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some new and interesting developments :
- checked distributor and spark plug cables and timing :
I have a good spark, timing and distributor seem to be ok, spark plug cables are in
perfect condition : resistance of the cables are :
cil 1: 3,08k Ohm
cil 2: 3,14k Ohm
cil 3: 3,10k Ohm
cil 4: 3,10k Ohm
cil 5: 3,10k Ohm
cil 6: 2,95k Ohm
cil 7: 3,06k Ohm
cil 8: 3,12k Ohm
to coil : 0.94k Ohm
- first tried to start with connector to coldstart valve disconnected, so no extra fuel
via intakes, so only fuel via injectors => ENGINE DOES NOT START
- then start with coldstart valve connected => ENGINE START for 2 seconds and dies
So impossible to keep engine running after start
Problem fuel supply? : clogged fuel filter? , bad fuel pump ?, clogged fuel pressure regulator ?
A sudden failure points to electrics but the CIS is nicely free of electrical parts.
The engine will work fine with the enrichment circuit in either position. At least it'll run. That's the valve and lines above the right side of the engine.
Since it starts on the cold start injector, you've got fuel and spark. At least to start.
One thing that can fail is the fuel pump relay. It's special in that it's ON for a moment when you turn the key (well, the first time and then some times after that.) and ON when it senses the engine turning. There's a wire for the spark controller (The "ECU" you identified) to the relay. It's a low-voltage signal so hard to measure with an ordinary voltmeter.
What you can do is stick in a jumper to bridge the power to the pump. Remove the relay (XVII) and put a jumper between contacts 30 and 87. Those are big ones. You'll need to make a short wire with two spade-lugs crimped onto the ends.
Don't leave the wire in if it works as it'll run all the time. Order a relay. The purpose is to cut off fuel when the engine stops. Like when the fuel line ruptures or you're in an accident.
A sudden failure points to electrics but the CIS is nicely free of electrical parts.
The engine will work fine with the enrichment circuit in either position. At least it'll run. That's the valve and lines above the right side of the engine.
Since it starts on the cold start injector, you've got fuel and spark. At least to start.
One thing that can fail is the fuel pump relay. It's special in that it's ON for a moment when you turn the key (well, the first time and then some times after that.) and ON when it senses the engine turning. There's a wire for the spark controller (The "ECU" you identified) to the relay. It's a low-voltage signal so hard to measure with an ordinary voltmeter.
What you can do is stick in a jumper to bridge the power to the pump. Remove the relay (XVII) and put a jumper between contacts 30 and 87. Those are big ones. You'll need to make a short wire with two spade-lugs crimped onto the ends.
Don't leave the wire in if it works as it'll run all the time. Order a relay. The purpose is to cut off fuel when the engine stops. Like when the fuel line ruptures or you're in an accident.
Let me know how that goes. Good luck.
Hi Glen,
I jumpered 30 with 87 while cranking the engine, fuel pump ran but same problem : engine starts for 2 seconds and then dies.
i did this several times but no luck. I checked my spark plugs, they are dry and black
It's kind of off the wall, and I could certainly be wrong, but have you checked your cam timing?
Sudden change, hard starting & poor running, distributor off for no apparent reason. Those all could be signs that the belt jumped a tooth or two.
On a 16v, you can unbolt the Driver's side cover, pull it back an inch or two and check the timing marks. Takes about 10 minutes.
Joe,
I checked my timing and belt is ok. Marks on cams are perfectly aligned with TDC point.
If belt had jumped, engine would have been damaged by valves hitting pistons
kr
Gerrit
That's not the fuel pressure regulator. The FPR is inside the fuel distributor. That's part of the "warm dis-enrichment" system or somesuch. It bumps the control pressure up on hot re-starts.
That's not the fuel pressure regulator. The FPR is inside the fuel distributor. That's part of the "warm dis-enrichment" system or somesuch. It bumps the control pressure up on hot re-starts.
I'm surprised the relay fix didn't make it work.
What else have you tried?
Who's next?
Glen,
the hotstart valve is the smaller barrel with the 2 wires. It is a magnetic valve that opens when hot.
the larger barrel keeps via diafragma fuel up to constant pressure and
feeds the WUR at the front if the engine .
My money is on the fuel pump non return valve not holding pressure which is giving you the hard cold start.
From cold ...try pulling the lead of the distributor and then cranking the engine over 5-6 times which should build up sufficient pressure to start the engine.
Reconnect the coil to distributor lead and it should start right up.
if it does then I'd suggest that you do a fuel pressure leakdown test to establish that your fuel system is not retaining pressure. It could be due to the NR valve or leaky injectors or a leaky FPR or FPD
Once you've started the engine and warmed it up a bit , if the engine will idle try removing the vacuum hose off the FPR valve . You should notice a distinct drop in rpm and a change in the engine note. You could also try removing the connector to the IAC valve at the same time and see if the idle improves .
My CO dropped from 12.00 to 1.70 ! and the HC dropped from 1260 down to 127 . I suspect a vacuum leak on my car so a smoke test is next
My ICV tested out ok for voltage and resistance and operated fine when linked up to a spare 12v battery but definitely wasn't working properly on the car . You might need to check that your Motronic unit is actually receiving data from the various sensors like the ICV TPS 02 AFM etc
Wow this is a lot of data to process, but I am already very gratefull for your expertise.
Hereby some questions before I start to test :
- NR valve : what is it and where is it located
- FPR : fuel pressure regulator : Is it the hexagon device with lines to injectors
- FPD : fuel pressure damper : is it the same as diaphragm damper ( 928.110.231.02) here
is a picture of the diaphragm I have :
Do I really need the diaphragm and could it be clogged so that fuel pressure
becomes faulty.
- IAC valve : what is it and where is it located
- ICV : what is it and where is it located
- TPS : what is it and where is it located
- AFM : what is it and where is it located
Unfortunately, I think peanut is describing an L-jet system.
I've got two 1980 Euro S cars, and a '79 CIS engine, and none of them have that can in the line. Looks like an accumulator to smooth pressure. In any event, it's in the control pressure circuit. The pressure regulator is on the left side of the fuel distributor and shouldn't need adjusting.
Have you put a timing light on it to confirm that it's sparking while it's dying?
Did it die while driving or just start refusing to start?
Seeing that you have an assumed no fuel to injector problem, I would look at two possible areas the get clogged with junk. the first area would be at the fuel distributor inlet line(the big hex thing in your diag.) the line from the pump screws into a fitting at the base. The fitting has a screen in it that can get clogged not allowing fuel to get in to the system. The next place would be the warm up regulator or as most call it the WUR. Thats the item in your diagram above on the far left. It also has in inlet screen that can get clogged, you must be careful when cleaning that screen so as not to poke any hole in it. I use carb cleaner and light shop air in a blow gun to clean mine. The WUR also acts like a FPR on CIS cars, so could be part of your problems. Also on your car you don't have TPS,AFM,or an ICV the closest thing to any form of idle air control vale would be the auxiliary air valve.
Good luck
Mike
What engine do you have?
1980 RoW S don't have a ecu.
Originally Posted by peanut
This could be more than one issue going on here.
My money is on the fuel pump non return valve not holding pressure which is giving you the hard cold start.
From cold ...try pulling the lead of the distributor and then cranking the engine over 5-6 times which should build up sufficient pressure to start the engine.
Reconnect the coil to distributor lead and it should start right up.
if it does then I'd suggest that you do a fuel pressure leakdown test to establish that your fuel system is not retaining pressure. It could be due to the NR valve or leaky injectors or a leaky FPR or FPD
Once you've started the engine and warmed it up a bit , if the engine will idle try removing the vacuum hose off the FPR valve . You should notice a distinct drop in rpm and a change in the engine note. You could also try removing the connector to the IAC valve at the same time and see if the idle improves .
My CO dropped from 12.00 to 1.70 ! and the HC dropped from 1260 down to 127 . I suspect a vacuum leak on my car so a smoke test is next
My ICV tested out ok for voltage and resistance and operated fine when linked up to a spare 12v battery but definitely wasn't working properly on the car . You might need to check that your Motronic unit is actually receiving data from the various sensors like the ICV TPS 02 AFM etc
Originally Posted by GlenL
Unfortunately, I think peanut is describing an L-jet system.
I've got two 1980 Euro S cars, and a '79 CIS engine, and none of them have that can in the line. Looks like an accumulator to smooth pressure. In any event, it's in the control pressure circuit. The pressure regulator is on the left side of the fuel distributor and shouldn't need adjusting.
Have you put a timing light on it to confirm that it's sparking while it's dying?
Did it die while driving or just start refusing to start?
Glen,
After overhauling the engine, it started the first time without any issues! I even drove about 4 miles with car. no issues what so ever.
the problem occurred 1 week later when I wanted to drive the car :
hard to start but it eventually started, then after driving the car for
about 1 mile, engine suddenly died, no possibility to start it again, I
started too many times so that battery was completely dead.
After towing my car back home, I never managed to start and kept it
running till now...
would it be a good idea to remove this accumulator, because not all 928S euro 300hp cars have this accumulator: here is a picture of same
engine without the accumulator:
sorry NR non return valve. I would expect it to be located inside or adjacent to your fuel pump. It maintains your fuel pressure in the fuel system ready for your next start up.
02-15-2017, 07:46 PM
