i have an '85 740 gle, and it works properly. when i go to start it, the tach does not go up to 400-500, it twitches while not really going anywhere.LaRy wrote:As I said, if the tach is showing 0 rpm when trying to start the dead engine, it is most probably one of those two components, otherwise not. Normally the tach is showing 400 - 500 rpm also when trying to start, if the ignition is OK.
740 GLE 1986 Petrol - Inconsistant Starting - Aaaarr
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billy
Yes, when its going (which is whenever I try to fix it) the tacho does just twitch - which I believe shows that its working on the electrical side (when its working!), does anyone know where the fuel pump solenoid is? As several of you have mentioned it - but not sure if its relevant to my car?
Thanks for all the elp so far!!!!
Billy
p.s. it would be easier to get rid of the wife and keep the car, cos it works fine for me!!!
Thanks for all the elp so far!!!!
Billy
p.s. it would be easier to get rid of the wife and keep the car, cos it works fine for me!!!
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Kmaniac in California USA
I, too, have a 1986 740 GLE sedan with B230F (no turbo, fuel injection) and automatic transmission. It always starts and runs well when cold, but will randomly fail to start when hot. I have owned the car for two weeks (no wonder I got such a great deal on this) and this has occured at least six times. A couple of times it restarted after 5 minutes, but once it sat for six hours until the sun went down before starting again. Sometimes when it has it's fit, it sounds like is tries to fire, but then just cranks. I am waiting for the next incident to confirm whether it is lack of spark or fuel. Will keep you posted. In the last 4000 miles the car got new spark plugs, wires, cap, rotor and coil, as well as a new in-tank fuel pump and filter sock. The fuel pump relay behind the ashtray works and clicks everytime. Any suggestions from others who have experienced the same problem would be appreciated.
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Kmaniac in California USA
Well, my Volvo did it again today. At 7:00 AM and 65 F temperature, it started and drove fine as I got my morning coffee. Six hours later, after sitting in the hot California sun on this 90 F day, it failed to start in my driveway. I hooked up my inductive pick-up timing light to the ignition system and got plenty of spark on all four cylinders and the coil. Leads me to think the problem is hiding in the fuel injection system. The car has 203,200 miles on the odometer and everything associated with the fuel injection looks original, except for the fuel filter. Any ideas which parts of the fuel injection system would be affected by the heat of the sun on a hot day?!? At least I know it is not the ignition system. I will keep all posted as I progress through the fuel system.
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Kmaniac in California USA
Eureka!! I think I solved the Problem!!!
I drove my Volvo on errands this morning, ending up at the local auto parts store to purchase fuel injection pressure testing equipment. When I went to leave, it won't start. It was a warm California day with the temperatures reaching into the 90's F. I sat with car for two hours trying repeatedly to start it. It would just crank. My timing light indicated strong spark. I got a ride home and returned with my tools in another vehicle. I spent another hour trying to figure out how to hook up the test equipment. Then a guy from the parts store comes out and says that he thinks it is the fuel pump. He then hads me a rock and tells me to tap on the fuel pump a few times. This should knock loose anything that might be hanging up inside the pump. So I take the rock, crawl under the car, and tapped the fuel pump about a dozen times. I get out, get into the car, turn the key and it starts right up! I immediately purchased a new replacement fuel pump, drove the car home and replaced the fuel pump. I am 99% sure that this will cure the problem. I will check back in a couple weeks to let you know how this is going.
I drove my Volvo on errands this morning, ending up at the local auto parts store to purchase fuel injection pressure testing equipment. When I went to leave, it won't start. It was a warm California day with the temperatures reaching into the 90's F. I sat with car for two hours trying repeatedly to start it. It would just crank. My timing light indicated strong spark. I got a ride home and returned with my tools in another vehicle. I spent another hour trying to figure out how to hook up the test equipment. Then a guy from the parts store comes out and says that he thinks it is the fuel pump. He then hads me a rock and tells me to tap on the fuel pump a few times. This should knock loose anything that might be hanging up inside the pump. So I take the rock, crawl under the car, and tapped the fuel pump about a dozen times. I get out, get into the car, turn the key and it starts right up! I immediately purchased a new replacement fuel pump, drove the car home and replaced the fuel pump. I am 99% sure that this will cure the problem. I will check back in a couple weeks to let you know how this is going.
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Kmaniac in California USA
After four weeks, the car starts first time, every time. No more starting problem. Both new fuel pumps did the trick!
Looking back, it is clear that the original in-tank pump was not working when I bought the car. I found fuse #11 blown a few days after buying the car. I replaced the in-tank pump for good measure. Since I was going into the tank to look at it, It was easier to replace at the same time than to put the old one back in. I discovered the old filter sock had deteriorated and had at least two holes in the sock. I suspect dirt entered the in-tank pump, fouling it and causing the fuse to blow. I further suspect the main fuel pump was fouled with dirt from the broken filter sock, which caused the intermittent starting.
Should you encounter a bad main fuel pump on your car, always inspect and/or replace the in-tank fuel pump, so that you can verify the condition of the filter sock. A bad or deteriorated in-tank filter sock will lead to fouling both fuel pumps with dirt. (Should you go to the trouble of taking out the in-tank pump, you may as well replace it while you got it out.)
Looking back, it is clear that the original in-tank pump was not working when I bought the car. I found fuse #11 blown a few days after buying the car. I replaced the in-tank pump for good measure. Since I was going into the tank to look at it, It was easier to replace at the same time than to put the old one back in. I discovered the old filter sock had deteriorated and had at least two holes in the sock. I suspect dirt entered the in-tank pump, fouling it and causing the fuse to blow. I further suspect the main fuel pump was fouled with dirt from the broken filter sock, which caused the intermittent starting.
Should you encounter a bad main fuel pump on your car, always inspect and/or replace the in-tank fuel pump, so that you can verify the condition of the filter sock. A bad or deteriorated in-tank filter sock will lead to fouling both fuel pumps with dirt. (Should you go to the trouble of taking out the in-tank pump, you may as well replace it while you got it out.)
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Guest
I had exactly the same problem with my 1988 740gle.
I spent 2 weeks racking my brain trying to figure out what was wrong.
There was a spark but it was very weak, so i changed the coil and leads, now runs like a dream.
Wulfgar
I spent 2 weeks racking my brain trying to figure out what was wrong.
There was a spark but it was very weak, so i changed the coil and leads, now runs like a dream.
Wulfgar
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mapleaf
I was in total depair when my Volvo started acting. Everytime I would get it towed to a mechanic, by the time they got to it, it would start! I had just under taken a 4 day roadtrip from Waterloo, Ontario, to Saskatoon, Saskatchewan, and a few weeks after my arrival it started acting. I have had the car for 2 years prior to this, it had never failed to start! Not being so mechanically inclined, I was in a whole pile of dung! I kept thinking of some type of electrical problem, as sometimes my car would suddenly start idling around 1400 rev while it usually sits around 700! If I kill the engine and start again, I am back to normal! Another symptom, in the past few days, is interference with my radio! The intank fuel pump had been replaced just prior to my trip, while the fuel pump relay switch was replaced 4 weeks ago. Prior to this week the intermittent start were spaced out roughly once a month, it has worsened: 3 times in the last four days! Today, I was lucky enough to be able to perform some tests: fuel is reaching the injectors, and the spark-plugs are getting energized. In one of the posted responses someone mentioned that his spark was too weak, how does one test this. I was able to get the spark to 'jump ' approx. 1cm using a little gizmo mechanics use. The one thing that stands out is the fact the car has always started first thing in the morning, it has always 'crapped' out after at least a drive. This is why I seem to be leaning towards the heat sensor as being the guilty party. Can anyone shed some light on 'my' issue? I am a bit desperate as winter is approaching and I live in the prairies!!! Another thing, it usually takes 4-5 cranks for it to start, is that normal? Only once did it ever happen to start on the first crank!
mapleaf
mapleaf
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cosmiclobster
I have a 86 740 turbo and it was doing the exact same thing.
The first test when your car stops dead in the road is to unplug the Air Mass Meter. This is the sensor that lives in a 3" hose that draws fresh air from the airbox. When your car dies, unplug this plug. If the engine starts right up, then the air mass meter has a problem, BUT, it is probably just too hot! Remove the air cleaner and look in the space beneath it. There is a flap that moves right to left. One way sucks in cold air from outside, the other way sucks in hot air from the preheater shroud on the exhaust system. I'll bet you dollars to doughnuts that this flap is not sealing off the hot air from the preheater. Unplugging the air mass meter is a limp home mode for when the computer is not functioning. In this case, the air mass meter is sending faulty info to the computer and the computer has the injectors running so rich the car will not run or start.
The first test when your car stops dead in the road is to unplug the Air Mass Meter. This is the sensor that lives in a 3" hose that draws fresh air from the airbox. When your car dies, unplug this plug. If the engine starts right up, then the air mass meter has a problem, BUT, it is probably just too hot! Remove the air cleaner and look in the space beneath it. There is a flap that moves right to left. One way sucks in cold air from outside, the other way sucks in hot air from the preheater shroud on the exhaust system. I'll bet you dollars to doughnuts that this flap is not sealing off the hot air from the preheater. Unplugging the air mass meter is a limp home mode for when the computer is not functioning. In this case, the air mass meter is sending faulty info to the computer and the computer has the injectors running so rich the car will not run or start.
Kmaniac in California USA wrote:Well, my Volvo did it again today. At 7:00 AM and 65 F temperature, it started and drove fine as I got my morning coffee. Six hours later, after sitting in the hot California sun on this 90 F day, it failed to start in my driveway. I hooked up my inductive pick-up timing light to the ignition system and got plenty of spark on all four cylinders and the coil. Leads me to think the problem is hiding in the fuel injection system. The car has 203,200 miles on the odometer and everything associated with the fuel injection looks original, except for the fuel filter. Any ideas which parts of the fuel injection system would be affected by the heat of the sun on a hot day?!? At least I know it is not the ignition system. I will keep all posted as I progress through the fuel system.
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