Great response, thanks for sharing all that information. You're right about decreasing the air gap when shims are removed, of course. I don't really know how critical the proper air gap might be, but since they give a specification for it, you should try to be within that range. You say your adjustable fuel pressure regulator is set at 2 bar - I see that the workshop manual says that factory FPR's are set to maintain the pressure at 3 bars. So you're not OVERpressurizing the rails, but you may possibly be UNDERpressurizing the rails. If that is the case, then maybe (?) the Motronic is compensating by increasing the time duration that the injectors are open, and that may be in conflict with your camshaft profile, or your ignition timing. I'm just guessing, it's food for thought. Your rolling road tests seem like the right way to go.
intresting, I may put a presure gauge on the rail and see what I get. My FPR is a fixed pressure type, ie doen't compensate for manifold vacuum. Once it's back running as it was I'll get it set up on the rollers. Do you think I'll be allowed out in the garage today?
CPS sensor turned up and fitted yesterday. Did you guys know its the same part for a Volvo 760 and Peugeoy 505 2.5l? Well it's made a huge difference to the running of the engine. The car started first time within a second of cranking which was a huge improvement. Smoke (steam) out the exhaust was constant both sides which is good. Had far more steam one side that the other before. I let it do a full warm up relearn which took about 30 mins for the fans to kick in twice. However, It wouldn't restart when hot unless I gave it some throttle. The low end missfire went but after reving it to 2000rpm or above the engine would not return to idle, it stalled everytime. This morning I started the car (again 1st go) and let it idle. I then adjusted the air bleeds on the throttle body to increase the idle speed. Mine was running before quite happily at 750rpm but Candellera who was helping thought that was too low. Screwed the idle bleed screws out 4 turns increased the revs to 1000rpm and it's running so much better. No stalling or engine hunting, and better throttle response. But why did we need to do this??? Tried testing the ICV that sit under the plenemb chamber by blowing down the air pipe whilst connecting 12v supply, but they were open all the time. Is that correct?? Assuming the ICV are ok. Is there an easy way to balance the throttle bodies? I'm concerned that one side may be open more than the other. Another thing I may try;- As my FPR is not connected to the manifold anymore, to blank the holes of in the manifold I have a pipe joining both sides together. I may remove this pipe and blank off each end, therefore the two sides of the manifolds won't be connected. Any thoughts?? Cheers for all the help so far!
No. The ICV (Intake Compensation Valve for those of you that are going to ask) is not supposed to be open all the time. It's only supposed to open between 3500 rpm -5500 rpm. It's to help with the mid-range torque. Look to see that the vacuum line going to the diaphragm, on the bottom front of the plenum, is attached to the solenoid on the 5/8 bank (inner bottom left rear of the intake runners, looking it from the back, right where the intake bolts to the head). Make sure that the line isn't just hooked up directly to the pressure tank, or to the vacuum nipple on the plenum for that matter.
Shemp, a.k.a NoDoubt , figured that one out. But I don't think he knew what model it was for. I didn't know it was also for a Pug. Thanks for the heads up, nice find for the Brotherhood!
huh? My 348 is stock and never had shims to change CPS position relative to the airgap to wheel. The gap is set but they tell you to make sure it is x mm away. What are you guys shimming?
The cps sensors, durrrrrrrr. According to the book, the gap between the tip of the sensor and the teeth on the pulley is supposed to be between 0.35mm - 0.90mm.
Ernie. We're talking about a different ICV, the centre valve under that opens mid range is working fine. Its the two other valves that open to allow air from one side of the throttle butterfly into the plenum. They're only fitted to 2.5motronic. Really anoyed today when it wouldn't start again. I think it the imobilizer again, I may get it replaced by an expert to ensure its working properly. I don't get a green led to say its working
