Stalling at stop lights/signs when warm/hot

[eagle-co94]

My G wagon is running Bosch K-Jet so I figured the issue may have occurred to someone with a D as well. Once I have been driving for 15-20 minutes and arrive at a stop sign or traffic light my G will stall. It always restarts just fine, but I have to feather the throttle a bit to keep it running. Once I do that it'll fall back to idle and I'm fine...until the next traffic light/stop sign.

Can anyone point me in the right direction for what to check? I really want to take the G off-road but won't if it's going to stall on me.

[Nicholas R]

I used to have this happen to me in 2009. Every stop the car would die. My mixture just needed to be adjusted.

[Elvis]

Hello idle and hello vacuum leak problem :-)


there's no weak without it...

[eagle-co94]

Did you mean week?

[Nicholas R]

Is the car an automatic or a manual? Mine was an automatic. If I recall correctly, I wouldn't stall if I dropped the car into neutral but that resistance from being in drive was enough to kill the engine.

[eagle-co94]

It's manual, if I push in the clutch prior to stopping I have to put it in neutral and feather the gas while stopping so it doesn't stall. I'm more concentrated on stopping so I don't try this much.

[Elvis]

Did you mean week?


OUCH yes James, you're right.

Check your mixture adjustment plug, it might be missing.

[Soundkillr]

Does the wur have vacuum once hot? If the thermo time switch under the intake has failed, the car could always have vacuum. It won't effect the car when cold, but once hot the car will load up like crazy and could stall. This happened to mine years ago. Replaced the switch and all was fine. Simple check is to pull the vacuum line at the wur when the engine is at operating temp. It should not have vacuum, if it does that could be your issue.

[David T]

Just because you have a vehicle, not a Delorean, that has the Bosch K-Jet system does not mean it is the same. Lotus also used the K-Jet system but none of the parts will fit a Delorean. My guess is you most likely have vacuum leaks and possibly a problem with the idle adjustment or if it uses an idle motor, something is not right with that system. The idle is too low. You can also have dirty, plugged up injectors. Any car running K-Jet is going to be around 30 years old and will be plagued with the typical aging issues, mostly vacuum leaks because the rubber parts get old and hard and crack.
David Teitelbaum

[Nicholas R]

I dont think he said anything about swapping parts with a DeLorean. Still, every K-Jet, or any continuous injection system really, works on the same principles. My friend had an 80's audi coupe GT with a 5 cylinder engine with a Bosch CIS system and it worked exactly like the DeLorean, just arranged differently. I was able to work on and diagnose his car just as easily as my DeLorean.

[David T]

I wasn't thinking he was going to swap parts. My point is that even though it is a K-Jet, the systems of each car are tuned to be used specifically for that make and model. Even when the parts look the same, if you check the #'s on the parts they will be different. That signifies that flow rates and pressures are specific to each. Having a basic knowledge of how a Bosch K-Jet works does give you a starting point but even the troubleshooting and diagnostics will vary. As always the best reference will be the manuals for that specific car. It is possible that the problem is with another system anyway. Maybe it's time to tune the car up with an air filter and spark plugs? Or maybe there is a problem with the timing or the advance systems.
David Teitelbaum

[eagle-co94]

Thanks for all the input everyone. Nick is right on point with my post. I'm looking for the general workings of K-Jet as I have very little experience with it. I had a LOT of help with 16336 so I learned very little about K-Jet then, and my '85 Mercedes 280CE ran flawlessly (other than an oil leak) so there was no need to tinker with anything. Now ask me about the LT1 in my '96 Impala SS and I could figure out most issues with it...and that knowledge would also carry over to the LS series some as well. I know a bit about 77-85 Mercedes Diesels as well as 2002+ MINI supercharged and turbo'd motors. I'm currently toying with a 2010 Challenger with the 6.1L, 2012 Charger with the 5.7 as well as another project, my VTEC swap into my '85 Mini.

Now that my G has developed an issue I figured I'd go to the best source of K-Jet knowledge I could find. The G-wagon community in the U.S. isn't very big, and many of the owners are driving diesels. I've posted threads on the G wagon forum and a couple Mercedes forum, but as suspected, I've gotten more information here. Now my only issue is locating parts for my G as it's "grey market" and not supported by Mercedes stateside. The motor did come here for a few years in some Mercedes models though, so I just need to see if the parts are the same and are available. I've already found one cracked hose, so hopefully that is the culprit, but now I've got a list of things to check.

[jawn101]

Thanks for all the input everyone. Nick is right on point with my post. I'm looking for the general workings of K-Jet as I have very little experience with it. I had a LOT of help with 16336 so I learned very little about K-Jet then, and my '85 Mercedes 280CE ran flawlessly (other than an oil leak) so there was no need to tinker with anything. Now ask me about the LT1 in my '96 Impala SS and I could figure out most issues with it...and that knowledge would also carry over to the LS series some as well. I know a bit about 77-85 Mercedes Diesels as well as 2002+ MINI supercharged and turbo'd motors. I'm currently toying with a 2010 Challenger with the 6.1L, 2012 Charger with the 5.7 as well as another project, my VTEC swap into my '85 Mini.

Now that my G has developed an issue I figured I'd go to the best source of K-Jet knowledge I could find. The G-wagon community in the U.S. isn't very big, and many of the owners are driving diesels. I've posted threads on the G wagon forum and a couple Mercedes forum, but as suspected, I've gotten more information here. Now my only issue is locating parts for my G as it's "grey market" and not supported by Mercedes stateside. The motor did come here for a few years in some Mercedes models though, so I just need to see if the parts are the same and are available. I've already found one cracked hose, so hopefully that is the culprit, but now I've got a list of things to check.

Check out this link as well: http://dmctalk.org/showthread.php?352-K-Jetronic-System

Lots of good resources in there but the one that stands out in my mind is the link I posted to a video on YouTube that describes the whole theory of operation behind K-Jet in pretty good detail. It really increased my overall understanding of the system, which is key if you're going to try and figure out what's wrong with it. I'm still no expert but I feel wiser for having watched it :)

[Dangermouse]

So, are you back stateside James?

[eagle-co94]

Yep! I "only" brought back 3 cars with me too (technically 4, but one was a friend's). It's about time to pull the D's out of storage and get to work!

[AirmanPika]

I had this exact issue on my car. I believe I fixed it by adjusting the mixture (honestly I forget...I haven't driven the car for a month right after "fixing" the issue)