1989 Sentra Power Lost at Low Speed or When Stopping

A great resource for Nissan Sentra, Infiniti G20, 200sx, Pulsar, NX1600, NX2000, Tsuru, Primera and Sunny owners.
1989nissanB12
Posts: 8
Joined: Sun Feb 11, 2018 11:40 am
Location: Saint Louis

Post

Has just 147k miles on it. Starts up fine. Drive a short distance and the trouble begins. Each time I've lost power it has been after stop and go driving, driving at low speeds or just stopped at a red light. 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 does not lose power. But once power is lost, it's impossible to get it back up to any kind of speed. Last time 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. Threw the stick shift into neutral and coasted all the way down the road to 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 causes all power to be lost. Thanks in advance for any help!


amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

Post

Tuneup.

Seriously, you have no real choice, you mention literally nothing done to car to keep it up maintenance wise and the problem can literally now be anything. The tuneup is needed as being in that state is the first thing one has to do to be able to point at more oddball things than the norm to go bad.

Dunno if there is any electronic control on that old one to tell of any operating errors in it but if so then someone needs to be reading that.

Could even be a dead engine, most will still start and seem to run at higher rpm but the rpm is the only thing keeping them going, get lower and they die to not run right. Coming and going of power is a bad engine hallmark, and why the basic engine condition has to be verified with a tuneup, it guarantees enough things are in place to then guess further.

1989nissanB12
Posts: 8
Joined: Sun Feb 11, 2018 11:40 am
Location: Saint Louis

Post

I do have a master mechanic trying (in vain) to diagnose the power loss issue. He formerly worked at one of the local Nissan dealerships so I have to assume tune up won't be the fix. I mistakenly thought it was so strange for a car to start right up (except for one time-see below), drive for a short distance and time, accelerate fine, and then lose all power at a stop sign. Thought someone would say "oh this happened to me and it was such and such".

Maintenance wise, a lot has happened in the last year. Here's a recap and hoping this helps. About a year ago, lots of oil caked on engine. Master mechanic finds distributor o ring leak and replaces it. Says surprised my car would even start w/all the sludge built up in the rotor (he cleaned it out) and says rotor looks burnt in spots as well. My bad, as we did not replace the rotor at this time. Six months ago, the local technical school took the car in for a rusted body and did sanding, new rockers, 4 fenders, and patched door rust holes. Then primed and painted. Along the way, they put on new tires, 4 new struts, did a front wheel alignment, a rear wheel brake cylinder, and a master brake cylinder. Two months ago, hit some big potholes and tailpipe separated from catalytic converter. Took to muffler clinic and they tell me flex pipe, cat, and tailpipe all leaking. Had all 3 replaced. Muffler shop also told me your muffler has less than a year left and it's rusting from the inside. Two weeks ago, I drive the car half a block and lose power. Throw it into neutral (in neutral the engine does not die) and coast into a parking spot. I figure easy fix-it must be the burnt rotor. New rotor, cap, and NGK plugs. On fresh start, car dies. Master mechanic pulls off air filter and sprays carb cleaner down the carburetor while I press the gas pedal. He says the engine is sporadically falling flat and sees it sometimes is not getting enough fuel. Believes it's bad fuel pump. New fuel pump installed. Fresh start of car while he observes carburetor and I press gas pedal reveals it's still choking at times but then sounds strong again so we go for test drive. Car runs beautifully. Four days later I drive a couple miles of stop and go and car loses power again. Most I can get is 5mph and lucky to make it back home. Master mechanic says then it must be your fuel injector. New (remanufactured) fuel injector installed. He checked positive battery cable, wires/hoses seemed alright, pulled off fuel filter which only had 10k miles on it. Black colored fuel poured out of it as well as some sold white gunk. Cleaned it out and reinstalled it. Fresh start of car and car sounds great. Test drive several miles and car performs well at low and higher speeds (we did not take it on the highway though). Next day I drove car a few miles and then lost all power again at a stop light. Master mechanic says could be the Mass Airflow Sensor? But he's not sure if his (modern) diagnostic equipment will be able to scan a 30 year old car. Note: no dash warning lights have come on during these episodes of power loss. In St. Louis so waiting for wind chill to rise above single digits to take another shot at this...any help greatly appreciated.

1989nissanB12
Posts: 8
Joined: Sun Feb 11, 2018 11:40 am
Location: Saint Louis

Post

Okay I got to the ECU today under the front passenger seat and it reads code 55 and keeps repeating 55.

amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

Post

Code 55 is no fault detected...........the car is pre-OBD and will not scan at all other than the basic codes you can get with no scanner at all.

If your 'master' mechanic is honestly telling you he's working on a carburetor and fuel injector and likely mass air device as well then you need a new mechanic. Fuel injector means there is no carb on the car and that old you may well have a feedback electronically metered carb. No injector, you have either carb or injector not both.

That old a system has very few codes and whopping numbers of things can happen to not post any codes at all.

Just like not changing the rotor you may be getting too tight again with the cash to change plug wires, which could do it too. Yanking them to change the plugs is a classic way to pull them apart inside to make them even worse than they were before.

Black color and white junk in filter if they use ethanol in your local fuel say it and the carb if so equipped will have fits and possible damage from that.

1989nissanB12
Posts: 8
Joined: Sun Feb 11, 2018 11:40 am
Location: Saint Louis

Post

Sorry, I'm not a car guy. But I know it has just one fuel injector for 4 cylinders. When I said carb, I believe I should have said throttle body. That is, the opening that people spray carb cleaner into to clean it up.

Spark plug wires were last done 20 years ago at 105k miles and came with a lifetime warranty. Car has 147k miles now. But the car first lost power before we replaced the spark plugs, distributor cap and rotor. So it's not possible anyone pulled on them. Do spark plug wires just die of old age and could they cause a car to drive for a short distance and then lose power ?

1989nissanB12
Posts: 8
Joined: Sun Feb 11, 2018 11:40 am
Location: Saint Louis

Post

My manual says GA16i engine type. Also, It's a a 4 speed stick shift.

Car guy here
Posts: 14
Joined: Thu Mar 31, 2016 6:31 pm
Car: Restored B12s

Post

You have a single FI TBI, with MAF (just inside air cleaner housing), FI (just behind MAF), FPReg behind that (rear side), TPS (to MAF's side), AACV (just behind that on the rear side), Mixture heater (just under that - between the TB and the IM), and FPReg hose that routes down onto the chamber. CTS on the pass's side under the MAF (somewhat). The MAFs were known to cause - and actually - enable - limping when they failed (with or without codes). Check MAF electrically when issue occurs. Same with TPS - it is a switch and a (modest) position sensor (check both). Check the FPreg hose and FPreg - if bad fuel was in the system, likely in FPreg and those TBI channels to and from the mesh screen on the FI. If hose never replaced, may be heating up and venting due to aged cracking. If replacing the FPreg, replace the FF and hoses to it and from it (to TBI) and may need to re-remove the reman'd FI to TBI-spray-clean out the TBI FPreg channels/passages. When the FI "cover" was removed to install the reman FI, were the 4 o-rings replaced? Ohm the SP wires - disconnected completely, and report back (#1 (far left) =, #2 =, etc). Ohm the dizzy cap's coil wire completely disconnected and report back. Check rotor brushes for carbon build-up - and concaving - and rotor edge - it will tell you if timing is off. Report back where rotor edge is "firing." Also, if dizzy o-ring was replaced (and dizzy was not), wise to re-check inside housing to ensure no oil is getting on the optical module's LEDs/photo diodes and 360' slit plate. Mechanic also can o-scope the 1' signals and 180' signals of the optical modules when the issue occurs. Check ign coil electrically and the power transistor. Both are together at the driver's strut corner. Put fingers under EGR valve "top" and lift up the valve and listen - does it open nicely; let go and listen - is it sealing tight when the bottom pintle drops? Also, you have 2 solenoids on the pass's IM side: one for combined EGR/BPT/vapor canister management (could be stuck or have open hose cracks) and one for AIV management (same possibilities). Former is supposed to work when cruising. Latter is supposed to work when car is cold and then shut off at 140'. Cat is also a possibility (clogged). Mech could try running with it disconnected. Re-remove the PCV valve and use carb-spray or TBI-spray and thoroughly clean it from both ends, repeatedly, till shaking is back to normal; if not, replace it with new one. When car cold, remove fuse box cover on pass's side and lay fingers on and around PTC mixture heater relay; have someone start the car; feel the relay click; hold fingers on the relay until car warms up; wait to feel "un-click"; how much time passes; report back if you feel the cold click, hot un-click and duration. During this same time, "listen" for AIV to "pop open" and "close." Report back. Nice work on the ECU code process.

Where is the car (state)?

1989nissanB12
Posts: 8
Joined: Sun Feb 11, 2018 11:40 am
Location: Saint Louis

Post

I'm in Saint Louis, Missouri. And thanks that should keep me busy.

Did just get a new catalytic converter 2 months ago, along w/a new flex pipe and tailpipe. Muffler is about to go-but assumed a muffler would not cause a car to limp home.

Since MAF was atop your list...I saw a youtube video where a guy starts the car and then pulls out the wiring harness/plug attached to the MAF. He says if the car dies=MAF is good. If car keeps running=MAF is bad. Is this valid? And if MAF is bad, could MAF cleaner help? The MAF is costly and hard to find anywhere.

Car guy here
Posts: 14
Joined: Thu Mar 31, 2016 6:31 pm
Car: Restored B12s

Post

Correct on muffler. To be sure, just place hand over tailpipe; strong full pressure good; restrained/overly restricted (doubtful), then no good. While there, run your finger inside tailpipe. Whaddaya see/get?

The GA16i MAF is different than modern MAFs. Not sure if that test would work or not. Definitely would Not spray it. The wires are self-cleaning. They clean themselves After you turn off the car (to exceedingly high temp). If you look at the 2 hot wires, do you see that they are fully intact (no breaks, no debris, no build-up).

You see my PM on the other forum (where you had posted)?

When the new cat went in, was a new O2 sensor installed? Why was the cat replaced?

1989nissanB12
Posts: 8
Joined: Sun Feb 11, 2018 11:40 am
Location: Saint Louis

Post

Yes thanks, I'm set up to get an email notification if anyone replies or sends a p.m.

Cat: Two months ago, hit some big potholes and tailpipe separated from catalytic converter. Took to muffler clinic and they tell me flex pipe, cat, and tailpipe all leaking. Had all 3 replaced. Muffler shop also told me your muffler has less than a year left and it's rusting from the inside. The shop did not mention a new O2 sensor, so assume they did not install one.

1989nissanB12
Posts: 8
Joined: Sun Feb 11, 2018 11:40 am
Location: Saint Louis

Post

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 (brand 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. We ran the ECM again in self diagnosis mode=mode 3. 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?


Return to “Sentra Forum / Infiniti G20 Forum / Pulsar / NX Forum”