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Well after $800 at the mechanic I was able to pass emissions down here. Car ran great for about a week, but that seemed to dissolve quickly.
Here is what was replaced:
Fuel Pump
Fuel Filter (a really big'n)
Fuel Pressure Regulator
Spark Plugs (others were fouled while tuning)
New coil for the Pertronix (apparently this wasn't upgraded when the system was installed)
When I got the car back from the shop, she ran like a completely new vehicle. Pulled smooth and hard, a genuine joy to drive. However, as the week went on she started doing this strange surging action. Throttle would be held constant, but the power would let on, then off, rhythmically. This continued for about a day, then instead of just losing a bit of go, she would drop out completely. Eventually she had mot not-go than go and sputtered to a stop. Luckily I was able to nurse her up into a parking area so she wouldn’t be sitting in traffic during the busy Phoenix rush hour. Had a tow truck take my wounded pride back over to the mechanic. An interesting note is that she started right up for him and he was able to pull her into the shop. Seemed to be running smooth as could be.
My guy hasn’t really looked at her yet, but suggested that maybe I just convert her over a Weber due to the age and the...unpredictability of the FI. Megasquirt is another option that I have been considering. Although I’m not sure how much that will end up costing. I do like the efficiency of a FI system, but it would also be nice to have her run reliably. I can do a lot of work myself. Basically had the mechanic get her tuned for emissions so that I would have a good solid base to do my work from.
If you have any suggestions or even ideas that I can give to my mechanic, I am all ears.
In any case, even when she was lurching down the road, she looked good doing it. :-)
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1994 Volvo 940 n/a Wagon
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Definately the fuel pressure I reckon I should take a peek inside the tank. What is the best (i.e. safest) way to do this in an apartment parking lot? My mechanic said it looked fine, but he said that the fuel pressure was fine too. I guesstimate about 4 gallons of fuel in the tank. I don't mind just getting new gas for her, but what is the best way to dispose of the old fuel? I have never messed with a fuel tank directly before, so I apologize if I seem overly cautious. As much as I would like to get this car running, I'd rather not blow myself up in the process. :-)
As an aside. Where is a good place to jack and support the rear of the vehicle. The original jack points are kind of there...but not really. I found a good spot for lifting where the front of the rear suspension attaches to the chassis, but was unable to find a secure place a jack stand.
Thanks again guys. I always value your advice.
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1994 Volvo 940 n/a Wagon
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I should have probably mentioned that the tank was sealed last May by the previous owner. I'll try to point my mechanic in the right direction there. Although I have a feeling that I will probably end up just driving the car back to the apartment and tinker with her here. My time is a lot less expensive than his.
I had checked the throttle position sensor when I first started having this issue after getting the car. It way too clean and shiny on the inside to be very old. I'll grab a bottle of starter spray and check for manifold and injector seal leaks. As well as test the sensors.
Any suggestions for draining the fuel tank in an apartment parking lot?
Thanks guys!
-Matt
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1994 Volvo 940 n/a Wagon
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The throttle switch on a D-Jet isn't like the TPS on a newer FI system. It doesn't report position to the computer, all it does is add some extra injector fires when the throttle is opened. An electrical accellerator pump function. (Well, it also signals when the throttle is closed so the computer can engage the specially tuned idle setting). All that it would do if malfunctioning is lead to a possible lean stumble if the throttle is slammed open suddenly. You could unplug it and drive it around and not notice much of a difference.
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posted by
someone claiming to be Thad Gilbert
on
Thu Jan 20 19:41 CST 2005 [ RELATED]
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I've had the same problem twice. Both times it was the sock filter on the fuel pick up like the others mentioned. In 33 years a tank can collect a lot of junk.
You can easly clean it by removing the large plug and then the sock filter. Blow all the trash out of it and put it all back togather.(Please drain your tank first with the small plug!)
Thad
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I would echo what others have said. Do not spend the big bucks to change the system. D-Jet is very reliable and pretty easy to troubleshoot. You will get little advantage, or be worse off, if you keep your engine as is and dump the D-Jet system.
I agree that the likely culprit is a rusty fuel tank, and that is something you can fix yourself for not much money. Other simple things to go over include:
--be sure the ground wire is in good shape, both the one on the intake manifold and the one from the engine to the body
--be sure the trigger points in the base of the distributor are clean
--be sure the throttle position sensor is clean
Those don't sound much like the symptoms you are having, but they are easy to check and likely need to be done anyway.
You might also consider switching mechanics. If they are telling you to ditch the D-Jet because it is old they are not doing you any favors.
If you have any questions about these suggestions feel free to e-mail me offline for more detail.
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I've had this "surging" of the engine at a constant throttle, and then the eventual engine cut out, only to start normally 30" later. Happened on a 1980 GLE with a v-6 (interesting engine). I believe the culprit is the sock filter on the end of the gas pickup inside the fuel tank. It gets clogged with debris and the high pres. fuel pump can't overcome the small inlet area, so the engine starves for fuel and cuts out, until the pessure can equalize again and then it will start right up. I have also been told by mechanics that this sock filter can be chemically melted by the addition of too much ethanol to fuel and end up clogging the inlet also. I took the in tank filter out of my 1800ES and did some preventative maintenance on it after learning this lesson the hard way on the interstate.
Bob1800ES
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D-Jet is a pretty solid system, if you have a stock motor there's little to be gained from switching to MS (assuming you use most of the D-Jet hardware). It just needs a good steady fuel supply - the fuel pressure should remain at 30 psi all the time, no matter what. Next, it needs good sensors (there are only 3) and good wiring connections to them. And lastly, it needs a good triggering signal from the distributor.
When 'debugging' a D-jet car, go over all the mechanical aspects first. Adjust the valves. Adjust the timing, check and clean the plugs. Check the fuel pressure - no point in messing with the system if the pressure spikes or plummets when you drive it around.
Lastly, google up some rational sensor readings and check them - cold and hot for the temp sensors, and the pressure sensor at room air and under a vacuum. If they seem fine, pull the multiplug and check the readings there (consult a wiring diagram to find the prooper pairs) to rule out dodgy wiring.
It can be a little frustrating when yuo have a 'sick' car, but there really just isn't that much to the system, and it does work very well for stock engines.
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Please don't convert to Weber downdraft... BIG performance drop compared to D-jet that's working right, particularly on a '71 motor.
Sounds like fuel supply problems to me. There's a "sock" filter inside the gas tank that can plug up as well as the external filter. Have your mechanic check fuel pressure while he drives the car (duct tape the gauge to the windshield, if nothing else) and see if it doesn't drop as you go.
Once the car sits for a while, enough fuel seeps through the plugged filter for the car to start and drive a few feet. That's my theory, anyway.
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A few years ago I had the Sock Filter Syndrome on a '73. I got a couple of replacements (from Swedish "something", I think) and was told that Volvo had said to remove them several years ago. That seems pretty drastic, given the crap it keeps out of the expensive pump.
This was from a supposedly former Volvo service writer or something like that. My final fix was a nice clean tank from Hirsch, in Phoenix.
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Bruce Young '93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.
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YES! listen to Phil!
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Mike!
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I'm inclined to agree - my 1980 K-jet 240GL had the same issue. Didn't discover it until midway through converting to carb'd B21A in desperation, had the car on the hoist & decided to replace the gas tank as it was very rusted. Pulled the drainplug & was rewarded with an inch of sediment/varnish in the bottom of the drain pan. The sock would clog as the fuel sloshed around while driving, starving the fuel pumps. Never caught the problem in the shop though, stationary it'd start & run fine with no drop in fuel pressure because the sediment settled back down & didn't get stirred up.
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