Hi all, sorry if fuel injection has been done to the death, but my type 4 2l FI is causing me issues and i cant seem to get to the bottom of them. Had it for just over a year and it ran perfect once i think. When i start it, it runs like a dog until it warms up (5mins) then normally settles down to a steady slightly uneven hum. But recently it seems very lumpy. I have just fitted a new distributer with electronic ignition, new coil, gapped the valves and set the timing. Timing seems very eratic when holding revs, but at idle sits nice and steady. Timing was 7.5 btdc but i have adjusted slightly to help the engine run nicer, so probably nearer TDC on timing at idle. It ran lovely on friday, had a lovely run out in the sun. Went out today, struggled initially to turn over and started reluctantly, ran like a dog until warm then ran ok, although felt flat on acceleration. However, as soon as i got to 45mph it started to kangaroo and shake. Off the throttle and ease it back on and i could nurse it to 55mph, just. This continued for a few miles until i pulled over. Let it idle for a few minutes whilst checking the noisy cupboard, pulled away and it did seem a little better and pulled upto 65mph although still holding back. I got home and looked at the fuel gauge! I put £30 in on friday, have done 40 miles at the most and have used half a tank! This would explain the carp running, but could someone direct me to which areas would cause this much fuel to go through. I think this has been an issue for the past year but has now started getting silly. Exhaust is heavily sooted, smells very rich to the point of making your eyes sting when behind it, and clothes need a wash to get rid of the smell. This was an issue when i first got it, but gave it a good service, new plugs, leads, oil and filter and it did run ok for a while. But now it just seems to of returned to being a dog and i am losing patience and throwing money at it for no real improvements. Fuel metering head has been opened and tinkered with and i thought i had it running better using the itinerant-air-cooled guide, but i am tuning by ear and not sure if this is making any improvements or just proving to be the cause!?? Any help/advice greatly received, or is there any fuel injection specialists in the leicestershire area that people can recommend.
LOL, I wish I was. I think fixing mine was just luck, and weeks of researching and learning about the FI, and tinkering. @Simon178 No time to reply now, I'll message later. Prepare yourself for some Babbling, I'll live up to my user name, lol. Presume you've checked for a fuel leak / smell, All vac hoses connected? Definitely replace them anyway incase split on the inside of the hoses. Check your air filter box hasnt come apart/ unclipped. Is your oil breather tank cork seal leaking? Check all your square elec connections to the FI elec components. Especially the Thermo Time Switch, which in hiding under the n/s air intake manifold hoses behind the dizzy. Just for my info - Has yours got a micro switch by the throttle cable? there are different systems. Mine doesn't have it. Have you replaced Manifold Air Take hoses? Has your EGR system been properly blocked off? I'm just saying a few things that come into my head, before I message will full info what to try and look for.
Cold start injector and aux air reg ok? Check all vac lines or just fit some new ones to be sure. Lots of info on Ratwells. Mine run awful until I changed the fuel filter (must be the correct square one for Fi)
Thanks for the replies @Babble and @IZZYBAY. I have done the fuel filter last year, not to say i cant still be blocked. This was a square plastic one. Regards vacuum lines, i have visually checked them and sprayed round them to check whilst running, nothing made a difference. The hose from the oil breather to the intake was very dry and seems to be a tapered hose with different sizes. Is there a list of hoses - lengths and diameter so i can start buying them to replace? Cant hurt to try the easier items as most seem to be pointing towards. This does seem to be an intermittent (anoying) fault as it ran almost perfectly on friday???! Mine is a '76, no micro switch by the throttle. It did have an open tube from the intake to the left side tin ware, presume this was the EGR??! Wasnt connected to anything so i made a blanking plate and removed it all. This made no difference though. There is the remains of what looks like a lever with a hole in the end, but this could just be a spring mounting post i suppose, thisnis next to the end of the egr pipe i removed from the intake. Not replaced any hoses so far, but have had most off to check visually. Happy to start replacing to rule them out, see above request for sizes and lengths. Had the auxillary air valve thing out the other day and cleaned it with carb cleaner. This seemed to move ok and must be working as the bus runs better once warmed up for 5mins. Air box ok, it is out quite a lot at the minute though. Plugs have been changed twice in 1200miles and are black all over. Oil due a change, currently running sae30 classsic oil?? Oil has previously had fuel contamination, but i found an injector had been wired wrong, 1 plugged to 2 and vice versa! Previous owners.. This has been improved but oil level does look high at the minute so maybe i need to look at the injectors a little closer? Please keep advice coming, i am just about ready to sell this pesky thing if i cant sort it, and my boys will hate me if i do!
Worth checking whether the cylinder head temp sensor is doing it's job. Run the engine up to temp, unplug it and short the lead to earth. It on the far left cylinder when looking in the back of the engine bay. http://www.ratwell.com/technical/TempSensorII.html
If the new electronic ignition is a Pertronix Ignitor II then it can suffer from dwell angle / timing modulation if the 12 volt feed is rough.. like as an electric fuel pump runs faster it causes more frequent wobble of the 12 volts. Two fixes - one put the pump feed on a fused relay straight from the battery rather than the coil Two : go to some other electronic module. I believe the Accuspark unit also adjusts dwell angle without modulation problems. You might have an issue with the thermo time switch and the 5th injector spraying extra fuel when it should not , making it very rich once the auxiliary air valve has warmed up and closed .
Hi, I'll try and explain the best I can how I fixed mine. I'm not a mechanic and knew nothing about FI, it's all self taught and lots of advice from peeps on this forum. TBH, I don't fully know what I did to fix it, as I just worked in sequence and took it all part, tested, cleaned etc. There are so many things it could be. The findings with mine were that the cork seal on the oil breather tank was leaking alot, when I took it off, it was full of 42 years of oil crud and the internal drain tube back to the engine case was blocked causing pressure inside I think. Here is a link to Samba about the cork gasket saying its a source of vacuum leak and other info https://www.thesamba.com/vw/forum/viewtopic.php?t=698926 Also on the oil breather tank, Take off the top round part - There is a diaphragm in the round bit on the top, when I blew threw it, it "Clicked" - so the diaphragm may have been stuck. - causing vacuum issue and crank case pressure ?? Here is a link to Samba, pictures and explaining how important the diaphragm is in the breather tower. https://www.thesamba.com/vw/forum/viewtopic.php?p=3557490 @davidoft and @pkrboo (Thank you) also found the O ring on the Air Flow Meter adjusting screw was split, take the screw out completely and have a look, but you'll need to reset the screw and mixture. I put tipex on the screw and wall and counted the amount of turns. Have a read through this for the amount of turns and the air flow meter. IMHO, dont adjust the internals of the air flow meter, it's a fine art that only wizards understand !! https://itinerant-air-cooled.com//viewtopic.php?t=7761 I think the diaphragm on the Decel Valve was also stuck, clicked and released when I blew through it. The Temp Sensor 2 was also replaced because it was running way too rich. There is a way of testing it on Ratwell or in the Bentley manual VWH sell them https://www.vwheritage.com/022906012-fuel-injection-temperature-sensor-for-1600-2000cc-vw-spare My S boot had a tiny split in it, I replaced it. Have a good look on the lip of it. As it's intermittent, it could be an elec connection. It was warm on Friday so it may have run ok because the Temp Sensor 2 was sensing the warmth ???? This is a good website, at the bottom there is a list of all the inj parts and pictures of them with descriptions. http://www.type2.com/bartnik/tech1.htm#fi Back of the Haynes manual has a bit of info about testing inj system parts, but bentley manual is better. (there is a Bentley manual pdf on line somewhere but I cant find it right now) Here's Ratwells link - see section 14 = really good FI help. It's for USA Smog Tests, but describes all the component issues. http://www.ratwell.com/technical/Smog.html#fi yes as @IZZYBAY and @mikedjames said , the cold start valve is a 5th injector, and maybe duff and flooding if it's not switching off, it's controlled by the Thermo Timer Switch, and may be why it's not starting very well. You can test it by disconnecting it and using a light test screw driver thingy. When you turn the key it should light up for 11 seconds and go out, meaning the cold start valve has turned off. This is also why I said to check the Thermo Timer Switch, if the square elec connector is correctly fitted - it's really awkward to get to. Testing this, disable ignition and crank it over (Follow instructions at back of haynes manual). As you've had the dizzy off, the connector may have been pulled/knocked. The Auxiliary Air Regulator opens and closes with temperature, so cleaning it out is ok, but you need to test it by blowing/sucking through it whilst its fitted in place (See back of Haynes manual) to see if its closing and opening. I replaced the elbow pipe mine https://www.customandcommercial.com...llary_air_regulator_elbow_8fslash74-79_10242/ Definitely replace the vac hoses and manifold intake hoses, visual inspection is ok, but under pressure there may be a split. Spraying the smaller 3mm on tick over there wont be much vacuum. Don't forget the one inch ish vac hose on the fuel pressure regulator, its separate from the other vac hose connections (see below Ratwell link) Here is a link to all the sizes, http://www.ratwell.com/technical/VacuumHoses.html This link shows all the vac hoses and also has lots more help further down the page. I got my 3mm from VWH https://www.vwheritage.com/n0203535-vacuum-hose-3mm-sold-per-metre-vw-spare My bus had sae30 in it when I bought it, but it runs better on 20/50, in my opinion. (Manuals say use 20/50) Mine ran ok at first with Electronic Ignition Module in it, but then started hesitation and misfired. I don't think the injection system liked elec ignition. The timing was adjusted for the elec ignition, but it still fried two dizzy modules , so I use points now. If your determined to fix it, like I was, I'd say work through all the inj parts - test and clean and replace. It's going to take time and patience. Its worth it when you fix it, The Feel Good Factor is great Well, there you go, I said I'd live up to my user name, lol. Useful or not, I thought I'd try and help you I'll help more if I can. All the best with it.
Mine is a late bay, Bosch fuel injection set-up. Had similar issues, mine was caused by a faulty pump, causing intermittent pressure and starvation issues. Fine for a few miles then would start to hesitate and loose power. I spent monthes changing leads, filters and hoses etc. Only sussed it out when it finally failed altogether and the engine wouldn't fire at all.
I had thought about the pump @Purple. When i operate the pump via the air metering box thing, the fuel makes a horrible noise, gurgling and whooshing, as it passes round the noisy cupboard to the pressure regulator. Is this a normal sound or indeed indication of a pump issue? The pump runs and stops on command though. @Babble, thanks for all the info and time you have given to write this. I will hopefully get out and start getting things to pieces again this week/end. I will be back to give my findings, if any, and ask more questions i'm sure.
My pump set up is an in-tank submersed pump as fitted to all late Brazilian bays, but the issues were all the same as you describe, and it was an intermittent fault, so the pump ran and stopped like yours does, but malfunctioned after running for a while, which makes you assume that its something to do with the ignition system when warmed up, rather than the pump malfunctioning after running for a while. If you look into fuel pump issues it can be anything from poor starting to poor acceleration and hesitation. Two things that stick in my mind - firstly I noticed very bad hesitation accelerating out of roundabouts, as if the pump couldn't cope with gravity affecting the fuel pressure. Secondly the pump whirred noisily when priming on the first key turn at start-up, but I hadn't noticed it until I fitted a new pump, which is virtually silent when priming. You might want to check that first, see how noisy your pump is when priming, especially of you've already noticed a noisy system. If it isn't the pump then at least you know you've got a brand new one fitted. With hindsight, I would have swallowed the cost of a new pump (mine was £44), rather than spend far more time and cost on replacing virtually everything else in the engine bay!
Gurgling means you might have an air leak on the inlet side of the pump... like despite the filter being newish its blocked with rust already so there is a vacuum in the pipe going to the pump from the filter that sucks air through any hole that closes up when the pump stops...
Hi, I've added a few more links in my above post, to Ratwell about the injection system, testing and checking the components . It's how they get these Buses through the Smog Test in US. and links for where to get spare parts here in UK Also two links to Samba about how important the oil breather tank seal and tanks round tower diaphragm are to crank case oil pressure and the vacuum system.
I had the same issue last year. Turned out to be the temperature sending 2 was loose in the head. But I was so frustrated that I Went for it and pulled everything apart of the fuel injection system and found multiple bad rubber pieces. If you have another computer I’d toss that in first. If it doesn’t fix the problem. Then tear it down and put it back together. I didn’t touch the injectors. Though
It's a small world ! Simons old bus is now mine...via Ian! It's been running fine all summer and we've been all over the place. Right on cue, as soon as the temp drops and the mornings are chilly the old girls not so happy....on one outing spluttering and misfiring etc.... I haven't a clue on injection either but decided to have a delve.... First thing found was the cylinder head temp sensor had worked loose and was rattling around in it's hole....so replaced with a new one and she ran a lot better. Tick over was still erratic when cold but as I was prodding and poking around it started to behave....checked the wiring and found cracks in the old insulation where the sleeving ends that may have been shorting out, so cleaned and taped up. Wasn't that! Further prodding around and wiggling stuff around the airbox would improve matters and get her idling nicely....closer look and the throttle body was moving slightly where it connects to the plenum on a tapered fitting....checked the two screws that hold it all in place and both were loose. Tightened up and all appears to be well! Fingers crossed this has solved a long running issue, as when she's behaving she's the sweetest type 4 engined bus I've ever driven !
air leaks would have been my suggestion, have you put thermal grease on the cylinder head temp sender ?
Ah...the old 'heatsink compound'...takes me back to my TV engineer days! May have to order some and give it a smear...would probably help to hold it in place once it's cured too!
