|
|
|
I have a 93 wagon with auto that starts fine and runs fine with one exception. Sometimes when the engine is warm, it will die after starting. You have to re start it and go to drive numerous times to finally get going. Past idle, it runs fine again. This never happens when the engine is cold. Any ideas as where to look first, or a sequence of steps to take would be appreciated.
|
|
-
|
|
|
Sounds to me like a classic example of "vapor lock". Insulate the fuel-rail & lines with "fire sleeve" (I've seen it on Ebay, auto-parts stores may sell it also). It's commonly used on aircraft engines to protect fuel lines, hydraulic lines, oil lines, etc.
|
|
-
|
|
"Sounds to me like a classic example of 'vapor lock'."
Yep. Sounds that way to me too.
But this is not a "design" problem needing a modification to fix it by adding extra insulation. It is not a "Texas" problem either. It is just the normal and commonly expected failure of a part to keep liquid where it belongs after a whole lot of experience doing it well in the presence of fuel and its various additives. Just a tired part, whether check valve, injector, or fuel pressure regulator.
When the faulty part is replaced, the rail will hold pressure after the pumps stop, and no amount of Texas sunshine or engine heat will force the liquid fuel backward past the roller cell pump. That's the reason for the resting fuel pressure test and the time specification, 1 bar or 14.5 psig minimum after 20 minutes.
Of course there are other things that could be affected by the heat buildup under the hood, yes, but the number one starting point is resting fuel pressure.
--
Art Benstein near Baltimore
Be nice to your kids. They will choose your nursing home one day.
|
|
-
|
|
|
Art, ( and others),
I checked the fuel pressure. It was 42 lbs. running. Killed engine, after 20 minutes...42 lbs. I must mention the car has not had the hot start issue in a couple of weeks. I suppose I will keep the gauges and hose in the car and test it again when it happens. Oh the joy of troubleshooting an intermittent failure.
Thanks again, to all of you.
|
|
-
|
|
|
Dave, (and others)
The failure to retain rest pressure isn't normally an intermittent issue, as its cause would be a faulty seal in the fuel system -- not something that typically heals itself. Could stretch to imagine a little rock in there, but the likelihood is your hot start failure isn't the usual vapor lock.
Strange readings you get, though. 42 psi running (at anything other than WOT) says your fuel pressure regulator is not seeing vacuum from the manifold. And 42 psi after 20 minutes resting has about the same meaning, as if there's absolutely no control. Yes, you do come up with some mysterious questions and answers, if your observations are accurate.
--
Art Benstein near Baltimore
Sometimes I wonder if our lives are all about the challenge of keeping gases and liquids where they belong.
|
|
-
|
|
|
Oops, I didn't remove and plug the vaac hose to the regulator. The pressure holding for 20 min. WAS accurate though. I will retest, properly this time.
|
|
-
|
|
|
I didn't expect you to remove the vacuum from the regulator, but your readings of 3 bar were what one would expect if you had. Curiouser and curiouser.
Fuel pressure as measured by a gauge at the rail would indicate 3 bar relative to the manifold vacuum, but the gauge doesn't reference the manifold, it references atmosphere surrounding it. Hence, at idle, the gauge should read closer to 2 bar. And assuming it was idling when you shut it off, the resting pressure after 20 minutes should be even less than that.
But point is, if the hot restart problem had the most common cause, you wouldn't have seen even 1 bar at the rail after 20 minutes.
You could repeat the fuel tests just to get some experience under your belt and understand the theory, but I guess you'll be suspecting electronics instead, such as the ignition power amp and its heat sink many like to blame for this.
--
Art Benstein near Baltimore
From Rock Auto's newsletter:
I had been planning on replacing all of the brake lines on my Chevy Silverado for some time, but never got around to doing it. But after a weekend of hauling loads of wood, one of the rear brake lines blew out and forced me to take care of the delayed repair. Since I would be doing all the work anyway, I also decided to replace the front calipers.
I was rushing through the job and not paying much attention. Once I routed all the new lines and put on the new calipers, it was time to bleed everything. But during the bleeding procedure, I noticed I had a ton of fluid pressure in the rear calipers and almost none in the front. Also, the pedal was not getting firm.
After about an hour of scratching my head and much colorful language, I discovered that I had routed the brake lines through the proportioning valve incorrectly.
But, my story does not end there.
I rerouted the brake lines to the valve and tried bleeding the brakes again. My father and I bled the brakes over and over and over, but the pedal was just not getting firm. I had bled brakes before, but never have I had to bleed them as much as I was. I looked on forums, asked friends who had similar trucks and looked at my brake line routing again; nothing worked. I eventually surmised that it might be the ABS module needing an electronic scan tool to properly bleed. I did not have that type of tool, so I threw in the towel and took the truck to a nearby shop.
The next day I got a call from the mechanic...I could not believe what I had done. I had put the calipers on upside down and on the wrong sides! With the bleeder screws at the bottom of the calipers, no amount of bleeding would have removed the air bubbles from the brake fluid. I had to pay the mechanic $240 to fix my blunder! Do not make the same mistake that I did. Take your time and do not rush a repair.
Cody in New Hampshire
|
|
-
|
|
|
Art,
I previously looked at the power stage, and applied new heat sink paste. I finally understand the principle of having the rack under pressure until the engine cools, to prevent vaporization. Thanks. The problem seems to have disappeared along with 100 degree ambient temps. The fuel pressure after 20 minutes rules out the vapor lock issue. I continue to scratch my head. Now, I notice a leaking steering rack, and have a 900 mile trip planned in 4 days! Oh the joy of being the family mechanic. Still love the 240s though.
|
|
-
|
|
|
Depending on how sudden this was, you might be able to take that trip with a quart of ATF packed away in the trunk, and postpone the rack replacement.
I've only had to replace one rack -- on an 89 we acquired for $600 in '03 with 280K on it. Came with a mess under the driver's side boot.
My experience with Jorgen (JAC Rack) was similar to other reports on this board - excellent. It is still leak free today 80K later.
--
Art Benstein near Baltimore
What engineers say and what they mean by it:
Engineering says: "Test results were extremely gratifying"
Engineers meant: It works, and are we surprised!
|
|
-
|
|
|
Thinking that I have reached the age of discretion, per bb brain trust, I purchased a bottle of Lucas Power Steering Stop leak. Wow, that stuff is THICK. I emptied reservoir, and filled with Lucas. I placed the car on jack, removed inner boots and cleaned inner tie rods with degreaser and a rag. Started engine, and turned wheel lock to lock a few times. cleaned boots, and re zip tied.
I am sending my daughter and grandkids from Dallas to Louisville in this car. I will send along a bottle of F trans fluid, or perhaps some more LUCAS? The car had a slow leak, so I dont expect a failure, and hopefully the Lucas will either swell the seals, or thicken the fluid, slowing or stopping the leak.
Getting an 89 for $600 in '03 with 280K on it, that functions, was a deal!
By the way, the wiper washers and int. wipers did not work, ( from time of purchase 3 years ago ) After 2 hours of troubleshooting, (dont ask), I realized the pump motors were fine, but the attached pumps were frozen. Dissassembly, corrosion removal, elbow grease, and presto, window washers! Yahoo!
Some play golf, some fish, I spend days laying over, under and inside old Volvos.
|
|
-
|
|
|
The intermittent, and new trouble never seems to end. Sluggish start. Alt.giving 14 V at alt, 13 at battery. Traced out wire to batt. and it was 50% frayed, wrapped with oil soaked electrical tape. Grafted a #6 wire on, heat shrink wrapped, and cleaned up other alt. wires, alt. terminals, and oil pressure wire. Oil pressure sender broke off when I pulled the wire off. Oh joy. Where do you get that round oddball connector? Had to improvise. 14V at batt. again. Daughter took it on a 200 mile trip today, spent the day, and a 200 mile trip back. Ran fine. After return, the car died in a drive through fast food chain line, and would not re-start. 800 mile trip planned tomorrow. Not in this car.
|
|
-
|
|
|
Eric has them. See this thread. https://www.brickboard.com/RWD/volvo/1667976/220/240/260/280/female_connector_oil_pressure_sender_part.html
|
|
-
|
|
|
You should start by measuring the fuel pressure. The spec is something like 20psi after 20 minutes rest. Numbers not as critical as understanding the rail needs to retain fuel pressure to prevent the heat soak in the engine compartment from pushing all the fuel back toward the tank leaving nothing but vapor in the main pump. Pump can't move vapor.
There are other possibilities but that's always #1 starting point. Fuel pressure.
--
Art Benstein near Baltimore
"Well, here we are, Mr. Pilgrim, trapped in the amber of this moment. There is no why." -KV
|
|
-
|
|
|
You should start by measuring the fuel pressure. The spec is something like 20psi after 20 minutes rest. Numbers not as critical as understanding the rail needs to retain fuel pressure to prevent the heat soak in the engine compartment from pushing all the fuel back toward the tank leaving nothing but vapor in the main pump. Pump can't move vapor.
Art, I am confused. The car starts right up after sitting for hours. Or weeks. But has trouble when hot. I have not heard the term "heat soak". There would be no pressure at all after a few hours would there? Is the rail supposed to hold pressure until the heat leaves the engine?
|
|
-
|
|
|
Hi,
You have been working over this engine pretty good. I have been away for awhile.
Traveled to a ship reunion, In Dayton Ohio. A lot of inventions started there for cars!
I think I remember that you have had several posts on several issues.
Glad to hear that you have ironed out a lot of them.
I think I remember that you were addressing fuel and spark issues heavily before.
Don’t remember if you changed the CPS?
Don’t remember if you worked over the ignition relay module behind the battery?
It’s a heat related fault device!
Art is starting with a heat related possibility because of your Texas location, I imagine.
If things can happen, they are always bigger in Texas! That’s their slogan!
I think he is going with engine heat rising up under the fuel rail and the hood getting hot from a larger than normal sun there in Texas! (:)
Art is thinking that the rail is “Consequently” getting baked.
On the 1993 the fuel line does serpentine around a bit before going into the rail.
Just as an experiment, you might try wrapping up the rail or just the extra length of line with aluminum foil. Do it just a little loosely or several turns to allow an air gap between the rail and the foil. This will deflect infrared rays from both directions from getting into the fuel rail.
So I want to ask, is this happening only during the daytime when the engine is hot?
Just a thought?
If you park over a hot asphalt parking space this might account for more of a fuel issue, IF, it heats up the pump or filter a bunch!
All of the above is a big O guess!
There are three things things that let pressure go, if they are weak.
A fuel pump check valve.
A weeping fuel pressure regulator.
One of four injectors, as this car does not have a cold start injector.
If you have one leaking injector it would would run rough until it cleared that cylinder.
Only trouble is, all of the above would have it do the same thing, almost all the time.
Excessive air is also a fuel related issue. Both ideas are lean related.
Another thing that I do not know if you addressed or not, is the flap in the air cleaner.
It stops heat from coming over from the exhaust manifold. That thing needs to be disabled into a permanent closed position! If always open it plays heck with the AMM.
If that thing is holding open it will create a leaner than normal fuel mixture upon startup as heated air is less dense with oxygen.
HOT air rises or actually can push heavier cooler air down with expansion. Lighter air will be drawn, along a pipe first, because it weighs less. It takes less inertia or force to get it moving first and therefore empties the top part of the pipe first.
This can cause a stalling situation “temporarily” for the lack of cooler incoming air being instantly being moved.
A crack or tiny hole in the accordion tube behind the AMM can cause stalling situations while idling at a stop light. If bad enough, it might be twisting open when the transmission engages on the weak mounts.
Is the air cleaners “ proper filter” in there and is it clean?
Believe it or not, the air filter acts as a minor baffle to stabilize air fluctuations from a moving car and from the engines operational changes.
But the whole “Drive gear thing” with the transmission and loading up the engine makes me think the IAC is sluggish in responding.
I have no idea how things being hotter could be affecting that component.
I would concentrate on it losing spark first or the IAC being slow, since you can stall it with the transmission twisting things under the hood as it goes into drive.
Heat and your actions are being claimed as consistent.
Phil
|
|
-
|
|
|
Ingnition spark amplifier. It mounted on a heat sink plate with heat sink paste. The paste dries out and causes heat soaked electronic failure. Replace....
|
|
-
|
|
|
Phil,
You have been working over this engine pretty good.
Don’t remember if you changed the CPS? Yes, it has a new CPS.
Don’t remember if you worked over the ignition relay module behind the battery?
I re "pasted" it.
Just as an experiment, you might try wrapping up the rail or just the extra length of line with aluminum foil. Do it just a little loosely or several turns to allow an air gap between the rail and the foil. This will deflect infrared rays from both directions from getting into the fuel rail.
I will try it, though we are into October, and I dont think I will see any more 100 degree days..
Is this happening only during the daytime when the engine is hot?
Yes
There are three things things that let pressure go, if they are weak.
A fuel pump check valve.
A weeping fuel pressure regulator.
One of four injectors, as this car does not have a cold start injector.
I will perform a fuel pressure check, and FPR test.
If you have one leaking injector it would would run rough until it cleared that cylinder.
Only trouble is, all of the above would have it do the same thing, almost all the time.
Excessive air is also a fuel related issue. Both ideas are lean related.
Another thing that I do not know if you addressed or not, is the flap in the air cleaner. Removed it long ago.
Is the air cleaners “ proper filter” in there and is it clean? Yes, yes.
But the whole “Drive gear thing” with the transmission and loading up the engine makes me think the IAC is sluggish in responding. I will check out the IAC.
I think I will place an LED light on the dash coiled around the coil wire to confirm fire when encountering the hot stall.
I took the car on a 500 mile trip this weekend. It hot stalled once when it was hot, 90* ambient. It did not hot stall when it was 70 degrees at night at a gas stop on my way home.
Thank you for your tips!!
|
|
-
|
|
|
Does your car have an ignition amplifier.....I know when hot condition cause failure, this item can suffer. Check for good spark when the next time failure happens. (Good Spark).On my 1989 740 turbo wagon, I removed as many connectors that have to do with the FI system and use small amounts of dialectical grease on the plug end and plugged each connector in several times and then clean any excess off. I figured the last time the connection was made is at the factory.It made a noticeable difference Don't forget to test your distributor rotor for 1k ohms...start with the simple things. If your flooding the engine, check or just replace the engine temp sensor for the computer. My friends 240 Volvo had a fuel pump relay cutting out. I just re-soldered the connections on the relay. Power goes through it the whole time it's running the pump, so the amperage draws and heats up the relay and disconnects if faulty.
|
|
-
|
|
|
True or it could be the CPS wire is fraying.I mended mine w aluminum heat tape from home depot.until I could get a new one..
|
|
|
|
|
