CUCV on hospice, wife wants to pull the plug

[johnpdo]

CUCV on hospice, wife wants to pull the plug...PROBLEMS SOLVED!! STILL ALIVE & WELL!

1986 CUCV sat all winter, then fired right up . Idles fine, and runs fine at street RPM's. If I get to 55 mph or higher, and take my foot off the fuel as in exiting onto an off ramp...there is nothing there when I put the throttle back down. For 3-4 seconds! Then a puff of black smoke out the back end and it surges on ahead at whatever speed the foot is slammed down on the throttle. This has been reproduced several times on the highway, and seems to be worse if I run the truck up to 65mph (I know). It does nothing, even if I pump the throttle. Will drop from 65mph to 55 before coming back in

Has a new fuel filter, Napa spin-on type with a water separator.
Throttle linkage was leaking diesel, so I swapped out the IP with a rebuilt Stanadyne. Then replaced the lift pump. STILL DOING IT!!!
Timing marks are lined up on the IP. Diesel guy I know says I need to advance the timing of the pump, maybe 1/8". If so, which way do I turn it? Is this done by trial and error. Getting a bit frustrated.

One other thing, it's a kick in the pants when it shifts from 1st to 2nd gear. Winds up pretty good in 1st, then wham, it pushes you ahead in 2nd. Added some transmission stuff that was supposed to help, and it did some, but still a kick in the back when it shifts. 2nd to 3rd is not so bad.
Ideas?

 

[m1008chevy]

To advance the timing on the injection pump turn it towards the driver side. For the transmission issue try adjusting the vacuum regulator valve, I believe counter clockwise if its shifting hard. Its the plastic piece bolted onto the left side of the injection pump.

 

[mike634]

Mine was shifting hard when I first got it. A vacuum line from the regulator was dry and cracked. After swapping it out it shifted fine.

 

[TGP (IL)]

Be very careful when advancing the timing.
Best way to break a crankshaft.
The marks should be always lined up if everything is with in Spec.'s
If in doubt find a reputable mechanic who has the equipment to check the marks(timing).
Tom

 

[goldneagle]

The hard shift issue is easy to fix. I replaced all the vacuum hoses and the vacuum modulator valve on the transmission since it was cheap and easy to do. Cost about $20 for all of the parts. Now it shifts smooth as silk!

 

[porkysplace]

It might help to include what model CUCV you have , 55 mph is about the top end for a stock pick-up .

 

[MarcusOReallyus]

The hard shift issue is easy to fix. I replaced all the vacuum hoses and the vacuum modulator valve on the transmission since it was cheap and easy to do. Cost about $20 for all of the parts. Now it shifts smooth as silk!

Do this before you even think about messing with the timing.

It might be 100% of the problem. If not, well, it's still small change, and money well spent.

 

[johnpdo]

Great advice, everyone! Since its Mothers Day weekend I have a few honey do jobs, but I am tackling this during the week next week, so I will give you some updates. By the way it's the m1008 pick up with a 6.2 liter diesel and has about 86,000 miles on it

 

[Keith_J]

The issue with dying on coast is injector pump, only way to fix it is remove and replace with a known good pump. Actually, it is just the vanes in the booster pump but at 86k, it is time for a new one.

 

[johnpdo]

Replaced the injector pump last weekend. It fixed the leaky seals, but the pause that happens when coasting is still there. Only happens when over 55 miles an hour it seems. I'm going to replace the fuel filter again to make sure I didn't get a lemon, as that has happened to me before. Its a spin on filter number 3123 from Napa that has a water separator. at least it's simple to do.

 

[RustyM923]

Try holding in 2nd gear and see if you can mimic the problem at similar rpm and throttle action.

 

[johnpdo]

Update: Put on a new spin-on 3123 fuel/water separator, cut 3/4" off the vacuum hose, used some spit and slid the freshly cut edge of the old line onto the modulator. Took her out for a spin Shifts like new, although I never drove a new one but it sure seems nice. Now to get a new hose. Probably will be the cheapest thing I do to this truck. Now the BAD NEWS!!! The dang pause after letting off the throttle still exists. Even at 45mph. I let it warm up for 10 minutes before taking the test drive.(Was talking to the neighbor at the fence). Idles very nicely, can rev the motor with the throttle nicely, but under load it's just a nice long (jeez, am I out of fuel) type of pause. Enough to say it is definitely not going to pull my trailer with a tractor on it yet. I do think it's the vanes in the pump. A lemon from the place that "rebuilt" it for me. Was an ebay site. I am pretty sure I didn't get the same pump back, but it sure looked pretty when I got it. Before I name names, I have sent them a nicely worded email today and will await their response. Not really looking forward to pulling that IP again, but now I'm an expert at it. ha!
Wishing all you mothers out there a Happy Mother's Day, and to the rest of you, remember your Mom.

 

[Recovry4x4]

CUCV on hospice, wife wants to pull the plug

Pull plug on non-understanding wife. LOL. If wife reads, it's a joke.

 

[johnpdo]

OK, here's the latest, and it's not getting better. Remember, at idle and low speeds it works fine. If >45mph and let off throttle, it pauses when I advance the throttle and has no power or revving of the motor for 4-5 seconds. Then it surges into power.

Called the company that did the IP rebuild. They were very helpful and said I should try several things...Here's what I did:

1. Disconnected the return fuel line and blew air down it with my compressor to make sure it wasn't blocked. I could hear air coming out the fuel filler opening with the cap off, so I'm saying that didn't work. Test drove it and confirmed, no joy.
2. Advanced the timing about 1/8". Didn't seem to change the sound, and didn't move the rpm much. Took it for a test drive. No joy. Tried 1/4" advance. Still no joy.
3. They said it could be the fuel we have now days, since it is "drier" and not as oily. Advised something that made me pause, but since they said do it, I tried it.... Took off the spin-on fuel/water separator Napa 3123 and emptied it 1/2 way. Then filled it back up with TRANSMISSION FLUID and spun it back on. They said it would smoke some, but might oil the innards of the pump (Hmmm, my old pump didn't need oiling, and if it didn't leak at the seals I would still have it on my truck). OK, big reveal... Some smoke, not as much as I thought it would be, ran a little rough and wanted to die a bit. I pushed in the throttle and gave it some rpms Hmm, seemed like it might have worked. Took it for a test drive....NO JOY!
4. Tried going in 2nd gear only to see if it still happened, as suggested by Rusty....No joy.

I am going to call them tomorrow, and they will likely issue me another mailing label. It goes by UPS. They sound like a good company, and are very helpful on the phone I am just a bit annoyed that I have to pull that pump again. I guess this time I'll be an expert at it. My neighbor and I have a saying...Anything worth doing, is worth doing twice.

 

[goldneagle]

Great advice, everyone! Since its Mothers Day weekend I have a few honey do jobs, but I am tackling this during the week next week, so I will give you some updates. By the way it's the m1008 pick up with a 6.2 liter diesel and has about 86,000 miles on it

Same as mine! Could be the vacuum hoses are originals and dry-rotted.

 

[TXFirefighter]

Adding about 2 gal of cheap ATF to my fuel tank makes mine run a lot smoother and seams to have more power.
Using ATF to fill fuel filters so something I was taught long ago. The ATF increases the lubricity of the fuel and it has a high detergent content that helps clean the injectors.
Anyway, you didn't hurt anything by using the ATF.

 

[eaw46]

Be careful using any ATF as the Red dye in it is the same as that in Off Road Fuel and if you ever get your tanks dipped by the DOT you would be hard pressed to prove you were not guilty. Eddy

 

[dstang97]

They say atf is not good to use anymore because of the additives. Use 2cycle oil instead. Sounds like a pump issue.

 

[Iceman3005]

New lift pump????

 

[rsh4364]

Certainly sounds like a fuel delivery issue.When I added a spin on fuel filter I also installed a fuel pressure gauge on inlet and outlet side of filter.Helps to pinpoint problems.If inlet pressure drops lift pump going bad or primary filter plugging or out of fuel.If outlet reading lower than input, than my secondary filter is plugging up.It helps a little.