Thread: Dead spot in acceleration?

The VE IACV does not look anything like the DE one according to the pictures in my Haynes manual and diagrams in my FSM ('97 B14). I also looked through eBay last night at all the Nissan IACV's listed there and did not see any that even resembled the one on my VE. I will get the Nissan Part Number off of mine and see if a stealer can recognize it. l believe that the internal parts can be cleaned to free them up.

My engine was installed in March and ran fine until a couple of weeks ago. Now it is flat until aboout 2500 RPM and then it takes off. It also bucks like mad when it is cold. I was just getting ready to start a thread about it when this one showed up. I plan to open up the idle screw to see if that helps.

gpsec can get you a new VE iacv..


the thing is the iacv's really suck balls on the ve's from what i've seen.. not sure why.. my car has similar issues while cold, an weather does play big part in how my car runs in the morning.. once shes warmed up she runs like a raped ape tho.. i think when winter time comes im going t ohave to start drivin the datsun again lol..

VE IACV from Gspec

Thanks. I looked in the SR20 section and did not see it. I set my idle to 1400 RPM last night and the car ran much better from stop, so I'm thinking that is the problem.

Definitely curious as to see any result or cure to this scenario. Mine does the same thing when the engine isnt to temp. Ive replaced the o2 sensor but not the IACV.

I'm going to try cap n' rotor, and o2 sensor first since i'm doing them anyways. THEN I'll replace the iacv. I do know there are iacv issues as well already because sometimes when I shift out of gear the car revs up then bogs then revs then bogs, like it's hunting real bad until the rev/bog levels out after 5-10 seconds of sitting at idle.

Mine does that as well canx2k, when i pull out of gear it hunts for the idle. Guess ill be replacing the IACV.

Maybe it needs cleaned?

Most of the cold engine drivability problems are from Nissan's warm up strategy. There are warmup maps and scales the ecu use when the engine temperature is below 149*F.
The engine is in open loop when the engine temperature is below 149*F, so changing the o2 won't help.

Below 149F/65C, the engine gets additional fuel and reduce timing to help warm up the engine. The timing stays static at 15 degree below 3k rpm and below a certain tp or load scale. That is why some have reported good accerlation after a certain rpm and throttle.

The hunting/pulsing result from the transition period between warm up and the normal timing and fuel maps . Right around 149F the engine jump back and forth between the two maps. The engine hunts because the timing goes from 15 to what ever the timing is in the main timing map and back again.

My solution was to lower the temperature of the off warm up temperature to 95F and reduce the cold start enrichment. Since our ecu is DE based for 259cc injectors, we have to reduce the cold start enrichment otherwise there is overfueling, and that result in a sluggish running cold engine.

lol great answer /\ I couldn't have said it any better... That's the best way to solve the problem

looks like i've got some tinkering to do ^^ hehe