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hard cold starting/running of '84 245dl[ALL/1998] posted by Thomas Graham on
Friday, 6 June 1997, at 10:15 p.m.
My '84 245dl with B23F starts very hard when the engine is cold. It takes several cranks before it will start and then runs poorly (lopes) and stalls for 30 seconds to a minute. After this period it runs well and it will start and run well until I let it sit for a few hours. I suspected vacuum leekage for awhile but have replaced all the hoses and even replaced the intake manifold gasket (vacuum gauge reads fine when the engine is warm). While doing so I noticed that the valves looked dirty with carbon deposits. I sprayed some fuel system cleaner on them (the kind that says safe for oxygen sensors) but am not sure it did much good. I suspect that these valve deposits are the problem but am not sure how to clean them. I have been using techron but haven't noticed improvement. I have also tried playing with the idle mix to no avail - the idea being that before the oxygen sensor kicked in the fuel mixture may have been lean. Please help with any suggestions Thanks
Re: hard cold starting/running of '84 245dl[ALL/1998] posted by Owen Woodland on
Sunday, 8 June 1997, at 6:18 p.m.
I have a '76 244DL with a B21E (injection), which has a similar problem, but I have it on good authority (from a Volvo specialist who has repaired the car and checked the problem) that my stalling problem is due to a worn Control Pressure Regulator, which on the B21E is the little rectangular beast just below and in front of the big rubber sucker which is part of the fuel injection system. Anyways, this explains stalling and hard running when cold, not to mention stalling if you try and give the car ANY gas when it is cold.
Re: hard cold starting/running of '84 245dl[ALL/1998] posted by Thomas Graham on
Monday, 9 June 1997, at 11:09 p.m.
Thanks for the response. My fuel injection system (LH jetronic) is not the same as yours (K jetronic, I believe) and does not have a control pressure regulator, but it does have a fuel line pressure regulator which I replaced recently and did not solve my problem. The fuel pumps are both new (the tank pump had failed and the main pump had begun to crap out) and I have done the electrical checking of the air mass meter, the inputs to the ECU and the coolant temperature sensor. I'm still looking for more suggestions. Thanks
Re: hard cold starting/running of '84 245dl[ALL/1998] posted by Shatz on
Tuesday, 10 June 1997, at 12:25 p.m.
Although my experience has been with an 80 and 86 240 (and I get confused about which problem went with which car!), two possibilities come to mind. On one of my cars I remember a cold start valve ( the CPR in the previous note?) that I replaced on one of them, probably the 80.
I have also cleaned the intake valves on both, essentially similar jobs. This suggestion came sraight from the Volvo shop. All you need is a can of carburator cleaner. Get the engine warm; shut it off; take of any or all of the vacuum connections to the intake manifold and empty about 1/2 of the contents of the can into the orifices. Wait 30 seconds and start it up and drive.
If it need more cleaning than that, it will need to be done at the shop. Volvo has a system that uses crushed walnut or pecan shells to bast away the carbon deposits .
Re: hard cold starting/running of '84 245dl[ALL/1998] posted by Mark Klein on
Tuesday, 10 June 1997, at 8:01 p.m.
You may have a fairly basic problem or even a combination of a couple different ones. Check the base idle speed. With the engine at operating temp, pinch off the air to the idle motor. You can use a pair of needle nose pliers and pinch the hose going to the idle motor where it comes off the air bellows. The motor should idle at about 600-650 rpms when the hose is closed off. If the engine idles lower than that, you need to clean and adjust the throttle housing and set the base idle speed to about 700-750 rpms. This can give a stalling for a minute or two when cold.
About the carbon on your valves. Techron is intended to be a preventive treatment. It won't do much in the way of removing accumulations which are already there. If you can find a product called 44K (made by BG Products- normally NOT sold in retail outlets, try some independent garages or dealers)use this for a couple applications. It goes in the fuel tank. This is the best I've seen at removing deposits. This will give very similar symptoms to what you are describing.
Air mass meter. I've seen AMM's check ok by a pin test but they won't adjust properly. With the engine at operating temp, check O2 sensor voltage with the sensor UNPLUGGED. It should be around .85 to .90 volts (not fluctuating- its in open loop)ideally. If not, adjust it to this value with the AMM. If it doesn't adjust, the AMM is faulty. The '84 is a metal body meter.... the more expensive one.
If none of this helps, please repost with any additional info. Either way, please let us know.
Re: hard cold starting/running of '84 245dl[ALL/1998] posted by Thomas Graham on
Sunday, 15 June 1997, at 11:09 p.m.
The air mass meter failed miserably the test you outlined for me (measure O2 sensor voltage while unplugged, engine warm). At the richest mix the voltage was still below 0.1 V. Adjusting the mix screw didn't seem to affect the sensor reading. Is the AMM at all serviceable or must I purchase one? Are they available used/rebuilt -- how much should I expect to pay? Thenks very much for your help.
Re: hard cold starting/running of '84 245dl[ALL/1998] posted by Mark Klein on
Monday, 16 June 1997, at 5:42 p.m.
They aren't intended on being rebuilt by any individuals. You can get rebuilt ones but I would be sure it is a Bosch rebuild. Some of the generic rebuilds weren't very reliable.
Re: hard cold starting/running of '84 245dl[ALL/1998] posted by Thomas Graham on
Tuesday, 17 June 1997, at 11:47 p.m.
Mark, are there any more tests I should perform to make absolute sure that the AMM is faulty? Is it possible that the ECU is not responding properly to the AMM output? And if so how would I know. I should add that when the AMM and O2 sensor are both disconnected the engine idles very unsteadily with a fairly rich mixture (~.8 or .9 V) as measured at the O2 sensor. Thanks again for your help.
Re: hard cold starting/running of '84 245dl[ALL/1998] posted by Mark Klein on
Wednesday, 18 June 1997, at 9:25 p.m.
With what you've determined already, that is enough to condemn the AMM. If it won't adjust properly, it isn't providing correct information to the control unit.
I wish I had better news.