From a previous post, I am working on a "new to me" 95' Prizm with 190,000+ miles on it. My main concern currently is a miss or temp. loss of power when trying to maintain a constant speed. Coasting is fine and hard acceleration is fine. I'm driving it every day and would like to lose this hiccup. Currently no CEL.
Last night I replaced the air filter and used some zipties to tighten the lid on the air cleaner box as it has lost both lower clips. Air intake leak was listed in the Haynes as a possible problem with these symptoms. I also removed and tried to fix the broken TVV that was bypassed. Not sure if I succeeded as I am not sure the valve opens when hot. For those who want to complete a similar repair, I would reccomend trying to find something that glues in to the hole where the old tip breaks off w/o drilling. I used a drill bit by hand to enlarge the hole a little bit and ended up cracking the inside portion of the valve. For this reason, I had to try and glue the new tip in to just the right depth so it would pretty well kill the vacuum when closed. As stated above, I'm not sure it opens when hot, will keep an eye on it and check after driving. See pics below.
Lastly, as I worked on this last night, I found the engine coolant to be sorely neglected. I assume any DEXCOOL (red) antifreeze is good and I will use distilled water. I've read the DIY system flush and will try that before replacing with new fluid. There is plenty of the old fluid and it doesn't run hot, but it sure looks pitiful (brownish).
I would take any guesses on my continued "gremlin". I don't want to be a "parts changer", but am doing some of the general maintanence stuff while continuing to search. Considered changing the fuel filter as it looks like it has been there forever, but wouldn't expect it to be the problem. The way it stutters, I will be quite suprised if it is not a brief loss of "fire" or "fuel" causing this. I will check timing and try to check the coil as well. The other possibility listed in the troubleshooting section is an intake manifold leak. I sprayed some carb cleaner on the topside today when I got home and had no change in idle, but I ran out of cleaner before I could really check it out.
Considered changing the fuel filter as it looks like it has been there forever, but wouldn't expect it to be the problem. The way it stutters, I will be quite suprised if it is not a brief loss of "fire" or "fuel" causing this.
Chris
the fuel filter could be your "Loss of fuel". a clogged up filter equals low fuel flow as you probably already knew that and at 190k i would recommend replacing it anyway since you dont know when or if it has actually ever been replaced. also, have your injectors ever been cleaned? lots of things could be wrong such as your fuel trim, carbon build up, mechanical defect in the injector like it being stuck open or stuck closed..... your exhaust may even be stopped up and has too much back pressure. these are just things to think about.
The reason I am leaning away from the fuel filter is the fact that once I get past roughly 3k rpm, it climbs quick and smooth to 4500 rpm, when more fuel should be required. Based on apparent mileage and appearence, it would be good to change and I will, but I would like to find my gremlin as well.
Checked injector resistance this evening, 13.5 - 13.6 ohms, within spec.
Checked pick-up coil, 212 ohms, within spec.
Tried to check ignition coil: I am not sure which lead is positive and which is negative, but it shouldn't matter as long as they are the two small bolts that I remove the wires from before checking. The Fluke meter I am using is not automotive and only registers to the 0.1 ohm. By simply touching the leads together I measure 0.3 ohm. When I measured the resistance between the two bolts (primary), I got the exact same thing, 0.3 ohms.
I tried to check the secondary, but this meter maxes at 400 ohms, so it simply showed OL (out of limit ) while the secondary could go clear to 15K ohms and still be in spec.
Lastly, I tried to check timing. After jumpering TE1 and E1 and locating the timing marks on the cover and crankshaft pulley, I warmed it up and let it idle down. Based on the cars tach, it was below 1K rpm by a little. It is near impossible for me to see the mark and the cover at the same time as the cover hangs out over the pulley (hiding the mark). I only saw one bolt to loosen to turn the distributor and it didn't provide much play. I'm used to being able to really swing the distributor on the old American stuff I have played with. What little wiggle I could get made no difference, so being stubborn, I removed the bolt all together and was able to get some better movement. Even with the bolt out, I could not get it to make an apparent difference in the timing, even when moving the distributor back and forth. I figured I would be able to move it to find the mark and then move it toward the timing mark to get close. All comments welcome.
I am either doing something wrong on the timing check, or there is a problem. I was on #1, farthest from the distributor.
There are two bolts that need loosening to turn the distributor. One at the front, and one a bit under and towards the rear. RPM being a bit under 1k is all right. Should be 850rpm or so. And you do not need to turn the distributor a whole lot. I think that it is not possible to adjust the ignition timing by more than +/-10 degrees.
Based on comments from a thread 7 weeks ago http://www.toyotanation.com/forum/showthread.php?t=368518&highlight=set+timing I looked for the second bolt to loosen the distributor. Here are some photos, but I am confident there is no second bolt and this distributor, based on Bitter's comments from the above link, I can only assume may be a later 95 that cannot be adjusted. When I remove the one bolt, I can rotate the distributor by hand and it makes absolutely no difference in the timing.
This distributor has an external exciter. I see in the Haynes to look on the VECI label, I assume that is a label on the bottom of the hood?? At any rate, I jumpered E1 and TE1 and using some offset marks (can't actually see the timing mark as the plastic marking area hangs over the pulley) have decided the engine is very near the 10 degree mark spec'd.
If I rev the engine, still jumpered, it advances to approx. 35-40 degrees and is consistent. After reading a little more, it would be interesting to remove the jumper and take a look to see if the timing is really jumping around. I have included a photo of the serial number and other tag for information sake.
Lastly, I will add that this car had a new transmission (from a junkyard) installed just before I purchased it. I am driving it nearly daily and it goes down the road quite well (though I would like to get rid of this intermittent stutter) and is getting 32 mpg.
Sorry for the long post, here are the pics:
"just and open hole where the second bolt would be??"
TIA for any help or ideas.
Chris
Last edited by NWMO 95 Prizm Lsi; 02-27-2011 at 09:27 PM.
Based on reading Bitters post again, I would agree it sounds like I didn't have it jumpered correctly. However, I checked a couple of times TE1 and E1 and when I start the car, the check engine light blinks. I will look again tomorrow. Jumpered properly, even when I apply throttle, the timing should not change, is that correct?
It could be I removed the jumper and checked again as well, I'm a little tired this evening.
TIA
Chris
Last edited by NWMO 95 Prizm Lsi; 02-27-2011 at 09:36 PM.
correct! The jumper diables the computers intervention in ignition timing. I havent had to do this yet, so I cant tell you for sure, but maybe there is a different place/connectors to jump? Other cars have a separate jumper wire pair.
With TE1 and E1 jumpered, the ignition timing should be steady at 10 degrees BTDC *on idle*. If you apply throtlle it will advance, even though the terminals are jumpered.
Now, when you disconnect the TE1 and E1 the timing should advance to 12-15ish degrees even *on idle*. It may jump around a bit like 12+/-2 degrees.
I checked the timing again, without being jumpered and it was as ganda1f stated, slightly advanced from the other night. It did not appear to be jumping around, quite steady, even when throttled up.
I see the knock sensor and the wires leading to the crankshaft position sensor, but didn't fight enough to get to or test either one. I checked voltage to the MAP sensor and found 5.0 as I should. This car has the OBD-1 system, I see no code related to the crankshaft position sensor, which seems a little odd.
Is it possible/correct for the 95 Prizm to have the distributor that cannot be used to adjust timing??
As I read back over my post, the coil should likely be checked again, possibly with a more precise meter. It would seem since I got the same resistance through the coil as I did just touching the leads together, that the coil has near 0.0 resistance, whereas spec. calls for 0.36 to 0.55 ohms.
I used the timing light to visually check the spark in all four wires and things looked fine. I'm not sure that is a fair test, but thought I would look for something that way. I will add that while revving the motor in nuetral, it seems quite smooth untill right around 3k rpm, where it picks up a stutter or shimmy and then smooths out agian as I go a little higher. PASSENGER SIDE MOTOR MOUNT??
Lastly, I am preparing to change the oil for the first time (@ 3,000 miles from last change). I have a WIX filter and am leaning towards Castol GTX for the oil. Any opinions?
All comments welcome, I'm sort of grasping at straws on the miss or stutter.
Is it possible/correct for the 95 Prizm to have the distributor that cannot be used to adjust timing??
All comments welcome, I'm sort of grasping at straws on the miss or stutter.
The car having an OBD-1 ECU I cannot see why it would *not* be possible to adjust the ignition timing. Important thing is to check and adjust the timing while the engine is fully warmed up and no accessories running such as defroster, AC etc. The water temp gauge should be about in the middle.
The distributor missing one bolt could very well be previous owner who did not bother to put it back on, as it is a bit awkward to get to.
Have you checked the distributor cap and rotor for wear?
You need a GOOD multimeter to read things that are less that 10 ohms. Typically when a coil is NOT open or shorted its OK, but sometimes the value can cause troubles when a component is out of spec.
If there was something wrong with knock or crank sensors it would trigger a CEL.
US emissions crap could have you with a non adjustable distributor. If there is no slot in the base than it stays where it is, but it sounds like its already right.
Timing light is perfect for checking spark. I didnt see anything about you changing plugs. You might need to change them and if the wells have oil in them you need to fix that too. Oil cooled spark plugs dont work very well.
When you get a hold of that better meter, check your throttle position sensor. It might be the cause of your stutter as well as a host of other things.
Keep at it. You're doing good work and asking the right questions.
Here is a link to an older post about the plugs. Has new NAPA distributor cap and Borg Warner plug wires as well. The only code I got was TPS, so I replaced it, possibly prematurely. I was using my VOM and didn't realize the upper limit was only 400 ohms, so I thought it was showing an open circuit when it may have been ok. It's a Fluke meter and is suppose to be quite good, but I guess it is geared to home electricians vs. automotive.
I'm going to drain/flush and replace the coolant & thermostat as well as replace the fuel filter this coming weekend.
This car spent it's first 10 years in South Carolina. I have no idea what the emmisions requirements are there, but this distributor is non adjustable.
Thanks for the help and encouragement. I will keep driving, studying and trying to figure out what the problem is.
Chris
Last edited by NWMO 95 Prizm Lsi; 03-01-2011 at 10:49 PM.
Here are two additional pics of the distributor, the first of the single bolt holding it in with no room for adjustment and the second, the backside where the second bolt is usually found.
I have experienced Chilton's etc. not being complete, as it is a very difficult task. The Haynes would lead me to believe the non adjustable distributors were not used until 98'. AND it appears the non adjustable distributors were controlled by the ECM after data collection from the crankshaft position sensor and the camshaft position sensor. I looked some tonight, but did not see a camshaft position sensor and again, Haynes indicates 98' for the start year on the camshaft sensor as well.
After posting the above and then searching briefly, I found this auto parts site showing this distributor as one of two possible oem for 1995.
Wow, this is quite odd. Could it be that the previous owner did not know any better and replaced the original distributor with a non-adjustable one? I have no idea if that would work at all. It certainly seems weird, given that you do not appear to have a cam position sensor, even though the non-adjustable distributor requires it.
Could there be a problem with Mass Air Flow or Manifold Absolute Pressure sensor? Not sure which one you have. Thought that if you have MAF and it is the kind with a flap that moves depending on the airflow, then there is probably some potentiometer whose resistance changes according to the flap's position. The airflow at 3k rpm translates to a certain position of the flap. If there is poor contact at that particular position, then the ECU would get false information about the airflow and act incorrectly with regard to fuel delivery.
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) while the secondary could go clear to 15K ohms and still be in spec.
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