Skip to main content

Revving freely at last!

After an enormously frustrating time trying resolve why the engine wouldn't rev above 1600rpm - the problem is now sorted!

After testing just about everything I could test this weekend has proven to be a breakthrough one. Some suggestions from forum members on tipec helped chase the problem down to something to do with the throttle position sensor.

Along the way I tested the fuel pressure which turned out to be good, as did various other sensors.



Although multimeter tests on the TPS proved it was healthy, the same readings were not being translated through to the DME connector end of the wiring loom. I realised that much earlier in the project cycle I had to extend the length of the wiring for the TPS in order to fit the S2 intake and throttle body.

Pulling the loom out from under the intake I could check the wiring and it was clear that it was a little more elastic than it should've been - and sure enough the connectors had come adrift essentially isolating the TPS from the DME. Which I'm presuming prevented the ECU from switching from the idle map to open throttle mapping and limiting the rpm to 1600.

With a quick rebuild of the TPS wiring extension and checking with the multimeter all the way the issue was resolved and the engine now revs freely!

However, all the testing did reveal that injector #4 isn't working properly and will need replacing as my attempts to fix it have not been successful. Using a 9v battery wired up to the injector brought no response and it did not "tick" like the other three.

With that injector fixed the engine will run even better!

Comments

Popular posts from this blog

Engine out the top - Easy Peasy

After reading numerous posts, the Porsche workshop manual and Clarks Garage step-by-step engine removal guide - I felt confident enough to tackle the job. But I wanted to remove the engine from the top.  As I discovered, it was pretty straight forward even for a novice! Result. I wanted to avoid removing the cross member and disturb the front suspension to do something I was convinced could be done easier from the top. Posts such as this one convinced me to give it a go at least. And I'm glad I did. In summary I was able to remove the engine from the top without needing to remove the bonnet/hood; torque tube; transaxle; bellhousing; clutch; clutch slave cylinder; cross member; front suspension; and radiator. Contrary to many so called internet experts opinions and many confusing threads this was painless and without dread. All that was necessary to remove was the starter; power steering pump and alternator (I figured to make the bottom of the engine narrower); intak

New Steering shaft bearing Nightmare removal

In my quest to tighten up the handling on the 944, I bought a new Needle Bearing from Porsche in an attempt to eliminate the fore-aft play in the steering at the top universal joint. The part number for the replacement is 477.419.059 and costs £88.86 posted from an OPC. Nothing like the effort required to actually remove the old one... I began the process by reading section 48 of Porsche Workshop manual. It appeared a simple enough process but two things bothered me: firstly, it required a chisel to remove a shear bolt (which in my limited experience never "shear"; and secondly a drill to remove two screws from the ignition lock. I was bothered because a quick look under the dashboard made it quite obvious that whoever had written the manual hadn't performed this task - well not without a dashboard in place that's for sure. I was bothered before I'd even started. Furthermore, the manual doesn't detail the replacement of this bearing at all - just the rem

Bellhousing & Clutch fork removal

Removing the bellhousing from the Porsche 944 engine is not as complicated as it may seem - such as in this situation with my replacement engine. When I removed the original engine I detached it from the bellhousing in the car and removed the clutch pressure plate bolts through the starter motor hole - see my other post for details . In this case I decided to remove the clutch fork pivot shaft bolt. Begin by removing the four 17mm bellhousing bolts - you'll find that the bellhousing doesn't detach completely from the engine. It'll feel like its hooking on something. That something is the clutch fork pivot shaft inside the bellhousing. The bellhousing will be loose enough to rotate - turn it 180 degrees and peek through the access port which is now on top - this is what you'll see: If the engine is still in car you'll be looking at this from underneath. The pivot shaft needs to be extracted from the clutch fork. It's held in place by a small bolt on the