Transmission questions...

[Jgreemo]

Hi,

I've got a 700R4 with a shift kit and some other upgrades but was wondering if the TV might be acting up. I'm not missing shifts, slipping or having any other problems, but stopped at idle in gear, the truck feels like it surges a bit, like it wants to move forward. It will also drop into OD at around 35 and lug a bit at slower speeds, in traffic say and it seems reluctant to down shift at slower speeds.

I had the transmission serviced a few months back and they didn't see any issues and I have new motor and tranny mounts and harmonic balancer, so the surging doesn't appear to be coming from other possible sources of vibration.

Might this be a overly tight TV cable? It seems my shift points are stacked too tight and with OD hitting early and the tranny then not downshifting, could it be something else?

Thanks!
Jon

[DmaxMaverick]

If the TV cable is out of adjustment, it won't be intermittent, and it won't surge at idle. The throttle valve may be fouled or worn out, but it sounds more like a torque converter beginning to leave you. Try some Trans-X or TransMedic (I prefer TransMedic). If it doesn't clear up in a couple hundred miles, it isn't likely the throttle valve.

[Jgreemo]

Thanks DMAX, I'll give that a try. I did pick up a bottle of Trans-X, since TransMedic doesn't seem to be carried by anyone near me.

Jon

[joeq]

Or the TCC solenoid may be going or stuck, causing the lock-up feature to malfunction. Maybe you could temporarily unplug it, to see if the problem disappears.

[Jgreemo]

Ran a bottle of Transmedic through it and it improved the shifting quite a bit, so it looks to be the TV.

That was until Saturday and coming back from a camping trip, I noticed low power and the shifting had gone the other direction, to being very stretched out. I'm also pushing more white smoke out and considering I had just filled up, it might be bad fuel. I'll be adding more Stanadyne and a new filter to see if that helps. I've got about 80,000 miles on my injectors, so it's probably a little early to replace them, but maybe not that early.

[DmaxMaverick]

Very often, transmission and shifting issues get blamed on the transmission, when it's only a symptom of another issue. Most often, it's a power issue, which as we know, can be caused by a long list of possibilities.

Fuel quality is another wild goose, in almost all cases. If the fuel is, in fact, #2 Diesel, nothing you do will add BTU's to the fuel, short of adding a higher quality fuel. Additives won't do it. Note: "Cetane" doesn't equal BTU. If you live in an area that "winterizes" fuel, by whatever means, seasonal changes can change performance levels. However, rarely do these changes affect anything to a noticeable degree. Fuel economy can be measured, but normal indicators of power shouldn't be affected. The climate that prompts the changes is a more likely suspect.

I suggest having a closer look at the fuel supply end. Verify it is providing sufficient pressure and flow. Change the filter, to begin with. At idle, open the filter bleed valve. It should continue to idle normally, while fuel continues to flow from the bleed valve. If it stalls, and/or fuel doesn't flow, you have a problem with supply, probably the lift pump or a significant restriction. Collapsed or kinked fuel lines aren't uncommon on these old trucks. Fuel pressure at idle should a minimum of about 4 PSI, but should never drop below zero, under any condition. You'll need to install a fuel pressure gage to see this. A poor fuel supply condition can cause any/all of the symptoms you are seeing.

[Jgreemo]

Thanks Dmax, as always, you provide some great advice and insight. I'm replacing the fuel filter this week (it's not my daily driver) and will check the fuel supply and lines. I'm also hoping to dilute the fuel if it's bad, just by regularly topping it off, but we'll see if that does anything. It was running so good on Thursday, to just have the bottom drop out on Friday post fuel up, I am really hoping this is something simple.

[Dieselfume1]

switching the fuel filter base (replacing it) made a big difference. Not so much in starting, but in power. At the same time I too was experiencing shifting problems (early shift points and wouldn't shift down out of OD to pass) The only thing I changed that could have mattered was the fuel filter base. It does have better power now as well.

It's a generic part from car quest that takes a slip on fuel filter that is MUCH cheaper than buying filters for your 6.2 I can get the part number if you'd like.

[Dieselfume1]

actually, found the part number, it's 524911

it has 4 ports, two inlet, two outlet, you'll need two plugs for the unused ports. you'll also need a couple of longer bolts and a couple of 2 or 2.5 inch spacers. (you can use the original mounting holes)

[Jgreemo]

Thanks Dieselfume, I had some issues with my fuel filter block a few years ago and switched it over to a Stanadyne FM100 unit. I've not yet replaced the filter but that unit has been faultless for a few years now, so I'm hoping it's just a fouled filter, though I'll check flow out of the unit with the engine running to see if the lift pump is still alive.

[DmaxMaverick]

For future reference....

For nearly any poor engine running condition:
Step 1 - Change fuel filter.
Step 2 - Any of a hundred possibilities, but most folks don't need step 2.

[Subzilla]

Also for future reference, personally, I change my fuel filters every year right before cold weather starts. Any water or goo in the filter can play havoc in the cold weather. Filters are cheap and easy in the garage or driveway when compared to sitting on the side of the road in 20 degree temps 35 miles from home changing one out. :eek:

[Jgreemo]

Replaced the filter and power is much better but not back to where it was pre-fill up. The fuel I drained out was slightly cloudy, even after sitting for an hour, and the while the white smoke is gone, my guess is it's still bad fuel. Lift pump doesn't have that many miles on it though I'll check it and the rest of the fuel system as soon as I can.

[DmaxMaverick]

If your fuel is "cloudy", or otherwise just not right, fix that first. Don't worry about problems you don't know about, yet.

[Jgreemo]

Thanks Dmax, that's what I'll focus on. I'm going to do a full fuel system check, but in the meantime, try and figure out what to do with about 30 gallons of fuel.

[Jgreemo]

Well at long last, after house move, travel, job change and getting settled, I finally got some work done on the Sub. Checked the lift pump (checked out ok), drained the fuel tank and replaced with fresh diesel (no difference), replaced a bunch of rotten fuel line (no difference) and now replaced half the injectors, I'm still seeing the same low power issue. Hopefully, it's the drivers bank and one of the last four is the problem. Funny, it starts fine, runs great for about 30 seconds, then starts pumping white smoke and low power. Anyways, we'll see once I get the next four in.

[Jgreemo]

About to do the last two injectors behind the A/C. Anyone do this one before? Is just loosening the compressor enough to R&R the front two injectors or would it be better to drain the system and remove it completely?

Thanks!

[Robyn]

No need to drain the system.

If access is tight, just loosen the bolts and or remove them and move the compressor enough to get to the injectors.

85b Burb IIRC has the AC pump on the LH side

Should be an A6 compressor (Long delco pump)

[Jgreemo]

Ok, so the injectors are replaced and I'm still generating a lot of white smoke. To recap, I've checked the lift pump (checked ok), replaced the fuel, replaced a lot of bad fuel line, a few fuel filters and now 8 new injectors (Kennedy). It seems to run fine for about 30 seconds to a minute then starts to stumble, just a bit and making white smoke (not steam).

Any thoughts on the fuel tank/float? Injection pump? Will be checking compression next.

Thanks,
J

[Jgreemo]

Compression check came back fine, with all 8 at 400+ (410 to 420) and within 10 psi of each other. Engine was only slightly warm as I couldn't get it to operating temp, but I did have the block heater on for a few hours and it was a warm day. Was going to do a leak down test, but skipped it since none of the cylinders showed low compression and they all charged up quickly.

My guess is an IP issue so it's off to the shop. As I have a phazer gear drive, I'm not too concerned about timing as I haven't moved the pump.

[Jgreemo]

New injector pump fixed it. Runs smooth now, but idle (fast and slow) are a touch low, so I'll be adjusting that. With new injectors and a now a pump, it runs smoother than it ever did before.