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'84 GL D24 Diesel Starting Problem[ALL/1998] posted by Dave Spriggs on
Saturday, 25 October 1997, at 8:32 p.m.
Here’s one that has me scratching my head. My ‘84 GL D24 Diesel has always started very quickly so long as the glow plugs were operating. Even in cold weather (20 DegF), it never took more than 3-5 seconds of cranking. But, beginning two days ago and every start since, it has taken 15-20 seconds of cranking. This is true even when the engine has reached and maintained operating temperature and been shut down for as little as 10 minutes. The difficulty in starting a hot engine tells me that it is not the glow plugs. The duration of cranking does not appear to be increasing or decreasing.
I considered a clogged fuel filter, a faulty fuel injection pump, or water in the fuel. But, once the engine starts, it runs smoothly with no decrease in idle RPM or loss of power.
OK, you diesel experts, what’s going on here?
Thanx/Dave Spriggs
Re: '84 GL D24 Diesel Starting Problem[ALL/1998] posted by Craig Murphy on
Sunday, 26 October 1997, at 12:24 a.m.
My guess would be that your fuel system is not maintaining system pressure once you shut it off for a while. My gas Volvo has had this kind of problem. It could be caused by the fuel accumulator sticking, which could prevent it from keeping line pressure. Or possibly air getting into the fuel system somewhere. This can be a problem especially on diesels because they are slow to prime once air is in the lines and they have higher injection pressure. You could check the system pressure by hooking up a gage in line between the accumulator and fuel pump, and then between the pump and injectors to test line pressure. A Haynes or Chilton's manual would give you the correct line-rest pressure. Since the car runs fine as you said, I doubt it is air getting into the system, but it is a possibility. Good Luck! Craig Murphy
Re: '84 GL D24 Diesel Starting Problem[ALL/1998] posted by Duane on
Sunday, 26 October 1997, at 8:18 a.m.
As a former owner of a Chevette Diesel ( OK you can stop laughing) with all service performed by self a little thought process on your problem.
Ten to fiftenn seconds to get pressure back up to delivery level in a diesel is too long. Maybe 5 seconds if the delivery pump is working properly. If the pump is on the engine and not by the tank then you have a fuel pump problem. If the pump is self contained and at or near the tank with a check valve then it is either the check valve or the pump. Since diesels generate their own injection pressure via the injection pump there is no need for a check valve in line unless Volvo put one there. The time from attemting to start to actual start in a diesel is such that a normal fuel delivery system would suffice to deliver fuel to the injection pump. If the pump is electric then fuel pressure would build up during the glow period.
You could test fuel line pressure to verify but there is no need to check injection pump pressure as long as the engine runs fine after starting. Besides, the pressure there is up around 2000 psi and the guage to check it is probably a lot more than you want to spend.
Concentrate on the fuel pump. The filter is probably fine as the engine runs OK after the initial start difficulty.
Hope this helps.
Duane
83 245 DL LH 2.0 M46wOD 153xxx
85 245 GL LH 2.2 AW71 116xxx
R.I.P. 82 Chevette Diesel 56HP Automatic :>)
Re: '84 GL D24 Diesel Starting Problem[ALL/1998] posted by Ed Lipe on
Sunday, 26 October 1997, at 12:25 p.m.
You're not going to find a fuel pump on the car because there isn't one. Don't try to find an accumulator either. The fuel is drawn from the tank by the injection pump. You can check the screen on the fuel pick-up in the tank to see if it's got a build up of crud on it. Try some Techron in your fuel for a while. The next simplest item would be testing the injectors. Find an independent authorized Bosch diesel service shop. The Volvo dealer won't have any diesel service tools. If injectors are the culpret only the nozzles are necessary if the cracking pressure is correct and the spray pattern is bad. Two nozzles are spec for the D24; the one for the US market costs twice that of the Euro spec nozzle. Direct E-mail me for more ideas.
Re: '84 GL D24 Diesel Starting Problem[ALL/1998] posted by Abe Crombie on
Sunday, 26 October 1997, at 2:36 p.m.
Ed is correct on the lift pump being integral with the injector pump. A cheaper and more readily available additive to attempt some fuel varnish caused problem would be auto trans fluid (garden variety Dexron would be fine). ATF contains detergents that are superb for diesel pumps and injectors. ATF doesn't do anything for gelling or water dispersion (typical diesel additives do contain these chemicals). The injector pump is expensive to repair, so if the slow crank is the only symptom, you could fit an inexpensive universal electric fuel pump which will contain a check valve that will address this problem.
There is another item that can be fixed on that pump that can cause this: the injector pump shaft seal. If it hardens, it can allow air to enter pump. This vents the pump and allows the fuel to back flow to the tank. Typically this seal doesn't leak outwards as the pressure in the pump will apply force to the seal lip and seal it against the shaft when engine runs.
Re: '84 GL D24 Diesel Starting Problem[ALL/1998] posted by Mark Klein on
Sunday, 26 October 1997, at 3:50 p.m.
One other thing no one has mentioned. The fuel return lines which run from one injector to the other (and back to the injection pump) can crack and get brittle with age. If any one of these develops a small leak, it can cause the injectors to lose their prime. Definitely one of the first, easiest and cheapest thingsd you can do is replace these return hoses. The #1 injector also has a plug for the last fitting. I would recommend getting the correct plug and hoses from the dealer. Don't have a coronary when you pay for the hose. It is VERY expensive for rubber hose but you NEED to have the correct hose to prevent this problem from occuring again in a short time. You might try the VW/Audi dealer if your Volvo dealer doesn't have this stuff in stock. You might want to price shop anyway.