sounds like a collapsed hydraulic lifter...which is causing a lazy valve....mayhaps? do an oil change, stick half a litre of ATF in, then fill the rest with oil remembering you need to be half a litre less with the oil...that might quiet things down a little

 

Low power, misfires (at high altitudes) and ticking (injectors?) at idle when hot were the symptoms I had when the IP was going out. Checking the oil pressure with a reliable gauge is a good idea.

You might try to add some SVO to the fuel to see if that makes a difference --- I guess you'd be having a hard time to get Power Service somewhere. Adding PS made a difference with the bad IP, SVO might, though I didn't try that.

 

cheers guys, gonna attack it today, the misfire is really harsh, very similar to the effects you get if you have to use a starter fluid in a diesel and it fires too early, really wondering now if the bulk of the problem is a leaky injector causing it to pre ignite at low revs.
gonna start with a good oil pressure test, if thats bad then the pans comming off but if it's good then I think I'll go for removing injectors to get em tested:think::think:

 

right, the oil pressure was just under 30psi at warm idle so we decided to try a nice new oil pump....

the manuals said you could get the oil pan off by jacking the engine up slightly.... not in a poxy van you can't, we jacked it up as far as the firewall would allow and couldn't get the pan out, we decided to drop the trans, remove the flex plate and it was still tight, the pick-up pipe caught in the pan and made removal really hard.

we found some scoring to the pump internals, some wear on the relief valve and evidence that the pan had been bashed in and the strainer had been tight against the pan.

we thought these could cause our low pressure so fitted a new pump, knocked the dents out of the pan and refitted everything.

still the same, 30psi with heavy ticking as soon as it warms up.

looks like next job is gonna be to replace a lifter which we're told can be done without removing the heads but can be a right pita in a van.

 

What's the oil pressure at cold idle (using 15W40?)?

 

yes 15/40, cold idle sees around 50psi

 

That sounds ok.

Any reason not to consider the IP going bad?

 

spent another day messing with no improvement, had it running for a while tapping away, trying to work out where the noise was coming from, the missfire got worse and we could tell it was the r/h bank that was missing and the noise appeared to be towards the front of the motor. removed the valve cover, removed the two front lifters, one had some damage on the roller so replaced them both, put it back together and it started but puffed from the intake, cracked all r/h injector line and all were firing but it was still puffing back out the intake. switched off and removed the cover again to double check the pushrods were seated correctly, couldn't see anything wrong, removed the wire from the ip to prevent it starting and turned it over on the starter, the puffing was noticable for a while then stopped. refitted covers, reconnected wire fired it up no puffing back?????
really confused now we kept it running and once warmed up the tapping returned, eventually the missfire returned and this time we had the aircleaner off so noticed that the missfire also cause a puff back out the intake?????

could it be a sticking valve???

come on guys help a poor old brit out here cos I've spent 3 days getting nowhere so far, any suggestions?????????:banghead::banghead::banghead::banghead:

 

valve could be fawked....bent valve....bad valve guide/seal....

 

must admit that I wondered if it was a sticky valve and the tick was actually the valve snapping shut, hopefully we should be able to check the compressions today, this might shed some light on the valves

 

well we did a comp test and thats ok.

owner had a hunch it could be an injector so spent most of the day removing them and replaceing them with another set that had been overhauled, guess what? yep it still taps.

if the ip was bad why would it only miss on one cylinder and only when hot and how would it make it tap and chuff out of the inlet???

guess we're gonna have to remove all the lifters if thats possible and check each one carefully, god I hate workin on dayvans, especially ones with extra sound deadening material everywhere, it makes access almost impossible

 

if the ip was bad why would it only miss on one cylinder and only when hot and how would it make it tap and chuff out of the inlet???

Only thing I can tell is that I could hear my engine ticking at hot idle when the IP was going bad. The ticking was gone after the IP was replaced. I don't know why it was ticking, could have been injectors or the IP itself, eventually the water pump, but water pumps sound totally different.

Misfires were only at high altitudes, and I can't tell which cylinder(s) were misfiring. My theory would be that the injectors and the IP were worn out unevenly so that misfires on particular cylinders might be more likely to occur than on others.

Keep in mind that when the IP is worn out, it very likely will screw up the injection timing because the IP isn't capable of building up fuel pressure to the injectors correctly. The injectors only open when a certain pressure is reached, and with a worn out IP that pressure can be reached at some time rather than when it's supposed to be reached --- or not at all. This can result in misfires.

Moreover, there seems to be some agreement that a worn IP acts differently when it's warm/hot from how it does when cold --- like no start conditions when the engine is hot but starting ok when it's cold/cooled down.

Considering all that and the 180k miles on it, I think the IP is at least suspicious.

I don't know what can cause blowing back out of the intake. Maybe seriously incorrect timing (due to worn IP) can cause that?

 

If it's that much of a pita project just replace em all and be done with it. Nothing worse than having to tear back into it again and again because of trying to be cheap the first go round. Next is the fact there was damage to the rollers on the lifters you replaced. Good chance there is more that look like that. The lifters you replace were on the cylinder that blew back right? It could still be a bad valve, you may have done the comp test and at that time it decided to work. The fact that it's blowing back into the intake is a good sign of bad problems. Get the head checked or both since it's in a van and not some thing you want to tear into again.

 

sounds to me like lee has it hit the nail on the head...i would seriously suspect the ip at this point...if its not the ip its the valves/heads....

 

thanks for all the help guys, having replaced the oil pump to increase the pressure and reconditioning the injectors we decided to go for the lifters, they were shot to bits, rollers with corners and needle bearings with loads of play. pulled a set out of another motor which all looked very good, fitted them and hey presto no tapping and no missfire, shame they made it so difficult to change them, prolly wouldn't have been too bad if it weren't a van

 

Interesting ... How did they get broken and how common is that? Is it because of the low oil pressure?

 

wear and tear/low oil pressure...good combo for trouble

 

And how was the cam? Some times they survive but not often.