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I recently had to replace my fuel line (from filter to fuel rail) as well as the rail itself. The only 2nd hand fuel rail I could find had the fuel line attachment further to the rear and didn't have a metal pipe that connects the return from the fuel pressure regulator to the fuel return hose - I had to splice this together using a piece of fuel line and clamps. The result was the same as the prior setup - just not as neat and tidy. The other thing that was different was that the two fuel rails had slightly different clips between the fuel injector and the fuel rail so while the clips attach they don't really hold the injectors tightly like before. However, the injects seem well seated and there are no apparent leaks. All of this seemed to work fine with the car running after this work.
Now the current problem which may/may not be related (but seems too much of a coincidence)
The car when cold (ie first start of the day) is hard to start. Takes 10-20 attempts. The engine doesn't catch as teh starter turns and splutters as if trying to start as I turn off the ignition. The check engine light flashes when this is going on. When the car eventually starts (which it has so far) it starts to run OK as it warms up except that there is a very slight hesitation is the throttle is pushes fairly fast. Before its fully warmed up it may stall when trying to pull away and be hard to start again. Once the car had warmed up it seems to start easily and consistently and runs fine.
I've checked all of the vacuum hoses, air intake etc and all seems fine. MAF seems to be working fine because detaching it causes the engine to run worse. I can't help but think its related to the fuel supply work somehow. Any ideas on how to narrow it down?
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So, last night I loosened the fuel rail and regulator, wiggled them around a little, pushed them tight and tightened then up. This morning at a cold start(as cold as its going to get right now) and a couple of times throughout the day it started perfectly. So all I can conclude is that I had a slight leak between the fuel injectors and the fuel rail or injectors and engine. I have some spare injector o-rings somewhere which I probably should install but right now I'm in 'if it aint broken' mode. So for now this looks like its fixed. Moral of the story - focus on what changed before the problem occurred.
Thanks for all of the ideas and dialogue. Hopefully this helps someone else.
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I assume this is for a 1992. From your description, it sounds like the fuel pressure regulator is not working properly, and you are running too rich during cold start. Take a look at the tail pipe while cranking the starter, and as soon as the engine 'catches', see if you see black smoke puff out.
The flashing CEL is caused by misfires on multiple cylinders.
--
Keeping it running is better than buying new
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I replaced the fuel pressure regulator about 2 years ago.
The thing I changed when I replaced the fuel rail was the hose of the return from the regulator. My old fuel rail had a 9" metal tube welded to the main fuel rail and a short hose came from out the back of the regulator to this metal tube. The other end of this tube then attached to the hose that returns to the fuel tank. Because the new fuel rail did not have this metal tube I used a piece of the spare fuel line I had that conveniently fit snuggly in the hose out of the regulator and the hose return to the tank. I used the clamps that we previously used to clamp the this metal tube. So I Rube Goldberged the connection back to the fuel tank.
I guess this resulted in the diameter of the fuel return geing reduced the the tube wall thickness of the fuel lien I inserted. Could this have thrown things off?
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I doubt that having a change in inside diameter of the return line will effect mixture. The far end is open in the tank--there's virtually no pressure. It has been suggested that the mixture is too rich - and that may be - but the opposite is true too - the symptoms could be attributed to an overly lean mixture. While you have checked that the injectors are secure - have you check for vacuum leaks there by spritzing either carb cleaner (makes a spike in idle) or with a water spritzer (makes a stumble at idle)? Worth a try. -- Dave
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I agree with you about the return hose - I don't see how that would effect things unless causes the pressure regulator to not work as previously- but mentioned it because it was the main thing that has changed.
I have sprayed choke cleaner all over and no change in idle
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Being a 1992, you should have OBD I?? Any fault codes recorded?
A fuel pressure gauge tied into the injector rail would tell a lot about fuel pressure when cranking, post shut-off leak down, etc.
Any chance you disturbed the coolant temp sensor or cold start valve while working on the car?
--
Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)
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Thanks Chris. Stupid of me not to do this previously.
I had the following ECU codes and no EZK codes:
2-3-2 - Lambda control - too lean or too rich at idle
1-2-1 - Mass air flow meter signal faulty or missing
I suspect the 1-2-1 was when i was playing around and disconnecting the MAF to see what happened
Anyway, I cleared the codes and the car started 3 or 4 times in a row with no problems. Not sure if that is because I had it running earlier (so it was warm) or the problem is fixed.I'll have to try it again once the car is definitely cold.
Would the very existence of those stored codes cause the problem and the clearing of them reset whatever? Or is this just a coincidence?
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"Would the very existence of those stored codes cause the problem and the clearing of them reset whatever? Or is this just a coincidence?"
It has in my experience. But the 121 at least should have alerted you by setting the CEL. Fully resetting the stored codes and adaptation is done easily in your '92 by momentarily lifting fuse #6.
I'm curious which ECU your car has. In 92 the original rail should have had the Schrader and not a cold start take-off if the chassis number is North of 457500, unless yours is a manual transmission LH3.1 -- I think. Either way, an AMM code should have set your CEL. It is just hard to know what has remained original in any 25-year old car.
I'm guessing the bubbles you were seeing may be an indication your tank pump isn't working, but the very fact you can see return flow, coupled with any confidence in your pressure regulator, speaks to sufficient rail pressure. When you originally posted, I thought maybe your car was lean, not rich, during cold start, and this is a common AMM fault, and a not-so-common ECT fault (shorted). You might check the resting output voltage of the AMM. I have found them to be trouble when below 1.3V on LH2.4. The ECU should be able to put them in range if above that. Sorry for all the guesses.
--
Art Benstein near Baltimore
"A gentleman is someone who can play the accordion, but doesn't." -as retold by Monte Leister
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Art - regarding your suggestion of "You might check the resting output voltage of the AMM". How specifically do I do that - which pins?
Also, tried a few things just now, problem is the car is running starting/now because its warm so hard to diagnose a problem that doesn't currently exist. In any case:
I checked the resistance of the coolant temp sensor. I was about 600 ohms when I measure it originally and went down to 25ohms after idling for maybe 15 minutes Is that OK?
When i disconnect the MAF the car stumbles, recovers and then runs seemingly a little roughly, but runs.
When I disconnect the vacuum hose from the fuel regulator nothing much happens.
There does seem to be a tiny stream of bubbles in the fuel return line but the fuel is flowing pretty fast.
I'm thinking of removing the fuel rail/injectors/regulator and reinstalling just to be sure. There are no leaks or smells of fuel so if seems like a long shot
i can't help but keep coming back to the fact that the only thing that has changed is a new fuel line and fuel rail and my slightly Rube Goldberg return fuel line.
Running out of ideas..
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Hi,
You say that nothing has changed except for the fuel line. I disagree. Every day that passes brings every part on your car one day closer to failure. It's also likely that you're seeing morning temperatures that are considerably colder than they were a few weeks ago. If you live in North Dakota then you may be enjoying the same snowstorms that my daughter reports. She lives a little north of you in Saskatchewan.
Ignition components like plugs, cap and rotor that are worn may work fine in good weather and then act up when it's bad. The fuel doesn't vaporize as readily in the cold, and cranking for 20 seconds is likely causing some flooding.
For what it's worth, I had pretty much the same symptoms you describe, and the culprits turned out to be spark plugs with .070 gaps. Good luck.
By the way, I'm heading out your way next week-end. I can't wait to roll along Route 2 from Grand Forks to Minot. That stretch in a 240 is as close to heaven as I'll likely ever get. Maybe I'll see you on the road.
Regards,
Peter
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Yes, trying to learn what's wrong is hard enough without the correct tools, much less when an sporadic trouble isn't occurring. It is a guessing game.
Two items one cannot "test" positively are the ECU and the AMM. By positively, I mean you can conversely test it defective for some overt and rare failures, but you can't prove it is good. That's why our BB community has always come to consensus anyone with an LH car should have at least one cheaply obtained (junkyard) of each, tested by substitution, and ready to use as a spare for troubleshooting. Cheaper in the long run than finding one urgently.
Your revelation that you've used vinyl in the return line interested me because I'd considered doing exactly that myself. I thought it would be great to be able to check return flow "at a glance" and see telltale signs of trouble like vapor in the stream as you noted. I've used vinyl in the tank before, but not yet returned to it years later to see if the ethanol-laced fuel we have has softened it, and like Chris mentions, am too leery of the fire risk to leave it in place under the hood longer than for a test. I wondered if there was a better material I could adapt.
A photo might help, and if you provide one, include the old rail too. It surprises me it didn't have the Schrader, which should have existed on the '92 build. And what did you get the replacement rail from? Of course, old cars don't necessarily have even the same engines in them they were built with.
Again, I'm curious which ECU you're running. Same concerns. Is it a -951 or a white-label -561? Do tell. Again, the CEL not being a symptom after a 121 doesn't bode well for confidence.
Back to your AMM, I'm not suggesting it needs to be replaced. The only sure way you know that is by subbing it with a known good one. I have made checks on many and found they don't reliably match with the adapting LH2.4 ECU if the resting voltage is less than 1.3 or thereabouts. It's hazy, because the ECU does, in LH2.4, widen its tolerance to adapt, hence the lack of a mixture screw which was used in the previous LH's to match AMM to ECU.
Making the reading is quick and easy, that's why I suggest it. If yours falls short, it is just another hint at the overwhelmingly common sense to procure a spare. Just connect your voltmeter to the pin with the white/red wire -- that's the output -- using the battery minus post as a reference for your meter ground. Turn the key to KP-II. Don't start the motor. Just read the voltage. You can massage the accordion hose slightly to see what a little air movement does to the reading, if you just want to see how sensitive this hot-wire air mass meter is in terms of millivolts to airflow, but that's not part of a test.
--
Art Benstein near Baltimore
"the worst data are better than the best theory," said Antonio Ereditato
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Hi Art
Chassis number is 460xxx. Automatic transmission. Original rail had no schrader and no cold start take-off.
Based on some Googling LH3.1 uses a MAF who's Bosch number ends in 001, LH 2.4 ends in 016. My MAF ends in 016 so I have LH2.4.
I've periodically started the car today and after resetting the codes its started nicely like before.
The true test will be tomorrow morning when I can be sure its a true cold start.
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"...the car started 3 or 4 times in a row with no problems..."
You said you used a length of hose to make up for the missing 9" section of tubing on the rail. I wonder if you may have somehow trapped some air in that hose. Is there any point along that hose that is higher than either end of the hose?
--
Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)
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No the hose it pretty much horizontal. Since the tube I used is clear (same of the fuel line I replaced) I can see the fuel return freely flowing (although it does seem to have bubbles in it)
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"...Since the tube I used is clear..."
Ooooo, I'm concerned that you may be confusing the high pressure (supply) side with the the low pressure (return) side.
Ordinarily, there is a high pressure line from the pump to the rail. Then a high pressure line from the rail to the regulator. Then low pressure from the regulator back to the tank.
You also mentioned earlier in the thread something about clamping one rubber hose onto another rubber hose??? That scares me. Maybe I have totally misinterpreted all this, but I just don't want you to have a Swedish bon fire.
--
Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)
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No danger of the Swedish bonfire!
I spliced the low pressure line exiting the regulator back to the tank.
Car runs perfectly once i get it started.
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When the car is cold and you expect a no-start, what would happen if you turn the ignition on-off-on-off-on-off several times to force the pump to prime several times before you actually crank the engine?
Can you post a photo(s) of how you've rigged the fuel lines?
--
Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)
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What model year?
--
Art Benstein near Baltimore
When electricians get sent to hell, they have to wire whole houses in UF.
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