defwheezer

After putting up with this problem (bucking and hesitation upon acceleration once engine was warm) for longer than I am willing to admit, I've finally found the problem! It turned out to be nothing more complicated than a faulty EGR component (the back pressure transducer, see Haynes manual). For $50 I replaced it and viola- car runs like a champ again!! I have posted this for anyone else who may have had this same problem since I've seen 2-3 post in various forums regarding this exact issue with this yr nissan z24 4-cylinder truck.

Thanks to all in the truck and SUV forum who helped me with other ideas that helped finally pin-piont the problem.

cb

Algot

Where did you find the part? did you get it from your local parts store or did you have to go to a dealership?

thanks,
john

defwheezer

Had to go to the Nissan Dealer to get that part.

defwheezer

Actually, the problem did not really get resolved by replacing this part, it just went away briefly (strange!). After finally figuring out how to use the diagnosis feature on the ECM I found the problem was, according to my Hanes manual, in the "Throttle Position Sensor Circuit" (Code 42 on the #40 model ECM in my 24zi). Note that this ECM has "44" as the all OK code, not "55" as in some other models. I replaced the throttle position sensor (~$100, but very easy to replace!) and now the problem really seems to be resolved. Yee-haw. References:

http://www.240sx.org/faq/articles/th...or_adjustm.htm

http://www.nissan4wheelers.com/howto...djustment.html

TurboNissanPrerunner

I have a similar problem, It feels as if my motor cuts out then starts back up when im driving sometimes. Hey defweezer was your problem similar like this. I also have a 86 hardbody with the #40 ecu. I think it might be by ecu. Did you go to the dealer for your tps?

defwheezer

Hey,

I did have to go to the dealer to buy the throttle position sensor (~$100). I have been told that when the ECM is going bad, the car will actually die altogether. Easiest thing to do is simply read the error code(s) off the LEDs on the ECM as described above. Good luck! BTW- Neither my local mechanic or the Dealers' mechanics could figure this problem out for some reason (they never checked the ECM codes is my guess).

cb

TurboNissanPrerunner

Cool, thanks man. yeah i think my ecu is dead now cause the truck will start and stay running for about 30 seconds and then die. I just ordered a used one and will install it soon. Ill keep you guys posted. Ill also try to read the error code(s). Does any one know what causes the ecu to go bad, just currious.

defwheezer

What code(s) does the ECM flash before you start the engine? Or after it dies? (easiest way to check is to remove the passenger seat, only 4 12 mm bolts, and turn the ECM so you can look throught the little window where the LEDs are while you're in the drivers seat).

craZgirl

I have an 86 2 wheel drive with 237,000 miles on it. Same problem and I loaned it to a friend. Since reading your thread I also handed her a bpt valve I had on hand. She changed it and said so far so good. Living in California I have to get this truck smogged and I probably better do it soon. I hope I don't continue down the same bucking road you've been driving on. Other than the bucking especially in 1st gear, the truck runs like a champ. It's got lots of power. Thanks for tip on the bpt. I think this site is better than my Haynes or my Chilton manual. Luana

hymes2162

I have a v6 pu se, and it sounds like the same problem I am having...do you think it could be the same thing??? starving for fuel??? I dont have any men around and I need to figure this out so I have my transportation back.. I have already changed the fuel filter 2x and the fuel pump, once the truck warms up it stalls out...think you could help??? please reply to hymes2162...thanks Linda

craZgirl

Looks like it time to follow the lead of those who came before us. The bpt only cured my problem temporarily also.
Looks like it time to pull out the seat and follow the haynes manual for the codes. I'm just glad I have more than one nissan. I'll get to mine later. Good luck, Luana

1997XETruck

For a discount on OEM parts, be sure to check out one of our sponsors - or give Joe at www.everythingnissan.com a call at 1-888-216-5328. You can typically save 25-30% off of list, and Joe's a great guy to work with!

Defwheezer - how did you get the TPS adjusted correctly? On some cars they're pretty sensitive - does the Chiltons manual go in to some detail on ohm testing it?

Heath

__________________
1997 Nissan XE Truck - 133,000 Miles
1990 Infiniti Q45 - 91,000 Miles
2005 Infiniti G35 Sedan - 34,000 Miles

defwheezer

One of the reference links I posted in this thread explains in detail how to adjust the TPS. I got "lucky" in that it seems to work fine at the random position I installed it (there is very little rotational freedom to adjust it anyhow in this vehicle). Basically it should trigger (resistance goes from infinity to some nominal value) just as the throttle is depressed (i.e., is changed from "idle" position to any "giving it gas" position).

cb

motorider475

damn dudes.....and chiks......my 97 hardbody is bucking right off idle under low load partial thrittle openings.......ecm gives me a cyl 4 missfire code......this is after i replaced the EGR cause some boner at the local hammer shop told me it was broken....BAM 120 bucks.....then he told me he cheked resitance on my injector and it was bad.....POW 114 bucks.....SAME PROBLEM.......so was like, "dude....are you gonna fix it or throw parts at it....cause i can throw parts at it all day and not pay a shop fee?"......SOOO.....went home....replaced fuel filter ..ZAP...5 bucks...nada.....found wire to IAT sensor broken...WHAM 69 bucks...STILL misfireing......cheked spark and its good....replaced plugs...ZAP...MORE MONEY......just did cap and rotor like 6 thousand miles ago.....WTF!!!??? i need to do a compression check to make sure its not my piston or valves......but ???.....if i unplug the EGR vacuum line the truck runs fine.....ANY HELP!!?? this pile is costing me more than i have in my budget right now......AHHHHH!!!!PLEASE PLEASE PLEASE help me......i cheked my BPT valve like it says in the manual and it seems to be operating normally...HELP ME!!

1997XETruck

It sounds like the classic EGR symptoms... I had this with a Chevy S-10 and unplugging the EGR valve solved it. Just don't run it like that for any length of time - your combustion chambers will be too hot! Any chance the "boner at the local hammer shop" put on a crappy aftermarket part, or just didn't replace it at all?

You mentioned that you replaced plugs, wires, distributor cap, etc at some point. Did the bucking come after that replacement? Did you use Nissan parts? If not, I'd go ahead and replace them with OEM parts - Nissans seem to be very sensitive to OEM parts.

Once you've tried that, I'd go ahead and plunk down the $$ for a Consult diagnostic at a dealership. You've thrown enough money into this one with parts... time to find out what's really going on.

Heath

__________________
1997 Nissan XE Truck - 133,000 Miles
1990 Infiniti Q45 - 91,000 Miles
2005 Infiniti G35 Sedan - 34,000 Miles