I have a 1973 1800ES with about 153000 miles on it. The car looks really nice and everything is straight and original but it has been running terribly lately. I recently took my car to a shop called Swedish Automotive in West Seattle. They worked on the car for two days to try and remedy an issue of poor economy. It turned out that my car was running 8 times the stock fuel flow setting at idle and 4 times at cruise. Swedish turned the fuel flow back down to factory specifications but the fuel economy only got worse. Right now I am only going about 180 miles on a toped off fuel tank with 90% freeway driving or about 15 mpg. That poor economy is something I can live with even though I know it should be more like 20 mpg. What I can’t live with is the way it’s running. The return trip from Seattle is about 45 miles on I-5. I averaged a cruising speed of 65 mph with no stops. When I came off the highway I pulled into a gas station to meet a friend. The car sat for about 10 minutes. When I jumped back into my car and turned the key the car took nearly 15 seconds to finally run. This is not normal on my car, usually it fires up immediately. I then proceeded to a traffic light, the car died. I started it back up, went to the next light, car died again. Although not to this same frequency my ES often stalls at stop lights now and runs very ruff. The day before I took it up to Swedish I redid the timing and adjusted to idle to factory specs. After Swedish worked on it though my car often and always simultaneously idles too high in park and neutral @ 1200-1300 rpm and too low in gear @ 500 rpm. Since this is such a wide gap in idle speed the car always dies when it is shifted into gear on my auto tranny. I called Swedish the next day and asked them what it could be. The mechanic suggested checking to make sure the vacuum hoses on the air intake manifold were in place and in good shape, they were. It still continues to run extremely ruff and idle the way I illustrated. Is another tune up in order? It’s only been 3000 miles since I replaced all the tune-up parts. I have brand new copper core spark plugs. And the timing was done the day before.

Another thing happened just last night. I was cruising down the freeway on my way home. It was a night when the car had been running particularly shitty. I was in third gear (this is a automatic remember) and I floored the accelerated to make a pass. The engine revved up to 5000 rpm but the car gained not speed. So I laid off the accelerator. Now the car would only go 30 mph. After cruising at this speed with out and improvement I slowly worked my way back up to 40 mph which was what the speed limit had been degraded to. After another mile or so I was back up to 60 mph and the car experienced no other problems such as this later that night. Although the old ruff running and high/low rpm persisted as always. Could anyone please tell me what is wrong with my car? My 1800ES is the first car I have ever worked on but I am pretty good at fixing things on it once I know what the problem is. If anyway could just give me a hint or a suggestion about what the problem could be attributed to I would be very happy.

Check the pressure sensor. Also, the vacuum connections at the distributor, the cold air auxilary, the return from the oil fill cap to the manifold, and the brake booster. I have a 73 ES and the bad pressure is where I started, but finally ended up at the cold air valve. Vclassics.com has excellent info on the D-jet, also goodspeed.com. I also have no real previous experience but found if I read carefully and followed the advice the problems can be cleared up. I also went to a crane electronic ingnition which seemed to help out alot. (when I bought the car I was getting 5-6 mi/gal, now as high as 24)

Jim 73ES 86/760

If your rpm went to 5000 and you didn't gain speed, sounds like your transmission is slipping.

This sounds very much like a vacuum leak to me, and a fairly major one. That's the only thing I know of that can make a D-jet car idle intermittently fast while dying under load, and it also completely throws off the FI computer. If you're sure the hoses are all good (including the ones to the fuel vapor cannister behind the grille???), check the manifold gasket.

Not sure what you mean by having the fuel flow adjusted, but vacuum leaks (a.k.a. false air) can make your injection system run very rich. I'd say the garage tried to tune around the problem rather than fixing what's wrong.

Get some starter fluid and spray around the gasket and anything else you might suspect of leaking -- the engine will speed up when you've found the problem area.

As far as I know, air leaks don't throw off the D-jet system, as it never measures air moving through a certain point (like almost all later style systems do in some fashion). So there is no measuring point that is bypassed by a leak. It just measures the manifold pressure, which is the grand total effect of all vaccum leaks plus the throttle opening, cold air valve, and idle bypass. Generaly a vacuum leak will just make the idle fast, and you won't be able to get it down with the idle adjustment.


Do some diagnostics on your FI system. Luckily, the D-Jet is about as simple as electrical FI systems can get - there aren't many gadgets to check, and they can all be checked easily with a multimeter.

Just as a guess, if your problems are caused by the FI system (and not ignition or mechanical problems) then I'd guess the fuel pressure regulator is flaking (psi should ALWAYS be 28 psi) or the Manifold Air Pressure sensor if going out.

I’m fairly new to working on this car and my maintenance manual is not too explicit about where the vacuum hoses are. I check the two that connects to the air intake manifold but I don't know of any others.