QuestionVon,
I have read many of your postings regarding the Datsun 280 and have learned a great deal. I have reasonable mechanical abilities but I don’t know my way around the 280.
My friend has a 1983 Datsun 280ZX that she bought new. It has been in her garage for 2-3 years (not driven or started). Last summer we charged the battery and got it running. I had the opportunity to drive it one day on the highway briefly. I didn’t drive it hard but wow that thing had nice acceleration! Not long after this her son was driving it (probably high rpms) and it developed an engine noise and so it was parked in the garage once again.
This summer she took it to a mechanic that discovered that probably due to a sticky valve (I assume from not being started for several years) the cap that resides under the rocker arm had come off the end of the valve stem. He replace this, added some MOA, adjusted the valves, and recommended the car get driven. The noise is now gone and we’ve been trying to get some miles on the car, however, it just doesn’t have the same pep it did last year. Actually, at first its high acceleration seemed to happen only at low rpms, but now doesn’t seem to occur there much either. I put fresh gas in it, though it probably still has plenty of old gas in it as well.
When I take it out on the highway and drive it at a steady speed it seems to have a small surge and the rpms drop some, as if it’s not getting enough gas, and then it might return to normal rpm though still not having any real acceleration. At one point it even seemed to struggle to maintain 65 mph and slowly dropped down to 55 mph.
I am thinking I should try changing out the fuel filter. I have the following questions:
How do I bleed off the fuel pressure to do this?
What would you suggest I look at next if the fuel filter doesn’t resolve the problem (or based on its storage)?
Is it safe to use gas with 10% ethanol?
Thank you so much for sharing your wealth of automotive knowledge with others
AnswerJeff,
The fuel pressure should be checked and it is probably a plugged fuel filter or a defective fuel pump. To bleed off the pressure you simply remove the cap on the fuel rail, on the engine, and use a rag so gas does not squirt on you. Then, remove the gas cap and replace it. That way the pressure if off the tank too and with the cap reinstalled the gas will not drain on you as much when you replace the filter. Jack the car up and use stands so the filter is down hill from you since you are going to get gas coming out to the tune of a half gallon or so. Have the new filter pre-positioned and rags and someone with a fire extinguisher. Also, no drop lights or open flame and do it outside to keep the gas vapors blowing away from you. You can check the fuel pressure with a fuel gauge screwed onto the valve on the fuel rail, where the injectors are, on the engine.
