Hard start after Euro S intake install
07-26-2010, 04:24 PM
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Hard start after Euro S intake install
I got the car started and running yesterday minus the supercharger. Took her for a spin and it felt amazing/runs great with the Euro S throttle body, plenum and runners. Feels like it's go much better throttle response and runs smooth as silk! The damn thing won't start worth a crap though. I had an L-jet ground issue a few months ago that wouldn't start the car at all. Once fixed it fired up instantly.
Only thing thats changed is the Euro S bits. Vacuum leak maybe? Runs great and doesn't skip a beat while it's started and fires up hot no problems. New temp II and time switch. I also unplugged and jumped the auxiliary fan sensor when I hooked up the electric fans for the SC.
I'm one pulley and some intake hoses away from getting supercharged, the rest is mounted.
I want to get the cold start issue fixed before the dyno to eliminate the possibility of a larger problem
Only thing thats changed is the Euro S bits. Vacuum leak maybe? Runs great and doesn't skip a beat while it's started and fires up hot no problems. New temp II and time switch. I also unplugged and jumped the auxiliary fan sensor when I hooked up the electric fans for the SC.
I'm one pulley and some intake hoses away from getting supercharged, the rest is mounted.
I want to get the cold start issue fixed before the dyno to eliminate the possibility of a larger problem
07-26-2010, 04:51 PM
#3
Nordschleife Master
I would look for vacuum leaks, connectors not connected, maybe vacuum routing, recheck that old ground issue.
Cold start and hot restart both having trouble?
Cold start and hot restart both having trouble?
07-26-2010, 04:59 PM
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Only cold start. I ran the two distributor vacuum lines to the only two connections on the Euro S throttle body. I guess I'll spray some carb and choke cleaner and see if I get fluctuations in idle. I'm hoping it's not that machined reducer ring for the flapper door I had made...
07-26-2010, 05:12 PM
#5
Nordschleife Master
My Euro S throttle body has I believe 4 ports, two in front, and two in back, with one of each located just above or just below the throttle plate. Ports below the plate never have more than a slight amount of vacuum (loss through the air meter and air filter), above the plate they are close to manifold vacuum. When the throttle opens the two in front are both below the plate, and the two in the rear are both above the plate. Which you use makes a BIG difference.
That said only cold start issues make me think temp sensor.
That said only cold start issues make me think temp sensor.
07-26-2010, 05:22 PM
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Ok that might be the issue because I just guessed on those thinking they might all be the same. I believe I have them hooked up distributor retard to the front of throttle body and advance to one of the rears and the rest plugged.
Last edited by chewy8000; 07-26-2010 at 05:39 PM.
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07-27-2010, 12:27 AM
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No Euro heads or cams. My 4.5L is pretty solid with new headgaskets less than 3k ago and still strong at 79,000 miles.
Looked at it tonight and lower distributor retard hose laying across the motor not hooked up... I forgot it wasn't long enough to reach a vacuum point. I'll hook it up when I get the right length, I'm betting thats the problem.
Looked at it tonight and lower distributor retard hose laying across the motor not hooked up... I forgot it wasn't long enough to reach a vacuum point. I'll hook it up when I get the right length, I'm betting thats the problem.
07-27-2010, 04:37 AM
#9
The vacuum lines need to be on the right connections, see page 26-3 of the workshop manual.
Is the cold start valve connected properly and working. It should operate when the engine is stone cold and the starter is cranking, only for a few seconds.
Is the cold start valve connected properly and working. It should operate when the engine is stone cold and the starter is cranking, only for a few seconds.
07-27-2010, 12:34 PM
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Can't I just make this easy and plug up the two outlets on the throttle body and just run the retard and advance distributor vacuum lines to the plenum for manifold vacuum? Or does one need to be below and one above the throttle plate?
07-27-2010, 01:19 PM
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07-27-2010, 04:24 PM
#12
Nordschleife Master
Looking now for some picts, a few in this thread, but I am not sure whats what. It says 32v, but Euro S and US 85/86 use almost the same throttle body.
https://rennlist.com/forums/928-foru...for-16v-5.html
What's the casting number on your throttle body?
What exactly are the individual parts in your system, its a mix?
Another throttle body, not sure which though.
https://rennlist.com/forums/928-foru...for-16v-5.html
What's the casting number on your throttle body?
What exactly are the individual parts in your system, its a mix?
Another throttle body, not sure which though.
07-27-2010, 04:59 PM
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My throttle body, plenum, and runners came off an 85' (Euro S) LH.
Here are the part numbers.
Intake runners
928 110 681 1R x 2
928 110 682 2R x 2
928 110 683 1R x 2
928 110 684 1R x 2
Plenum
928 110 159 0R
Elbow
928 110 199 3R
TB
928 110 530 0R
3.3" diameter
Here are the part numbers.
Intake runners
928 110 681 1R x 2
928 110 682 2R x 2
928 110 683 1R x 2
928 110 684 1R x 2
Plenum
928 110 159 0R
Elbow
928 110 199 3R
TB
928 110 530 0R
3.3" diameter
07-27-2010, 08:14 PM
#14
To most people, "euro S" means a K-jetronic 80-83. That originally had a distributor with vacuum advance and retard. What you have is the intake off a "euro S2" with lh-jetronic which got its ignition timing from the flywheel.
The distributor with two connections uses full engine vacuum for the advance, and a vacuum connection which is only above the throttle plate when the throttle plate is closed, for the retard. In your case, you might try running with the retard on the distributor just left unconnected (don't seal it or it will hinder the advance).
The distributor with two connections uses full engine vacuum for the advance, and a vacuum connection which is only above the throttle plate when the throttle plate is closed, for the retard. In your case, you might try running with the retard on the distributor just left unconnected (don't seal it or it will hinder the advance).
07-27-2010, 09:10 PM
#15
Rennlist Member
what did you do with the cold start. am i reading it wrong, but is the euro stuff on the Ljet system?
if so, you need to do some tricks to help cold start.
first and most important trick, is that you would route the cold start circuit to a port that is not used on the plennum (those lines would have been going to the heads side port on the US heads as that port feeds the intake valve ports) on the euro heads, that same port externally, feeds exhaust, so pumping in fuel and air to that port is a bad idea, unless you want a flame thrower.
if so, you need to do some tricks to help cold start.
first and most important trick, is that you would route the cold start circuit to a port that is not used on the plennum (those lines would have been going to the heads side port on the US heads as that port feeds the intake valve ports) on the euro heads, that same port externally, feeds exhaust, so pumping in fuel and air to that port is a bad idea, unless you want a flame thrower.