# 88 Sentra will not idle, Please Help!



## jstollfu (Nov 17, 2004)

I have a 88 Sentra 1.6, 4 speed, it has 132,000 miles on it. The car will start right up, when the idle starts to level out after start it will surge up and down from an almost stall to a idle of 2500rpm, it will do this for a few seconds then it will die, when driving it will die when the clutch is depressed. It has a new fuel filter, new plugs. I have checked for vacuum leaks and there are none evident. I cleaned the Idle by pass valve. Can any one help??? Bad idle motor? Bad TP sensor? any ideas?? Thanks! 

It could be EGR... Maybe I'll just block it off as a test? I don't have to pass any emission tests in my area so who needs EGR!! Does anyone know why the sensor on the side of the throttle body that looks like it could be the throttle postion sensor have two connectors? is one a throttle postin connector and the other a closed throttle sensor? 

Let me expand on the symptoms. It always starts right up after it stalls, The idle speed will increase after start up, then the idle will lower. When the idle speed lowers, to what should be the normal idle speed, it starts to surge up and down. From a almost stall to a high ilde RPM of maybe 2500 RPM or so. It continues with the surge for a min or two, then it stalls. When driving if the clutch is depressed it will not idle, it stalls, but again it always starts right back up. Can flash codes be pulled from this car? If so, how it that done? It does not seem like a vac leak, I have checked for vac leaks with carb cleaner and could not find any. Does any one know of any common vac leak areas on the 1.6L?? It seems like the idle by pass solinod/valve is not responding correctly, I took the idle valve off and cleaned it, it was a little dirty but not bad. Is the idle motor a stepper type motor? or is it Pulse width modulated? I jumpered power to it and it opens and closes electrically. But I'm still not sure how it is supposed to work.. Any ideas?? Anyone... Help Please!! 

Thanks!! Josh...


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## greenbean699 (Jan 18, 2004)

jstollfu said:


> I have a 88 Sentra 1.6, 4 speed, it has 132,000 miles on it. The car will start right up, when the idle starts to level out after start it will surge up and down from an almost stall to a idle of 2500rpm, it will do this for a few seconds then it will die, when driving it will die when the clutch is depressed. It has a new fuel filter, new plugs. I have checked for vacuum leaks and there are none evident. I cleaned the Idle by pass valve. Can any one help??? Bad idle motor? Bad TP sensor? any ideas?? Thanks!
> 
> It could be EGR... Maybe I'll just block it off as a test? I don't have to pass any emission tests in my area so who needs EGR!! Does anyone know why the sensor on the side of the throttle body that looks like it could be the throttle postion sensor have two connectors? is one a throttle postin connector and the other a closed throttle sensor?
> 
> ...


You can try and adjust the throttle position sensor if it has one. You can also see the codes of the computer by taking a small flat screwdriver and turning the idle adjusting screw on the back of the computer. Make sure the key is on and then you have like 6 modes u can select. The both green and red lites wil blink at the same time. If you want it in mode 1.....let it blink once and then turn the screw back quickly to see the code given then. Hope this helps


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## Slacky (May 31, 2004)

will it rev up?


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## jstollfu (Nov 17, 2004)

Where is the computer located? I guess I'll have to break down and buy a shop manual. can anyone suggest a decent manual? Haynes?? 

It does rev up just fine, in fact In drove it 120 miles on the highway the other day with it not idling right. And it still has decent power, and got 32 mpg... So I don't think its a base engine problem.. I need to understand more about how the electronic control system works on this car to figure it out..


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## Crazy-Mart (Jul 14, 2002)

youll be better to get the FSM for the sentra b12 then ... the haynes doesnt cover the electronic part as well as the FSM ... i suggest looking on Ebay as the dealer will be expesive IF they still have some ...


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## jstollfu (Nov 17, 2004)

Yea I was thinking of looking for a factory manual as I know those aftermarket books don't offer a lot of daig information, more of just how to take it apart and put it back together info... 

Anyone have any further suggestions on the idle problem???


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## Slacky (May 31, 2004)

im not sure but there is a write up on how to put the ga16i throttle body on which would be a good upgrade and btw the computer is under the passenger seat, just put the seat all the way back on the rails and take the front cover off with 2 screws to get at the plugs and i have a computer if yours is bad then again so would your local pick and pull junkyard


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## jstollfu (Nov 17, 2004)

Well I put the throttle body back on last night. I plugged off the EGR tube, And it still has the idle surge. When I 1st started it cold, the idle raises and maintains, but it seems like once it warms up and goes into closed loop?? It starts to surge. It sure seems like it just sputters and shuts off the fuel.. I unplugged the vacuum line ot the fuel psi regulator and it did not seem to make a difference.. How does the fuel PSI regulator work on this car? A drop in Vacuum should be more fuel PSI?? I'll try to check for codes this weekend.. Any other suggestion?? I'm gonna figure this thing out... Josh-


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