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I was cut off the other day and had to brake so hard that the enginge stalled. Later that day after driving about 20 miles, while sitting at a light, the engine began to idle rough and hesitate until RPM's were brought up to 750-1000.
The car idles fine in park or neutral and gets worse as engine load is increased (a/c or transmission load) The problem begins after the car is driven for about ten minutes and was intermittent for about 4 days. Last night I had time to change the fuel filter (Rex/Regina)hoping I just sloshed a bunch of fuel tank sludge into the filter. That seemed to work and I drove around for 20 minutes with a/c on and stopped numerous times with no problems.
This morning even when cold, the enginge idled rough with no load and was pinging as it struggled to idle. As I increased RPM's the engine still ran rough. I had to catch a flight so the wife took me to the airport.
Any thoughts on what might have happened during that hard stop and what to check when I get home next week would be welcomed.
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Well, I think I have it fixed now.
Even though the Regina fuel pump had been replaced with a genuine Volvo unit within the last 6-10 years (I drive maybe 10,000 miles per year at best), I decied to order another pump. I based this on the fact that my idle symptoms got worse as the fuel in the tank got lower. I figured pump output was being aided by the weight of the fuel above it.
I put the new pump in yesterday and BINGO, all seems to be right in the world again. Thanks for all of the input everyone!
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Well, I started her up this morning and she ran like a champ. I wish I could narrow the problem down to on single thing but I can't. If I had to guess, the trottle body cleaning was the most important part of the equation. In addition to that I:
-Changed the fuel filter
-Checked all grounds
-Blocked off the failed warm air intake and modified to cold only
-Cleaned the Intake Air Tepmperature probe.
-Sealed some leaks in the flame trap tubing
Thanks for all of the input! I hope this helps someone down the road.
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Oh and by the way, my gas mileage has almost doubled after sealing off the warm air intake from the exhaust manifold.
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Well, today it started doing the same thing and got worse the more it was driven. Every time the engine would roll back to idle it would begin to bog down and the engine would ping, stutter and die. Once stalled it would take quite a bit of cranking to get it started again. I got it home and began to unplug things like the CPS and TPS. The engine of course would die when the CPS was disconnected so that was working well. When I disconnected the TPS, the idle dropped to 600 RPM and held steady. I went on a 30 minute drive and stopped at lights as often as possible, NO STALLING PROBLEM! The symptoms don't fit a bad TPS but with it disconnected the problem is gone. Thoughts?
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Maybe time for a new fuel pump. I've got the same car and the fuel pump doesn't die all at once, it goes gradually.
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posted by
someone claiming to be mmal231294
on
Fri Oct 22 01:36 CST 2010 [ RELATED]
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Check your timing to make sure you didnt jump a tooth on timing belt.
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Idle Air Control Valve? and while you are checking this clean out the Throttle body..good luck
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Checked the IAC. Seems to function Fine.
The fuel pump is about 10-12 years old so it is possible that it is going. I will definately check and clean the throttle body when I get back. The timing of the problem begining after the sudden stop makes me wonder if it is not a bad electrical connection somewhere. This engine ran like an absolute top prior to the incident an is almost clean enough to eat off of.
The timing belt is less than a year old but it could use a new cap and rotor along with wires. Injectors were removed and serviced about 7 years back. Thanks for the input. Keep it coming.
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I once hit the brakes hard and the non-secured battery tilted and pulled the connector off, which on a main drag in NYC was not so fun, so something like that may be in order. Maybe one of the relays got pulled, or a connector somewhere.
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That is what I'm thinking. I get home sometime tomorrow and will work on it Thursday. I'll report back when I have an answer.
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Got home today after a week and tried to fire the old girl up. She fired immediately and then would quit after releasing the key. I did this several times and then touched the gas pedal, she fired right up and idled at about 1100-1200 RPM. after a few minutes, the idle came down and she ran smooth. I finally got a check engine light that indicated Fault 3-2-1, Signal Missing to/from Cold Start Valve. I'll look at the Radio Supression Relay and report back.
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I also got at 1-2-2 fault once tonight. I can't find much in the FAQ's about the Air Temperature Sensor and where it is located.
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...based on Service Bulletin # 135 from January 1990 (applicable to '89 and '90 740 and 740GL), which says that 3-2-1 may be a false code, due to a circuit modification related to the Cold Start Injector/valve..
As a quick check, peel back the Cold Start connector boot and see if the Blue-Green + wire has been disconnected, taped off, and replaced by another wire (color unknown) directly from the starter solenoid.
If so, you can confirm the modification by checking for continuity from CS pin 2 to starter auxiliary terminal 15a or 16 down on the solenoid. If there is continuity, the RSR is no longer in the CS Injector circuit.
QUOTE: "As a result of this modification . . . Fault code 3-2-1 (cold start injector) will be permanently stored in the self-diagnostic memory. However the Check Engine Light (CEL) will not illuminate."
10/27/10
I know this doesn't address your current problem, but didn't want you to be chasing a wild goose.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Yep looks like I have that mod. That would explain why the 3-2-1 fault is always there. Thanks! I did a ton of work today. Cleaned the trottle body, battery terminals and all grounds. Fixed the airbox intake that was sucking hot air all of the time. Cleaned the AMM probe (regina). Plugged a leak in the tube leading from the flame trap to the throttle body intake. The engine was stone cold by the time I finished and it started and idled well. I'll check again in the morning, temps are supposed to get down to 60 tonight (I know, poor me!).
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"Cleaned the AMM probe (regina)"
That "probe" is a temp sensor monitoring inlet air temp, an important part of fuel mixture control in Regina FI. So fixing that airbox intake was a good thing.
FWIW, my 940 has no duct and blocked airbox flapper getting cold air all the time. It starts and runs well at –20°F and colder with no problems.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Thanks Bruce,
I thought that might be the temp sensor I had asked about earlier in this thread but wasn't sure. I went out this morning crossed my fingers and turned the key, she fired right up and idled fairly well, only a touch of roughness that lasted a couple of minutes (seemed slightly rich). I think that will be solved with a new cap, rotor, plugs and wires. The coil is original do you think it would be a good idea to replace it at this time?
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Thanks, I had seen the note regarding that on the FAQ's. I will take a look tomorrow.
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