K-jet 8v running issues

Thanks for the input guys

Collie - I'll add the vac pipes to the list of things to check. Are there any that you think I should particularly look out for?

Mike H - defo calibrated in clean air. I thought it would be the same both sides as well. I check twice to make sure I inserted the probe the same both sides but it still came out as above.

 

Ah......

 

Sounds like your WUR is not controlling the Control Pressure properly during warm up - no short cut here to fitting a pressure gauge and measuring it.

I have had lots of success in the past in cleaning the WUR - it is nothing more complicated than a mechanical pressure controller - you can split it and inside you will find a bi-metal strip with a heater resistor on it, they both cause a pin to apply/reduce pressure on the metal disc that varies the control pressure (all due to heat from the engine as well). You can undo the 4 screws that hold the disk in place and clean it carefully, along with the inlet and outlet gauzes.

Next on my list would be injectors - if they have done 90K plus then you would really benefit from some new ones - test them for spray pattern and more importantly leakage, some of you poor running can be because the engine is trying to wash away the leaked fuel and recharge the empty lines.

Next would be the pressure relief valve fitted to the end of the fuel pump.

The above all assumes that you have done the easy stuff like timing etc

 

Thanks for the input mate. I'm gonna have lots to do check between the quality street and turkey sandwiches!

 

Update.

Had a good read of the Haynes last night so I went out and checked the resistance across the WUR connector pins and measured 26ohms (as per haynes).Then I checked voltage at the plug and measured 13v.

I have yet to take the WUR off and inspect it but will do that in due course.

However, just after starting the engine to check the WUR voltage, I noticed fumes (steam like i.e. visible) coming from the Intake gasket area. I can only assume that the there is an issue with the inlet gasket or alternatively its coming from the exhasut manifold (difficult to tell at this stage).

Would a leak affect the running of an engine to the degree that I have mentioned at the beginning of the thread?

In addition, something which I hadn't noticed before was a constant hiss coming from the same area.

I'm not sure if the hiss is to do with all the VAC hoses and associated controllers in that area of it is either the inlet of exhaust gasket gone.

After about 30 seconds the 'fumes' disappeared but the hiss remained and was constant.

 

The hiss sounds like an air leak. More likely that you'll get this from hoses than from the manifold gaskets.

The 'fumes' could just be condensation steaming off with the heat.

 

Update.

Still got to check the VAC/air hoses but I had the WUR off earlier today and had a look to see if there was anything amiss.

I cracked it open and the WUR was absolutely spotless inside and everything seemed to be fine. Although I don't really know what to look for if something is not right but seeing as I checked it as per Haynes i'm not sure the WUR has anything to do with my running issues.

In regard to VAC/Air hoses connected to the inlet manifold, is it worth just replacing them all with OEM parts rather than mess around trying to find which one is leaking?

 

if you get a can of easy start, with the engine warm and running, spray it at various parts of the engine. if you hear a change in engine note when you spray it in a certain place, it indicates a vacuum leak as it gets sucked in and burnt. o-rings around the injectors frequently go hard and suck air.

 

This may sound daft but try disconnecting the electrical connector on your 5th injector (cold start device) mines been unplugged for about 5 years now & I've had no starting or warm up problems since. I've no idea how or why but it worked.

 

Doesn't sound daft to me. When starting from cold a couple of times I un-plugged it but it didn't make any difference.
In fact, I tried unplugging the WUR, fifth injector, plus the white plug on top of the TB (with the green and black/yellow wires) but none made it run differently i.e. increase or decrease revs.

I'm gonna see what I can do about the air/vac hoses and double check the cam timing this weekend.

 

I have an '86 K-Jet 8V and mine had exactly the same issues as you. I've sorted the cut out part of it by doing the vac hoses, this had the biggest effect. The problem is only apparent in cold weather. The other issue I have is the hunting around until it gets warm, I've not solved this really, however it is definately better. I changed the oil recently and this has made a gigantic improvement in all aspects of the engine. Fuchs Titan XTR from gsf.

Next on my list is new injectors and o rings for them, it should improve economy too.

 

Hello Mate,

Your car has EXACTLY the same symptoms as mine. Did you replace all the vac hoses with genuine parts (if so do you have part no.s etc to save me some time)?

Cheers

 

I did not buy any genuine parts. This is something that only trial and error will solve. There are so many places it can leak. I found the bung in the top of the rocker cover and the 2 tubes from the throttle body had the biggest leaks on them. The tubes have a sleeve that is used to seal either end - replace this with a new tight one. Your dizzy advance is on the end of one of them. If this is good then things are a lot more stable - less hunting around and cutting out.

 

A little update.

I double checked the timing today and found that the dizzy was a tooth out!! (good shout Mike H). I went for a quick run around the block and what a difference. It pulls cleanly from the bottom with no flat spot before 2k.

Doddsy - I've changed all the rubber VAC hoses as well (the ones between the dizzy and air box and inlet manifold) but I need to check some of the larger rubber hoses as I think some may be cracked if Mike H is correct about the constant hissing noise.

 

Ok, after having some success yesterday with timing, I have noticed something else.

There seems to be a sort of continuous metallic 'barking' sound now which is particularly prominent when cold but is still there when the engine is warm.
Its the sort of noise you get when two dry rusty parts rub against each other, only its continuous as thought its one of the rotating parts of the engine.

It sounds external but I can't work out what it is.

I can't help thinking that maybe the alternator belt is too tight and has buggered the alternator as it sounds not too disimilar to when the last one failed. Could this be it?

Oil levels are fine and no low oil pressure so I'm pretty sure it's not internal.

Any thoughts anyone?

 

Jonny - took the cam belt cover off (whilst engine was warm) to check and whilst it appeared to have stopped the noise, I double checked and lightly revved the engine with it off and the noise re-appeared at a certain revs (about 1300 - 1500 I think).

Whilst lightly rvving the engine, I tried to find where it was coming from and seemed to keep coming back to the alternator.

I double checked the belt and it's not too loose or to tight.

 

Well, I still haven't found the source of the noise but I have a few other things to check.

In the meantime, I made sure all the mechanical timing was spot on, and then did the ignition timing with a strobe (with dizzy vac unplugged).
I then did the CO at work and wound it up to 1.5 so no more flat spot and much better pull and performance when up to temperature.

From cold, it starts on the button and idles just over 1K for approx 5mins and then settles down.
However, once it settles down (and as it gets warmer), the revs drop to 750-800. After a minute or so the valve next to the airbox (the one attached to the strut tower) cuts in and raises the revs to about 900-950.
During the above time when the car is warming up (whilst driving along), when coming to a set of lights or revving the engine at a stand still, it can drop down to 800 revs again before the valve cuts in and raises revs to 900 again.

Is the above caused by an air leak of some sort? I want to change the seals on the injectors as I understand that these can perish and leak.

Now its running more consistently, it also seems like it misfires ever so slightly at idle. I realise that this could be down to a number of things, but is there anything that I shouldbe looking for first before I go looking for a needle in a haystack?

Cheers