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I have an ongoing intermittent problem with my 240 that is driving me nuts/ rendering the car unsafe to drive. I've had it into a Volvo specialty shop multiple times and they've never heard of such a problem, and have found nothing...so now I'm throwing it out to the internet to see if anyone can help me! I have a 1993 240. On a fairly regular basis after I've been driving at highways speeds, as I come to a stop I will be almost completely stopped when all of a sudden the engine will rev way up, rendering my brakes useless. So I shut the car off, pull my parking brake and restart the car and it's back to normal. I've almost rear ended people numerous times while trying to come to a stop at a light or pulling into a parking spot. Im leaning towards it being an electrical problem? The shop I take it too says the IAC is very simple and would be unlikely to be the culprit. At this point, I'm willing to pay to throw a dart and replace something just so that I feel like I'm trying to address the problem. Any guidance/ advice would be greatly appreciated. Thanks!
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I think the excess air has to be coming in through the AMM in order to inject the additional fuel needed to rev the engine 1,000's of RPM. Excess air without a matching increase in fuel would more likely cause the engine to stall. So, how would excess air coming in through the AMM get to the intake manifold to mix with excess fuel from the injectors? Either the throttle plate or the IAC valve is opening.You can easily test if the IAC valve could cause the extreme RPM's you are experiencing. Remove the air hoses from the ICV and connect them together with a piece of tubing. Then start the engine.
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I had the same scary problem with my 1993 240 wagon. It occurred several times while driving at highway speeds. I had to shut the engine off and put the transmission in neutral, otherwise acceleration would have been out of control.
My mechanic diagnosed problem as follows: "Test and found worn out idle control valve." The mechanic replaced the valve and problem has not happened again.
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Välkommen to the brickboard?
If you seek in-person diagnostic from folks local to your area, you may get a response from someone near you in WA-state.
Yet beware of meeting folks in person to service your 240. Always weirdos seeking such opportunity.
Observe Sars-Cov-2 / COVID safety protocols.
Sites serving your region:
Volvo Club of America. See the Pacific NorthWest chapter in Portland. Send email and ask for help.
https://vcoa.org/index.php/club-overview/chapters/chapter-map
iPd in Portland has website forums. get an account, and ask for help here.
https://forums.ipdusa.com/
Else, I'd suggest a facebook forum and other contacts.
If in WA & OR and maybe Western MT, Northern ID, we have (copy and paste session into new browser tab or window while you logged into facebook)
Pacific Northwest Volvo Club of America Chapter on FaceBook
https://www.facebook.com/pnwvcoa/
Volvo Owners of the Pacific Northwest
https://www.facebook.com/groups/vopnw/
Oreggon Volvo Tuners:
https://www.facebook.com/groups/22505205325
Login and join and once accepted, enlist forum members to help you.
Volvo Owners of the Pacific Northwest Classifieds
https://www.facebook.com/groups/VolvoClassifiedsForThePacificNorthwest
If you seek a part.
Your Volvo specialty shop is incompetent and / or dishonest.
What has your Volvo specialty shop replaced / serviced? There exist different specialty shops in the Puget Sound and Pullman, WA areas.
What repairs can you perform? Do you own a set of auto repair tools, a test light and electric multimeter?
Engine control on your 1993 is not hard to diagnose. Yet one or more simultaneous symptoms can confound the individual performing root cause diagnosis.
Your 1993 Volvo 240 Bosch engine control is equipped with a (today) primitive on board diagnosis. Copy and paste URL into a new browser tab.
https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm
Does the dashboard speedometer display show a CHECK ENGINE light that remains on after engine start? Do you see a CHECK ENGINE light when you turn the key so the dash lights are on, yet before engine start?
When you use the brakes to stop, do the pedal feel off when you press the brake pedal?
Not much help here:
https://www.brickboard.com/FAQ/700-900/EnginePerformanceSymptoms.htm
Perform "1. Diagnostic Test Mode 1: Fault Code Retrieval". If the red light flashes out a code in sockets 2 (fuel) and 6 (ignition) other than 1-1-1, repeat the procedure. Record the codes and compare with the tables.
How many miles? What condition? You care for it with regular engine oil changes, air induction intake inspection, motor mount replacement every ten years, what color is the brake fluid (we hope not black), and so forth? Automatic or manual gearbox?
When the engine races, air intake manifold vacuum drops, so vacuum drops quickly and when so, and you are pressing / working the brake pedal to stop the brake power assist booster loses the vacuum it stores for the brake power assist, resulting in a hard brake pedal.
The engine breathes primarily through the air filter box, through the in-line AMM (air mass meter sensor) / MAF (mass air flow sensor), through the connected large accordion hose
Is the throttle body original? Do you use regular mineral oil or synthetic? If mineral oil, you perform oil changes every 3000-5000 miles?
Have you ever inspected and replaced the throttle body, and connected linkage and throttle cable? The gas pedal binds? It moves freely, with engine off. The gas pedal moved freely and returns when you remove your foot from the gas pedal. May be easier to move with your hands to feel for a bind.
Do you have an automatic transmission? If yes ....
The braided steel cable inside both the sheath protecting in in the accelerator pedal cable and the automatic transmission cable can wear inside the sheath, causing the throttle to not return to the closed position when you remove your foot from the accelerator pedal?
Somewhat more remotely may be an issue with electrical that powers engine control and also the engine control signaling. Using the OBD test may provide a clue as to fault.
Any exhaust leaks you are aware of? No need to hear them, yet failing exhaust that does not seal at unions, mostly upstream of the catalytic converter can be an associative cause.
The shop tested the electrical system at the batter and the engine so the high current grounds between battery, alternator, and engine are not loose or faulty?
We can discuss the air filter box flappy valve to blend preheated air in the air filter box another time as no one replaces the air filter box preheat flappy valve thermostat. (the always fail to hot, and left to fester your AMM failed, and the CHECK ENGINE light illuminate on the dash.)
Not an exhaustive set of causes to diagnose. I'm unsure of smaller vacuum line connection like that at the brake booster and air intake manifold re large enough to pass enough atmosphere to cause the engine to race. A fault of the brake booster at either the front, at the bottom, with valve that plugs in at the front with the whit vacuum valve, at the rear inside the passenger cabin, or failure of the diaphragm, will cause the engine to move to high RPMs.
I'd concentrate on throttle body action and connected linkage and (gas pedal, automatic transmission kickdown) cables. Unless you have M47 II manual 5-speed gear box!
Questions, please. We can also help you find a better service shop depending on your location.
Hope that helps.
Awaiting your response!!! We want to halps you!!!!
--
Beh.
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Check engine light is not on, I use conventional oil and change it every 3k miles. I am not aware of any exhaust leaks. The gas pedal does not bind, I do not know if the throttle body has ever been changed, but I haven't had it changed it since I've owned it. The reason I've been leaning towards thinking it's an electrical problem is because it doesn't seem like something is just getting stuck or bound up. When the car acts up, I will be slowing down, the car is behaving normally and I'll be almost at a complete stop and suddenly it'll feel like I've pushed the gas pedal to the floor... almost like something is commanding the car to accelerate out of no where. I don't actually know if the car is equipped with anything that could do such a thing but that's what it feels like.
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Hi ANDoleshel,
If I could, I'm pleased to arrive in person, with mask on, and diagnose the acceleration problem.
I did not consider asking.
Like a duh on my part. Sorry.
Yet Uncle Phil Machine Man asks you about cruise control and you reply indicating no.
1993 uses LH-Jetronic 2.4. No LH-Jetronic 3.1 in 1993 as Uncle Art has reminded us many times. I forget.
Phil Machine Man mention the throttle position sensor in the LH-Jetronic 3.1 throttle position sensor (potentiometer).
Your 1993 Volvo 240 has LH-Jetronic 2.4 using a throttle position switch (TPS). If the connection between the LH-Jetronic 2.4 throttle position switch and the wire harness (actually as connection to the LH-Jetronic 2.4 fuel injection computer [ECU] through the wire harness) is disconnected or connection interrupted, the engine races to about 1500-2400 or so RPM.
The LH-Jetronic 2.4 for some reason is very forgiving with a failing TPS, the failure begins as intermittent. No fault code is set as the then Bosch engine control is forgiving or fault tolerant.
Closing the throttle (gas pedal release) so the TPS may cause a fault of the fuel computer losing expect connection to the TPS inspite of other sensor input.
If you engine bay is bates to oil and grime, certainly around the throttle body, the TPS to wire harness connection may be fouled. There can be loss of ground connection, and the fuel computer expects that connection to ground through the TPS. Yet if a factory original TPS, it may be time to replace it.
Phil Machine Man and others already mention inspecting the TPS (throttle position sensor or switch = TPS).
So maybe ask some capable to inspect it, clean the connections, ensure the TPS ground is connected, and / or replace with new. The TPS switch lasted for about 25 years in my 1990 and 1991 240s with the TPS switch. I was able to replace these as I noticed the issue before any fault code was set.
Again, you may want to check the OBD fault codes in my prior response to you.
Also, Mitchell Service wiring diagrams. 1993 240 PDF shows LH-Jetronic 2.4.
http://www.v8volvo.se/mekartips/volvo/index.html
Sorry to not imagine and think it through and then suggest seeking the poor help you may find and I try to reverse on the facebook sites. I site the "Mighty and Powerful Art Benstein's Clean Flame Trap" Web Site for these folks to reference.
A writing exercise for me.
IT Systems and IT Systems Migration Validation Writer? Well, we'll see in some days. Too bad not in WA-state or a Nordic nation.
--
Beh.
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Ando,
Perform "1. Diagnostic Test Mode 1: Fault Code Retrieval". If the red light flashes out a code in sockets 2 (fuel) and 6 (ignition) other than 1-1-1, repeat the procedure. Record the codes and compare with the tables
Look in the FAQs for more detail as even a non-mechanic can extract any codes which may be helpful.
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Hi,
Thanks for the chat back it helps to keep the enthusiast’s enthusiasm going to keep the cars in service!
We do love the dependability and simplicity of these cars to make your own repairs!
Since you do not have a cruise control that only leaves the possibility of a wire sticking out inside the sheath, as it’s about the only way that I know cables fail unnoticed.
If you push it with your hand smoothly and it repeatedly goes back up to or very near” the stop tab of the pulley bracket, its probably ok. Have someone watch it move the pulley as you do it though.
They might observe something else hanging the pulley!
A147,000 mike car is a nice low milage car and I want to say it’s not the cable ... but a dirty throttle body just came into viewing!
Again it’s a lot of air and the IAC should not do that as it’s spring loaded to shut unless otherwise commanded to open.
Maybe it can stick, if really worn out or dirty but you say you’re changing the oil regularly and hopefully they or you clean the flame trap screen. It’s a 150k time interval and that narrows things up a bit.
The TPS or throttle position switch can cause an late idle or no idle program to stay engaged.
Hopefully you have the one that exhibits a click and not the potentiometer one on the LH 3.1?
A dirty throttle body is not a major operation to clean up and from what you are saying in might need a little TLC.
An automatic transmission can leave you a little disconnected from feeling exactly what the engine is doing as far as dying or bucking and jumping with a stick shift!
I know they made movies on cars or trucks becoming “possessed” but so far I haven’t seen Volvos used? 240 Volvos were not your conventional “style changed, throw it away” car!
No doubt I have seen odd characters used in them to promote the fact that the character might be a little odd. ((:-) William Hurt did!
Since you possess it, we will give you the benefit of the doubt that it’s only something realistic within the needing maintenance realms.
Keep being a Brickster!
Phil
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Clean the cluster of ground wires inside on top of your engine. Check the function of the power brake check valve by the master cylinder. When it start failing the engine run intermittently poor.
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Have you checked the brake booster check valve ? When it starts to fail, the engine will try correcting the engines speed to keep from stumbling.
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Hi, thanks for your responses. Unfortunately, I do not possess the skills, tools, or patience to work on my car myself. I used to work as a service advisor at an independent repair shop for 10 years (who unfortunately didn't work on Volvos) so Im probably more informed than the average customer, but i don't turn wrenches.I'm open to taking my car to a different shop, but I live on Whidbey Island and as far as I can tell there are only 2 shops within a few hours of my house. There's Rainbow in Bellingham and Daisywagon in Seattle. As for the vehicle itself, it is a 1993 240 sedan. Automatic transmission, non turbo. It has 147k miles on it, I've owned it for about 3 years and I usually put about $1500 a year into it. I probably should just give in and sign up for Facebook so that I can join all those cool Volvo groups that I'm sure are a great resource...but I really don't want to do the whole social media thing Haha.
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I had the same scary problem with my 1993 240 wagon. It occurred several times while driving at highway speeds. I had to shut the engine off and put the transmission in neutral, otherwise acceleration would have been out of control.
My mechanic diagnosed problem as follows: "Test and found worn out idle control valve." The mechanic replaced the valve and problem has not happened again.
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When the car was in the shop, he mentioned the IAC valve as a possibility but on my invoice he wrote:
"I have driven customer car over 100 miles trying to confirm complaint. Used choke cleaner down the intake tube to the idle air control unit and followed up with some lube. This particular IAC is opened by power and closes with a spring, so I have doubts about it opening unless it had a command or short in the harness. The fuel engine management ECU runs the idle and could be swapped,but I doubt this is the problem"
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Im thinking about just replacing the IAC valve as a good guess... any suggestions for brands? IPD? I'm always leery of aftermarket parts. So much garbage out there.
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Most people here are reluctant to throw money at a car without a firm diagnosis, but having a good spare part is often beneficial.
In your situation, you might want to invest in this to test with.
https://www.ebay.com/itm/90271799-Idle-Air-Control-Valve-Fits-Fiat-Peugeot-Saab-Volvo-1985-2000/191556591853?fits=Model%3A240%7CMake%
Another Brickboard member has done an internal analysis and reports that it seems well made and similar to OE. I've been running one in my 90 240 and it's been smooth as silk for 6 months. You can always upgrade later if you're feel the need.
It can be swapped in less than 5 minutes with little more than a screwdriver.
regards, Peter
PS In 1969 I was a teenager and I hitch hiked around N. America with my dog. We headed north from Vermont, west across Canada, then south from Vancouver B.C. Others were doing the same thing and many colleges at the time had bulletin boards with listings of people willing to let travellers crash with them.
So we went to the university when we got into Seattle and were referred to an older couple on Whidbey Island. They were among the most pleasant and interesting people I've ever met and we hung out there for almost a week. It was fall and their homestead, the weather, and the island were spectacularly beautiful. Since then,I've driven by couple of times without stopping, but thanks for mentioning the name. It reminds me that it's a place I'd like to revisit. Our youngest daughter has recently relocated to Vancouver B.C. so it will happen if this covid thing ever gets in control.
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That makes sense - the equivalent of a big throttle opening which kills vacuum and makes the brakes unboosted, just when you need them to be real boosted.
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My first thought was some sort of vacuum leak from the brake booster....
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Hi there,
Wish you a 240 tab Welcoming to the Brickboard!
You if come back and tell us what fixes this, you too, can become a Brickster!
I really liked the ending you have about throwing a dart at the car to hit the problem. (:-)
I have a story that follows you line of thinking.
This reminds me of a day when riding a motorcycle, during my high school days with a riding buddy girlfriend on the back.
We were on a city back street and ran our bikes up over a very steep but also a down-sided hill, at night!
Never thought about how steep so It surprised and/or scared all of us.
All the weight, of course, landed on the rear wheel.
We drove on for a few miles and I felt the rear end wiggling and it wasn’t her!
That tire became really low so I made it to a gas station.
We took the tire off the rim to fix the tube. They had a water tub at the station.
There wasn’t a hole in the tube anywhere, I mean nothing!
My buddy suggested that we “stick a knife in it” and fix that hole!
I said, What?
He was serious, but We both ended up laughing and consequently didn’t do that!
Motorcycle tubes were not normally found at your local gas stations in those mid 60’s.
I did change out the valve core though since car tires were plentiful!
It is nice that valve cores are still universal today!
By the way, It never leak down again!
So in your case, it might be electrical, if you have a cruise control, maybe with a glitch? Rare but possible?
Not many ways to get air into an engine other than through the throttle plate!
Were you using the cruise control or happen to leave it on during any of those “road trip stops” you experienced?
I think you probably have kept your eye on that or the mechanics should have check it out!
Depends on how thorough they want to be, these days,
Many of them look for the quickest buck and the shops demand it!
The term “Overhead” has two meanings , financially, intellectually and pride
I believe that on your car the cruise operates the throttle from UNDER the dash!
It’s not the most comfortable place to see things easily.
I want to say it’s just as possible the throttle pedal is being bothered by wiring activated by your feet if you don’t have the felt protection in place over the pedals?
A bad throttle cable can hang open the throttle if one and the same are used from under the dash?
We are talking about the throttle plate being held open about an eighth inch or so, to rev the engine!
Check the throttle pulley for smooth operation
I also would be looking for hanging wires or loose electrical connections above the pedals.
If you don’t have cruise control that still leaves a possible internally frayed cable.
Expect more posts, as the site hasn’t died off yet! Newer cars are not as fault free!
Phil
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The IAC valve bypasses a small amount of air around the closed throttle plate. It should not have any affect when the engine is not at idle.
You can remove and clean the valve and check it's function with a battery. If you end up buying one I would recommend Bosch as it is the OE part.
Dan
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"It should not have any affect when the engine is not at idle."
Oh, but it does. IAC is a misnomer. I found that out while driving with a DMM connected to pin 33 on the ECU.
The ECU also controls the IAC when engine braking in order to keep the intake manifold pressure - and with it the crankcase ventilation - constant.
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ANDoleshel,
Just this week we changed the main engine harness in a 1987 240. In this case, power for the alternator light shorted to the wire for the water temperature gauge and it fried the temperature compensater board mounted on the instrument cluster.
I wonder if something similar is happening, but to 1 of the wires for the IAC motor on your car.
Is there any chance your main engine harness has problems?
The insulation on the wires can deteriorate and flake off and sometimes this can happen inside the harness where it can't be seen.
About 10 years ago we changed the harness on a 1985 244 and although we knew the exposed ends of the wires were loosing insulation, we were very surprised when we dissected the main trunk of the harness that goes under the intake manifold. Upon slicing open the crispy PVC sheath, we found very little insulation remaining on the large bundle of wires inside and what turned into a small pile of insulation bits.
We couldn't believe this car drove in!!
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com
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Haven't seen this on a '93 yet (nor anything beyond '87) but Eric describes what I found on my '84, and, I think in general through the early 80's what fueled Dave Barton's replacement harness web page.
--
Art Benstein near Baltimore
If you tell the truth, you don't have to remember anything.
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Car is not equipped with cruise control, but I will check for wiring down by the pedals. Thanks for the suggestion.
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Cruise control running amok?
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The vehicle is not equipped with cruise control.
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