# 1989 Sentra All Power Lost at Low Speed or When Stopping



## helpout (Sep 28, 2016)

Yes, it's still alive! Has just 147k miles on it. Starts up just fine. Drive a short distance and the trouble begins. Each time I've lost power it has been after a series of stop and go driving, driving low speeds or just sitting at a stoplight. When power is lost the best I can manage is 5 mph and even that entails "riding the clutch" w/the gas pedal depressed to make it back home without the engine dying. At higher speeds (say 35 mph and up) it will not lose power. But once power is lost, it's impossible to get it back up to any kind of speed. A few hours ago it played out like this: I did about 2 miles of stop and go driving with no issues. Then got the car up to 40 mph when I reached a major road. Threw the stick shift into neutral and coasted all the way down to zero at a stoplight. When the light turns green, all power was lost and I'm barely able to pull to the side of the road. To sum up: starting up no problem, higher speeds no problem, but if stop and go/low speed/stoplight then power is lost after short time. Thanks in advance for any help!


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## helpout (Sep 28, 2016)

I need to make an edit of my above post. One time the engine did start up and then promptly die. Next try and all other tries it starts up without hesitation. So I should Not have written "starts up just fine/no problem" in my first post.


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## rogoman (Dec 16, 2004)

Please specify what engine and transmission is in the car. Perform an ECU code readout to see what codes are set; since the engine management system is not OBD-II, you'll have to get access to the ECU and use the readout procedure. Refer to: http://www.nissanforums.com/b14-95-99-chassis/84062-how-manually-pull-define-ecu-error.html

There's a good chance that the camshaft position sensor is marginal; it's located in the ignition distributor. It's not a replaceable item, the entire distributor needs to be replaced.


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## helpout (Sep 28, 2016)

Should read one time the engine did die immediately after starting up. Sorry I don't seem to be able to go back and edit my posts...


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## helpout (Sep 28, 2016)

It's a B12 1989 Sentra with a GA16i engine according to the manual. 4 speed stick shift, 2 door body style. It's called the "Base Sedan". 

Will the tutorial for B13/B14 also apply to a B12? I read somewhere the ECU is under the seat but the tutorial says on the floor hump.


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## Car guy (Mar 31, 2016)

Not to counter Rogo (he's good), but, actually, the crank angle sensor (optical module) can be replaced (in the distributor). If it is the sensor, let me know and I will provide the procedure. Takes about 15-20 minutes. 8 phillips screws and 3 bolts.


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## helpout (Sep 28, 2016)

Okay got under the seat and got the crazy ECU cover off without disturbing the wires. Code 55 keeps repeating. Which I believe corresponds to nothing wrong. I did sit in the car for about 15 minutes and listen to the idle. Took video as well. The idle does seem weak after the car warms up (after about 10 minutes).


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## helpout (Sep 28, 2016)

My mechanic will stop by today. Wondering does Code 55 eliminate anything ? Or is everything still on the table...


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## Car guy (Mar 31, 2016)

Nice work on the ECU process. Yes, the 55 means nothing was caught by the ECU. This is good! Saw you have much more info on the ********, so posted info for you there. Will keep checking both sites.


Edit: It keeps blocking me listing the other forum you are on, even w spaces between letters. Well, check there too.


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## helpout (Sep 28, 2016)

Thanks to all for the help. My mechanic didn't show up so no progress to report. Meanwhile, I went to take a second ECU reading and the car turned over and then promptly died. Not sure if that helps narrow things down.


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## bob89sentra (Sep 15, 2005)

Code 55 and car giving problems?
I have experienced this at least half a dozen times across 3 different GA16i cars.
Check first your spark plug wires, spark plugs distributor cap and rotor. (I have seen a handful of differing symptoms come from these daemons)
next you can check fuel pressure, low fuel pressure in specific (you want to have 40PSI minimum of fuel pressure).
Also check your spark coil, when they get warmed up they can start to get weak spark giving issues similar to what you describe

As for the CPS as mentioned above you can replace the optical sensor, BUT I have seen them fail 2 times (in 20 years), and both times I got a code in the computer.


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## firstforme (Feb 21, 2018)

As bob89 said check spark plug wires. With engine running remove one wire if engine sounds worse then then you know the wire is good. Do one at a time and make sure after you do one to put the plug wire back on spark plug (I have know people not to do that). If you pull a wire and the engine runs the same then that is the suspect wire. I did have a different car with a similar issue and the catalytic converter was stopped up and replaced it. Just a thought.


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## helpout (Sep 28, 2016)

Thanks for all the input guys. I'm getting lots of tips from Car guy as well. Found a new master mechanic to come out later today. The first master mechanic basically abandoned me after replacing the spark plugs, distributor cap and rotor, fuel pump, and fuel injector all to no effect. His next guesses were for me to buy a new MAF or find another throttle body at a salvage yard. I declined due to the expense and the fact that he didn't test them first to see if anything was defective with those parts. Did replace catalytic converter, tailpipe and flexpipe a few months ago. Spark plug wires 20 years old but only 40k miles on them. Will report back after new mechanic gets out here...


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## helpout (Sep 28, 2016)

Located a 2 nd master mechanic and he came out today to try to fix what the 1 st master mechanic had given up on. I turned the car over and he listened to idle at various rpms for about 15 minutes. Then the car suddenly dies. He mentions fuel pump but I tell him I already replaced it. He mentions fuel filter but I tell him we cleaned it out previously (black liquid and thick white slop had poured out of it). Each time I turn over the car it is dying quicker and quicker. I get out of the car and notice a lot of white smoke coming from the tailpipe. He says white smoke could be an engine cylinder head gone bad. Meantime, he removes air filter and starts spraying at various angles down the throttle body. When he sprays the engine stops choking, it smooths out and the idle stabilizes. He determines the engine is starved for fuel. He mentions fuel injector but I tell him I already replaced that as well. We recheck the fuel filter even though it has already been cleaned out by last mechanic. He removes my fuel filter and hooks up a fuel gauge and gets constant pressure reading of 47. With the old fuel filter (only 11k miles on it) removed, car is now idling beautifully and I think we’re all done. Sounds great for about 10 minutes then starts sputtering. He says RPM sounds too low but car has no rpm/tach gauge. Previous mechanic also noticed low rpm while replacing plugs, distributor cap and rotor and had tweaked the distributor cap as a fix. New mechanic adjusts idle upward to what he believes (by listening) to be about 7,500 RPMs. Now we both hear engine idling well and it revs high without falling flat. We let it idle for about 20 minutes and then drive it about a mile to Advance Auto and buy and install new fuel filter. End of story?

Nope. Car rested and an hour later I go for test drive (groceries). It's a grocery store car and gets mostly short trips. 4 miles into my trip in 4th gear at about 40mph I feel power loss. Stepping on gas has no effect on speed. Then acceleration kicks back in and I make it to grocery. Car rests while I shop. Starts right back up (it always starts up) and did make it home but can feel car is gonna die if I keep going. The only thing different about power loss this time was that I was going at a high rate of speed (40mph) whereas all other times it failed at low speeds, stoplights, or failed during idle. It also failed one time (about a week ago) after turning it over from a cold start-so it fails not only when engine is hot but also when cold.


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## Car guy (Mar 31, 2016)

Okay, so unfortunately, there are _multiple _problems.

A.
The car is not firing correctly.
Coolant is entering 1 (or more) cylinders.
Compression is being lost.
Likely culprit is compromised head gasket.
Tail pipe (per video) IS showing coolant combustion (re-looked at that part at the end of the video; it was hard to pick up at first; had to watch it several times to finally spot it).
Engine is sucking in coolant.

B.
Idle speed is off.
Throttle plate was adjusted (finally figured out the _nut _reference) (probably _opened _too much in so doing).
Timing should have been checked and set via dizzy (slight) rotation.
Car idling too high.
Rad fan running too soon and too often.
Idle should be 800.

C.
Timing may be off (likely is).
Should be 7' BTDC.

D. 
Timing chain guides sound worn .
Timing tensioner (oil controlled) worn.

E.
Car running too hot.
Due to A. or B. above and/or stuck closed thermostat (which may have caused coolant-combustion compromise). 

Recommendations:
1. Have a compression test performed. 1 (or more) cylinders will be down. You will need to decide if you want to incur the expense of correcting the coolant-combustion compromise, at that time.
2. Have timing checked at crankshaft with timing light, at idle, on #1 SP wire, and have dizzy position re-adjusted until 7' BTDC (car should be at operating temp ... and rad fan cycling should be off).
3. Set idle back to 800 (have throttle plate re-positioned). May need to do 2 along with 3, here.
4. Feel coolant hose at and to ensure thermostat is opening. Thermostat sits facing firewall between pass's strut tower and intake manifold. Sits in a multi-way feed-hose aluminum housing. You will know you found it when you see the rad fan switch and its wires sticking out the end (facing the firewall).
5. Keep eye on coolant reservoir level, if continuing to drive it, till issues are tackled.

If you proceed to have the head gasket job done, that is the time to replace both timing chain guides and the tensioner (it enters from the firewall side) - and chain.

Unfortunately, the compression (coolant consumption) must be addressed and 2 and 3 must be done (at a minimum), with 4 (as test-determined) if the car is to be saved.

Good news is: dizzy, coil, power transistor, coolant sensor, rad fan switch, MAF, TPS, IACV, exhaust system, entire TB, and trans are all okay. 

Sorry for the bad news. But, a path forward exists.

At least you now know.


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## helpout (Sep 28, 2016)

In case you guys are wondering how post #15 came to be, I'm posting the link here. Not for sure whether it's okay to post a link on here though. 

https://1drv.mhs/v/s!AixACD1v4AoNg_M18pF4aLwdTIELIg


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## rogoman (Dec 16, 2004)

helpout said:


> Located a 2 nd master mechanic and he came out today to try to fix what the 1 st master mechanic had given up on. I turned the car over and he listened to idle at various rpms for about 15 minutes. Then the car suddenly dies. He mentions fuel pump but I tell him I already replaced it. He mentions fuel filter but I tell him we cleaned it out previously (black liquid and thick white slop had poured out of it). Each time I turn over the car it is dying quicker and quicker. I get out of the car and notice a lot of white smoke coming from the tailpipe.


You gotta be kidding about the black liquid and thick white slop had poured out of the fuel filter. There's a good chance that the fuel tank, fuel pump and line running up to the filter is probably loaded with crud; the system needs a good cleaning out. Even though you replaced the fuel filter, some of the remaining crud is probably finding it's way to the fuel injector and causing problems. The previous owner certainly didn't maintain the car properly.


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## helpout (Sep 28, 2016)

When mechanic #1 poured the fuel out of the old fuel filter, it spilled out black. Not black and viscous, but black colored gasoline. A scary white colored stringy looking, goopy thing did splash out onto the concrete. If I had to take a wild guess, I would say some plastic/rubber broke off, heated up, and the fuel filter caught it. Then the good news: Before the fuel filter incident he installed a fuel pump so we got a good look at the gasoline (about a quarter tank) and it looked all clear. Other good thing is weeks later mechanic #2 also emptied out the old fuel filter (before replacing it) and clear colored fuel spilled out-much to my relief. Only caveat is that the car has barely been driven in a month due to all these repairs. The previous owner is me. I'm the original owner and have never flushed out the fuel lines...unfortunately. Only thing I can add is about a year or two ago my fuel gauge stopped rising to the top. So I pump the gas and the pump clicks off but when I drive away the needle is still below full.


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## helpout (Sep 28, 2016)

Sorry post #16 is a dead link. It was just a vid of the engine and exhaust. Hopefully this link will work better:


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## bob89sentra (Sep 15, 2005)

So watching the video...
I do not believe you have any timing chain issues,
The idle sounds good.
I would like to hear it rev up with a quick throttle opening. 

IF you did have a blown head gasket, a compression test would show a variation between cylinder compression of 15+ psi.
An easy check for a blown head gasket without compression gauge on the engine (I have had two blown head gaskets on different ga16i motors):
With engine completely cold take off the radiator cap (not the reservoir cap) and start the engine. You will get coolant spraying out of the radiator as soon as you start the car if the gasket is blown between the coolant port and compression. If the coolant does not spray out in the first 10 seconds (you will see a geyser), then you don't have a blown gasket in that area (could still be blown between oil port). 

I know you said you have new wires, plugs, ect, but humor me. At night when it is dark start the engine and raise the hood. Take a squirt bottle of soapy water (I use windex) and spray along the wires from the head all the way to the dist cap with the stream mode. You will hear snap-snap-snap and see the flashes if any of your wires have an issue.


Another test, hook up a fuel gauge In-Line after the fuel filter:
Start the car, and the pressure should go up to 43-47PSi very quickly.
Shut off the car, and watch the pressure, an hour later you should still have at least 40PSI.
Start the car again, and rev up the engine quickly while watching the fuel pressure, does it drop at any time you pressed the pedal, or did the pressure stay steady?

You want more tests to run? 
With engine cold pop the hood and look on the passenger side of the engine above the thermostat housing for the yellow plug (your ECU coolant temp sensor).
There is a wire safety clip to remove the connector, unplug this connector and hook an ohm meter to the 2 terminals in the CTS not the harness plug. You should have about 2000 ohms at 70F, and more ohms if it is colder. Next start the engine and continue to watch the ohms. The ohms should drop below ~300 ohms when the engine is fully warm. If it is outside this range, then you have a bad CTS

Depending on how much more you want to dig, I can give you other things to check, but this should be a good start.

BTW congrats on keeping a b12 GA16i alive for so long. I still have 2 GA16's running, and I have seen just about every symptom you can with these cars over 20+ years


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## helpout (Sep 28, 2016)

Updated Description of Issue: 1989 Sentra idles rough, idles and then dies, loses power (that is, goes into limp mode) at stoplights, loses power driving at low speeds, loses power driving at higher speeds (40mph). The farthest I've been able to drive before losing ability to accelerate is approx. 4 miles. Although the car frequently dies during idle, I don't ever recall it dying while driving. Instead, the engine is still running but without ability to accelerate. There is no check engine light. The one constant: the car always starts. That is, it always turns over. 

Mechanic Recap and Inability to Scan: 1st master mechanic gave up after replacing spark plugs, distributor cap and rotor, fuel pump and fuel injector. 2nd master mechanic gave up after testing alternator, getting 47 psi on fuel pressure gauge, and replacing fuel filter. His last guess was engine cylinder head failure due to white exhaust smoke. Yesterday, 3rd mechanic came out to give it a try. 3rd mechanic arrived convinced it was a clogged catalytic converter. I informed him new flex pipe, cat, and tailpipe already installed at a professional exhaust shop due to rusty pipe separation and rust hole leaks. His highest priority was to hook up his OBD1 scanner to my car. He has a connector which he labeled "1990 Sentra". It did not fit my 1989 Sentra. Without the use of his scanner, we spent the next 6 hours testing the car. Assuming he labeled the connector correctly, does anyone know if the 1990 Sentra has the same scanner plug in/receptacle under the dash as the 1989 Sentra?

Testing: Mitchell resource gave 140-180 compression range as acceptable. With the car running, but cold, we got 160-185 compression range on the cylinders so my mechanic concluded the engine is good. He tested the battery and his multimeter went right to green=good. He ohmed the 20 yr old spark plug wires: 9k, 8k, 9k, and 6k. He said don't sweat the 6k b.c. that is the shortest wire. He pulled the new spark plugs, tested them and measured the gaps. We did not test the new distributor cap and rotor. He tested the coil wire and got 6000 which he said was "good enough". He tested the grounds. During EGR testing, the car "stumbled" which according to Mitchell indicates proper EGR functioning. For kicks we ran the ECM again in self diagnosis mode. Still spits out code 55=no faults detected. Oil he said was okay, just overdue to be changed (4,400 miles on it, not 5k as I had thought). I spent most of my time feathering the gas pedal trying to keep the car running so actually more testing was done that I did not see. Also replaced 10 feet of small diameter hoses-my receipt reads 9/32" but quickly ran out of hose before complete. Does anyone know the proper diameters and approximate lengths of the different hoses to purchase?

My current (3rd mechanic) is very experienced but not with the Nissan brand. One of the biggest challenges was identification/location and proper testing procedure for the different components. Can anyone link me to such a resource?


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## helpout (Sep 28, 2016)

*head gasket*



bob89sentra said:


> So watching the video...
> I do not believe you have any timing chain issues,
> The idle sounds good.
> I would like to hear it rev up with a quick throttle opening.
> ...


Did you mean 15+ variation between different cylinder test results? Or 15+ variation testing the same cylinder multiple times? I ask because the 4 cylinder results ranged from 160-185. Also, my mechanic was questioning the variation on multiple tests of cylinder #1 . I remember a result as low as 140 when I was flooring the gas, but then we switched positions and when he hit the gas it rose above 160. 

Spark plug wires are 20 years old. But we ohmed them and I posted results (see post #21 ).

Would the geyser trick or water spray trick work if the car starts and then immediately fails? I can't keep it running very long. 

Mechanic liked your fuel pressure idea but we didn't implement yet. Did get steady PSI of 47 on initial test.

We did try to get to the CTS. Instead, Car guy informed us we pulled and tested the Radiator Fan Switch by mistake.

Also I believe the coil wire measured 6000. But you mentioned when the coil warms up it can fail. So do we need to heat up the engine before taking the measure ?


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## helpout (Sep 28, 2016)

*MAF Mass Air Flow Sensor aka Mass Air Flow Meter*

Just realized I never circled back to sum up. For the next guy who reads this...cold engine total loss of acceleration (some call this loss of power) while driving with engine still running, cold engine start and stall, cold engine idle revs up and down again and again before warm up, and cold engine car stalls if gas pedal is touched. Then in the latter stages of MAF failure, loss of acceleration even after full engine warm up. Replaced the MAF and problem solved.

I'd like to add that there are truly Amazing people on this board. All you need to do is reach out for their help!


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