240 hesitation and yes i have searched already.

[blazincat]

Before ignoring me or flaming me I have already searched and read everything I can find. Ihave also posted in the 240 tech forum. All that being said 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.

This is where I searched and everyon said the MAF was the problem. I got a new MAF 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 starts to bog 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.

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

Thanks ahead of time. Steve

[Acecool]

Did you check the ecu twice?

The first time you check it, it shows any stored error codes, the second (you turn engine key to off, then back to on, initialize and then it should show new ones)

I had that problem, except it got stuck around 2500 rpm..

Start the car, and take each injector plug off seperatly, one at a time.. Does that change the idle or cause it to stall?

Notice no difference? That fuel injector may be bad..

When was the last time the fuel filter was changed?

[blazincat]

I didn't know that about the ecu. I will check it tomorrow twice tomorrow.

I did the injector check and the engine just about stalled for each time I disconnected one.

The fuel filter is a few month's old. I did a full tune-up when I got it.

Thanks for the info. Steve

[Acecool]

Ok, try this then, get a cane or something like a stick you can use to rev your engine to about 1500 RPM.

Then try disconnecting each one, one at a time..

Should start sputtering bad if they work..

[smokin240]

Could be spark plug wires or bad grounding. I had both of those issue's with my ka24de that caused serious sputtering. Good luck man.

[blazincat]

Ok so my car still has issues.

I got a friend to idle it at 1500 and at 2200 and I disconnected the injectors one at a time and it ran worse each time.

I have checked the ground and have actually added another ground from battery to frame to engine block.

The plug wires read good with my meter and are only a few months old

I checked the ECU about 10 times and every time it came up 55 which is no codes stored.

Any more suggestions, guesses, anything??????????

Thanks

[Acecool]

Try this

Open the hood at the auto parts store and buy two plugs (in one pack) OF HELP! plugs, rubbery things, ask the guy for the right size...

Take the tube off the AIR INTAKE that goes to a small black box..

Take the clamps and put them around the plugs then refasten the plugs and put the hose in the truck incase you need it..

Does that sort you out? I will take pics later.

[blazincat]

I will get the plugs tomorrow and put them on and I will post back the results.

I know what little black box you mean, but what is it and what does it actually do?

[smokin240]

Check your fuel pressure and make sure your timing isn't f'd up. Could be something in the rotor too. Check the metal tabs inside the rotor, make sure there's no build up of any type.

Do all those things, if they are f'd up then they cause your exact symptoms.

[rotorimp]

OHM the tps to make sure it is working. It can definitely cause this problem.

[blazincat]

I got the rubber plugs and installed them and the car still runs the same.

This weekend I'm going to check the fuel pressure, EGR, TPS, and some other sensors. I'm also going to replace some vaccuum lines that are starting to crack.

Thanks for the help and keep the good info coming.

[essjedix4]

well i kinda had this problem to have u thought about the front or rear resonator being plugged cuz i was having hesitation probs on my 95 240sx and the more i pushed the gas the slower it went untill it released and i put a new catback exhuast and that fixed the problem for me so that might be sumting u shuld look at

[Clearalbino]

My 95 is doing the same thing, its getting very frustrating.

[rogoman]

The CAT may be plugged up.

Here's a way to test for a plugged up CAT:Connect a vacuum gauge to a good vacuum souce. At idle, the reading should be around 20 InHg. Start raising the RPM; a gradual drop in the vacuum reading from idle to higher RPMs, indicates excessive back pressurein the exhaust system.

[blazincat]

I checked the CAT the easy way. I removed the exhaust system at the downpipe / CAT. It is held together with two bolts. Anyways the CAT didn't look clogged, but I wanted to hollow it out anyways so I went to work on it with a hammer and big flat blade screwdriver. After that I made sure everything was out and bolted it back up. Unfortunately it didn't help.

[slipnfall]

Definately check into your EGR: while idling, manually pushing on the EGR diaphram should kill the car.

Disconnect the EGR(single vacuum line) and take it for a test drive. Your EGR control valve may be fudged(I'm pretty sure the KA24E has a BPT valve).