won't go over 3000 RPM

[blazincat]

Please help I have a 1990 240sx with the ka24e motor. The car starts fin but idles a little rough. The real problem is when you push the gas, in neutral or in gear, the rpms start going up but around 3,000 RPM the engine starts to hesitate. The farther the gas pedal starts to go down the worse it gets and the RPMs start dropping.

I took it to a nissan dealership and they looked at it and told me to replace the fuel injectors and the swirl control valve. I did this and it did not fix the problem.

I am lost and need direction. Any help would be appreciated.

Thanks ahead of time. Steve

[teddy]

A swirl control valve lol? I've never even heard of that.

More than likely it's a maf related issue. That's the key symptom of a bad maf or the maf wiring is wrong. In your case, if there's something wrong with the wiring, it's probably something that got corroded or came loose. If you have a voltmeter, check the voltages of the wiring to the maf.

[180fan]

the 24e should have the swirl control valve, near the bpt and egr and some other solenoid that I forget the name of. If it's the scv, I think it's got lines that run to your egr which would cause it to stumble, but wouldn't limit you to 3k. I'd suggest you look at your mafs and complain to that dealership.

[popogto]

a loose maf connector may cause the ecu to go into fail safe mode which wont let you rev higher than 3k

[let5l1de]

I agree MAF. disconnect batt. & maf connector. turn on headlights (or try to... lol) to drain system of energy stored. Reconnect everything and let it run throughout the initial start up stage to hot idle stage. May take a few min. If not fixed, I have a MAF avail

[blazincat]

I got the MAF today and installed it. It helped. The car idles alot smoother but it still has the problem. It still won't go over 3000rpm. The engine rev's up slowly and around 3000rpm it bogs down and the farther I push the pedal the worse it bogs down. I checked the ECU after changing the MAF and it didn't give any trouble codes.

Does anyone have anymore suggestions.

Thanks Steve

[teddy]

did you get another ka-e maf..or a ka24de maf?

[blazincat]

I don't know for sure. I ordered it through partsamerica.com. The website asks for the year, make, then model and then it automatically selects L4 2.4L. I am hoping that since the 240didn't come with the ka-de that year that they sent me the ka-e which is what I need.

Any suggestions on how to find out?

[blazincat]

I contacted partsamerica.com and they said it was the right MAF. I have tried checking the ecu and all I get is 55, no trouble codes. I have checked the injectors and injector wiring by disconnecting it while car running, one at a time, and the car almost cut off for each one.

Does anyone have anymore ideas about my problem? PLEASE HELP!!!!!!

[bb4_96]

Did you think about checking for a fault code on the ECU? If the ECU is in safe mode it'll be happy to tell you why.

[blazincat]

checked it and only code was 55.

[ricebike]

you should get your diag $ back from the dealership, then...

check for vaccuum leaks?

reset ecu when you installed new MAFS?

there's also a sticky to check for the various emission control devices on the engine... like teh air regulator valve...

check coolant temp sensor/plugs for corrosion...

but since you have code 55... guess you concentrate on vac / intake tube leaks... mebbe check the physical condition of the engine via compression leakdown tests mebbe? <shrugs>

[blazincat]

I found a couple of cracked vaccuum lines. I'm going to be replacing them this weekend and I am also going to do a compression test.

I'll put the results as soon as I have em.

[grnsilvia]

I had the same problem. The car would start up fine and idle a little rough but once i'd push on the gas in neutral the tach would rise fine. Take it out on the road though and the car would fall on its face. I got a used mafs from a friend of mine and installed it (as well as replacing the fouled plugs) and it runs...kinda. Only problem now is that when it gets into boost the car falls on its face again. I'm hoping its because the gas inside is about 8 months old and after I run the tank dry and put fresh gas in with new spark plugs it will resolve the problem.

I read on another post that people w k&n airfilters have been getting clogged mafs from the oil.

[grnsilvia]

Found out that the when the engine torqued the alternator was grounding out on the hard line for the power steering system and it was grounding out the whole car. I now have no power steering but at least my car is running a lot better.

[StuntingShaggy]

Tell you something about the significance of vacuum lines. When I replaced my stock intake with a bolt-on I left one of the sensors off on accident. I started the car but no matter how slightly I tapped the throttle it would die. Make sure ALL your vacuum lines are secure and in good condition.