Injection pump transmission relationship

[Dvldog8793]

Howdy
1998 Sub with 6.5 4L80e

Can a failing injection pump cause transmission no TC lockup? Or any other transmission issues?

Will a failing pump throw codes?

I know my pump is needing some work but can that cause lack of TC Lockup?

Trans seems to work good with no problems or slipping. kinda mushy shifts but pretty normal.

No SES, no Codes that I am aware of.

Thanks!

[More Power]

Any problem that can result in preventing TC lockup should set a trouble code. Are you sure the TC isn't locking?

[Dvldog8793]

Fairly sure but I have not run a scanner in real time. I will try that.
Will a failing pump throw a code?
As much as this thing is hoping around (fish-biting) going down the road I would think there should be a code and a light.....?

[arveetek]

Fairly sure but I have not run a scanner in real time. I will try that.
Will a failing pump throw a code?
As much as this thing is hoping around (fish-biting) going down the road I would think there should be a code and a light.....?

After I had owned my Tahoe for a while, I discovered the previous owner had removed the bulb in the SES indicator. I guess he didn't like looking at the light being on all the time!!

It could be you simply have a missing or burned-out bulb in the SES lamp.

Casey

[strykerAKAmack]

My TC was unlocking at speed 60-65 mph
no codes or anything , just an rpm jump .
I replaced the brake light switch .
So far so good no more erratic behavior
Part was under $15 shipped .

[Dvldog8793]

Howdy
SES light is functional, it lights up in the starting protocol.

I hadn't thought of the brake light switch but will change it out as I have one. Not sure if that is what the problem is because the IP is showing severe symptoms.
I am just trying to figure out how the two problems could be related without a SES light or trouble code....?

[DmaxMaverick]

The brake lamp switch is the most likely suspect. Brake switch activation/deactivation would be seen by the PCM as a "normal" function, so if it isn't performing as it should, the PCM won't likely see it as a problem. The switch is multi-function, so it can be bad while still operating the brake lamps correctly.

[Dvldog8793]

Howdy
OK...replaced the brake switch....no change, except now I know that the brake switch is new.

This is a you-tube video of the symptom. It starts at about 30 seconds, watch the tach, If I set the cruise it will hold better going uphill than straight and downhill is the worst.

http://youtu.be/ZGHiElOPBDU

Near as I can tell I have checked everything that I can without a scantool. My laptop cable is out on loan. Once I get it back I will try a real time scan while running.

Transmission runs through all gears with no slipping.
Is this just the failing pump?

Just cant figure why it would be so symptomatic without a code?

[phantom309]

Looks to me like your FSD is going bad...

it seems like its "fixhbiting"

does the cruise still work ok?

[strykerAKAmack]

That's what mine was doing before my PMD failed .
Mine was still under the hood but not on injector pump but on the side with a heat sink .
I picked up a extension cable and a DTech PMD and relocated to the front behind center of bumper .
My pump acted up for about a week before it gave up the ghost , After that was replaced the rpm jumping showed up {after a while} but that was related to the brake switch ,I too thought it was related to injector pump , since{brake switch} been replaced all has been good .

[Dvldog8793]

Welll....
PMD replaced
Brake switch replaced
fuel filter replaced
Lift pump replaced
Same issues so it looks like the IP is next....:mad:
Oh well....230,000 on the factory pump isn't bad.

[strykerAKAmack]

Welll....
PMD replaced
Brake switch replaced
fuel filter replaced
Lift pump replaced
Same issues so it looks like the IP is next....:mad:
Oh well....230,000 on the factory pump isn't bad.

I've had all the same replaced haven't had to get to IP......yet
Only other thing I got would be hows the injectors themselves ?
Both expensive , But just me would want to be sure that its just not one injector giving me all the trouble

[phantom309]

I have three FSD's,. all are mounted on heat sinks with long extension cables,.
the one right now thats running the truck is just tossed on the inner fender over by the master cylinder,. the one on the front bumper quit after two surges a while back (i must remember to mount the spare properly)
The third one i have will run the truck but the motor has much less performance with it and the cruise doesn't work,.
so its just an 'emergency' emergency back up :D

My experience with injection pumps, is they either work or they don't , nothing in between,.
yrrmv.

[Robyn]

A failing PMD will many times not toss a code. A failing DS4 will usually code when its having issues, but I have seen them do exactly what you are seeing.

Best thing to do is get a top notch scanner on the beast and watch the readouts "realtime" and see whats going on.

Another thing would be to get a fuel pressure gauge on it and watch the pressure while running.

First thing is to swap the PMD and see what shakes.

PMD is always a likely suspect.

Driving down the road though and having a PMD fail while rolling usually will set a pulse width error code.

[HeavyChevy95]

Have you thoroughly checkd for air leaks yet?

Replaced the lift pump too. Did you drop the tank, inspect the sender and replace the fuel strainer too?

If the answer is NO to both of those questions, might hold off on condemning the IP just yet..

[jggiedeman]

I didn't see if the Burb was 2WD or 4WD. I had previous issues with the connectors on the front diff engaging device and connections on the transfer case. Both can cause you to drop out of and stay out of OD.