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B21 Kjet low idle, no power, '78 242

Hmmm wish I had seen that earlier...I pulled an injector, stuck it in a bottle and started the car because I couldn't think of any way to get them to operate. It ran for about 3 seconds, let off a loud pop, and now it barely runs at all after I reinstalled the injector...hope I didn't break anything. I sprayed around the injector to see if the seal was bad, but no change in idle. Stepping on the throttle makes it stall out.

Also there was no fuel in the bottle, just an odor, and it didn't move at all even though it was just sitting on the top of the engine.

I'll try again the proper way, but obviously something bad happened.
 
I did 1 injector like that, it was quiet and in no danger of popping outta the bottle, didn't seem like that much pressure. Had an atomized V pattern with a white stripe in it, didn't look that bad or that great according to pics and videos I watched on K Jet injectors. I might just replace them rather than cleaning them, they are pretty cheap @ $40 each
 
Focus, man. That injector doesn't sound very bad from your description. If it wasn't pissing out a solid stream, it may meet minimum requirements.

Do you have 4 identical bottles? You should run all 4 injectors at the same time so you can compare the amount of fuel they put out. This will tell you something about the fuel distributor also.
 
I have four identical bottles. I will try that tomorrow. After reading about K Jet injectors (mostly info on Mercedes but should still apply) having the injectors cleaned should be on the maintenance schedule. I watched several videos on what the spray pattern should look like, mine look like the better dirty ones, but not as good as the clean ones. I do not have any faith in the old seals so they will definitely be replaced, already ordered. The injector socket things look fine at least.

Pretty disturbed that it barely works now, certainly couldn't drive it anywhere.

It seems to me that if the injectors are good, the only thing left is the fuel distributor. I guess I can worry about that when I get there haha.
 
I have four identical bottles. I will try that tomorrow. After reading about K Jet injectors (mostly info on Mercedes but should still apply) having the injectors cleaned should be on the maintenance schedule. I watched several videos on what the spray pattern should look like, mine look like the better dirty ones, but not as good as the clean ones. I do not have any faith in the old seals so they will definitely be replaced, already ordered. The injector socket things look fine at least.

Pretty disturbed that it barely works now, certainly couldn't drive it anywhere.

It seems to me that if the injectors are good, the only thing left is the fuel distributor. I guess I can worry about that when I get there haha.
There's a thin o-ring on the injector socket things as well.
 
Ya, ordered those also. The injector I pulled was very dirty on the outside, chunks of crud all over it. Tip was discolored but no chunks at least.
 
Ok, all 4 injectors put out the same amount of fuel. #2 and #4 injectors were pissing a stream off to the side at idle position, which slightly improved as the metering plate raised up. It still looked like vapor and not a hose, but very concentrated to one side. #1 and # 3 were better. None of them drip.

Waiting for my seals to ship now.

One thing I found that I feel I should mention is that removing the gas cap results in a loud sucking noise. It seems the longer the pump is run, the louder the noise. I replaced the cap with a new one I had sitting around but it still does it. The fuel tank has all 3 lines going to it if that matters, it does have a charcoal canister I believe.
 
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Got the fuel pressure tool, hope to use it tomorrow. I threw new fuel pumps in, which made a fractional improvement. Now the wideband can read the afr at part throttle, at the very leanest edge of lean. Full throttle is still over 18 though.

The frequency valve thing is not working apparently, no vibrations or noise from it.

If your AFR is over 18, I cannot image that the car would run well at all.

You checked the fuel spray pattern, you checked the fuel pressure, did you try disconnecting the frequency valve and then adjust the fuel trim screw in the fuel distributor? If someone messed with that screw before you got the car then they could have made the thing run horrible.

On my car with a Lambda-Sond if I perform this operation I can get the car to idle fine by adjusting the fuel trim screw. It runs better with the Lambda-Sond working overall because it adjusts the AFR in near real time as the car is driven.

The Lambda-Sond appears to have quite a lot of control over the AFR when everything is adjusted properly. Remove the Lambda-Sond from the equation by disconnecting the frequency valve and making the fuel trim adjustment.

BEWARE!!!

The fuel adjustment screw is unbelievably sensitive. You could easily go too far one way or the other and it would be a nightmare to get it back. If you need to go more than 1/8 turn either way make darn sure you document exactly how much you turned it so that you can get it back to square one.

Once you prove that you can get the car to run decently without the Lambda-Sond, reconnect the frequency valve and start troubleshooting the Lambda-Sond functionality. You might very well need to set your fuel trim screw back to where you found it before you made any adjustments when you get to this step, depending what is actually wrong with your car.

I have an innovate Wideband on my 242 and I can trick the Lambda-Sond into making the engine run richer, and it can be made to run really rich at idle. The Lambda-Sond has the capability (in my car at least) to exert a lot of influence over the AFR.

At full throttle in 3rd gear I can keep around 14:1 AFR. I might be able to make it go richer, I haven't really tried. At idle I can push it to at least 11:1 AFR.

If you do decide to adjust the fuel trim, just be really careful like I mentioned above and take note of what you changed.

If you can't manually make the car run richer with the method I outlined above, you have other problems somewhere.
 
Yes it runs terrible. Now it doesn't run hardly at all, not sure why, the only thing that is different after all my testing is the black spot starting on the NEW fuel pump relay.

I have not tried to adjust the fuel adjustment screw, I have been following everyone's patient step by step diagnosis routine, because K Jet is all new to me. If I'm out of things to test, that makes sense to adjust the fuel screw. I wouldn't be surprised if it was messed with.

I have to wait for my injectors and seals to arrive, in the meantime I have to do something about this appalling fuel pump relay setup. I ordered a 4th relay to install :grrr:, that's the 3rd new one...
 
Have you done the relay-relay conversion you described?

I have been away and just tried to catch up with you saga. That fuel adjustment screw is really a BFD and you need the earlier mentioned dwell meter to adjust it. While I understand the big picture of your wide-band sensor operation how it may link to dwell of the frequency valve is a little vague.

The fuel adjustment screw is unbelievably sensitive. You could easily go too far one way or the other and it would be a nightmare to get it back. If you need to go more than 1/8 turn either way make darn sure you document exactly how much you turned it so that you can get it back to square one.

That 1/8 turn is indeed critical.
 
Thanks for checking it out! I have not done it yet but I do have the relay. I will probably get that done tomorrow, while I'm waiting for my new relay and other parts.

Guess I will check out ebay for a dwell meter, I asked around and I don't know anyone who owns one.
 
One thing I found that I feel I should mention is that removing the gas cap results in a loud sucking noise. It seems the longer the pump is run, the louder the noise. I replaced the cap with a new one I had sitting around but it still does it. The fuel tank has all 3 lines going to it if that matters, it does have a charcoal canister I believe.

The charcoal canister or the lines to it are plugged. I had this happen. Beware, the vacuum can collapse a tank. Unplug the line to the tank at the canister and try to blow air in, If the air flows free, swap out the charcoal canister. It is possible to cut them open and replace the charcoal with pelleted activated charcoal from a fishtank store. Temporarily I just left the gas cap a little loose. That car is carbed, but I did notice that if I opened the gas cap when the engine was running, and released the vacuum, the engine sound/rpm changed a little. The vacuum could be making the pump work harder but I dont think it would cause all the issues you are seeing. It may be adding to them a bit though.

Btw, charcoal canisters are very interchangeable, there are a couple basic types but within a type, they can usually be swapped between car makes and models. As far as I remember they are 2 hose and 3 hose, though I dont remember what the difference is.
 
Ah, thanks. I blew through the line at the fuel tank end, it took some pressure and sounded like the sound a balloon makes when you let the air out while stretching the end, squeaky kinda noise. I will try it from the canister end. Good to know about interchangeability.
It is a fairly good amount of vacuum, I was wondering about vapor locking the fuel pump, that happened to me before on a Porsche 944, which did cause serious running issues.
I found a sweet tested Snap On multimeter on ebay with dwell for a good price, but I don't know if it's complete. If it is, I will get it. If it's not, I'll grab that one from Amazon
 
Ah, thanks. I blew through the line at the fuel tank end, it took some pressure and sounded like the sound a balloon makes when you let the air out while stretching the end, squeaky kinda noise. I will try it from the canister end. Good to know about interchangeability.
It is a fairly good amount of vacuum, I was wondering about vapor locking the fuel pump, that happened to me before on a Porsche 944, which did cause serious running issues.
I found a sweet tested Snap On multimeter on ebay with dwell for a good price, but I don't know if it's complete. If it is, I will get it. If it's not, I'll grab that one from Amazon

I forgot to mention to blow into the hose at the canister end with the gas cap off. Don't want to pressurize tank, just test if line is plugged.
 
One thing I found that I feel I should mention is that removing the gas cap results in a loud sucking noise. It seems the longer the pump is run, the louder the noise.

That is crucial info. Are you sure it is sucking and not pressure? The way the tank vent system works is by letting air into the tank by way of the filler cap, but the cap does not let any air out if working properly. All air leaving the tank travels in a pipe that goes to the charcoal canister (should be under the hood on rt side near the washer tank). At the tank end, this pipe is connected to a little spigot on the filler pipe.

The vent pipe should have a check valve in it so air can leave the tank but cannot enter it that way. I have seen the check valve near the filler pipe (in the trunk) and I have seen others under the hood next to the connection to the charcoal canister. The vent pipe is small and it or the check valve can become blocked. I have had a crack develop in my tank due to oil canning after the check valve was blocked for some time. The tank would try to inflate during warm days, then relax in the cool night.

Needless to say, if your filler cap is not letting air into the tank, causing suction in there, it will affect the running, while if there is pressure in the tank from a blocked vent or check valve, it shouldn't have any affect on the running.
 
That is crucial info. Are you sure it is sucking and not pressure? The way the tank vent system works is by letting air into the tank by way of the filler cap, but the cap does not let any air out if working properly. All air leaving the tank travels in a pipe that goes to the charcoal canister (should be under the hood on rt side near the washer tank). At the tank end, this pipe is connected to a little spigot on the filler pipe.

The vent pipe should have a check valve in it so air can leave the tank but cannot enter it that way. I have seen the check valve near the filler pipe (in the trunk) and I have seen others under the hood next to the connection to the charcoal canister. The vent pipe is small and it or the check valve can become blocked. I have had a crack develop in my tank due to oil canning after the check valve was blocked for some time. The tank would try to inflate during warm days, then relax in the cool night.

Needless to say, if your filler cap is not letting air into the tank, causing suction in there, it will affect the running, while if there is pressure in the tank from a blocked vent or check valve, it shouldn't have any affect on the running.

Mine was for sure under vacuum (blew a vape cloud at it and watched it suck into the tank) First I swapped in 2 known good gas caps and neither made a difference. Unblocking the line to the charcoal canister did fix it.
 
The fuel pressure is critical. Have you been able to watch it while you drive?

The 18:1 thing is what I'm hung up on. I spent time driving around with my Wideband and I kept adjusting what the Innovate controller was telling the Lambda-Sond. If I was getting 18:1 or higher under load the car would be undriveable. My car idles best at around 12.5:1 AFR, but you can smell unburnt fuel at that level so I run it around 14:1.

If you have good fuel pressure and the fuel pressure is not giving issues while driving, I wouldn't focus on the relay. If you don't have good fuel pressure, then you would need to sort that out.

If you have good fuel pressure, and you don't have an engine miss, your cam isn't installed incorrectly, your AFR is 18:1 and you also don't have an exhaust leak contaminating the AFR reading, you should suspect the Lambda Sond or the fuel distributor. It's easier to troubleshoot the fuel distributor in my opinion, it has no electronics in it. That's why I recommended pulling the plug on the Lambda Sond for testing.

I'm telling you this based upon my experience while trying to chase down fuel problems on my 1978 K-Jet car. I'm definitely not pulling this out of my rear.

I bypassed the fuel pump relay and wired in my own relay.

I replaced both fuel pumps.

I ran new wire to the under car fuel pump and installed a dedicated relay for it, when I discovered that there was a significant voltage drop at the pump.


I installed a voltage booster in the trunk and wired it into the in tank fuel pump so that I could overdrive the in tank pump and observe the behavior. I did this after I discovered quite a large voltage drop in the rear of the vehicle as well. I delivered up to 18v to this fuel pump during testing, and I could audibly hear the pump running harder.

I installed 2 different fuel pumps in the tank until I found one that worked well (the higher volume IPD pump worked great). I attribute this issue to the fact that you can't buy the original high pressure Volvo pump anymore, and the replacement pump that I got along with the first in tank pump gave me "cavitation" sounds in the fuel system and a performance issue after the car had been running for a while. The overdriven pump proved that the in tank pump wasn't delivering what the high pressure pump needed, at that point I found a higher volume in tank pump.

I replaced the rubber fuel line from the tank to the fuel pump.

I replaced the fuel filter.

I replaced the injectors and injector seals.

I purchased a kit to check my fuel pressure (and tested it).

I replaced the fuel pressure accumulator because it leaked.

I replaced all of the normal stuff like plugs/wires/cap, etc.

I replaced the O2 sensor, first with a normal narrow band, then with an Innovate Wideband and controller.

Make 100% sure you fuel pressure doesn't drop while driving or under a load. Your AFR should not be at 18:1 at idle. My car would barely idle at 18:1, if at all while in gear.

Check your compression, just to rule it out. It's easy to check. The plugs are easy to remove.
Check your cam timing.

Thanks for checking it out! I have not done it yet but I do have the relay. I will probably get that done tomorrow, while I'm waiting for my new relay and other parts.

Guess I will check out ebay for a dwell meter, I asked around and I don't know anyone who owns one.

I have a dwell meter, but I didn't use it. In my opinion, the fuel distributor needs to be set so that the O2 sensor will have plenty of leeway to make adjustments to be on the lean and rich side of the spectrum. I have not been able to tune the fuel trim screw to a position that works well at idle with and without the Lambda-Sond plugged in. Ultimately you will need to have it tuned so that it works well with the Lambda Sond. I believe the purpose of the dwell reading is to get you right in this ball park, but it's not black magic. If you have a Wideband, you are already ahead of the curve because you can actually have an accurate view of the rich lean swings. The only thing I don't have is the C0 meter.
 
Can you drive it with the gas cap removed to see if this impacts performance? You really need to be able to verify the correct fuel pressure, not just for a few seconds in the driveway, but all of the time. You need to confirm this.

The charcoal canister or the lines to it are plugged. I had this happen. Beware, the vacuum can collapse a tank. Unplug the line to the tank at the canister and try to blow air in, If the air flows free, swap out the charcoal canister. It is possible to cut them open and replace the charcoal with pelleted activated charcoal from a fishtank store. Temporarily I just left the gas cap a little loose. That car is carbed, but I did notice that if I opened the gas cap when the engine was running, and released the vacuum, the engine sound/rpm changed a little. The vacuum could be making the pump work harder but I dont think it would cause all the issues you are seeing. It may be adding to them a bit though.

Btw, charcoal canisters are very interchangeable, there are a couple basic types but within a type, they can usually be swapped between car makes and models. As far as I remember they are 2 hose and 3 hose, though I dont remember what the difference is.
 
The reason I believe it is vacuum is because loosening the gas cap results in a a loud noise, but my hand does not smell like fuel. I have had fuel tanks pressurized that make your hand stink after taking the cap off. I will try the notsofresh method and blow some smoke towards it upon opening.

This car had the original metal filler cap, with not holes in it at all. I replaced it with a brand new filler cap that has holes in it. Bought it a few months ago for my other car. No difference between caps. I can try another known good cap just cause I have it though.

From the trunk side, the charcoal canister line is difficult to blow through with my mouth. Blow hard enough and you get the squeaky balloon sound. I gotta try it from the other end, and will look for that check valve.
 
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