79 928 K Jet problems
12-14-2017, 01:05 AM
#1
79 928 K Jet problems
Hello, I'm not sure there is an answer for this question, but there is a 79 928 with fuel system problems and the car no longer runs. I there any ballpark guess on what (how much) a fuel system problem could turn into if a person rolled the dice and bought the car not running? I understand there are likely many parts of the system but any idea? $1000? more? Are they fairly easy to sort out?
Thanks!
Thanks!
12-14-2017, 02:08 AM
#2
Rennlist Member
They aren't complicated. Just make sure to get a set of gauges and set the pressures correctly. That will usually solve 90% of the issues people have.
Rebuild kits for the fuel distributor are inexpensive as are shorter injectors from Mercedes if your originals are worn out and goobered up.
You should be in around $400 in parts and tools to rebuild the system yourself.
Just make sure you replace all soft lines so that you don't end up with a rolling fire hazard.
Rebuild kits for the fuel distributor are inexpensive as are shorter injectors from Mercedes if your originals are worn out and goobered up.
You should be in around $400 in parts and tools to rebuild the system yourself.
Just make sure you replace all soft lines so that you don't end up with a rolling fire hazard.
12-14-2017, 08:00 AM
#3
Rennlist Member
Hello, I'm not sure there is an answer for this question, but there is a 79 928 with fuel system problems and the car no longer runs. I there any ballpark guess on what (how much) a fuel system problem could turn into if a person rolled the dice and bought the car not running? I understand there are likely many parts of the system but any idea? $1000? more? Are they fairly easy to sort out?
Thanks!
Thanks!
No matter how long it sat read up on how the system works before you start. The “benefit” of the system is minimal electronics, but the flip side is that it works on precise variations between two fuel pressure systems that require surgical level cleanliness inside the system. Besides hours of reading in this forum the Bosch fuel injection book by Probst is good for this. The only special tool required is the CORRECT fuel pressure gauge and is essential for diagnostics.
Typically long term sitting completely contaminates the fuel system. If you’re going to go for it you can expect to replace the fuel strainer, fuel pump, fuel hoses from pump to accumulator, filter, accumulator, hoses at right side of engine. Expect to rebuild or replace the warm up regulator and fuel distributor, and expect to service or replace injectors and expect to clean the fuel tank. A contaminated system takes a lot of hours and money to sort out. There’s threads in here on all of this.
12-14-2017, 03:08 PM
#4
Three Wheelin'
One of the reasons I no longer just leave my car standing (K-jet) during the winter lay-up period, three years back , I thought it might be a good idea not to start the car during it's lay-up after reading it wasn't a good idea to start it, this resulted in all sorts of fuel problems and also a big bill for getting it sorted. I now, as I have done all the years previous to this, start the car and run it up to temperature and beyond and move the car around, plus some Sta-bil in the tank and don't have any issues, also running the air-con keeps that in working order.
K-jets don't like hanging around idle for a length of time !
Ken
80 928 S
5 Speed
UK
K-jets don't like hanging around idle for a length of time !
Ken
80 928 S
5 Speed
UK
12-14-2017, 07:29 PM
#6
Nordschleife Master
Are you planning on doing it yourself?
Or paying a shop to do it for you?
As with most jobs on these cars, parts and special tools aren't cheap, but are available.
Paying someone else to do the labor can get ridiculously expensive, and it gets worse if you don't have a tech that knows these cars, as opposed to a "European Car Specialist" who doesn't have a clue about the peculiarities of a 928.
Or paying a shop to do it for you?
As with most jobs on these cars, parts and special tools aren't cheap, but are available.
Paying someone else to do the labor can get ridiculously expensive, and it gets worse if you don't have a tech that knows these cars, as opposed to a "European Car Specialist" who doesn't have a clue about the peculiarities of a 928.
12-14-2017, 07:51 PM
#7
Rennlist Member
It can take a while to work through all the possible issues with a problematic CIS system. The books you want are Probst and Ben Watson - the latter being very practical, with a good list of what can cause the common problems, and the pressures you should see at various temperatures. I have had good results from loading the fuel with stuff like Marvel Mystery oil or similar, and bridging the pump relay to circulate fuel around the system, and clean out debris. One of the engine bay fuel hoses (I think the return line?) was NLA when I was last in there, but mine was not cracked or damaged at all, so I lived with it. Apart from general crud in the system , the commonest problem seems to be crud in the WUR (warm up regulator) causing a high control pressure, which can make them hard to start when cold, and also prevents you from getting more than ~20mph out of the car. For the purposes of buying negotiations, look up the cost of a WUR($300 exchange, but there are rebuild kits out there), fuel pump, and distributor, and quote them to the seller. Once the system is back to specification, they are terrific - mine starts first pop in midwinter, and never misses a beat.
It can be fixed, but most important part is the condition of the rest of the car - you dont want to spend $10k and still only have a $5k car....
jp 83 Euro S AT 57k
It can be fixed, but most important part is the condition of the rest of the car - you dont want to spend $10k and still only have a $5k car....
jp 83 Euro S AT 57k
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12-14-2017, 09:12 PM
#8
Drifting
I found something called 'BlazeCut Fire Suppression System' on the web that looks promising in preventing a 'Shark Flambe`' A 6 foot section is $160...sounds good to me. Web Site: jogrusa. com/products/BlazeCut fire suppression system.
12-14-2017, 11:19 PM
#9
Rennlist Member
If you refer to the danger of failed fuel hoses from old age etc, I sheathed my hoses with a flame resistant silicon hose, with fibreglass lining - Firesleeve, from the metal pipe connection, up to the top connection. These will contain any small leaks, and make it dribble out the bottom instead of spraying on the manifold. 5/8" size could be slid over the hose from the top after breaking to top joint.
jp 83 Euro S AT 57k
jp 83 Euro S AT 57k