SV: [ROVERNET - UK] Re:Rough running SD1

jan.tillberg at jan.tillberg at
Wed Oct 10 16:32:06 BST 2007

Hi again!

I'm new to rovernet, perhaps I just answered you? Please let me know!


-----Ursprungligt meddelande-----
Från: rovernet-bounces at [mailto:rovernet-bounces at] För Dermot Harvey
Skickat: den 10 oktober 2007 16:42
Till: rovernet at
Ämne: [ROVERNET - UK] Re:Rough running SD1

My first guess would be partially clogged fuel injectors, but it's worth checking your fuel line pressure first. Find an old mechanical oil pressure gauge. Depressurize the system and attach the oil pressure gauge to the cold start fuel injector. Take the hose from the air filter to the airflow meter off. Stick a rag in the airflow meter. This will turn on the fuel pump when the ignition is on. You should get a steady reading of about 40 psi. Turn the ignition off and watch how slowly the pressure drops - the longer it takes the better.
If your fuel pressure is OK you should remove the fuel injectors and test them for flow rate and spray pattern. This is a messy procedure.  
I have a test rig using an old  fuel pump and pressure regulator. The injectors should deliver 125 to 150 ml per minute and you should have a conical spray pattern. You might be able to find a shop that has testing and cleaning equipment for fuel injectors. Sometimes the injectors can be cleaned.If not you can buy new or rebuilt ones.
Before you put everything back together, be sure your fuel filters are reasonably new and carefully check the rubber fuel lines. If there is any sign of checking or cracking you should replace the rubber lines making sure only to use high pressure fuel injection hose.
The other possibility is that your ignition module is faulty. I think by now most people are using Lumenition or Pertronix modules, but if you have the original module inside the distributor it has probably about had it.

Good Luck!

Dermot Harvey
Spectral Kinetics

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