Thread: Weird hesitation issues??

Hey guys,

First of all, hello! Im new to the forum as you can see and I look forward to getting to know some of you and get my SE-R running well again. Hopefully, you guys can help me with this hesitation issue...here we go...

The car is a 1996 200sx SE-R, auto, no mods, 100k. All of this started a while back when I got a check engine light and noticed the engine was bucking under part throttle and hesitating. Check the codes and it came up with an EGR function code. I went under the hood and disconnected the EGR vavle and the car ran totally fine for a while until the hesitation returned a month or so later. Fast forward a bit, I put a new EGR valve in the car, cleaned all related parts, and the car did the same bucking under part throttle and hesitating under acceleration. So, I disconnected it again. The hesitation is still there and the EGR issue is still there. Does anyone have any ideas? Im frankly all out on the EGR issue. The hesitation could be the MAF or the TPS but usually those parts are in a "work or do not work" state meaning the sensor either works or does not. Guys, I need your help!!

Thanks in advance everyone,

Ryan

My first suspect would be the O2 sensor. WOT it's fine right?

For the most part but the car does seem to be way down on power at WOT. The hesitation is less noticeable at WOT than at POT. Also, I think I figured out the problem with the EGR part of the equation. If I disconnect the vacuum hose from the fuel purge canister the bucking stops. I think there is an internal vacuum leak in the purge canister or a clog of some kind. Keep the ideas coming guys...we may help a lot more people than myself in the end!

Thank you,

-Ryan

check out my strange constant velocity issue thread - that's all the researched things you can to do check for your hesitation. It's in the 'general sr20' section.

Thank you, I will do that!

-Ryan

Knock Sensor?

Check your EGR passages ... I see it alot on these ..just fixed it on my 99 B14 ... all but one of the passages in the EGR get plugged in the manifold ...so when your at Part throttle and the EGR opens it kills that one cylinder thats getting all of the EGR ..... You can test it by hooking up a vacuum pump to the EGR valve , slowly give it vacuum and if it kills just one cylinder thats your issue ... the engine should run rough with EGR open at idle , but it should be all 4 cylinders rough , not just one ....

EGR and purge use the same vaccum line so if you unhook that line while its running , your unhooking the EGR also ...

To fix it you pull the upper intake plenum and remove the big allen plugs in the lower manifold then run a small screwdriver through the holes and vacuum them out ....

Tried that, its has to do with the EGR valve opening and closing. When the EGR valve opens the engine bucks and hesitates, if it stays closed the engine runs very smooth. What is going on?

-Ryan

replace your egr dude -they're cheap.

Take the top hose off the bpt (still attached to the egr) and suck on it when the car is running. If idle boggs, it's fine. if not, then you know it's stuck. You can pull it off and clean it, but in my experience, just replace it for the $35. Did you clean the bpt valve yet? that should be done same time as replace of egr.

It has been replaced, now I think it has to do with the EGR Temp Sensor getting a faulty reading and causing the EGR Vacuum Solenoid to open prematurely and causing the bucking. Now I just need to replace the coolant temp sensor and the knock sensor and we should be good to go!

Thanks for the reply though!

-Ryan