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Discussion Starter #1 (Edited)
I just helped my roomate rebuild a 1987 nissan sentra with the 1.6L and the carb. The car starts good and idles fine, but it will not rev past about 4000 rpm

Symptoms:
1.) Slowly depressing the gas pedal the car will rev to around 4000 rpm, but will not go past.
2.) Flooring the gas pedal will cause it to rev to about 3000 and then stumble and stay around 2300-2500 rpm.

Things that are new:
Distributor cap and rotor
plug wires
air filter
fuel filter
reman head
rings
seals
bearings


I also checked the oxygen sensor and it seems to be operating properly. Has anyone else had symptoms like this? If so what was wrong?

Otherwise: what else should I check? I am stuck here

One more thing to add: I have not checked the compression, but the car will run on any one of its cylinders so I assume that is not the problem
 

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Viva el iPod
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Carb'd cars don't have MAF sensors, although it may very well be a problem with the ECC (electronically controlled carburator) system. If you are not worried about emissions (or you do not have restrictions), and it is indeed ECC, swap your carb out with something not electronically controlled, like a Weber 32/36.

YOu might have a problem with your ignition system though, so check your distributor, coil, etc.
 

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1987sentra said:
I have started looking at the car a bit more and it is single port fuel injected.

ahh...the lovely TBI. Yeah check idle air control and maf. and ditto on checking ignition system...could be timing is a bit off.
 

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Ex-mod/nissan guru
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Maf sensor is shut. i always have a spare myself in the car but if its staying at 2300-2400 when you floor it ... its the maf... but it shouldnt go past 2500 anytime... its a fail safe from the ecu.
 

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Nissan Junkie
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I have fucked with this problem a long time and have no damn Idea what it is I have changed out the maf twice and just about everyting else on the TBI cept the IAC but I have unplugged it I also changed the distributor no help I think my t-belt may be on wrong making the cam to advanced or retarded I still need to check that I should do it today but I am lazy. I also get no codes in the ecu. I hope this helps some.
 

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Discussion Starter #8
Crazy-Mart said:
Maf sensor is shut. i always have a spare myself in the car but if its staying at 2300-2400 when you floor it ... its the maf... but it shouldnt go past 2500 anytime... its a fail safe from the ecu.
If I floor it it will spike to around 3000 and then settle around 2300- 2500. However, if I gently depress the gas pedal it will make it up to around 4000 rpm before it will not go any further.

Also, I have rechecked the base timing and it is correct, I have checked most of the ignition system and replaced cap, rotor, wires, spark plugs (and gapped them properly).

I am going to pull codes off the ECU today and then I will test the airflow sensor with the method from the haynes manual. I'll let you all know what I find.
 

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Discussion Starter #9
Well, the ECU had no codes...

However, the haynes manual had a method for testing the air flow meter and using that it appears that it is dead. Where is the best place to get another one- nissan dealer, pick-your-part, etc?
 

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pick-your-part : and if it fits in your pocket : its free.... at the dealer if i remember correctly it was around 350$.
 

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Discussion Starter #11
I'll be checking pick-your-part tomorrow (and Bucks auto parts here in Calgary) I phoned the dealer for a price and they want $275. So hopefully I can find a used one (sensors are $7 each at Bucks)
 

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Discussion Starter #12
OK, I found one at pick your part but I haven't been able to check it yet. However, I put it in the car and the car is running the same as before. The only other evidence I have now is that the car is running pig rich. The exhaust is blue and it has turned the end of the exhaust pipe and the floor underneath to black. Is there anything else that could cause this rich condition? Or is running very rich a typical symptom of a failure of the air flow meter? Thanks in advance.
 

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Discussion Starter #13
Just to let everyone interested know... the problem is fixed. The vacuum line which runs to the air injection valve (off the side of the intake) was not connected.
 

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Hi, I don't suppose you still have your spare sensor? They are all but impossible to find here in central WI. The yards don't keep anything past 1990. My TBI Sentra gives me the 'bad MAF sensor' code, but I haven't been able to locate another sensor since the car started misbehaving in early January.
Please let me know,
Thanks.

Horseshoe
[email protected]
 
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