1985 Crx Si Pgmfi Problems.... My Car Runs Bad Help Me.
#1
Posted 13 January 2013 - 06:56 PM
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#2
Posted 13 January 2013 - 08:34 PM
#3
Posted 13 January 2013 - 11:10 PM
My first suspect that the temperature change from cold to hot is not registering in the ecu so the ecu is piling in the fuel. So check the wiring from the engine temperature plugs. They do corrode and get broken insulation.
After that it will get tricky to solve.
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"I can't believe it - Ive just been passed by a sh!tbox"
#4
Posted 14 January 2013 - 12:28 AM
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#5
Posted 14 January 2013 - 09:53 PM
It could be a faulty temp sensor, or a bad fuel pressure regulator, or it the main relay, or a bad fuel filter too, maybe the coil is faulty or the distributor, maybe there is a vacuum leak on it where the timing control diaphragm is. my 85 Si did the same thing. Check the map sensor too. couldnt hurt. but it could be a corroded faulty wire, something so simple could cause some crazy issues.
What he said.
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#6
Posted 17 January 2013 - 06:23 PM
Ok i will check the fuel pressure regulator
Where is the map sensor located??
I replaced the main relay sometime ago too.
The car has an msd coil I don't think it's bad but I will check it.
As far as the distributor I will check that too.
Now Eec mentioned vacuum leak on timing diaphragm that's the back plastic round piece with 2 vacuum lines on the distributor right???
One other thing I forgot to mention is it has been running sort of hot.,,,, so I will check temp sensor.
One other thing also is why when the pgmfi light comes on does the car run fine??
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#7
Posted 17 January 2013 - 07:16 PM
For example, I run a blacktop D16 head and dissy and ecu from a gen 2 crx in a gen 1 crx. When coasting down a hill, the light comes on, because (as far as I can see) under low fuel closed throttle conditions the fuel is effectively cut, and the O2 sensor part of the ecu throws a mixture fault as the data falls outside the programmed limits. Engine runs fine, I haven't bothered doing anything after the first episode and check that its not a problem, and I turn the engine off and on to get rid of the damned check light.
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"I can't believe it - Ive just been passed by a sh!tbox"
#8
Posted 17 January 2013 - 10:51 PM
Also, make sure the injectors are all clicking. Easy with a stethoscope. The backyard trick is to take a long flathead screwdriver, press the blade firmly against what you want to listen to, and place your ear on the handle.
I'm guessing when you pull the plugs, hey are pitch black? Possibly even moist. You're running rich. There are only so many things that will cause that. So you're on the right track to narrowing it down by just knowing it's a rich fuel issue.
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#9
Posted 18 January 2013 - 12:00 AM
the map sensor is on the right side of the intake manifold behind the 4th fuel injector, pretty much above the alternator if your looking from the driverside top of the engine.
if there is a leak in the diaphragm on the distributor it will not adv the timing properly its like prehistoric VTEC lol.
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#10
Posted 18 January 2013 - 02:00 AM
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#11
Posted 18 January 2013 - 06:20 PM
If there is a bad sensor or suspicious reading from a sensor, the ECU will "realize" there is an issue, go into "open loop" mode and turn on the PGMFI light and then control the timing and fuel injection based on a general "safe/limp mode" fuel map programmed into the ECU. All the info that it needs to run OK in this "safe mode" is engine rpm and a vacuum signals. You will get worse mileage if you keep running it in "safe/limp mode" with the PGMFI light on, but I don't think there would be any long term damage to the engine.
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#12
Posted 18 January 2013 - 10:15 PM
Now Eec mentioned vacuum leak on timing diaphragm that's the back plastic round piece with 2 vacuum lines on the distributor right???
Yes, that's the one. The port closest to the distributor is your primary advance pot. You can test it with a vacuum pump... or by simply sucking/blowing on the vacuum line attached to it XD If there are no leaks in the pot you won't be able to blow/suck through it.
Also check the line itself for cracks and such.
Check the upper pot as well, but that one is not very important as it is only used under very cold starting conditions.
#13
Posted 23 January 2013 - 10:26 PM
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#14
Posted 24 January 2013 - 01:29 AM
The single wire goes to the gauge, there should be a 2 wire sensor in the same area (probably a little more buried) that will go to the ECU.
Universal O2 sensors are fully compatible. There is really no difference between them and a direct fit from the same brand other than a plug.
Also, your O2 sensor shouldn't be effecting anything at idle, or under most conditions really... The exhaust temps tend to be too low for proper sensor readings on non heated O2 sensors (like on the 1G) Because of this they are really only used under sustained cruise. They also aren't really used under power conditions (IE, WOT) regardless of RPM because the conditions vary too rapidly to make any effective changes.
Combine all this with the fact that you've replaced the O2 and it didn't fix the issue... I'd guess it's not the O2
I'd look at the temp sensor and the map sensor since these are really the only 2 the ECU uses under most conditions to calculate your fuel mix.
Beyond that, it only really leaves fuel pressure, injectors, and spark.
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#15
Posted 25 January 2013 - 10:57 PM
One other thing I also wanna mention that if I'm driving quickly the problem doesn't really occur above 3000 rpms I obviously get problems when below that and when accelerating from gear to gear. And I can't just sipped every where. So basically around town stop and go driving sucks BAD.!!!
Again everyone thanks for all your replys and support the beast will live again....I'm not giving up.