throttle on diesel sticking

[dang]

Just bought my 80 diesel caddy. I was driving on the highway and the throttle seemed to stick on full throttle then it went away. I put it in neutral and it just revved all the way up so I put it back into gear. Luckily it went back down. Is there a spring or cable I need to adjust. I sprayed the cable with some silcon grease hoping that would help. Thanks in advance, Dan.

[mortskeg]

Hey dang- is this what you are describing?
You are driving down the highway, and it seems to stick full throttle, even though you can release the pedal and it returns to the idle position? Feels like you just kicked on the "nitrous" and some nice smoke coming out the back. If this is the case then lookout! This was the demise of my beloved 1.6d.

If this sounds like the problem then you are probably floating oil up through the breather and injesting it though the intake manifold. The engine for that brief sprut is running purely on oil and nothing will slow the engine down as long as this is happening (including turning the key off as that just stops the delivery of diesel).

Since you have an 80 you may still have the 1.5, this problem is more common on that engine. The engine should have been modded to have a split breather where the just above the valve cover the breather spilts and one leg goes down to the block where the vac pump exhaust runs in. You can see where mine splits right in front of the air cleaner box and curves down to the block:

http://img.photobucket.com/albums/v400/glen_ekstrom/newengine.jpg

In addition to this many people have installed a plastic tray between the cam and the valve cover (this is standard on later models). This works to keep the oil in the engine and have less head up and out the breather. You will know if you have this or not by opening up the oil cap and if you can see cam lobes then you don't have it. My 1.5 engine has it on there and it make putting the oil in more of a pain but if it keeps my engine from eating itself then it's ok by me. By adding these two things (breather and tray) you should be able to prevent "engine run away".

I had this happen to my 1.6 a couple times while I was on the freeway (this was after my timing belt had slipped and caused some damage to the engine, but it still ran great other than this prob) and it wasn't a problem because there was no traffic around and I just rocketed up to about 75-80mph (still in gear) which kept a good load on the engine. However later that day I was heading down a 50mph highway, down hill, the traffic light in front of me turned red, and the pickup started to take off. I had no choice but to push in the clutch and brake and let the engine wrap up (no overspeed protection here as that is governed by the injection pump) and listen to the demise of my diesel engine. It was not a good sound and I wouldn't have been suprised if I had sent a rod though my oil pan or a piston through the hood. Poor 1.6:(

Even after this I will still take diesel over gas any day and I have been driving the 1.5 trouble free. Needless to say, if I ever own a diesel that hasn't been properly modded with the breather and oil defector, I will be buying them pronto. I think that vw parts place? sells the oil defector tray thing. Or I have seen them on the later 8v gas engines too, so you could probably find it at the wreckers. (My woman's 90 jetta gas had it)

If this is not the problem you had then I just did some serious typing for no reason, but I'm sure that someone else will have this problem sooner than later as it is pretty common as I have come to find out.[xx(] HOpe this helps.:)

edited to remove old forum coding (centering)

[dang]

That sounds like what happened. I can see my cam and I have a turbo on my 1.5. Could I put a pcv valve on it? Thanks.

[dang]

No pcv. I think part of the problem is with the turbo oil return goes in directly over the breather so when I am cruising at highway speeds more oil is going back to the valve cover. Guess I will have to re route that also. Do I install a T fitting from the hardware store in the valve cover and the exhaust side of the vacuum exhaust? Thanks.

[mortskeg]

Really? a 1.5 with add on turbo? Sweet. Yeah, I would think that a t-fitting right above the valve cover leading to a t right at the block where the vac pump exhausts would do the trick as long as you avoid getting funky bends in the hose where oil could pool. I will check if there is a part# listed for the hose that is on mine. I would definately find one of those trays that goes over the top of your cam. I can't imagine that a wreckers would charge more than a couple bucks for one plus the cost of a new valve cover gasket if yours is in need of replacement. Well worth the cost if it helps with not having your engine destroyed.
Since you have had runaway already I would try to avoid driving the pickup until it has been modded and then carefully to make sure that it is a-ok. let us know what you come up with.:)

[jonny]

thank ther mortskeg for the heads up, my caddy doesn't have the plastic tray either, now i can prevent it before it happens[8D]

[early_911]

mortskeg

My diesel has done this three times (only had it a week :( ) . . . as a temp measure I've disconnected the breather hose that goes to the air box . . . but it's smoking from this pipe now (think the engine is telling me it's had enough). My questions are:

1) If I reconnect as you suggest above, will the fact the hose is smoking mean I've wasted my time and money (the system will remain pressurised and I'll get the high reving problem again - i.e. leave the hose loose and simply get funny looks each time I come to a stop because of the smoke).

If it is worth trying the 'upgrade' as you suggest,
2) have you got a couple of photo's showing how you did the 'split' thing at the top of the valve cover, and also one where the hose connects to the 'block where the vac pump exhaust runs in'?

3) The oil deflector tray . . . can I simply buy the tray, or do I also need a new valve cover?

Any help apprehiated.

Thanks guys

Phil

[mortskeg]

911-
Yep, unfortunately when this starts happening it is usually a sign of more serious engine troubles, but it is amazing how long one of these will "limp by" even with huge problems. The bad part is that the engine run away will eventually try to toast the engine, or try and make you smack into the person infront of you. So it is worth these two parts for the margin of safety that they bring, but I'm not sure if it is a cure all if the engine is really bad.

That being said-
if you reconnect the hose without modification chances are you will experience the run-away again. However, leaving it loose will make the biggest imaginable mess of your engine compartment and possible respitory distress on your part due to all the oil. I tried this for a bit on mine before she blew and it was bad news.

The good news is that it is easy to upgrade, luckily I didn't have to do it on my 1.5 since it came with the parts already in place here is a closer picture of where the valve cover breather splits:
http://img.photobucket.com/albums/v400/glen_ekstrom/breathersplit.jpg

This is actually a VW part, and I'm guessing still available or easy to find in the junk yard. All it is is two rubber hoses fused together to form a y. I don't think there is anything special going on there- it just allows excess oil should it get up there, a way to return to the block. I guessing that you could also just cut your orig. hose just above the valve cover and splice in a T-fitting, then just use another piece of hose to run down to the block. Here is a pic of where the breather goes into the block:
http://img.photobucket.com/albums/v400/glen_ekstrom/crankbreather.jpg

The sprayed blue hose is the lower part of the valve cover breather and the reddish the exhaust from the brake assist vacuum pump. The plate that is bolted to the block has 2 hose fittings on it instead of the usual one, one going straight out for the vac hose (exhaust) and the other running vertical for the breather.

As for the oil no-splashy up into the breather tray- It will fit under your stock valve cover and should be the same part of any A1 & A2 gas or diesel 8V. Except for wasserboxxers or whatever else is different but you know what I mean. It simply rests ontop of the cam assembly (doesn't actually touch the cam) and you put your cover back on. Here is a picture of one installed-
http://img.photobucket.com/albums/v400/glen_ekstrom/oilsheild.jpg

Note that you do not see any cam-lobes.

Hope this helps. :td

[early_911]

Cheers mate that's exactly what I wanted/needed to know.

Actually the loose breather only dispenses oil vapor (I stuck a bottle on the end of it and it hasn't caught anything) . . . so sounds like (compared to yours) mine isn't that bad (but still bad).

Ordered the deflector . . . will sort out some hose and see what happens.

Once again . . . big thanks mate.

Phil

[Early-1800]

Don't want to state the obvious but have you changed the oil to make make sure its got some fresh correct grade stuff in the sump? Not sure it make a difference but probably worth trying for the sake of £10?

[early_911]

Well had a look last night . . . . there's nowhere for the breather pipe to go to down below . . . the thing the red and blue pipes go to (in the picture above) . . . is just a blacking off plate. There's nowhere on the 'brake assist vacuum pump' for the red pipe to go to either.

I propose to
a) install the deflector
b) reconnect to pipe to the air box
c) using a 'T' (taken off the original breather pipe) run another longer length of pipe underneath the car somewhere
d) change the oil
e) consider an engine rebuilt :rolleyes:

If any part of this proposal is wrong . . . or I'm missing something fundamental. Let me know.

Phil

[early_911]

Update . . . I'm pleased to report no problems since my 'mods'

The breather simply goes out to the front grill. The air filter seems to remain clean . . . happy bunny. Just back from a 400mile trip and she ran great . . . love it to bits.

Phil

[cmh_brickster]

Post pictures please. :)

[GypsyR]

A turbo oil return that is routed into the valve cover? That can't be good. Number one rule of adding a turbo is to make sure the oil drain goes DOWN, preferably directlyto the oil pan. There are any number of OEM examples of how the factories do just this and VW 1.6 turbodiesels are fine examples. The drain must be also rather lage large, again many OEM examples. The reason is that oil exiting the turbo tends to be "foaming" and doesn't flow well at all. Thus a turbo supply line can be the size of a pencil but the exit line is big enough to stick your thumb into.
I suspect a part of your problem is that extra foaming turbo oil is being dumped into the valve cover and isn't draining too well. Maybe dumped isn't the correct term since the valve cover is about level with the turbo. No way is the oil exiting the turbo as well as it should.
If you poke around you'll probably find a number of oil drain pics so you can see what should be on your engine. If you have no luck, let me know. I have a bare engine equipped with "turbo" pan, and drain hose on the stand in my garage. I can see about posting a pic for you if you need one.

[toddshog]

Gypsy, I believe they were talking non-turbo motors, at least that is what I was assuming.

I do have another question about this problem that seems to be fairly common. Has anyone experienced engine runaway running synthetic oil? I don't know much about synthetic oil but would assume there is less of a petrolium base to it therefore should be less of a chance on it igniting and the engine running away. I am also pretty sure on 2-stroke oils that it doesn't burn at all, just exits the exhaust.

[GypsyR]

That sounds like what happened. I can see my cam and I have a turbo on my 1.5. Could I put a pcv valve on it? Thanks.
:rolleyes:
And yes, synthetic and most certainly 2 stroke oil can also fuel engine runaway. A fully warmed and operating diesel engine can run on a surprisingly wide variety of "fuels", at least for a short time.

[toddshog]

Gypsy, my bad on the turbo, read this post quite some time ago then only re-read the original post before replying......... assuming it was the original engine supplied with the caddy. As for the syn oil, what I was wondering was the flash point of the oil compared to petroleum based oils. I realize that a diesel will run on a wide varity of oils but I am still not convinced syn will ignite. I run straight castor (bean oil) in my racing karts and this oil does attempt to burn (just look at the smoke produced) in these motors but when I run syn oil, there is no smoke just an oily film sprayed all over the kart, no smoke at all. I am not so sure that syn would ignite and runaway that is why I asked if anyone experienced this running syn.

BTW, pic too small, what are ya sitting on? Shovel or evo?

[Darth Garry]

But I doubt your go carts are running a 30:1 compression ratio either. A Diesel will pretty much burn anything. I would not recommend running synthetic as a solution to the runaway problem, it may *help*, not sure of the specs, but my gut says it'll burn. If you want to keep the engine alive, do what Mortskeg did with the split hose and baffle, and keep your fingers crossed. And if it ever does run away, stop, put it in high gear and stall it out.

Garry

[GypsyR]

Actually a '74 ironhead Sportster, my main ride since 1987.
Synthetic oil may indeed have a higher flask point but will still burn. A used car dealer's secret is to change the oil in an "oil burner" car to Mobil 1 full synthetic. This has no effect other than the smoke from the tailpipe will be almost invisible. The car is still worn out and burning oil, it just isn't so obvious.
An interesting observation about two-stroke oil, I've never run anything but bean oil. I believe everybody I know that's into racing does too. Seems like a synthetic oil might run cleaner if it's coming out of the tailpipe rather than burning. If I were still actively racing, I'd sure look into that.
Under enough pressure and heat there isn't much that ISN'T flammable. The combustion chamber of a diesel an ideal place to prove this.

[ajrn]

Mort...

Do you always run your timing belt "uncovered?" Is there an advantage-- or is it just easier to cnange the belt, and monitor 'for demise?'

I too, have a non 'baffled' and 'y-tubed' '82 1.6.. I have to repair the vac pump this week (can't stand the brake effort!).. I'm going to look at your diagrams a few more times, and create some 'home-made' y-tube of my own..

At first, I thought the 'y' was attached to the vac side of the pump.. I was trying to figure out how the engine ever got enough air to run! :screwy:

[cmh_brickster]

My caddy has the 1.6 without a drain to the engine block. It only has a breather hose going from the valve cover to the intake box. As a solution, how about removing the breather hose, plugging the hole on the airbox, and adding a breather filter to the top of the valve cover? Would this be a bad solution?

[cmh_brickster]

For my solution I ended up plugging my intake box breather hole. Then I ran a hose all the way from the valve cover breather hole underneath the car and out near the exhaust pipe. I believe I have eliminated the danger. The only side effect is the breather hose exhausts a little bit of smoke. It's not pleasant, so I may make a T fitting on my new breather hose and from the T run it into my intake box in an effort to get rid of those fumes.