not have any CEL's or codes for 2 and 6.

It seems like when I give it more than 15-20% throttle the timing is retarding and it stops making power. Also, the idle is extremely rough and this weekend it started a new thing where if it isn't warmed up completely before I tap (literally tap) the throttle it will die, and the motor floods with gas.

Here is a link to the video: YouTube: Volvo 240 Bogging

Thanks

Well, as of this morning it won't stay running. It will start, idle extremely low and then stall after 5~ seconds. If I even slightly tap the gas peddle it stalls. And when it stalls it floods the motor with gas, so I have to unplug the injectors, turn it over until that fuel is burnt, then plug them back in and start it again. I still haven't had a chance to make the Fuel Pressure Tester, hopefully tomorrow I can, just thought I'd give an update.

Sounds frustrating!

Did you check the ignition wire order re the FAQ section found?

Seems like there is too much fuel, so testing fuel pressure is key, although I thought there was an easier way to test the FPR by pulling out vacuum line (look it up). Is FPR new or used, certain the replacement is good?

Maybe take a read on your spark plugs?

Sorry! Can't offer more, although you may be on verge fixing it...

The ignition wire order is definitely correct. The FPR is brand new, I bought it in February. I just swapped out the spark plugs in March, but maybe they're fouled by now. I ordered some new ones on Monday, hopefully they'll be at my house today.

is FPR correct pressure? turbo is 3bar, non-turbo 2.5bar On a non-turbo the extra pressure could make fuel flood problem.... (grasping for straws, again)

Yeah, it's correct. Here is a new video of it dying at idle. YouTube: 240 dies at idle So after it dies like that, I have to go unplug the injectors, try to start the car so that it burns up all of the extra gas, then plug them back in and try to start it again, but it just floods the motor again.

The new plugs didn't help at all, the old ones were all fouled and had a little oil on them. At this point I think I am going to have to take it to a shop. I built a fuel pressure gauge, but then realized I can't test the pressure if it isn't idling. I don't really know where to go from here.

"I built a fuel pressure gauge, but then realized I can't test the pressure if it isn't idling. I don't really know where to go from here."

You can run the pumps with the engine off by "jumpering" (connecting) the LEFT side of fuse 4 to the LEFT side of fuse 6 (fuses 6 thru 10 always have battery 12V on the input side).

The pumps should run immediately, so have your gauge ready to test pressure. With engine off, the FPR senses atmospheric pressure, so it acts like Wide Open Throttle (WOT), setting pressure to the 43.5± psi upper limit.


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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Thanks for the tip. I wasn't sure if it would give the same kind of reading. I'll try this out soon.

Re plugs: I suggest *reading* them, what are old one saying about combustion? Look for spark plug charts.

Re extra fuel: Maybe your one or some fuel injectors are dirty or broken? try searching for broken fuel injector symptoms. Follow the logic: Fuel is present but too much. Assuming the FPR is working, then (someone correct me if I'm wrong) there is only the fuel injectors remaining that are dumping too much fuel. Although, there maybe an engine sensor that is incorrectly signalling the ECU?? I dunno...

Video: can't hear much, but the check engine light seems like a clue...

Shops: Hopefully, you have a Volvo specialist in your area that honest and smart.

The video was more to show it dying instantly at idle. If I try to give it gas it dies even faster. I've swapped out the fuel injectors and the results are exactly the same. I found a Volvo specialist about 20 miles south of me in Escondido, CA. He seems to have a great reputation Volvo Service Escondido.

Also check at Turbobricks.com for possible mechanics in your area (actually do a search on google with "site:turbobricks.com" then add your specific query)

20 miles is the closet option? That would be a pain all around, both for initial fix and any further follow-ups under repair warranty.

Hi,

Not that it makes any difference but is your car LH 2.4 or 3.1?

Have you pulled the front hose on the fuel pressure regulator? Is there a strong fuel smell?

Travis

It's a 2.4. The hose does smell of fuel when I pull it but I assumed that was from the motor repeatedly flooding when it stalls.

Go to the 700/900 FAQ-Fuel Injection-Fuel Pressure Regulator and try the quick test to check fuel flow amount.

Travis

coil shorting underload?

I've tried another coil and that didn't fix anything. Thank you for the suggestion.

I had similar symptoms when my fuel pump relay was filled with water from a leak at the firewall. I replaced it and it immediately came back to full power.

I will not mention that I replaced both pumps, the fuel pressure relay, and the filter in an attempt to corrected the issue.

Hawkeye

I just replaced my Fuel Pump Relay and that didn't make a difference. Thanks for the input though :)

Have you checked the timing marks for the timing belt, may have slipped a tooth?
Dan

Yeah, I've checked the timing marks and everything was perfect. I was hoping that was the issue, it would have been an easy fix.

I listened to the video again about 5 times, and that's one strange event that you're having.
It sounds almost like a "Jake Brake" on a Semi that uses a compression release on the cylinders to act as a brake....you've heard them before when a Semi-Rig is going down hill.....Chaaaaaa.....Chaaaaa........

Back to the timing.
Are you sure that the camshaft is in proper timing with the crankshaft?

steve

Yeah, I know exactly what you mean. The timing definitely seems to be retarding. I am sure that the camshaft is in proper timing with the crankshaft. I've checked both physically and with a timing light, it wasn't my timing light so I can't check and see what the timing is doing when it's bogging. The bogging only happens when at idle and giving it more than 20% throttle. If I want to drive, I have to barely touch the gas until the motor reaches 1500~ RPM and then I can apply more gas. Once I am driving, it is completely pointless to give it more than 20% throttle because it doesn't produce any more power than it did. If I do it is only for a second and then it picks up again.

As I mentioned in another post, it seems similar to the symptoms for a bad Crank Position Sensor (as listed here), but Tony H said that it would sound different.

I'm going to the junkyard today to get parts for a fuel pressure tester. Hopefully this will shed some light onto something.

"The bogging only happens when at idle and giving it more than 20% throttle. If I want to drive, I have to barely touch the gas until the motor reaches 1500~ RPM and then I can apply more gas. Once I am driving, it is completely pointless to give it more than 20% throttle because it doesn't produce any more power than it did. If I do it is only for a second and then it picks up again. "

Sounds like a classic failed AMM, are you sure the spare is good? Maybe contacts pushed back in the connector.
Dan

I have tried three different AMM's, two of which were on my friends cars and the other one was a spare that my friend had. I'll double check the connectors. Thanks :)

Good answer.
That's my second guess.
Easy to check with a timing light.

steve

I listened to the video, and it sounds to me like the engine is losing ignition when you try to rev it up.
Do you have a tachometer in the car?
If so, watch it when you rev the engine and see if the tach drops to zero.
This would be a indicator of a ignition problem.

Hope this helps
steve

Could this be as silly a thing as a bad electrical ground that is "disconnecting" when the engine rocks a certain amount - as in too much torque/load to where the connection breaks? Possibly a strain on the AMM harness? It does sound like ignition is disappearing, but this may be deceptive. I'd suggest making up a new grounding lead or using a jumper cable to fake one to temporarily make a complete grounding path during testing.

Also, my Bentley manual isn't too good about explaining the TPS function any farther than the off-idle switch. In most every other car, the TPS is a potentiometer that varies resistance to tell the ECU where the throttle plate is vs RPM vs airflow/manifold press. In those cars a WOT switch is also incorporated. Is our TPS simply an off-idle switch??? Being throttle position sensitive makes me want to blame the TPS.

Good luck, you'll get it figured out! Nice clean engine BTW!
Steve

I just installed a tachometer last week, it does not drop to 0 when it bogs. Thanks for the reply

Watching the video my thought was low/poor fuel pressure. Because when you sort of "punch" the throttle like that, the FPR senses more atmospheric pressure (less intake vacuum) and should raise the fuel pressure to accommodate the larger air volume that comes with wider throttle opening.

Yours sounds like it's getting the extra air, but not matching it with needed fuel. I'd start by measuring fuel pressure at idle (36± psi), and a simulated Wide Open Throttle (45±psi) by removing and plugging the FPR vacuum hose while idling.

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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

I checked the fuel pressure and it's fine, but I found out that it's giving way too much fuel. Basically every time I start the car it is flooding the motor with gas and the plugs get soaked. I've replaced the ECT, but I'm wondering if maybe the ECT that I replaced it with could have been bad?

I'll have to build a Fuel Pressure Tester over the weekend. In the mean time, I was just looking through the FAQ and stumbled upon this post with identical symptoms, they found that the Crank Speed Sensor could be at fault. Do this seem likely to you?

Crank sensor usually will sound like an Electrical Cut out more then a bogging .
When the CPS fails it shuts off Fuel and Spark.
I think I'd look at fuel pressure first.
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.lyse.net/brox/TonyPage4.html http://cleanflametrap.com/tony/

Thanks for the reply Bruce. I haven't checked the fuel pressure yet, I will as soon as I can get my hands on a fuel pressure gauge.

plugged exhaust?? How was the condition of the cat when replaced?

I replaced the cat because the car failed smog, after that it passed smog. I thought it might be a plugged exhaust as well, so I ran the car with the muffler detached and that didn't make any difference. Thanks for the suggestion though.

Sorry, I forgot to mention this but I have also replaced the intank fuel pump and the base timing is perfect.

Well you have thrown lots of parts. Didn't see any mention of harmonic balancer. It could have separated and jumped time.
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Post Back. That's whats makes this forum work.

Thanks for the response, I forgot to mention that I have checked that and it was fine.

I believe I would do a compression test.
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Post Back. That's whats makes this forum work.

I did a compression and leakdown test about a month ago. The numbers weren't great, but they were around 150~ +- 10. The leakdown test showed that cylinders 2, 3, and 4 had 10% loss and cylinder 1 had ~15% loss.