perplexing engine problem(s)

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tonyg
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My tercel:: stock 85 wagon,automatic

perplexing engine problem(s)

Post by tonyg »

Hello all.This is my first post/question on this forum however I have read it with great interest for several months. I have been monkey wrenching my sons 85 automatic 4x wagon over the last 18months. About a year ago I replaced the timing belt and water pump at 190 thousand km however since then it hasn't been insured(sons 2nd vehicle). In November he asked me to look at it again as he couldn't get it running. I managed to get it started with difficulty and it had to be babied to even kept running without stalling. I started by replacing the fuel filter and fuel pump after draining the tank and replacing with fresh fuel and adding isopropyl alcohol.I also checked the cam and ignition timing.Still no improvement.After checking the spark plugs, wiring and coil for proper resistance I checked for vacuum leaks tightened the manifold bolts adjusted the valve clearances and did a compression test. All cylinders were within 10lbs but all were low-110-115. Head scratching time. I pulled the carb and rebuilt it with a Rock Auto kit. I found the idle circuit was plugged and the secondary wasn't opening as the diaphragm was pooched. I figured Id solved the problem with the idle circuit opened up and the carb rebuilt but no, still couldn't get it to run normally from cold on the choke or even after warming up. It simply idled very weakly and application of throttle without delicately feathering it would lead to stalls. When I did manage to get it past idle it would rev freely without missing or backfiring and engine temperature was in normal range. Putting it in drive invariably resulted in stalling and hard starting. After some consideration I decided that rather than try to trouble shoot all the vacuum operated pollution circuits I took the leap and purchased a redline 32/36 weber carb kit with electric choke. I read all the positive feedback on the forum and decided it was the best course of action. However after a careful install including a Holley regulator much to my dismay I have been experiencing almost exactly the same symptoms-difficult starting, weak fragile idling and stalling when trying to drive away. Ive checked the fuel pressure (3.5lbs) replaced the distributor cap,rotor and even the ignitor. All for naught and VERY frustrating so Id be grateful for any suggestions/ help from you guys.
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Petros
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Re: perplexing engine problem(s)

Post by Petros »

welcome to the forum!

your first problem is you should ALWAYS start out with DIAGNOSE THE PROBLEM BEFORE YOU TRY AND FIX IT!!!

Replacing parts at random in desperation to get it run properly means you have replaced a lot of parts that were likely good, and predictably you spent too much, wasted a lot of time, and got frustrated. For example I do not know why you thought adjusting the valves would change anything, if it ran good before the problem, it is not the valves, that does not change.

Second you should have come here sooner, but happy to have you here now. Where are you located BTW, perhaps if someone is not far from you they can drop by to a look-see.

Your symptoms sound like a vacuum leak, when it runs lean it is hard to cold start, has a flat spot or stalls right off of idle, and runs weak. usual this is caused by loose or cracked vacuum line, or misrouted to the wrong place. use the vac diagram and chase all vac lines from each location, end to end and inspect for cracks or breaks in the while you do it. likely many of your have been removed with the new carb, but there still should be some in place that are not connected to the carb (like the one to distributor, carbon canister, etc). Also check all of The other vac sources and vac operated equipment like the brake booster and the hose that runs to it.

if all of the rubber parts are good and routed correctly, also check under the carb, the manifold gasket, and even look for cracks in the intake manifold. the intake manifold is not prone to cracking, but there should be a support braket behind the power steering pump from the underside of the intake manifold to the side of the block, many lazy or careless mechanics do not reinstall this steel bracket. But without it the aluminum manifold eventually cracks. not easy to notice, but we have seen it on the forum, darn hard to find that one too.

Easiest way to look for vac leak is to use a can of carb cleaner, starter fluid or even propane gas. with the car idleing, spray small puff of fuel at different places around the carb, vac lines, gaskets, etc. Test by placing a puff down the carb, the engine should speed up with the extra fuel. when sparying it around the intake parts when you find the leak you will hear the engine speed increase and drop back. keep squirting it until you locate where it is.

some times you can not find it, so it may be internal part on one of the vac operated equipment like the EGR, brake booster etc. In the device manual (available for free down load elsewhere on this forum) there are simple tests for each component, usually not tools required.

Another thing that can cause weak performance is spark timing is way off, or the centrifugal weights on the advance are rusted stuck. Though with that one it usual runs okay at idle but get weak as RPM increase. Check your spark timing, set it at 10 deg BTDC, not the factory 5 deg BTDC.

Anything that can make it too lean will make it act that way. Some how too much air is getting in the engine. Or not enough fuel. since it acts that way with either carb, it is not likely the carb, but something else. Not likely, could be a cracked head, usually you have a lot of other symptoms, so I would not worry about that one. if you have a cracked fuel line that allows air to get sucked in, this would be all rubber fuel lines up stream of the fuel pump, and it gets fuel starved. inspect the site glass on the float bowl to verify the bowl is full (that is on the stock carb, not sure if the aftermarket carb has that).

if there is not obvious source of vac leak, you might check spark strength. in the service manual there is a good section on trouble shooting, with symptoms, and a table of what to check, and instructions on how to check it in the chapter section.

check these things and get back with us.

Good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
xirdneh
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Re: perplexing engine problem(s)

Post by xirdneh »

i had a car with the weber that did not run well with the main jets that it came with
i think they were 140 or 145
ran better with smaller jets
that being said, checking the stuff petros mentioned is the first step
Love those Tercell 4x4 wagons but they sure suffer from road noise.
pantah
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Re: perplexing engine problem(s)

Post by pantah »

I can't find an image of the intake manifold support to know what it looks like. I tried to find it on my tercel but didn't see it. Any help?
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Petros
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Re: perplexing engine problem(s)

Post by Petros »

it is just a steel brake under the manifold assembly, just forward of center (about in line with cylinder #2). It mounts on the side of the engine block ahead of the head pipe, but behind the power steering pump. It is hard to see from above, but once you can get a good look at the underside of the intake/exhaust manifold it becomes obvious. It uses a single 12mm bolt into the side of the block, and I think two up into the underside of the aluminum intake manifold. it is a steel bracket, almost triangular shaped, with flat flanges where it bolts to the side of the block and to the underside of the intake manifold.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
tonyg
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Re: perplexing engine problem(s)

Post by tonyg »

Sorry for the Very tardy update: After much frustration and head scratching I finally returned to the only issue left that I hadn't followed up on namely the low compression-110, 112, 109 and 111. I initially rejected it as the cause of the no start or start but run roughly and stall with no power problem. Ive had High mileage toyota pickups and other japanese sedans with very low compression that never failed to start and run. Moreover everything I thought I knew about compression problems was that there was only a serious issue if there was significant variations between the readings for each cylinder. Nevertheless out of frustration/desperation I finally pulled the head and took it to a machine shop. The head gasket looked fine and the head measured true with no measurable warping. As it turned out all the exhaust valves were burnt, intakes all good and valve guides fine. Bores were fine with no measurable scoring or ridging and insignificant carbon buildup on the crowns or c/chambers. Withe exception of the burnt valves, not surprising in a 4 cylinder toyota with only 180T kilometres. However I was surprised about all 4 valves being burnt. i can only surmise that the exhaust valve rocker clearances were set too tightly or the timing had been retarded for a long period or both. In any event once back together with new gaskets and valve guide seals it fired right up and runs like a top! The only issue subsequently has been the charge and brake lights coming on intermittently. A new set of brushes didn't solve the problem (a Bosch rebuilt) and it seems to kick out slightly over 14v when the lights go out. I checked all the cables and grounds and its a new battery reading 13.5v at rest. So its off to a Nanaimo automotive electrical shop for bench testing and TLC. A curious problem I thought new brushes would cure but no such luck. As other may run in to this Im sure Ill let you know what the diagnosis and cure involves. Cheers
tonyg
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Re: perplexing engine problem(s)

Post by tonyg »

Had alternator checked out and its good. Technician suggested it is likely the belt slipping as there was black rubber powder around the pulley. He indicated that with cheaper belts,Dayco in particular once they slip they glaze up and thereafter it doesn't matter how tight you install they will always
slip regardless of how much load is placed on the system. Once home I checked the belt - a Canadian Tire Motomaster- only a year old with minimal useage nevertheless a cheap belt and so likely confirming the techs diagnosis. Ordered new, better quality Continental belts from RA - 19 bucks for both alt and PS delivered to the door as opposed to local NAPA and Lordco price of 45 before taxes for economy grade belts. Only downside is the wait involved-usually 1-3 weeks but we are in the middle of a postal strike in this country so who knows! Will let you know how it turns out. What I will say is that we in Canada are being ripped off on a grand scale. The price differential and lack of choice for parts is, to my mind, totally unjustifiable and intolerable so almost always now my go to supplier is RA.
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Petros
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Re: perplexing engine problem(s)

Post by Petros »

you can buy "belt dressing", an inexpensive tacky glue that is compatible with the belt to prevent slip. Most auto parts stores carry it. should let you know if belt slip is the problem.

I can not remember why, perhaps annoying belt squeal and I did not want to tighten it any further for fear of wearing out the water pump and alternator bearings, but I used it once and it worked well to stop belt slip. It seems to me some brands of belts make the annoying squeal when it is very cold out, squeal would go away after it warmed up. I caulked it up to "cold slip", the belt dressing fixed it.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
tonyg
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Re: perplexing engine problem(s)

Post by tonyg »

Thanks a good suggestion but since I have already had a close look at the alt/wp belt and it is clearly showing signs of premature failure I went ahead and ordered new belts. Another good lesson in why using cheap parts can backfire.Fortunately, In this case it has not been an expensive or disastrous reminder.
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Petros
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Re: perplexing engine problem(s)

Post by Petros »

I have had some bad experience with cheaper belts, one time on another car (that had 3 different belts to drive each accessory), brand new belt failed with about ten mins of drive time, and took out the other belts. leaving my wife stranded with an overheated car. I once bought a project tercel where a failed timing belt had wrapped itself round the tensioner and pulled it out of the front of the oil pump housing, damaging it. So a delayed the belt replacement resulted in a much more costly repair to pull the front of the engine apart and replace the costly oil pump assembly.

Cheap belts are not worth it.

while you are at it, verify the pulley is properly aligned so the belt runs straight. if the mount is loose or misinstalled a misaligned pulley will wear the belt out fast.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
tonyg
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Joined: Thu Sep 28, 2017 11:10 am
My tercel:: stock 85 wagon,automatic

Re: perplexing engine problem(s)

Post by tonyg »

Well the plot thickens.I installed new continental belts and Voila!-- or so I was hoping/expecting but no, the problem persists. The charge ,overheat and brake warning lights continue, as before, to come on and off in a random fashion and for varying periods of time not connected to increased load, engine temperature or rpm. When the lights come on the heating fan definitely slows down suggesting the alternator stops charging but on closer investigation using a voltmeter across the battery the reading remains at about 14.5 regardless of the warning lights being on or off . However as I continued watching the voltage actually spikes up to 16volts for very brief periods consistent with a reduction in rpm and the CMH relay on the passenger side clicking on and off. The manifold heater controlled by that relay(and the computer) I removed when I installed the Weber. As the alternator is charging the battery I can live with the goofy warning lights flashing on and off however Im more worried about the voltage spikes damaging the battery and/or the alternator. This little car has had lots of tricks up its sleeves! Any thoughts?
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Re: perplexing engine problem(s)

Post by xirdneh »

I would try another alternator
Love those Tercell 4x4 wagons but they sure suffer from road noise.
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Re: perplexing engine problem(s)

Post by BaileySims »

I've got a spare stock alternator you can have if it's the correct one for you. I'm sure it's the internal voltage regulated one.
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tonyg
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Re: perplexing engine problem(s)

Post by tonyg »

Yes I may end up doing that but for now as I just had mine tested by a very competent shop and they gave it a clean bill of health Ill have to presume(and my gut tells me) its something other than the alternator. On Vancouver Island particularly where I live -Port Alberni- these cars are few and far between and so 2nd hand parts are like hens teeth. I have discovered that the 80s 4 cylinder toyota pickup has the same alternator but with quite a bit more output so I may explore that as a boneyard option if I can't sort this out. Thanks Bailey for your very generous offer. If we lived about 1k miles closer I would take you up on it. Besides you should keep one as a backup.
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