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240 running problems[ALL/1998] posted by Philip Eng on
Saturday, 30 August 1997, at 1:30 p.m.
I am posting this for a friend:
He has a 1984 240 GLT Turbo sedan, automatic, B21FT with CI fuel injection and approximately 140,000 km.
Problem: Off the line under steady acceleration or attempting to pass, throttle response is very slow and sluggish. Under hard acceleration the engine would be trying to cut off like a series of hiccups. The diagnosis he received from a dealer was the catalytic converter had melted and became plugged thereby restricting the flow of exhaust and at last performance. After installing a new catalytic converter the problem still exists.
Recent work on the engine includes fuel pressure checks, retiming of the cam and a new timing belt to rectify a difficult cold start and a rough idle. Also work was done to free up a seized wastegate. Any suggestions to this problem would be apprecitated. TIA.
Re: 240 running problems[ALL/1998] posted by Dave Stevens on
Sunday, 31 August 1997, at 1:16 p.m.
I'm guessing it's the fuel pump relay giving an intermittent or weak response. On a B21FT with the CI system I recall that the relay also controls the auxiliary air valve, so if the car also has cold/warm start idle problems then this could all be related. For the price of the relay it's almost worth just putting in a new one on spec.
I not too sure how the timing belt could have much to do with cold start and rough idle.
(MXTuner: Okay, Mark, that's my best guess, now let's have the other possibilities)
Re: 240 running problems[ALL/1998] posted by Mark Klein on
Monday, 1 September 1997, at 3:09 p.m.
I think the '84 has an idle motor instead of an aux air valve. I'm not sure of this and will try to remember to check tomorrow. I agree about the belt business. Even if the cam was off a tooth, I've never seen that affect cold start/rinning.
I'm wondering if the prepump is working. When they did the fuel pressure test, did they also check fuel volume? If the fuel filter is partially clogged, the pressures at idle could be fine but at higher rpms it could be running extremely lean.
Re: 240 running problems[ALL/1998] posted by james keating on
Friday, 5 September 1997, at 5:32 p.m.
thank you everyone for assistance with the 84 240gl sudden idle surge problem.
It sounds like the CIS is the problem. The car is not an automatic though it is
manual. The problem appears to be worsening, the car will do it not only when
downshifting but also while driving at near highway speeds. Some other questions: I looked up the CIS in a haynes manual and it has several parts
including an air control valve, coolant temp sensor, and electronic control unit. Anybody got a pick what component is most likely the culprit? Also, one
response mentioned a CIS motor. I did not see this in the diagram. Is it called
something else? One last thing; the car does not always do the idle surge.
Today, on a 7 mile trip in and same out from town. there was no problem. The
car is very hard to restart if it is turned off before the idle settles back
down which can be an increasingly greater period of time. thanks again- jim
Re: 240 running problems[ALL/1998] posted by Mark Klein on
Saturday, 6 September 1997, at 11:36 a.m.
The CIS motor mentioned is the same part as the air control valve, just called by a different name. It could also be called an idle motor or even an idle stabilizer. Different manufacturers, different names, same part.
Make sure you're looking at the LH injection system. The CI fuel system is totally different.
Re: 240 running problems[ALL/1998] posted by Randy Riggs on
Tuesday, 2 September 1997, at 10:08 p.m.
There are many things that could cause these problems. They may be related.
Cold start, rough idle, and sluggish acceleration could be either a vacuum leak, (check around the injector seals) or a hole in one of the turbo hoses ( remove and take a real good look at them). If it has an intercooler, it could be that (or rubber hoses) leaking as well. It could also be dirty injectors (they can be cleaned and tested)
The cutting off under hard acceleration may be caused by a broken hose that goes
between the waste gate and the pressure side of the turbo. If the hose is broken boost pressure can't be regulated. If the boost pressure is too high, the fuel will be cut off so you don't damage the engine.
Also check: Compression, plugs, wires, cap and rotor, air and fuel filters, valve adjustment.
Does it run good under full throttle? (except for the cutting off)or does there seem to be no power no matter what? If there is no power no matter what, the exhaust could be plugged somewhere after the converter.
Good luck,
Randy