Hello all. I try to run the 6.9 at least once a month to keep the suspension pumped up and everything else from seizing up. For the last 6 months it's been in the garage hovering around 45-50F garage. Several weeks ago I decided to fill up the 6.9 since gas as $1.49. Cold startup was normal maybe 2-3 seconds of cranking before a 5 minute warmup before taking off as I normally do. On my 0.5 mile trip the gas station while running at 35mph the car starts to lose power and feels like its misfiring but still running, when I try to depress the accelerator the car stutters and chugs even more losing power but no backfiring. I apply very light throttle to maintain speed as cars are approaching and engine was still somewhat limping with the engine surging at very low rpm 1000-1200rpm (as I recall) at 20mph as I roll into the gas station. Once filled up (5 minutes or so) it starts up fine surprisingly and runs for maybe 2 minutes when at a speed of about 25mph (residential zone) again the engine suddenly the engine start stuttering and losing power and running rough. I stab the accelerator and the engine cuts out. The engine does immediately restart but will only go just above idle maybe 1100-1200rpm. If I try to accelerate the engine cuts out. I ended up limping the car back home with my feet off the pedals for fear of stalling it. Once the car was finally home it simply would not start again.
In my attempts to start (5 seconds of cranking at a time) on the 2nd or 3rd attempt the engine turns over but just for 1 second or less and then nothing after that.
In the past two weeks I have:
- Replaced all 8 injectors (all new Bosch brass body)
- Resistor 0.4ohm
- Resistor 0.6ohm
- Bosch Coil
- Distributor Cap
- Distributor Rotor
I have double checked the spark plug wire order. I have checked one of the spark plugs and the tips are not wet light brown in color but the plug threads are wet with gas. Perhaps too much fuel? I can smell a lot of gas in the engine bay (the air filter is off).
I haven't been able to take the fuel distributor off since several of the injector lines won't budge and even with the flare wrenches the points are starting to round. I have checked the air sensor plate and it does move freely and returns to the resting position with the ignition off. It seems like the plunger is not moving in time with the plate, if depressed completely and then pressing back down a moment later it seems like the plunger is slowly catching up with the air sensor plate. Maybe after 20 seconds its full tension is restored. When the car's ignition is ON there is a lot more force on the air sensor plate. I can't hear the fuel pump running when the air sensor plate is depressed but I can hear some fluid movement though the fuel distributor.
I am working on getting the cold start valve off to see if it's spraying but haven't been successful yet.
As for the WUR, I have no idea if it's working or not. Maybe it's injecting too much fuel?
This is a lot in one post but does anyone have any thoughts!? :(
Welcome to the "House of fun" ;D I think that is a song by British group, Madness ;)
Start simple first. Make very sure you have no vacuum leaks, there are many spots that may have a poor connection, or the rubber boot connecting a nipple to a hard vacuum line might look fine but actually leaks.
Also to properly diagnose fuel related issues on K-Jet you MUST have a fuel pressure gauge plumbed into the system, no other way. There are set points and ranges within which the system operates under various ambient and operating conditions, and you have to check these first as a base line before you chase other gremlins.
I am sure other members will chime in as well.
Has this issue appeared after or before the work?
I wouldn't start ripping into the CIS further until everything else has been checked. From what you've described, the fuel distributor is functioning correctly.
I would look closely at the ignition system first, making sure there hasn't been a mistake in assembly etc.
It would be worth checking air hoses and the like in case there is a large vacuum leak.
Tim
I may have to dig up the vacuum pump and splice it somewhere since the engine obviously will not run. The hard lines have cracked in several places and I have used rubber boots to splice them together.
I do not have a fuel pressure gauge unfortunately and was trying to exhaust all of my options before either acquiring one or just taking it to a knowledgeable shop
@Tim The issues appeared before the work. Right up until I drove it to the gas station the car ran fine. I started with the injectors since there is a lot of deferred maintenance which is entirely my fault but it was unclear as to what was causing the no start situation. It has all gone pear shaped now!
I will check all of the vacuum connections again and check the electrical as well. I did my best to photograph and put everything back exactly the way it was before installing the new parts. Does it matter which way the resistors go? I noticed that they interlock and so they are oriented in opposite directions.
I once had the same exact problem. In my case, it was a combination of loose rubber collars (x2) at the bottom neck of the air metering body and a sticky fuel distributor main plunger + plate not well centered (it's adjustable).
Hard to say you have the same problem, but from your description I had exactly the same symptoms. The 2 collars I'm referring to are the ones connecting the air metering body and the throttle butterfly assy. But in reality your air leaks (causing fuel mixture to go out of wack) could be coming from many different places. What is for sure is the fact that the leak is massive to cause that condition.
Good luck in your search.
Please keep us posted.
Ps.: I noticed you're in Wisconsin. Are you close to Oshkosh? I use to fly/land there every year for the biggest air show in the world. Great memories indeed.
Is your fuel pump still good? Quick check to disconnect fuel inlet to FD, Jumper relay or apply 12v directly to pump. There is a spec somewhere about vol\minute.
About the resistors, they do go a specific way as from memory the coil runs at 12v when cranking and drops to 6v when the engine's running hence the two resistors. I'm nowhere near my car at the moment but can take a pic of the orientation tomorrow.
Tim
I'm going to take a contrarian view here and suggest that it's a fuel problem. At the onset it started OK but then bogged. To be sure, check the vacuum stuff as suggested. But get that fuel pressure gauge as daantije suggests and check pressures. It will reveal much. Good luck!
Buy a pressure gauge set for $100 USD, and be sure that your WUR is giving you proper pressures.
@revilla Yes, I am about an hour away from Oshkosh. Airventure is definitely a must see!
@rumb I can unbolt the fuel inlet to the fuel distributor and test the pump. I will try to create a jumper cable and try it as polymathman demonstrated in your post back in 2016 or is that for a different car?
@raueda1 I am somewhat inclined to think it's a fuel issue as well. I had just a few spare minutes and I rechecked and reseated as many of the vaccum fittings as I could see. I noticed the EGR white and red rubber connectors are very greasy and loose from age. Can anyone reccomend replacement hard lines and the rubber connectors in the red and white colors?
I noticed on one youtube video that there is a Fuel Hose/Line; Inlet Fitting between the fuel line and the distributor. Does this have a screen or filter on it? I tried removing it and it's wrenched down far too tight and cannot remove it. I am wondering if it's worth replacing at all?
I did pull the #5 spark plug and set it on the valve cover and cranked the engine. There is a nice bright white spark so I am not immediately inclined to think it's ignition related.
Yes that coupling has a fine mesh screen and they can become plugged with crud. Best to remove it and to soak in carb cleaner and to blow it out with compressed air.
I will have to give it another try to remove it tomorrow. It was probably installed with an impact wrench!
Try soak overnight in PB Blaster that stuff has saved my bacon more than I'd like to admit 8)
The WUR also has screen in it too (below the fittings.
You could soak that FD strainer in thinners overnight to remove any crud.
Tim
It's a fuel problem.
Get a gauge.
Follow the Tech info on K jet on the Tech board under the library tab on this site.
First thing to check is your pump delivery volume. Spec is 1 lt/30 secs. To do so you need to disconnect the delivery hose entering the fuel distributor (FD) and place a container. Then you need to make the pump run. There's a less complicated method to do so rather than creating a jumper. In fact is the method recommended in the kjet CIS manual. Locate the blue connector on top of your FD. Remove the securing wire so it's easy to connect/disconnect quickly. Put your key in position 2 (without cranking the engine of course). Once the hose inside the container, disconnect the blue connector. You should hear the pump running. If not, she's dead or you have a bad electrical connection or a bad relay. This relay is used in many places in your car. Some people call then ice-cube and they have an aluminum case. Swap one temporarily to check if your pump now runs. If she does, the relay is your issue. But measure the its delivery volume anyway.
All the above can be done while you buy your pressure gage. There's a second easy method but it requires 2 people. Place the hose inside the container as explained above. Put your lever in R or D. Try to start your engine, it won't start of course thanks to the safety switch, but you should hear your pump running while the key is in crank position. One person measuring the 30 seconds and keeping the key in crank position, the other attending the hose/container at the engine.
Please let us know your findings so we can continue to help you diagnose the problem.
Cheers
I am definitely planning to test the fuel pump output tomorrow.
In the meantime is the best CIS pressure tester the S&G 33800 model? It seems to be the most purpose built tester I can find so far.
There are a bunch of K-Jet units out there. They are usually marketed for Porsches. There is not much to them. It is a fuel pressure gauge, a valve, and a set of adapters. The only thing that really matters is that you have the proper adapters. I bought Tool Aid P/N 33865 and have used it to tune my WUR after I rebuilt it.
I am also having the similar issues you are having.
I brought a 6.9 back to life from 10+ years of sitting. After replacing the fuel pump and filter, I got it to run, it ran fine and started up with no issues at first. Now after I took it around the block, it idles very low (around 550rpms), shakes/misfires bad, and when throttle is pressed, it wants to die and sometimes does. But if I press the throttle then let go of it, it Revs up smooth for a second then goes back down to 550rpms.
I am thinking that maybe something from the fuel lines/tank got into one or more injectors blocking them off or possibly catalytic converters clogged? But I'm not sure if mine has catalytic converters or if those are just resonators.
Something I was reminded of recently is the fuel strainer in the tank. It's a good spot to start for troubleshooting particularly if you suspect fuel delivery issues. You could change the filter at the same time.
Tim
When I got my 6.9, I had all these issues, and everything had to be replaced. The gas tank looked brand new when I started tearing things apart, and it had black primer rather than the body paint color. I'm not sure whether it had been replaced at some point recently in the car's life, but it looked brand new. I found rusty garbage in the lines, the fuel filter was clogged, and a brand new pump that the seller had put in was having a hard time pumping. I dropped the tank and had it coated. The strainer's screen had separated from the body and was allowing trash to enter the pump. It didn't make it past the filter, but whatever. The seller was honest enough with me and knew that I knew what I was getting into. The 6.9 had been sitting for 10+ years on his lot, he never got around to working on it, so he sold it. It ran and drove, and he said that it would easily go a few miles but to be really careful about doing that before replacing the accumulators. Indeed, he was able to load it on a carrier trailer, and the persons who took it off the trailer were able to drive it about a mile where it broke down right in front of the house.
It started, ran, and all that, but there were so many of these problems that cropped up as expected that you really can't point your finger at one thing. I ended up replacing all the lines, the filter, the strainer, the accumulator, and the pump. Forty-year-old lines are a fire hazard. I also cleaned out the little metal can (30cc looking thing). Everything was looking good, I was getting good, clean fuel, and the engine was still dying rather quickly, and the idle was terrible. The seller told me in the beginning to replace a cracked green O-ring in the back of the distributor on the mechanism where the system pressure is set, and that actually seemed to help, and it certainly needed to be done, but it didn't solve the problem. He then walked me through adjusting the mixture by 1/16 of a turn in the distributor, and when that didn't solve the problem, he suggested to buy a set of gauges and tune the WUR. I bought the gauges, removed the post from the WUR, put it on a lathe and drilled and tapped it, got some Viton O-rings from McMaster and replaced the O-ring under the metal diaphragm, and got the engine to start and idle beautifully. The seller and one of my Porsche buddies both told me that I had to have the gauges, and they were 100% right about that. Bosch put out some temperature vs. pressure graphs, and you have to go by these. The ones for the 6.9 are in the combustion manual IIRC. That's where I am now, and I am currently working on a new impeller, seal, and shaft design for the water pump as the weep hole was leaking after the engine idled for a while.
Indeed I am a big advocate of the "base line" approach, and even though it might be pricey to replace all your fuel related components, as well as spark related, I am of the opinion that after 40+ years you need to do this, even if it is just for safety's sake, especially the fuel hoses, "Car - B - Q"'s ain't fun, guys :o
This is also why I favour KJET over DJET, to blanket replace all KJET items is a cake walk and cheap compared to DJET. KJET was a lot more prevalent and was installed in millions of cars and multiple brands over the years, so you will always find parts for them at reasonable prices, DJET not so much.
Well I lightly cleaned my injectors today on the 6.9. Took them off and put some cleaner in the feed side and blew them with compressed air.
Now it runs a bit better. It doesn't want to die now when I press the throttle. It actually revs up. Misfire is still present though. I guess little by little we'll figure her out.