# '88 Hb z24 help



## MikeL00 (Sep 17, 2010)

Let me start off by saying I have searched these forums and checked the ecu for codes(no codes found).

Problem: Power cuts out at about 2k-2.5k rpms in every gear *except* 3rd for some weird reason. In third i can accelerate from low to high rpms with no loss of power. In all other gears power cuts out, I keep my foot floored on the gas and no response until the engine slows down to a low rpm, then it kicks back in.

I replaced the spark plugs, cap and rotor and fuel filter, it did not help.

So I take it to a shop. They say they couldn't replicate the problem. I go down to pick it up, as I pull out of the parking lot it does it. I have the mechainic hop in and show him whats up. Next day he calls me and says he got a 045 code injector leak. They replace the two injectors, said they road tested it and everythings great.

Went down tonight after the shop was closed to pick it up. Pull out of the parking lot and does the exact same thing, feels no different from when I brought it in.

Before the shitty mechanic replies, any help would be appreciated!

edit: He also wanted to let me know that upon cold starts white smoke is coming from the exhuast and my head gasket could be leaking.


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## SPEEDO (Jun 9, 2003)

kinda sounds like its in fail safe mode... has anyone tried to pull codes?


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## saudade (Apr 10, 2010)

I've had this happen twice but mine did it in every gear including neutral.

Once it was one of my ign coils. Don't recall which one but one cuts off around 2.5K by design. Coils are the same. Try swapping them over. When this was the issue, it was consistent. All the time, every gear. Once I swapped the coils, it ran OK, then I replaced the bad coil.

Second time was a bad splice joint in the main harness that fed power to the injectors. This was intermittent. Sometimes it puked at 2.5k-ish, sometimes not. Did it in every gear though including neutral. Moving the harness around (like changing the injectors) may have restored the connection until it shifted again and broke the connection.

check out:

http://www.nissanforums.com/hb-truck/160226-86-5-z24i-engine-cutout-solved.html


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## saudade (Apr 10, 2010)

I was also told it could be a bad Mass Air Flow sensor (mounted on the side of the TB). This was not my issue but I'd expect a bad MAF to show a code.


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## MikeL00 (Sep 17, 2010)

saudade said:


> I've had this happen twice but mine did it in every gear including neutral.
> 
> Once it was one of my ign coils. Don't recall which one but one cuts off around 2.5K by design. Coils are the same. Try swapping them over. When this was the issue, it was consistent. All the time, every gear. Once I swapped the coils, it ran OK, then I replaced the bad coil.
> 
> ...



Yeah i saw that thread yesterday when I was searching. This morning I switched the wires on the coils and had the same problem. I came back home and unhooked the battery for a minute. Started it up and drove it with no problems 

@speedo the mechanic said he got the 045 code which is why he replaced the injectors. I think hes full of shit though. I don't think he got any codes. 

Doesn't the CEL need to be on to get codes from the ecu?


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## saudade (Apr 10, 2010)

Mine didn't show any codes at all except for the 23 & 24 codes (easily cleared). However, I was able to look down the throat of the TB while running (air cleaner cover off, of course) and saw a difference in fuel flow from the 2 injectors.

I would have expected some kind of injector related code but none ever showed.


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## MikeL00 (Sep 17, 2010)

hmmmm interesting.

Do you think my ecu could have been in fail safe mode and by disconnecting the battery it cleared that? Or cleared the supposed 045. I know the mechanic didn't do it because the nuts and bolts on the battery cables were rusted together, i broke both bolts trying to get them off.


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## saudade (Apr 10, 2010)

So it's running OK for now? You can reset the ecu without disconnecting the battery. Given your batt connections were pretty nasty, can't say I blame him for avoiding them.

I suppose it's too late to ask now (but I will). Did you get your old injectors back? Chances are they're still good since swapping didn't fix it. 

I spent about $800 in parts before I used a 5 cent crimp connector to fix my cutoff.  Some of it needed changing anyway (cap, rotor, wires, plugs, FF and a bunch of vac lines). Now I have a new fuel pressure reg, new coil, reman MAF, and an entire TB with all sensors, sitting in a box in case I need them one day. Since I'm keeping the truck indefinitely, might as well stock the parts.

Keep us posted.


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## GeoBMX4Life (Mar 25, 2010)

You may want to spray the plug connections to your sensors, as this will ensure the connection is 100%


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## MikeL00 (Sep 17, 2010)

saudade said:


> So it's running OK for now? You can reset the ecu without disconnecting the battery. Given your batt connections were pretty nasty, can't say I blame him for avoiding them.
> 
> I suppose it's too late to ask now (but I will). Did you get your old injectors back? Chances are they're still good since swapping didn't fix it.
> 
> ...


Nope, didn't get the injectors back. I test drove it on Friday for about 10 min. Went through all the gears, up and down hills...etc etc with no problems. I haven't drove it since, so we will see how it does.



GeoBMX4Life said:


> You may want to spray the plug connections to your sensors, as this will ensure the connection is 100%


What sensors?


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## GeoBMX4Life (Mar 25, 2010)

Your MAF plug in, TPS, and O2 sensor on the air filter. If any moisture or corrosion gets to these, they won't function properly. MAF and TPS are on the throttle body, and the O2 is on the left underside of the air filter housing.


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## MikeL00 (Sep 17, 2010)

GeoBMX4Life said:


> Your MAF plug in, TPS, and O2 sensor on the air filter. If any moisture or corrosion gets to these, they won't function properly. MAF and TSP are on the throttle body, and the O2 is on the left underside of the air filter housing.



Will check those out. Thanks!


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## GeoBMX4Life (Mar 25, 2010)

MikeL00 said:


> Will check those out. Thanks!


 No worries, just keep us updated!


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## MikeL00 (Sep 17, 2010)

Just took the truck for a drive. It seems as if my original problem has been solved. Although now there is a hesitation when I step on the gas. When starting out from a stop I have to hit the gas pedal 2-3 times and rev it before letting out the clutch or it will die. Its smooth going up in revs, it's just that initial push on the pedal when starting from a stop and upshifting. It's driveable but it makes starting out from a stop on a hill a pain.

Any thoughts???


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## SPEEDO (Jun 9, 2003)

might check the accelerator cable and linkage first, just to make sure there is no binding any where... then maybe the tps


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## MikeL00 (Sep 17, 2010)

SPEEDO said:


> might check the accelerator cable and linkage first, just to make sure there is no binding any where... then maybe the tps



accelerator cable and linkage looked fine. 

I notice it only does this when the engine is warm, no hesitation at all when it's cold.

how do I go about checking the tps? am I looking for corrosion, dirty???


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## MikeL00 (Sep 17, 2010)

After two days of driving good it went into fail-safe mode again last night. Apparently disconnecting the battery will take the ecu out of fail-safe mode. I wish I would have checked for codes when it went into fail-safe mode. I disconnected the battery to reset it so I could get to work this morning. 

Just got home and checked for codes and got a 55. On the way home it did have that initial hesitation when giving it gas, even died on me while starting from a stop on an incline. I checked the connections on the o2 sensor, tps and maf, they were very clean but I gave them a litle shot of cleaner anyways. Question about the tps, there are three prongs on the tps and on my connector there are only two receptors looks like there should be a third, anybody have a pic?

Any other suggestions??? I'm hesitant to take it to a shop after spending $500 on new injectors that didn't do a damn thing.

Thanks again!


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## MikeL00 (Sep 17, 2010)

Bump

Anyone?


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