"Kick" while driving

[kane67]

Hi All,

1994 K2500 Suburban, 155t miles...
When driving OD ~50mph (3.73, 285/75/16 tires) and there comes small uphill (light load for engine), it sometimes make a clear short "kick" or like fast off/on "thing"... :confused:

What I've done:
- wastegate solenoid changed (turbo makes a nice whistle)
- fuel pump changed
- PMD changed (made a cooler for it)
- K&N cold air

Nothing helped. A/C on or off does not make difference.
I'm starting to to wonder transmission because when rpm is about 2000 (with O/D), it makes unfrequently this "kick". But when I drive with D about same rpm 2000-2500 (50-55mph), I don't feel any kicks (except personally from this great car ;) )

Can transmission (converter /lock) make such thing? Is there different oil pressure vs rpm? Lock solenoid?
Second thing might be the injection pump, but why I don't get this kick when driving "D" gear... hmmm... I'm lost :o

If there's anything to check /test myself, please let me know.

Thanks and all the best!

kane67

[surreysinner]

Ive been gettin the same thing. If im going up a hill and the truck is not pulling big boost and hi rpms its does that.

I was thinkin possible injector since they have not been done in over 100 o00 km.

[deerefanatic]

My grandma's truck does same thing.... from 48-56 mph..... I think TC lockup dropping in/out rapidly is doing it.... If you accelerate hard through that range, it doesn't do it. Also, my grandma's truck will do it even on the flat if you're lightly accelerating through the above mentioned speed range......

[kane67]

Hi,

Huoh... "good" to hear I'm not alone :o
I wonder if changing the lock solenoid would help.

Well, it's worth to try...

Best Regards, kane67

[Chevylover]

Should be normal. 48-56 mph or around 80kmh is exactly the speed, when the auto tranny close the torque converter clutch. But if you accelerate a little or a small hill comes up, the TCC will open again. If you increased you speed over about 95 kmh or 60mph the tranny should not re-open the TCC if a small hill comes up or you slightly accelerate, only if you push the pedal to metal.

Cu,
Sven

[jdcude]

I have had the same issue I think. I would describe it as if some one shut the engine off for a millisecond. Not like it dropped down a gear or the lock up convererter went from OD to Drive. A definite "Hitch". I have seen some people use stutter, but stutter brings to my mind "duhhhhh du du duhhhhh"
it's more "Duhhhh d Duhhhh"... very short in duration. For me it would happen so infrequent I never payed much mind to it. But on my last trip hauling my camper it became very frequent and I found my self hopeing just to make it home. I suspect and ordered a new FSD, and cooler as I have a new filter and lift pump. I will let you know when the part comes in and what effect if any it has in the problem.

[kane67]

Well, I just replaced new FSD (did hope it was the guilty one...) but didn't help. It's exactly a very fast off/on feeling what I doubt to be from injection pump etc.
And it's really a strong "kick", not like normal TCC release.

Well, I ordered lock solenoid. Next week I'll change oil + filter with solenoid.
Hope the best :rolleyes:

BR, kane67

[jamesvtr]

have you thought about the the filter harness for the injection pump they are like 50 bucks or some thing and when they go sour they cause a miss or "kick" when cruiseing

[kane67]

Hi,

Filter was changed 5k miles ago. (you mean fuel filter?)
Still, it makes "kick" only when cruising with OD.

-kane67

[Chevylover]

Hi,

Filter was changed 5k miles ago. (you mean fuel filter?)
Still, it makes "kick" only when cruising with OD.

-kane67

This is what he meant :

Optical_Sensor_Filter_Harness (http://www.ssdieselsupply.com/product_62_Optical_Sensor_Filter_Harness.html)

http://www.ssdieselsupply.com/images/products/fullsize/62--20041226175457.jpg


Cu,
Sven

[jdcude]

It looks like this is some kind of mod to a harness to eliminate electrical "Noise" from the alternator from interfering with the injection pump. Kinda like what you have to add to the 12v line when you add an amplifier for your stereo to eliminate the "Whirr" from you alternator. Is this assembly OEM or is it a modification?

[Husker 6.5]

It looks like this is some kind of mod to a harness to eliminate electrical "Noise" from the alternator from interfering with the injection pump. Kinda like what you have to add to the 12v line when you add an amplifier for your stereo to eliminate the "Whirr" from you alternator. Is this assembly OEM or is it a modification?

That is an OEM part. It is critical for operation of the injection pump. Also, check your fuel shut-off solenoid (1" dia. 2 1/2" tall cylinder with 1 wire coming out of it on the front top of IP) to see if the power lead to it is tight, and the connector is good. The solenoid itself could be going bad, and momentary shut-offs would starve the IP, causing the hitches or kicks you describe.

Hope this helps.

Husker 6.5

[w_huisman]

That is an OEM part. It is critical for operation of the injection pump....

Husker 6.5

Why is it critical?

Mine has been sitting on the shelf for the last 25,000 - 30,000 miles.:D

[Husker 6.5]

Why is it critical?

Mine has been sitting on the shelf for the last 25,000 - 30,000 miles.:D

The harness does two things.

1. Provides a constant reference voltage to the optical sensor.

2. Prevents exteraneous EMF and voltage surges from reaching the sensor. (Much like isolating the power source for hi-po automotive stereo systems so you don't listen to your alternator whine and sparkplugs crackle).

Since the difference in input and output signals is in millivolts, you can see how an accurate signal to the ECM is critical for determining fuel characteristics for the computer to compensate on the timing and duration of the injection pulse. You could run with out, but why run the risk of potential damage to either the sensor or ECM? ($$$)

Husker 6.5

[kane67]

Hi all,

Well, I changed trans oil + filter and the "lock solenoid" :(
It didn't help. I did a good test drive with gears 2, D and OD and I noticed same kind of "kick" when driving 2 gear only. It's always close to 2000rpm (+/- 200). I believe it must be somekind of "internal fault" in IP.

Anyway, in future I will replace shut off solenoid and place the optical harness when I order injectors fromm ssdiesel :)

BR, kane67

[3bals]

I lnow you guys said you changed fuel filters recently, but it's possible to get a bad (dirty) batch of diesel. And there is always the possibility that your filter/screen/sock on the pick up tube in your fuel tank is partially clogged from conaminates too.

I have a manual tranny and I experience a "kick or studder" on occasion, while pulling a heavier than normal load up a long grade. With exprience, that tells me that my fuel filter is starting to get dirty. Without the load doesn't do it unless I really get on it going up hill. When it really starts to anoy me, I change the filter and all is well.

I have to change filters more than normal because of the blended WVO fuel that I'm using. A prematurely clogged filter usually happens shortly after I've hurried the filtering during my blending process. So I've learned to take my time and filter thoroughly before fueling up, otherwise I'll pay for it with another $15 filter in my truck, instead of a $2 filter in my processor.

Anyhow what I'm saying is, check your fuel supply. It sounds like a fuel starvation issue to me.

Jody

[deerefanatic]

the local diesel place said it's a timing issue. They said they can retime to get rid of it, but it reduces power somewhat, and since it's not dangerous, to just leave it alone unless it bugs ya........

[kane67]

the local diesel place said it's a timing issue. They said they can retime to get rid of it, but it reduces power somewhat, and since it's not dangerous, to just leave it alone unless it bugs ya........

Ok, this is something what I thought it must be (IP)... and it's doing it like once / hour I'll let it do so ;) Engine is L65 with new PMD+ #9 resistor.

Thanks all for your comments! This is REALLY a good forum to read & learn.

Best Regards, kane67

[soundwaves]

I have this exact same problem and its driving me crazy. I replied yesterday to a surging post above which is exactly what I have. The kick your describing is another way to put it. 50-55mph stumbles, kicks, surges like crazy unless I motor through it or accelerate through then coast and repeat. I really hope someones figures this out soon because Im going mad.

[kane67]

Well, I called Monday to local Stanadyne mechanic. He thought it would be air or IP advancer not capable to advance in time (well, that's what I understood). He said it may be worn after 150k miles driven pump. He asked me to advance IP what I did (about 3mm).

Now I've been testing it over 200 miles without feeling a kick like before.
Only once a "light kick" maybe... well, now I'm too sensitive for everything :o

2000rpm (+/- 200) is the most used in daily run, in future pump will be repaired if symptoms goes more bad (I hope not :) )

-----------------------------------------------------------------------

In Finland, D fuel cost 1€/litre = 1.33 US$ x 3.8L = ~5$/gallon.

;) kane67

[sixnickel]

You guys with this kick problem this is what I would do. I would hook up a fuel pressure guage to the "T" valve (water drain ) with a hose long enough to get the guage up under a wiper blade so I could watch it while driving. Making sure the hose does not get pinched under the hood. Also making sure you don't drive into any thing while watching the guage! I had the lift pump go out on my K3500 SRW. It started good, ran good but stumbled or some might say "kick" under a load! It felt like a bad plug wire on a gas engine. If you have 3lbs or more pressure when it stumbles you should be able to rule out the fuel supply system. The first thing you did when this problem started was CHANGE the fuel filter right? The PMD/FSD will make it do this also I don't care if it is on a heat sink or not if you don't keep 23 inch pounds of torque on the mounting screws they will fail!! I recently bought a 7/64" bit for my inch lb torque wrench and you would be surprised how tight 23"lbs is IT IS TIGHT!!! Without being tight the PMD/FSD will get hot and fail!! I learnd the hard way!!!

[deerefanatic]

Mines alot tighter than that. I didn't use the measly bolts for the pmd. I used a piece of heavy angle iron as a clamp-bar and used 3/8 bolts (7/16 head) throught the heatsink with washer and clamped her down to about 20 FT-LBS!! :D

Plus arctic silver heatsink grease!!......... On a 6 x 12 heatsink...... Can ya tell I like overkill? :D