Whistling sound after changing glow plugs

[cobia2017]

I changed all eight glow plugs and the glow plug relay today to get m1008 starting correctly and now it does, however, afterwards while driving I noticed a slight but unquestionably noticeable whistling noise that is proportional to RPM’s (ie higher RPMs = louder whistling and vise versa; almost sounds like a turbo) also noticed that transmission shifts much later/shifts at much higher RMP/speed in all/both shifts…I’m thinking some sort of vacuum effect…I did not use grease or anti-seize on the plugs so I’ll go back and add that tomorrow (perhaps air passing through plug threads? Doubt it) …anything else anyone can think of? Thanks

 

[WWRD99]

I changed all eight glow plugs and the glow plug relay today to get m1008 starting correctly and now it does, however, afterwards while driving I noticed a slight but unquestionably noticeable whistling noise that is proportional to RPM’s (ie higher RPMs = louder whistling and vise versa; almost sounds like a turbo) also noticed that transmission shifts much later/shifts at much higher RMP/speed in all/both shifts…I’m thinking some sort of vacuum effect…I did not use grease or anti-seize on the plugs so I’ll go back and add that tomorrow (perhaps air passing through plug threads? Doubt it) …anything else anyone can think of? Thanks

Maybe you bumped the vacuum line going to the trans...there's a valve at the the throttle cable that feeds off the vacuum pump back where a distributor would be in a gas engine...shouldn't be that tough to find.

 

[cobia2017]

Ok I’ll have to look for that…I was in that area, removed that resistor so as to bypass it because it kept smoking …but that is where a distributor would be

 

[Mullaney]

I changed all eight glow plugs and the glow plug relay today to get m1008 starting correctly and now it does, however, afterwards while driving I noticed a slight but unquestionably noticeable whistling noise that is proportional to RPM’s (ie higher RPMs = louder whistling and vise versa; almost sounds like a turbo) also noticed that transmission shifts much later/shifts at much higher RMP/speed in all/both shifts…I’m thinking some sort of vacuum effect…I did not use grease or anti-seize on the plugs so I’ll go back and add that tomorrow (perhaps air passing through plug threads? Doubt it) …anything else anyone can think of? Thanks

.
EDIT: The CUCV diesel uses a vacuum pump so the suggestion below doesn't work. Thanks reloader64 Vacuum leaks are easier to find than you might think. OR maybe I should say that figuring out where on the motor you should search a little harder. Starting fluid in a spray can... Short shot... Pointed at the rubber hoses... If the motor speeds up, you are on to something. If not, move to another spot. Repeat.

MY GUESS is that since you replaced the glow plugs, you have "unshielded" glow plugs now. Are they factory stock? The whining / whistling sound maybe is coming through the radio speakers?

 

[WWRD99]

Ok I’ll have to look for that…I was in that area, removed that resistor so as to bypass it because it kept smoking …but that is where a distributor would be

Yeah probably a good thing to remove that...the vacuum pump has a tee in it the might be leaking...I replace all that vacuum line just so it's good. It' good that it whistles...you know it's making good vacuum!

 

[cobia2017]

So is the vacuum line a rubber hose or a hard line? I didn’t think about the whistling being a good sign! Appreciate your help

 

[cucvrus]

Smoking resistors? Only time I ever had any smoking resistors was when I was off road and they were wet with mud. And resistor's do get hot. When you say smoke is it light smoke or heavy smoke. Asking because I never seen them smoke more then a small bit from moisture and mud, dirt being on them. But the last question you asked was about the vacuum line. It is rubber from the vacuum pump to the Vacuum control and rubber and metal down to the transmission modulator. Good Luck.

 

[reloader64]

"Vacuum leaks are easier to find than you might think. OR maybe I should say that figuring out where on the motor you should search a little harder. Starting fluid in a spray can... Short shot... Pointed at the rubber hoses... If the motor speeds up, you are on to something. If not, move to another spot. Repeat."

That won't work on a diesel, the vacuum doesn't come from the air intake. Starting fluid will just be sucked into the vacuum pump.

Scott

 

[Keith_J]

Glow plugs seal on the chamfer past threads. They do not have tapered threads. Just a tiny bit past finger tight. A 1/4 inch ratchet is more than adequate.
Vacuum leak is my guess too. On CUCVs, there is only one vacuum device, the transmission. Trace from the pump to the vacuum regulating valve on the injection pump (top hose to transmission)
Here, a hand held vacuum pump with gauge is handy. The hose to the transmission should hold a vacuum when tested at the VRV on the IP.

 

[cobia2017]

Smoking resistors? Only time I ever had any smoking resistors was when I was off road and they were wet with mud. And resistor's do get hot. When you say smoke is it light smoke or heavy smoke. Asking because I never seen them smoke more then a small bit from moisture and mud, dirt being on them. But the last question you asked was about the vacuum line. It is rubber from the vacuum pump to the Vacuum control and rubber and metal down to the transmission modulator. Good Luck.

Yea it was a decent amount of smoke that made me uncomfortable, no mud and no water… a little dust and the system had been not altogether working properly for a couple months (bad relay) so it may havecollected some dust but I thought I gave enough time to burn that little bit of dust off…anyway, so I took resister out and wired 12V from the other small 12v bus on firewall that is just beside the relay so as to get around the resistor

 

[cobia2017]

Glow plugs seal on the chamfer past threads. They do not have tapered threads. Just a tiny bit past finger tight. A 1/4 inch ratchet is more than adequate.
Vacuum leak is my guess too. On CUCVs, there is only one vacuum device, the transmission. Trace from the pump to the vacuum regulating valve on the injection pump (top hose to transmission)
Here, a hand held vacuum pump with gauge is handy. The hose to the transmission should hold a vacuum when tested at the VRV on the IP.

Ah that is good to know thanks! I’m a little more than “slightly more than finger tight” but nothing crazy and used a dab of anti seize this time

 

[cobia2017]

Yea it was a decent amount of smoke that made me uncomfortable, no mud and no water… a little dust and the system had been not altogether working properly for a couple months (bad relay) so it may havecollected some dust but I thought I gave enough time to burn that little bit of dust off…anyway, so I took resister out and wired 12V from the other small 12v bus on firewall that is just beside the relay so as to get around the resistor

Also, I did find the vacuum hose, it’s dry rotted and has a big crack, I tried a temp fix with duct tape but I believe air still leaking bc still that whistle

 

[WWRD99]

Also, I did find the vacuum hose, it’s dry rotted and has a big crack, I tried a temp fix with duct tape but I believe air still leaking bc still that whistle

Hopefully that's all you need to replace! There is a very short piece at the trans too....might want to change that as well since you'll have a few extra inches left over from the few feet you buy...probably need about 2 1/2 feet.

 

[cobia2017]

In conclusion and so that others may benefit, this is what happened: after I replaced the glow plugs and the GP relay, (Napa ST85 but ST94 also works) but, because of a bad glow plug card (not known at this time yet) the glow plugs stayed on all of the time, this apparently draws about 100 amps and had my alt 1 working super hard which made the whistling sound. (co-incidentally, when I removed the resistor bank, i did damage the dry rotted vacuum hose in this location which caused a late shift into 2nd and 3rd and this was rectified with a new hose however the sound remained), at this point the truck would start but the alternator would run super hot/too hot to touch and the whistling sound turned into a screeching sound. It was determined that the GP card (under dash) was the issue by removing the card and starting the truck by short grounding relay and all of a sudden the bad alt sounds went away, no bad alt 1 heat generation, and appropriate alt 1 charging of about 14.6 V. I ordered a new card from John at Hillbilly Wizard. The card is made by Atenna Climber. The card is awesome. It has added feature of a green light to show when on and red light to show when relay is closed and then red light goes off when relay back open.