442 84 Hurst mixture control solenoid wont energize

Highredline

n00b
Thread starter
Jun 18, 2021
2
1
When I turn the ignition key to "on" before turning to start, my fuel mixture control solenoid doesnt click and doesnt want to start. my 88 Monte does click. If I remove the Olds carb and connect it to the Monte's MCS plug, it clicks. I have replaced the Hurst brain box ECM with another ECM and it still doesnt click on the Hurst engine. Can anybody tell me if their MCS clicks when ignition turns to ON position. My Hurst has not ran in at least 4 years and I cant remember if it is supposed to click.
 

oldsmobile joe

Royal Smart Person
Nov 12, 2015
1,708
113
mpls
yes, its supposed to click. you proved it with the swap. you also proved the ecm and wiring are ok. sound like you need a need mixture control solenoid.
 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
5,414
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MC Solenoids from GM have been discontinued for 25 years now.

Original p/n is 17068805, superseded in 1983 to 17067343

If you CAN find one, try to get a Delco.

BUT, since they're like hen's teeth nowadays...I don't even know who sells them aftermarket.
 
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Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
2,629
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Galaxy far far away
MC Solenoids from GM have been discontinued for 25 years now.

Original p/n is 17068805, superseded in 1983 to 17067343

If you CAN find one, try to get a Delco.

BUT, since they're like hen's teeth nowadays...I don't even know who sells them aftermarket.

Carbs Unlimited rebuilds mixture control solenoids.
 

79 USA 1

G-Body Guru
Sep 2, 2011
716
93
Cheektowaga, New York
When I turn the ignition key to "on" before turning to start, my fuel mixture control solenoid doesnt click and doesnt want to start. my 88 Monte does click. If I remove the Olds carb and connect it to the Monte's MCS plug, it clicks. I have replaced the Hurst brain box ECM with another ECM and it still doesnt click on the Hurst engine. Can anybody tell me if their MCS clicks when ignition turns to ON position. My Hurst has not ran in at least 4 years and I cant remember if it is supposed to click.


Am I reading this correct?
When you hook the Hurst carb to the Monte Carlo SS MCS wiring the solenoid clicks correct? Same carb and MCS hooked to the MCS wiring on the Hurst will not.
The MCS then is working, you need to trace the wiring harness in the Hurst back and possibly look for a broken or cut wire as a starting point.
 

69hurstolds

Geezer
Supporting Member
Jan 2, 2006
5,414
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Yeesh. I didn't read the part about testing it on the Chevy. If it's clicking, it's good. I just zeroed in on the comment that the solenoid needed replacing so of course I provided part numbers.

The MC "Hammer" Solenoid is hooked up via terminal 18 on the ECM for the ground side. It has power from the ECM fuse. The ground wire side has the pigtail with the green connector you hook the dwell meter to. So if there's an open or a short in that ground wire somewhere, that will make sure your solenoid doesn't operate either.

If you're still interested in the troubleshooting, you COULD check the OHMs on the solenoid plug on the solenoid itself to see if the wiring is intact. Should be between 20-32 ohms if good according to CSM. If <10 ohms, it's toast, and replace/rebuild.

I have heard Oldsmobiles do not cycle click like Chevies just by turning it to "ON". Come to think of it, I don't recall the clicking going on in any of my Olds engines except when running. It's been way too long since I've tuned/checked a carb on one of these cars.

You've already proved that the solenoid is good by hooking it to your Chevy. For others, you could also unplug the MC solenoid, hook the MC solenoid directly to 12V source and ground the other side and it should click once. It's likely the only sensor equipment on the engine I can think of that you could possibly put a full 12v to without risk of toasting it. Click means good. No click means trouble.

Get the engine warm to operating temp, and in closed loop and check the dwell (dwell is better with an analog meter on these things as the digital meter may swing too fast to figure out what your dwell is, or "closed time" for the metering rods, which should be 30 degrees in six cyl. mode which equates to 50 percent duty cycle). If you have a meter with a duty cycle setting, that's even easier because you want it close as possible to 50%. If the dwell "freezes" where it is and looks stuck, put your hand over the choke and strangle it for air slightly. This should make it run more rich, which if your still in closed loop, it SHOULD want to lean out your mixture, by increasing dwell. If it doesn't move after doing that, and you know the solenoid will cycle, you're likely out of O2 sensor range (your temp should still be ok) to do anything, so the ECM will lock in on it's last known signal and go into "open" loop. Rev it part throttle again until the O2 sensor starts putting out good feedback that the solenoid can use. If the solenoid is working but not even close to 30 degrees on 6 cyl dwell, make the carb adjustments necessary to get your duty cycle where it needs to be.
 
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84 W40

Master Mechanic
Dec 9, 2009
405
93
69hurstolds is correct Oldsmobile engines never clicked in the on position engine not running. If your MC was clicking when hooked up to chevy thats tell me its working fine. I would do service test that 69hurstolds provided.
 
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Highredline

n00b
Thread starter
Jun 18, 2021
2
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Yeesh. I didn't read the part about testing it on the Chevy. If it's clicking, it's good. I just zeroed in on the comment that the solenoid needed replacing so of course I provided part numbers.

The MC "Hammer" Solenoid is hooked up via terminal 18 on the ECM for the ground side. It has power from the ECM fuse. The ground wire side has the pigtail with the green connector you hook the dwell meter to. So if there's an open or a short in that ground wire somewhere, that will make sure your solenoid doesn't operate either.

If you're still interested in the troubleshooting, you COULD check the OHMs on the solenoid plug on the solenoid itself to see if the wiring is intact. Should be between 20-32 ohms if good according to CSM. If <10 ohms, it's toast, and replace/rebuild.

I have heard Oldsmobiles do not cycle click like Chevies just by turning it to "ON". Come to think of it, I don't recall the clicking going on in any of my Olds engines except when running. It's been way too long since I've tuned/checked a carb on one of these cars.

You've already proved that the solenoid is good by hooking it to your Chevy. For others, you could also unplug the MC solenoid, hook the MC solenoid directly to 12V source and ground the other side and it should click once. It's likely the only sensor equipment on the engine I can think of that you could possibly put a full 12v to without risk of toasting it. Click means good. No click means trouble.

Get the engine warm to operating temp, and in closed loop and check the dwell (dwell is better with an analog meter on these things as the digital meter may swing too fast to figure out what your dwell is, or "closed time" for the metering rods, which should be 30 degrees in six cyl. mode which equates to 50 percent duty cycle). If you have a meter with a duty cycle setting, that's even easier because you want it close as possible to 50%. If the dwell "freezes" where it is and looks stuck, put your hand over the choke and strangle it for air slightly. This should make it run more rich, which if your still in closed loop, it SHOULD want to lean out your mixture, by increasing dwell. If it doesn't move after doing that, and you know the solenoid will cycle, you're likely out of O2 sensor range (your temp should still be ok) to do anything, so the ECM will lock in on it's last known signal and go into "open" loop. Rev it part throttle again until the O2 sensor starts putting out good feedback that the solenoid can use. If the solenoid is working but not even close to 30 degrees on 6 cyl dwell, make the carb adjustments necessary to get your duty cycle where it needs to be.
Special thanks to 69hurstolds: i finally got the time to pick up a new battery and reinstall the original carb earlier this week. Wife helped this time by turning the key while I dumped fuel in the primaries to keep it running and it finally pumped fuel into the carb and it is running. Since it has sat in one spot for I think closer to 6 years (in Florida garage, no freezing weather) , do you think I need do anything special to the transmission since it has sat that long. This has a metric trans.
 
Oct 14, 2008
7,230
113
Melville,Saskatchewan
Double check the TV cable adjustment for the Metric 2004R.
 

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