74 2.0L, bizarre behavior |
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74 2.0L, bizarre behavior |
Java2570 |
Aug 27 2011, 05:28 PM
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#1
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Senior Member Group: Members Posts: 649 Joined: 7-May 11 From: Fishers, IN Member No.: 13,035 Region Association: Upper MidWest |
I'm back with more questions re: my 1974 2.0L. Since replacing my distributor contact plate (bad ground wire) I've had issues with how the car runs and idles. Currently, I've put back in the old contact plate and tried to back track through every thing I've taken
apart, etc. I have replaced the intake runner boots and gaskets also. I just replaced the AAR valve with a known good one. As of today, the car will start and seem fine for about 1-2 minutes, then it starts running rougher and dies altogether. When I attempt to restart it, it refuses to start, like it's flooded. What I at first thought was a lean mixture problem now appears to be a rich mixture issue. I forgot to mention that I've also replaced the CHT sensor with a new one from PP, it's a 012. I am only getting a reading of about 1.3K cold (sensor alone) and about 1.8K cold with the ballast resistor that came with the wiring. I know that is lower than it should be.... I haven't been able to get the car warmed up enough to check the warm temp resistance. I checked my MPS today and it seems to hold vacuum but I've not checked the unit with a meter yet. Can I do this without testing through the harness via ECU? Would a bad MPS cause a scenario such as I'm having? I have also wondered if the injector seals are leaking vacuum; I see no problem with fuel leakage anywhere. I did find a couple of bad wire connectors today so perhaps in all my messing with the dizzy, I caused an issue with a wire. Prior to all of this, the car was actually running pretty well and it didn't seem to have a major issue save for a few slight vacuum leaks with hoses. Sorry if this is long winded and perhaps hard to follow but am I missing anything that could be an issue? I really thought it was either the AAR or CHT that was causing my running problems but now I've seemed to have made it worse and it's driving me crazy!! Any other ideas? Thanks! |
underthetire |
Aug 27 2011, 05:56 PM
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#2
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914 Guru Group: Members Posts: 5,062 Joined: 7-October 08 From: Brentwood Member No.: 9,623 Region Association: Northern California |
I don't think a 74 2.0 is supposed to have the head temp resistor. Also, what is the idle speed set to with the new aar? Should be ~1700 when cold.
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Java2570 |
Aug 27 2011, 06:20 PM
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#3
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Senior Member Group: Members Posts: 649 Joined: 7-May 11 From: Fishers, IN Member No.: 13,035 Region Association: Upper MidWest |
I don't think a 74 2.0 is supposed to have the head temp resistor. Also, what is the idle speed set to with the new aar? Should be ~1700 when cold. Right, it's not supposed to have it but was added by a previous owner for some reason. Regardless, I'm not sure it would make a difference to the current condition. I can remove it but it will just make the resistance lower and leaner. The confusing issue continues to be that it acts like it's a too lean mixture in that I can't adjust idle or ECU but it dies out after a couple minutes like it's too rich. I'm just not sure what is happening or why....it makes no sense to me. I suppose the next step is to start at the complete beginning and go through everything starting with valve clearance, fuel, etc. As far as I know, everything was good prior to the start of my dizzy repair when I afterwards, I couldn't get the idle to adjust and if I hooked up the dizzy retard vacuum hose, the car would drastically drop in idle. Now it just seems like multiple problems that don't have any reason...it's just strange! |
Tom |
Aug 27 2011, 06:35 PM
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#4
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Advanced Member Group: Members Posts: 2,139 Joined: 21-August 05 From: Port Orchard, WA 98367 Member No.: 4,626 Region Association: None |
It almost sounds if your idle is set too low. the AAR makes it idle high until the AAR warms up. How high is the idle when the AAR is cold. Should be about 1800 RPM's. When the AAR closes then the idle should be 900 - 1000 or so. Maybe your warm idle is set too low?. Can you adjust the throttle screw to bring the idle up when warm? You may have had a vacuum leak before and the idle screw was adjusted to compensate. Now that you have replaced the intake runner boots and gasket, ( vacuum leak repaired) you need to adjust the idle screw to bring the idle back up.
hope this helps, Tom |
Java2570 |
Aug 27 2011, 07:08 PM
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#5
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Senior Member Group: Members Posts: 649 Joined: 7-May 11 From: Fishers, IN Member No.: 13,035 Region Association: Upper MidWest |
It almost sounds if your idle is set too low. the AAR makes it idle high until the AAR warms up. How high is the idle when the AAR is cold. Should be about 1800 RPM's. When the AAR closes then the idle should be 900 - 1000 or so. Maybe your warm idle is set too low?. Can you adjust the throttle screw to bring the idle up when warm? You may have had a vacuum leak before and the idle screw was adjusted to compensate. Now that you have replaced the intake runner boots and gasket, ( vacuum leak repaired) you need to adjust the idle screw to bring the idle back up. hope this helps, Tom Your idea does make sense....I haven't been able to adjust the idle with the air bleed screw though. I haven't been able to try the last couple of days due to it dying on me rather fast. I am going to check my timing tomorrow, perhaps it needs to be slightly advanced. I just checked my fuel filter and it looks good from when I replaced about a month ago. I'll do some more fiddling Sunday and see how it goes; I won't give up dammit!! |
larss |
Aug 27 2011, 11:21 PM
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#6
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Member Group: Members Posts: 428 Joined: 10-September 09 From: Sweden Member No.: 10,787 Region Association: Scandinavia |
Would a bad MPS cause a scenario such as I'm having? No, from my experince the car starts and runs (but wery badly) witout the MPS connected at all if everything else is in order. Your suggestion of checking the timing is a wery good idea - can make wonders to these engines. /Lars S |
Java2570 |
Aug 28 2011, 08:26 AM
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#7
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Senior Member Group: Members Posts: 649 Joined: 7-May 11 From: Fishers, IN Member No.: 13,035 Region Association: Upper MidWest |
Would a bad MPS cause a scenario such as I'm having? No, from my experince the car starts and runs (but wery badly) witout the MPS connected at all if everything else is in order. Your suggestion of checking the timing is a wery good idea - can make wonders to these engines. /Lars S Tried again this morning after checking the timing; it was a little too retarded. It does idle about right but I'm getting some hunting so there is still a leak somewhere. Same old story though, after a few minutes (it ran longer this time) it dropped from about 1000 rpm to about 600 and started to die. When I tried to restart, it won't fire. I will add, it was at about 1700 rpm at cold start and when the aar closed, it went to around 1000. At least there is some progress but it still is dying and not restarting so I'm unclear about what is causing this. |
Java2570 |
Aug 28 2011, 08:41 AM
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#8
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Senior Member Group: Members Posts: 649 Joined: 7-May 11 From: Fishers, IN Member No.: 13,035 Region Association: Upper MidWest |
I don't think a 74 2.0 is supposed to have the head temp resistor. Also, what is the idle speed set to with the new aar? Should be ~1700 when cold. I did find out why it had a ballast resistor in it; this engine had a 017 sensor from 1973 and thus needed the ballast to bump the value. Not sure why they put that sensor in the car? I just wonder if the new sensor I installed is bad or iffy.....taking a read from the unplugged lead still is only giving me 1.3K (without ballast) which is pretty low. Is it common for these to vary so darn much? Perhaps I should order a couple more and see if I can get a better one; or any ideas? I don't if this is causing the car to die or not but I suppose if there is a bad wire in the harness, it could. I already have replaced a couple of iffy looking connections but it didn't really change anything. |
Java2570 |
Aug 28 2011, 09:52 AM
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#9
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Senior Member Group: Members Posts: 649 Joined: 7-May 11 From: Fishers, IN Member No.: 13,035 Region Association: Upper MidWest |
I took off the passenger side injectors to look at the seals and the small inner seals are cracked and suspect; will go ahead and replace all the injector seals. Certainly could be causing issues! I'm getting faster at taking things apart and there is less cussing!!
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underthetire |
Aug 28 2011, 10:07 AM
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#10
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914 Guru Group: Members Posts: 5,062 Joined: 7-October 08 From: Brentwood Member No.: 9,623 Region Association: Northern California |
The injector seals will usually make it idle higher, since it basically creates a vacuum leak when they are bad. Those are available from flaps btw..
I would go back and check valve clearance at this point, ignition, coil, fuel pressure etc.. Make sure your coils not hooked up backwards as well, I've seen this twice now, both times the car would run till the coil overheated, don't know why. |
76-914 |
Aug 28 2011, 10:14 AM
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#11
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,500 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
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Java2570 |
Sep 3 2011, 02:12 PM
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#12
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Senior Member Group: Members Posts: 649 Joined: 7-May 11 From: Fishers, IN Member No.: 13,035 Region Association: Upper MidWest |
Hi everyone - just wanted to make mention that my car is now running quite well after being down for 2-3 weeks with assorted issues. I found the CHT sensor that I had gotten from PP was reading low value when installed in the head and while the car was running, it would flood and die after a few minutes. What I think was the problem in reality was that sensor was not properly seated in the head and was making the mixture ultra rich and flooding. After installing a new sensor and making sure it was all the way in, I was able to start my car and actually drive it! I also found that I have at least one bad or marginal relay on my relay board. I was able to swap out the ones from the headlights and I bought some new ones to replace all of them. I am now able to adjust my idle like normal and things seems good. The only issue I have now is the vacuum canister is leaking; doesn't hold vacuum well on the retard side. I have the line from the throttle body plugged now; should i try to replace the can? I've read varying reports of it helping fuel economy and idle reliability. Thoughts? Also, for what it's worth, I did all this myself without coming here and asking more dumb questions. I just kept reading my manuals and looking at the Anders website to gain more knowledge about the Djet components. It has been frustrating but a good learning experience!
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