FAQs about Fuel Injectors/Starting.

  • Any help for cold morning starts and bucking acceleration?
  • How about warm start problems?
  • Any help for cold engine performance?
  • Any advice for a slow cold idle?
  • Any answers for cold acceleration problems?

  • Any help for cold morning starts and bucking acceleration?

    Date: Wed, 22 Jan 92 19:03:22 PST
    From: senator@cco.caltech.edu (Bill Bradley (D NJ))
    To: volvo-net@me.rochester.edu
    Subject: Cold morning starts and bucking acceleration

    My father's '84 240 has had similar starting cold weather performance as John Abt was describing(dropping idle, over recovery, and having that repeat for a while) plus lousy cold weather acceleration(this is in Pittsburgh, so it gets notably below 28F) The oxy sensor, cold idle, etc checks out right on the button, and Chiltons had no suggestions. The local Volvo Rep(Barton Volvo, very helpful people, their service department will give suggestions to help you fix your car) said that it's probably deposits on the intake valves which affect the car a lot more when it's cold, but it goes away once it gets hot. Has anyone had any experience with cleaning the intake valve(the service department will blast the valves, but said that just knocking them loose with a screwdriver might do the trick) to improve cold weather starting and acceleration?

    Also, as a tip to the volvo-netter, I'm not sure how common this problem is, but I just came across a third volvo with the same problem and it's simple solution. All the ones I know of are '78 or '79 but let me know if anyone with a different vintage has experienced it. The car will run fine, but if you're doing >35-40 MPH for a while and slow down, the car will buck when you try to accelerate. The cause in the three cases I've seen is a sticking venting valve on the fuel tank letting a vacuum build in the tank(and quite an impressive one if you try to remove the cap when it's been doing this, you'll know what I mean) A little WD-40 on the vents and the problem goes away.


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    How about warm start problems?

    Subject: how about warm start problems? (fwd)
    To: volvo-net@me.rochester.edu (volvo-net)
    Date: Thu, 23 Jan 92 19:54:17 CST
    From: volvo@zaphod.b15.ingr.com (M Palmer)

    Then one day <armadillo n. a Texas speed bump> said:

    >Now, the car only starts without effort first thing in the morning. Any
    >other time it is a struggle, like cranking the starter for 30 secs before
    >the beast sputters to life. (or even multiple tries) Could it be something
    >with the starter and/or the way it was replaced? The mechanic asked me
    >if it had done this before, and I said no, and he said something about
    >a fuel <something> was not sending fuel to <somewhere>...sorry, I can't
    >remember what he said since it didn't make any sense to me (that is, I
    >don't understand this stuff very well, if you can't tell :-).

    This sounds like a problem I once had on my '77 242. The check valve had gone bad on the fuel pump. This is a small reed valve or a ball-n-spring valve that keeps fuel pressure in the lines and injection parts while the car is turned off. The fuel leaks back into the tank when this valve goes bad, and a cold start or immediately starting a just turned off engine is fine, but anywhere from 5 min. to 4 hours after it is shut off it is a bear to restart. This was about a $30 part, and 1/2 hour to replace myself.

    >What I'd like to get some opinions on, is that could the mechanic have worsened
    >the condition, and is this something that might be expensive to fix.

    Don't know what your mechanic could have done by the starter to trigger this. I could just be a coincidence (it could happen) :-)


    Michael G. Palmer | claimer dis: ether: volvo@zaphod.b15.ingr.com | In no way speaking for | Intergraph, Corp.

    Date: Fri, 24 Jan 92 10:22:30 EST
    From: wiegman (Herman L. N. Wiegman)
    To: JJOY@lucy.wellesley.edu
    Subject: Re: how about warm start problems?

    Joy, [best of luck in Tex-sas!]

    > Now, the car only starts without effort first thing in the morning.

    both Eric and Mike Palmer mentioned the check valve. This has been a problem on more than one Volvo. It is something that should be fixed first (it is hard to diagnose a bad one, you will need lots of time etc... the $30 is cheaper than your time or a mechanic's)

    The starter has a large relay in it which is controlled by the key. Once the key is turned the relay connects the battery terminals to the starter motor's feild coils. This is a heafty connection, big wires and carries a fair amount of current. The contact points of the relay can wear out over time. After a while there is very little current carrying capability left. That is why the starter wouldn't do anything sometimes. A good connection becomes 'hit er miss'.

    Solution = new or rebuilt starter (used ones also available, but you may have to replace it after a year or two, but only costs $35-$45.)

    > could the mechanic have worsened the condition, and is this something that might be expensive to fix.

    There is no correlation between the starter replacement and the check valve going bad. Could the warm start problem be due to something else? Good question. Another component is the "control pressure regulator." It is a squarish box found about 4" below the the intake manifold. The first step is to CLEAN AND CHECK ALL ELECTRICAL CONNECTIONS. Too many people have components fixed, when the problem can be atributed to a bad connection. Lot's of waisted money and parts. A tooth brush and some WD-40 is all one needs. (an old tooth brush that is :)

    >but if you backed off, and tried again it would start right up warm or cold.

    You may not have noticed the warm start problem before. I think the fuel pressure might have come back up while you tried to start the car with your old starter (the hit or miss one). You would not notice the car's inability to start due to lack of fuel pressure, because the starter wouldn't perform. So perhaps the check valve has been going down hill for a few months now. Or perhaps the mechanic tugged on the wire harness when he replace the starter.. now you'll have to have him (or yourself) chekc the electrical connections below the intake manifold.

    The ignition lead should also be checked to the coil (i.e. check spark) There is a single wire with termination on the end which sticks out by the brake booster unit. This wire is a test point for the ignition. If 12 volts is sensed when the key is in the ON position then one knows that the key is sending the signal to the ignition. Unfortunatly, corrosion and age can cause a bad connection at the ignition coil or the back of the alternator (the same wire goes to the back of the alternator, it is very close to the exhaust and oil filter, so it can easily be dammaged). Look for a single red or brown wire with a spade connector on it. There is a slim chance that this may be part of the problem.

    best 'o luck,


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    Any help for cold engine performance?

    Date: Sun, 26 Jan 92 23:34:03 EST
    From: mm@lectroid.sw.stratus.com (Michael Mahler)
    To: senator@cco.caltech.edu
    Cc: volvo-net@me.rochester.edu
    Subject: '84 cold engine preformance

    > Well, thanks for the advise to Michael Mahler, but unfortunately
    > the flaky acting Volvo in question is an early '84 and was build before the
    > external cold mix adjust.

    Then it's done in the control pressure regulator by a vacuum applied under the fuel pressure diaphragm. On some of them, there's a delay valve built in that can go bad and cause no vacuum to be applied, hence no rich acceleration when cold.

    This may also not be the problem at all, but it's something to check.

    > in the winter) and if anyone else is wondering if they have the set-up
    > Michael described, that's only the ones that have the heated O2 sensors
    > that have the external mix adjust(I'm not 100% sure on that, so if anyone
    > knows otherwise, please pipe up)

    Nope, mine has the one wire sensor and external fuel enrich.

    Date: Wed, 9 Dec 92 17:05:20 EST
    From: hwiegman (Herman L Wiegman)
    To: hwiegman@ASTRO.GE.COM, hrl@equalizer.cray.com
    Subject: Re: cold start injector

    as I recall from my '79 242 the thermal time switch is located by the # 4 intake runner. It is basically stuck up against the fire wall. It screws into the head and is exposed to the cooling fluid. The basic idea is that the switch is closed when cold and it is connected in series with the cold start injector. The current which flows to the injector also heats up the bi-metalic switch.. the colder the car.. the longer it takes to heat that bi metalic switch... the longer the cold start injector is on.


    12 Volts ===============/ =================injector=== gnd
    thermal switch
    with bi-metalic contact

    the cold start injector is easy to find and check. it is positioned on the intake manifold between the #2 and #3 intake runners. It is quite close to the top of the whole motor and the wires are easily removed to check for voltage. (there should be 12 volts accross the leads when the car is started in cold weather). The 12 volt signal should fall about 10 seconds later when the thermal time switch opens up. You can check this with a simple light bulb and wires.

    The aux air valve can also be easily inspected and checked.


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    Any advice for a slow cold idle?

    Date: Wed, 9 Dec 92 16:54:57 CST
    From: barnett@mcc.com (Jim Barnett)
    To: hrl@equalizer.cray.com
    Cc: swedishbricks@me.rochester.edu
    Subject: slow cold idle

    There are quite a few possibilities - mostly, I'd check for vacuum leaks all over - hoses on the idle bypass, injector seals, any hose that could let air leak into the fuel system after the air-flow meter.

    I had a problem with rough idle on my 80 240 that went away as soon as the car warmed up a bit. It turned out to be the injector seals - the way I figure it, they had hardened and gotten compressed, so there was a vacuum leak around them. But as the engine warmed up, the block expanded (I'm guessing) and sealed the gap.

    - Jim

    Date: Thu, 21 Jan 93 14:27:34 PST
    From: danp@oregon.cray.com (Dan Phillips ext 2499)
    To: swedishbricks@me.rochester.edu
    Subject: rough idle


    I'm new to the group, so forgive me if this topic has been hashed out before. Recently, my 86 240dl started dying when first started and then proceeded to idle very rough. At first I thought it might be the alcohol that has been added to the fuel in this area. But after a couple of tanks with an injector cleaner,the problem continued. With the high cost of parts I rule out Easter egging on these newer vehicles, so I took it to my mechanic. He eliminated an ignition problem and suspected the air flow sensor (right off of the air cleaner). To test his theory, he unplugged the connector leading to the control module and the idle smoothed out immediately. After replacing the $260 part my car runs perfect! I don't know if this is a fool proof method worth risking the money, but thought it might be useful to some of you. I've heard that on older vehicles the air flow sensor can be cleaned to fix this type of problem.

    On a side note, my mechanics are great! Two guys who used to work for a local dealer and ventured out on their own. They have 34+ years combined experience on Volvo's, and don't gouge on parts and labor. Best of all I get to talk directly with the mechanic and always have the best mechanic working on my car! If you can find guy's like this in your area, give them a try.


    Date: Wed, 31 Mar 93 11:50:29 -0500
    From: bw738@cleveland.freenet.edu (Ed Wetherell)
    To: swedishbricks@me.rochester.edu
    Subject: blue wire + 47k = fixed start problem

    heres a question for all you DL/240 people..a local independent volvo mechanic (and good friend) suggested the following fix to cold start problems on my parents '84 DL. i figured i would ask if anyone has hard of this:

    add a wire with a 47k ohm resistor between the

    starter (not the main lug or the solonoid spade,

    a third that is actually on the starter) and the

    blue wire in the efi harnass (splice in near

    the wire for the lamda sensor).

    the justification is that it sends an (extra) enrichment signal to the computer when the starter is running. im not sure where he heard of this but im fairly certain it was through a volvo tech bulletin (or some shuch thing from volvo). if there is already a blue wire attached to a third point on the starter, this is not valid. It sounded like a problem that wasn't severe enough for a recall or only showed up after X miles and X years..

    any comments would be greatly appreciated. i claim no responsibility for anything posted here, so use this info at your own risk..


    Date: Thu, 22 Apr 93 13:02:53 CDT
    From: barnett@mcc.com (Jim Barnett)
    To: swedishbricks@me.rochester.edu
    Subject: Fuel Pump/Filter Epilog and cold running problems

    >>>>> "MM" == Michael Mahler writes: MM> Also, lousy cold running on 240's (early models) can mean spent MM> injectors. If you have K-jet and you have more than 90k or so, MM> replace the injectors and their seals before you go about spending MM> the big bucks on all those sensors and regulators.

    I strongly second this - I fixed a whole bunch of cold idle problems (to the extent a car in Texas can have cold idle problems :-) on my 80 240 by just replacing a few injector seals. K-jetronic appears to be _very_ sensitive to leaks. Check for them before you spend a cent on anything else.

    - Jim

    Date: Thu, 22 Apr 93 15:11:56 EDT
    From: wiegman@orion (Herman L. N. Wiegman)
    To: memsthd@prism.gatech.edu
    Subject: Re: cold running problems
    Cc: swedishbricks@me.rochester.edu

    Mike Wileman, [and others interested in the majic 47kOhm resistor mod.]

    The 1984 LH cars seemed to have a marginal cold start enrichment which did not work too well in the extreme cold. The '85 cars had an improved "brain" which solved the cold start problems.

    I am not sure what the "improvement" was. It could have been some form of extra compensation on the cold start electronics. I think the 1984 and newer US cars have only 4 injectors (no Cold Start Injector), so the computer pulses do all the work of cold running enrichment.

    COLD START and COLD RUNNING problems (stumbling) are two differnet beasts. Cold Start is essentially limited to the time that the starter is engaged and a few seconds after that. Cold Running problems generally refer to the one to two minutes of operation before the engine is warm.

    Mike Mahler and Jim Barnett hit one of the nails on the head with their posts about K-jet cars with Cold Running problems.

    >by just replacing a few injector seals. K-jetronic appears to be
    >_very_ sensitive to leaks.

    An other "nail" on the K-jet cars is the Aux. Air Valve which is suppose to raise the idle a bit. Ideally it will prevent much of the stumbling.

    LH cars (B-23,230,234?..) should not have Cold Start problems. They may have Cold Running problems after they age.

    The LH cars w/ stumbling should have the temp sensor checked, the intake manifold/chabers cleaned (Carb cleaner), and the fuel injectors cleaned (Techron), the FI seals should be checked.. anything else? check the Air Mass Meter?

    I have the Volvo-Net Cold-HotStart wisdom in a 15k byte file. Interested?


    Herman L.N. Wiegman -> wiegman@orion.crd.ge.com
    General Electric - Corporate R&D, Schenectady NY
    - the Flying Dutchman in the DSP Swedish Brick -

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    Any answers for cold acceleration problems?

    Date: Tue, 27 Apr 93 09:12:04 EDT
    From: wiegman@orion (Herman L. N. Wiegman)
    To: swedishbricks@me.rochester.edu
    Subject: Re: Cold Accelleration Problem

    Gary, Nick, Brian, et al, [ stumbling FI problems in cool weather ]

    >{ Bingo.... >Ditto...

    Same here... like wise... me too... etc.

    I also suffered from this problem of COLD HESITATION last year. The problem progressively spread to a COLD START problem. The advice that was given to me (from many of you) was straight forward and simple...

    1) use some Techron [ I purchased 12 bottles from Auto Ego ]

    2) check the Aux. Air Valve (1976-1882) [ I oiled it w/ WD40]

    3) replace the rubber injector seals and inspect the injectors themselves [ the seals cost $7.45 for eight of them and the injectors were $15 each (K-jet CI type)... LH injectors are mucho bucks..]

    4) spread garlic on the hood and chant Gregorian Psalms...

    I forget which had the most significant impact, but 2) and 3) come to mind as being significant contributors to a better running brick. The proceedure was simple and took less than one hour. The B-23/0 motors may take a few minutes longer due to the location of a third O-ring on the fuel delivery pickup.

    good luck all,


    Herman L.N. Wiegman -> wiegman@orion.crd.ge.com
    General Electric - Corporate R&D, Schenectady NY
    - the Flying Dutchman in the DSP Swedish Brick -

    Date: 29 Apr 1993 13:45:20 -0400 (EDT)
    From: V093P9MD@ubvmsb.cc.buffalo.edu
    Subject: Re: Cold Acceleration Problem
    To: swedishbricks@me.rochester.edu

    I have mentioned this before, but will repeat it since we have a few new members. I was able to solve a cold acceleration probem by cleaning the connections to the high-voltage coil. The problem was one that had slowly gotten worse over 2 years, dispite the use of techron, and the usual maintanace, and hours of mental grinding trying to find the problem. The coil eventually got so dirty that it started to spark past the side, and then subsequently refused to start. I was amazed at the simplicity of the simplicity of the fix as I had gone through the throuble of replacing the wires, plugs, etc. nottoo long before.

    So use the techron to prevent buildup, and clean the coil if you have 80,000 miles plus. It's cheap and very easy, and it might (I hope) solve your troubles as well.

    Happy Motoring,


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