Nissan Sunny 1988 1.6 engine: jerking problem

Hello everybody,

I have one small and one big problem with my Nissan Sunny 1988 1.6.

1.) the small problem: When I start the engine, it runs at 1400 to 1500 rpm idle because of the cold-start injection system. But it takes way too long to get back to normal idle at about 900 rpm. I guess the problem is the thermo-sensor which reads the temperature of the engine block. Is my guess right? What else could it be?

2.) the bigger problem: When driving at about 35-40 mph when I want to accelerate and push the throttle too fast the engine "coughs", jerks and slows down. On the other hand when I accelerate and slowly push the throttle pedal it accelerates fluently. What could be the problem? Where should I start?

3.) Not a problem, but... does anyone have a map of the engine? I mean some directions how to find all those sensors... (like for example the cold-start-engine-temperature sensor)

I already did all the diagnostics available in this type of E.C.U. (I. to IV.) with these results: Mode I: the green LED would blink very slowly, and I don't know if it made it the 5 flashes / 10 seconds. It could also be 3 or 4 flashes /

10 secs. Mode II: Sometimes it showed that the mixture is too rich (only green LED lit) and sometimes that the mix is fine (both LEDs lit) Mode III: no error code. Only 44 meaning that everything is OK. (But I might have erased some codes, because I disconnected the E.C.U. from power to get it out from under the passenger seat. After driving for about 30 minutes, no new error appeared.) Mode IV: TPS = OK, Starter = OK, Speed sensor = OK Mode V: Everything OK. No LED flashing for about a minute. (didn't watch the entire 5 minutes)

Thank you for your responses in advance.

Ondrej

Reply to
Nndrej from Slovakia
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Just to specify the problem better:

- The jerking occurs when I want to accelerate and push the throttle pedal too fast.

- It happens at almost any rpm, but most often between 2000 and 3000.

- I cannot get over 3000 rpm when driving. No way. At 2900 it starts to jerk whatever I do, and the rpms fall.

- When the car is stopped and shifted to Neutral, I can easily get the rpms to 4500. No problem in this situation.

Today I checked the spark plugs, and one has corroded contact with the cable. I also shortened some vacuum tubes that had cracked ends.

Here are my candidates (possible causes of the problem):

- Air Mass sensor (could cause bad mixture)

- Lambda sensor (the sensor in exhaust) (could cause bad mixture)

- Ignition cables and spark plugs (the spark not strong enough)

- Throttle position sensor

- fuel pump or fuel filter (insufficient supply of fuel)

- EGR

- injectors

Also, the first problem seems to be gone - the idle rpms go to 900 quite fast (3 - 5 minutes).

Reply to
Ondrej from Slovakia

No.2 is either a weak spark or a weak mixture, my bet is on a weak spark. If you close your plug gaps down to 2/3 normal and the problem goes away or reduces substantially, you've proved it.

Reply to
SteveB

When is the last time you did a regular tune-up, replace spark plugs, ignition wires etc?

Also, I seriously doubt its the fuel pump or feul filter. Stopping abruptly at 3000 rpm means its something electrical.

When you mention not going over 3000 rpm, that's usually a strong indicator of a bad air mass sensor.

I would suggest that your replace the air sesnor with a used one, and if that doesn't work, give the car a thorough tune-up.

CD

Reply to
Codifus

I have no idea about last tune-up. I bought the car just a few weeks ago.

Actually it doesn't stop so suddenly, but it slows down when I step on the throttle. If I keep the throttle at about the same level, already from say 1500 rpm, it steadily goes even past 3000 to about 3300.

Today my uncle helped me to remove the spark plugs and No. 1 and 4 were fine, No. 2 and 3 were pretty burnt black. We also decreased the gap and filed them slightly. I plan to replace them ASAP. But on a test-ride after the spark plug cleaning the problem was still here. IMO if the problem was really in the spark plugs, it would have decreased at least.

So now I plan to start by replacing the cheaper things like the spark plugs, the fuel filter, then maybe the air mass sensor.

BTW: the engine is E16i (

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) andthe car model is N13 if you'd like to know.I downloaded also some factory service manuals: for N13 Pulsar(australian version with SR16DE or SR16DE engines) and for N14 (butthis one also used the SR16DE engine). The check procedures are thesame I guess, but the values of pressure, resistance or whatever mightnot be the same. Also these model seem to use different ECU and displaydifferenc error codes. Fortunately I have an article about thediagnostics for this particular model.

Reply to
Ondrej from Slovakia

Since you don't know its service history, best thing is to give it a thorough tune-up. Sprak plugs, wires, rotor, cap, and feul filter.

Could be, but you should also keep in mind that with today's electronically controlled engines, the computer can compensate significantly for a degraded spark plug up to a point. Since you did find 1 or 2 bad plugs, just change them all.

Good plan.

I'm in the US and we have the SR20DE here. One of Nissan's great motors. My Sentra has the GA16DE.

CD

Reply to
Codifus

Hi guys,

I replaced the spark plugs today and went for a test ride.

The problem is still present.

After the ride I removed the spark plugs, and No.2 and 3 are black, No.

1 and 4 nice and clean. Just the same as the original spark plugs.

I also measured the resistance of the cables and No.1 is about 12.5 kOhm, the rest are less (linearly decreasing). So it seems the cables are OK.

It seems that pistons No.2 and 3 get a weak spark...

Could it be the distributor ???

I also already ordered the ignition cables and the fuel filter. I'll go pich it up today and hopefully replace it tomorrow.

Looking forward to your replies.

Ondrej

Reply to
Ondrej from Slovakia
Reply to
Ondrej from Slovakia

If 2 & 3 are black after only a short run you may have worn piston rings on these 2 cylinders as this would also allow oil to pass from the crankshaft to the firing chmber. Do the exhaust gases look blue? If so this would also indicate worn piston rings.

Reply to
Oso

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