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Hi, My 1990 240 5-speed wagon will crank, but no spark. Was running fine when I pulled in at home the other night. The only gauge lights that come on when key is in On position are Service, Check engine, and the yellow arrow on the far right that I think is shift position. Usually all the various lights come on in the pre-crank test display. The coil is hot at the primary terminal in that key position, but no spark at the secondary when cranked. The coil checks out ok with the proper ohms. I would guess the instrument problem and the no spark are related, but my manual isn't much help with that question. Thanks for any tips, Chris
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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don't worry about the coil, etc. you have an ignition switch problem. the fact that all the lights that should be on and aren't tells me this.
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Chuck, that's what I thought too. Seems we have a hard time connecting on the forum, so Chris found me by email and let me know the warning light issue was the D+ wire fell off the alternator tab. I'll post here if any new developments occur, but the access is very spotty for anything of an urgent nature.
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Art Benstein near Baltimore
"I usually take a two hour nap from one to four." -Yogi Berra 1925-2015
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Hi Chris,
Start with checking for OBD codes at ports A2 & A6
The computers often point to the fault.
Bill
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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The OBD just shows 1-1-1, no codes present.
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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At first glance, your post sounds like the effect of an ignition switch failure. Just be aware my memory says the switch for 1990 and later is different from those older models before airbags.
--
Art Benstein near Baltimore
I thought growing old would take longer.
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Tried to use my Haynes manual to take out the ignition switch, but it just says that after taking off the under dash and steering column covers, to unplug the electrical connector and take out a retaining screw. I've no idea how that 3 layer plastic connector with the open sided little tang on the end safely comes apart, plus it looks like there are two screws facing the cabin in the metal casting.
Checked the amplifier/power stage as instructed in the manual. With key on checked for voltage at terminals 4 and 2. It said voltage should be present. It was at 4 but not at 2, which seems reasonable considering 2 just seems to be a ground! Then it says to crank it with the connector out while checking for voltage between 5 and ground. It fluctuates between 0 and roughly 1.5v.
As stated, coil resistance is within spec. Manual says to check the ignition control unit switching function but doesn't say how to do that!
Looking at the wiring diagram I don't really see how those gauge indicators are supposed to light in the key on, not running position just before cranking. It just shows the positive going to most all of them in that position, but how it completes the circuit to test them all I don't see.
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Tried to use my Haynes manual to take out the ignition switch, but it just says that after taking off the under dash and steering column covers, to unplug the electrical connector and take out a retaining screw. I've no idea how that 3 layer plastic connector with the open sided little tang on the end safely comes apart, plus it looks like there are two screws facing the cabin in the metal casting.
Checked the amplifier/power stage as instructed in the manual. With key on checked for voltage at terminals 4 and 2. It said voltage should be present. It was at 4 but not at 2, which seems reasonable considering 2 just seems to be a ground! Then it says to crank it with the connector out while checking for voltage between 5 and ground. It fluctuates between 0 and roughly 1.5v.
As stated, coil resistance is within spec. Manual says to check the ignition control unit switching function but doesn't say how to do that!
Looking at the wiring diagram I don't really see how those gauge indicators are supposed to light in the key on, not running position just before cranking. It just shows the positive going to most all of them in that position, but how it completes the circuit to test them all I don't see.
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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The ignition switch is a small-screwdriver and mirror adventure, and deserves a bit more diagnostic before removing and replacing it. Yes, the connector just pulls off, meaning toward the firewall, and that exposes the two slotted screws retaining the switch to the lock.
Let's go over those warning lamps again. You say only CEL, Service, and Upshift lamps are on in test mode KP-II. The alternator D+ terminal provides the "ground" return through diodes in the instrument cluster for the Battery, Parking Brake, Brake Failure, and Bulb Integrity warning lamps, but the Oil Pressure and SRS lamps have independent grounds.
Because you're getting 12V at the power stage even during cranking, it could be the warning lamp symptom is not part of the reason there's no spark.
You're right on the readings at the power stage and coil, but the "ignition control switching function" or EZK or ICU output is that fluctuating voltage at pin 5, which is pretty hard to trust using a digital multimeter while cranking. The ICU gets power from two sources, one battery and one ignition switched battery. The battery source is through that 25A fuse on the fender. A good check of that circuit is to see 12V at the orange wire into the AMM with key on.
This test verifies the 25A fuse circuit (and all its potential for corrosion) passes current under the full load of the engine management electronics and fuel pumps. I'm guessing your car has LH3.1 fuel control.
--
Art Benstein near Baltimore
https://cleanflametrap.com/ign_sw.html
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Hi, Hard to get on the site. I keep getting an error message saying to try again later. Hope this email reply goes through! I'm at a loss for a next step troubleshooting this. Should I get a new coil after all, and is there a test for the red/ white wire at the negative terminal at the coil I can try? Can it be the ICU or even the ECU? This is my daily driver, if I can get it to drive again.....
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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I know it is hard to get on. I waste a lot of time; not sure why. Must be because the folks on this forum are good people, especially if they keep trying too.
You replied to my last suggestion, but without saying what I asked. Just said it is your daily if you get it running, and asked what parts need to be replaced.
Let's go over those warning lamps again. You say only CEL, Service, and Upshift lamps are on in test mode KP-II. The alternator D+ terminal provides the "ground" return through diodes in the instrument cluster for the Battery, Parking Brake, Brake Failure, and Bulb Integrity warning lamps, but the Oil Pressure and SRS lamps have independent grounds. Describe again exactly which lamps pass lamp test and which don't.
The ICU gets power from two sources, one battery and one ignition switched battery. The battery source is through that 25A fuse on the fender. A good check of that circuit is to see 12V at the orange wire into the AMM with key on. What were your results?
--
Art Benstein near Baltimore
Dear Walter,
I hope you can help me here. The other day, I set off for work leaving my husband in the house watching the TV as usual. I hadn't driven more than a mile down the road when the engine conked out and the car shuddered to a halt. I walked back home to get my husband's help. When I got home I couldn't believe my eyes. He was in our bedroom with the neighbor girl.
I am 32, my husband is 34, and the neighbor girl is 22. We have been married for ten years. When I confronted him, he broke down and admitted that they had been having an affair for the past six months. I told him to stop or I would leave him. He was let go from his job six months ago and he says he has been feeling increasingly depressed and worthless. I love him very much, but ever since I gave him the ultimatum he has become increasingly distant. He won't go to counseling and I'm afraid I can't get through to him anymore. Can you please help?
Sincerely,
Sheila
Dear Sheila:
A car stalling after being driven a short distance can be caused by a variety of faults with the engine. Start by checking that there is no debris in the fuel line. If it is clear, check the vacuum pipes and hoses on the intake manifold and also check all grounding wires. If none of these approaches solves the problem, it could be that the fuel pump itself is faulty, causing low delivery pressure to the carburetor float chamber. I hope this helps.
Walter
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Hi, Hard to get on the site. I keep getting an error message saying to try again later. Hope this email reply goes through! I'm at a loss for a next step troubleshooting this. Should I get a new coil after all, and is there a test for the red/ white wire at the negative terminal at the coil I can try? Can it be the ICU or even the ECU? This is my daily driver, if I can get it to drive again.....
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Your memory is excellent, Art. 1990 240 ignition switch is p/n 9447805. Fitment is listed as 1990-on 240, 1985-on 740/760/780 (includes prior to airbags) and 1991-on 940
If it isn't the ignition switch (would also be my prime suspect with such odd symptoms) and all fuses are double checked as okay then my next guess would be possible multiple problems, including a bad CPS as one of the common suspects for a mystery no-start with no spark.
The LH 2.4 OBD system can be used to quickly and easily verify there's a CPS signal getting through to the ECU. Refer to Engine OBD diagnostic test mode 2 (DTM 2) on port 6 in the 700/900 FAQ here, except it fails to note don't turn the ignition off after attempting cranking in order to keep the OBD system alive during and after the test as that also will turn off the flashing LED. As much as there are Check Engine OBD codes for a missing CPS/RPM signal (1-3-1 on port 2 and 2-1-4 on port 6), in my experience they are rarely ever set unless it's an intermittent/weak signal. (The ECU knows when it's getting the signal, but doesn't know when the signal is completely missing as it seemingly can't tell the diff between that and the engine simply not turning over, so a bit of a Catch 22.)
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
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