# 91 Nissan 2wd cyl 1 misfire



## DarrellJ (Aug 31, 2014)

Howdy all, I have a big problem and need some help.

I have a 1991 Nissan 4 cyl with a misfire.

when idling the number one cylinder doesn't want to work.

I pulled the fuel rail and looked while it was cranking to make sure fuel was coming out of the injectors.

pulled the timing cover to look at push rods and valves, they are moving.

Timing chain looks good.

I also checked compression on the cylinder, it's fine, within specifications.

I checked with a timing light to make sure I'm getting spark, and I laid the spark plug wire against some metal while running to make sure I have spark.

So, unless I'm missing something.

I have fuel, spark, compression and timing but it's not working?

When idling it runs really rough like a cylinder is missing. I pull the #1 plug off the plug and it doesn't run any rougher, just the same, I put it back.

I then pull the next wire off the plug and it runs rougher, put it back it's fine. I do this with the 3rd and 4th cyl with same results. It runs rougher.

New spark plugs in it, no difference.
New cap and button, no difference.
Moved spark plug wires from one to the other (yes both ends..) no difference.

No engine code is showing.

Yes this is the KA24E motor, I think those are the numbers.

HELP!


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## DarrellJ (Aug 31, 2014)

no suggestions?


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## jp2code (Jun 2, 2011)

I don't think there are lots of people on here, so replies take a week or so.

Have you downloaded a free service manual? Let me know which one you have, so I can give you the right page numbers.

In the pic below, the 1990 model should work fine for your truck. Just go to the link shown in the address bar.


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## DarrellJ (Aug 31, 2014)

I have not! didn't know about it. Thanks for the link, I'll try to D/L it now.


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## DarrellJ (Aug 31, 2014)

Ok, I have it, ( the d21 for 1990)what page should I look for?


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## jp2code (Jun 2, 2011)

EF & EC 194 is where troubleshooting the electrical stuff starts.


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## jp2code (Jun 2, 2011)

*Page EF & EC 252* has a section to look at and understand about the injector wiring and the sensors it uses.

A sensor or some wire could be bad.

*Page EF & EC 292* has a section on checking your injectors to see if they are OK.

I'm leaving work in about 5 minutes, which means supper, watching the news, making the kids get their homework started, etc. But, I'll be back before I go to bed (I think).


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## DarrellJ (Aug 31, 2014)

worked on it and discovered a ring was broke it wouldn't keep enough compression while running.


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## bobbydangartner (Apr 18, 2013)

Darrell J I think I may be having the same problem. Did you run the compression again? How did you determine it was a broken ring? and which ring was it?

Mine has a slight miss and lately I smell raw gas when I start it in the morning.
Occasionally it acts like it is not firing on one cylinder at all but then goes back to the minor stumble. Ive done everything I can think of. Had the head off a year ago when the gasket blew and changed the timing chain.

I ran the computer diagnostics too I am confused about Mode V as it flashed four green flashes, three times each, of four. But there is no code description for Mode V. 

Its running rich.


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## DarrellJ (Aug 31, 2014)

what we wound up doing was taking a static compression test (not running) and it showed compression was fine.

then we did a running compression test and found that when it was running it would not keep compression, as a result, stumbling and missing.

there is a guy who does nothing but diagnostics on engines and he had never seen that before until he did it.

Main reason why it won't keep compression when running, broken ring.


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## smj999smj (Jan 1, 2006)

bobbydangartner said:


> Darrell J I think I may be having the same problem. Did you run the compression again? How did you determine it was a broken ring? and which ring was it?
> 
> Mine has a slight miss and lately I smell raw gas when I start it in the morning.
> Occasionally it acts like it is not firing on one cylinder at all but then goes back to the minor stumble. Ive done everything I can think of. Had the head off a year ago when the gasket blew and changed the timing chain.
> ...


Mode V is real time diagnostics and the code is flashed 3 times, so you would have a Mode V Code 4: Check the ignition signal. Check the harness continuity when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.


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