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Hi there, please I need some assistance I have done basically every thing to this Porsche baby and has cost a load of money but now at the last final touch she starts but refuses to rev!
The motor was redone as she overheated and the rings needed to be done and her crank was cut and new mains and bigends replaced every thing new, I even took the petrol tank out flushed and replaced with a new fuel pump and I bled the injectors but she starts but does not rev at all, soon as I slightly push the pedal down she dies immediate,I am not sure what could be the problem maybe if you throw me a life line with suggestions I can have a check please
I had a similar issue after timing belt r&r, turn out my distributor was off by one notch. Set engine at tdc, rotor was slightly before reference mark, should have been slightly after reference mark.
started, ran, but wouldn’t rev.
Had a similar issue with my '79 K-Jet car where the pressure valve in the Fuel Distributor got stuck while I was doing the rest of the work. It's the one that screws in from the side and has a spring, then you use a small magnetic pick-up tool to retrieve the actual needle part. If it comes out easily, it's not stuck. If it doesn't, it is going to need some working of penetrating oil into the other ports next to it until you can free it up and it slides smoothly. Car would idle but wasn't getting the right fuel pressure and would go full lean when I pressed the accelerator and not rev. Maybe something else to look at if not the distributor timing.
First this comes out If this part shown on the top is stuck in the FD, and won't come out with a magnetic tool applying oil in this side port and the front port where the component unscrewed from may free it
Thank you so much, I will try all 1st trying the fuel distributor,Thank you for the pics helps alot ,If not that, then Ill move on to the distributor to see on tdc,if not then last the AFM connector wires do you perhaps have a pic showing the wires diagram please, Ill keep you posted thanks again
Thank you so much, I will try all 1st trying the fuel distributor,Thank you for the pics helps alot ,If not that, then Ill move on to the distributor to see on tdc,if not then last the AFM connector wires do you perhaps have a pic showing the wires diagram please, Ill keep you posted thanks again
Start off with the ignition timing check. You can use a timing light to verify it's at spec. Best to do that before disassembling pieces of the fuel distributor/metering unit.
In fact, you'll want to do a little more pressure checking with a gauge kit before you disassemble the distributor to get to the pressure regulator needle. The proper CIS gauge kit connects at the two lines running to the warm-up regulator. The kit allows you to check the supply pressure, and also to read the control pressure going back to the metering unit. The specs for supply and control pressures are in section 25 in the workshop manuals, and are slightly different depending on manual vs. automatic gearbox. Take a look at the charts and the descriptions there, and you'll see another clue, the one about the vacuum levels applied to the warm-up regulator while testing. Look carefully at the rubber vacuum hoses and connections, particularly to the warm-up regulator. Cracks, splits and damage to the vacuum connections will affect the control pressures, messing with mixture. If you find supply pressure is good but control pressures are not, vacuum may be the problem.
For sure, don't go blindly turning the mixture adjustment bolt in the top of the metering unit, the one that requires the long Allen key. If you feel you must turn that, keep very careful track of how you move it, so that you can move it back when you fix the control pressure.
For the connections that Pete shows, the fuel supply and return connections, know that there is a brass screen in the supply side. That screen has a bad habit of corroding and turning to tiny metal bits if allowed to sit dry for an extended period. The metal bits will cause the pressure control valve pin and piston to stick. Plan on replacing all the brass filters if you have things apart there.
Two great books on the CIS system, one the Watson book, the other is by Probst. Both have good theory explained, along with some troubleshooting hints. Some feel the Watson book covers more about modifications for performance add-ons, but either will fill out the info in the WSM for getting the car running right again.
Cleanliness is next to function with CIS, to the extreme.
Us cars 78 & 79, Euro cars 78 - 83 are K-Jet. CIS.
US cars 80 - 84 are L-Jet.
The two systems are totally different.
Troubleshooting tips for one are completely useless for the other.
Ok I sure she is Euro cause she is right hand drive and on my papers in RSA says 83 but that is always debateble as that is actually when the car gets registered on the road here by us , here are some pictures of how she looks Porsche Her Motor Euro on Plate
Telltales include the CIS warm-up regulator and the individual metal fuel lines to the injectors. The engine number is stamped into the top front of the engine on the rib just to the rear of the water pump and the mechanical cooling fan bracket. The ZZZ in the vin on your number plate tell us that it's a non-US car, more research needed on the number to determine original market.
Telltales include the CIS warm-up regulator and the individual metal fuel lines to the injectors. The engine number is stamped into the top front of the engine on the rib just to the rear of the water pump and the mechanical cooling fan bracket. The ZZZ in the vin on your number plate tell us that it's a non-US car, more research needed on the number to determine original market.
Yup. CIS (K-Jet) car.
Right hand drive would definitely rule out a US car.
Have gone threw timing the all the other goodies and still no luck on the rev
I'ver seen three similar threads. The things that resolved the issues in the other cars are:
1. have the fuel distributor (professionally) rebuilt
2. have the fuel injectors (professionally) inspected and cleaned
3. unplug the MAF to see if the behavior changes, if it does get the MAF rebuilt through Louis Ott
04-13-2020, 07:32 AM
928 S /4.5 Jet Tronic Starts Does Not Rev
