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-   -   Car hesitation problems (http://www.houston240sx.com/showthread.php?t=71604)

smolka 08-25-2014 03:42 PM

Car hesitation problems
 
So I got a kade here that has a hesitation problem at low rpm under low throttle. For example this usually happens in 5th gear around 2500 rpm and giving it 10-30% throttle. The car just doesn't want to budge past the rpm it's in, but if I give it half throttle or more it clears up. Also, this doesn't happen all the time and it does it in just about any gear. Parts I replaced: CTS, adjusted tps and made sure it's getting correct volts, injector o-rings, cleaned maf.

Only mod is it has a ram air and aftermarket cat
Also got new plugs, wires, and fuel filter on the way. Doubt that's it

I have a feeling it may be knock sensor, dying injector, faulty maf, faulty tps, or faulty wiring harness/ground issue.

If anyone has had this prob before please lmk

z31dude 08-25-2014 03:57 PM

dude, get out of s-chassis, they are not for you.

smolka 08-25-2014 04:08 PM

Me getting out of an s-chassis is like you getting out of being fat. Just not gonna happen

z31dude 08-25-2014 04:37 PM

after these past 4 days, it looks pretty likely.

Ilya240sx 08-25-2014 05:53 PM

check ecu for codes.

1stock240 08-25-2014 06:44 PM

Funny that's like the exact opposite of what mines doing. Good at part throttle up to about 25-2800 rpm. Give it more than about 30% throttle on gas pedal or go above 2500 rpm car just starts pulsing and acting like it wants to cut out. Happens more in 2nd -4th but will act up in any gear depending on throttle. Take it out of gear and it'll rev to about 4k with no problem. Unfortunately with mine and yours symptoms there doesn't seem to be that exact know what the problem is based on the symptoms. It could be any number or combination of things. Kinda sucks because google gets you no where. No one ever cra back with a resolution.

Ilya240sx 08-25-2014 08:45 PM

Both of you need to check your Fuel Pressure by installing a gauge on the return of the fuel rail.

Also need to check your maf for voltages, resistances.

Also check what your spark plugs look like, if there are any oddballs or if they are old or dont look right

Stinetime 08-25-2014 09:50 PM

never mind my post. didnt see you tested TPS

1stock240 08-25-2014 10:58 PM

Going to start diagnosing tomorrow. Shift work sucks. I'll be getting off a 7am tomorrow. Few hours of sleep then flip back over to a day schedule.

PacS14 08-25-2014 11:30 PM

For both of you there might be more than just one thing wrong with it since these are old cars now:
1- MAF not just clean it, open it and check the contacts inside, solder them if need to, or do it just in case.
2- knock sensor, if your MAF tripped even if it was just temporarily and the knock sensor was bad already it can cause the issue you both experience, you can test by unplugging your knock sensor, then resetting the computer even if there were no codes, with a scan tool none of that unplug the negative or whatever crap that will not completely work.
3- AICV valve in the back of the manifold plugged or dirty, a quick way to clean is just unplug the vacuum hose and hit it with carb cleaner or brake cleaner while the car is running, the put the hose back on and see if it made a difference.
4- vacuum leak somewhere, if you have never replaced all the vacuum hoses now is a good time to do it, actually this should be number one.
5- somehow the timing skipped, check just in case also check distributor cap and rotor.
6- with these older cars instead of just replacing parts try to narrow it down by troubleshooting. And on these cars a MAF circuit board will hardly ever go bad most times is just dirty or the contacts inside separate enough cause it to fail.
7- if you still can't fix it sell it to me I'll give you $500 on the spot for your car

z31dude 08-26-2014 09:02 AM

Quote:

Originally Posted by PacS14 (Post 1029690)
For both of you there might be more than just one thing wrong with it since these are old cars now:
1- MAF not just clean it, open it and check the contacts inside, solder them if need to, or do it just in case.
2- knock sensor, if your MAF tripped even if it was just temporarily and the knock sensor was bad already it can cause the issue you both experience, you can test by unplugging your knock sensor, then resetting the computer even if there were no codes, with a scan tool none of that unplug the negative or whatever crap that will not completely work.
3- AICV valve in the back of the manifold plugged or dirty, a quick way to clean is just unplug the vacuum hose and hit it with carb cleaner or brake cleaner while the car is running, the put the hose back on and see if it made a difference.
4- vacuum leak somewhere, if you have never replaced all the vacuum hoses now is a good time to do it, actually this should be number one.
5- somehow the timing skipped, check just in case also check distributor cap and rotor.
6- with these older cars instead of just replacing parts try to narrow it down by troubleshooting. And on these cars a MAF circuit board will hardly ever go bad most times is just dirty or the contacts inside separate enough cause it to fail.
7- if you still can't fix it sell it to me I'll give you $500 on the spot for your car



lmfao, #7 I love it.

smolka 08-26-2014 10:36 PM

Noticed it happens a lot worse when engine is warm. Doesn't happen with 5 min of starting the car

PacS14 08-26-2014 11:38 PM

I hope you consider my #7 recommendation lol

darkdrifter11 08-27-2014 01:13 AM

I remember when my car use to not rev up past 2.5k rpms it struggled a lot to get to 5k. Found out after replacing spark plug,wire, distributor cap, fuel pump, fixing timing, etc. Only reason was cause I was getting to much air to my air filter from not having that fan shroud so I just got a oem one and now it pulls hard through all rpms. Hope this helps yall. But I'll take #7 recommendation seriously ;) lmao

_LJ_ 08-27-2014 08:04 AM

Quote:

Originally Posted by darkdrifter11 (Post 1029807)
I remember when my car use to not rev up past 2.5k rpms it struggled a lot to get to 5k. Found out after replacing spark plug,wire, distributor cap, fuel pump, fixing timing, etc. Only reason was cause I was getting to much air to my air filter from not having that fan shroud so I just got a oem one and now it pulls hard through all rpms. Hope this helps yall. But I'll take #7 recommendation seriously ;) lmao

Really too much air to your air filter caused it to run bad? and a plastic shroud fixed it?



Have any of you checked your STARTER.......?



old skools will get that!

smolka 08-28-2014 08:16 PM

so i replaced my 5spd ecu with an automatic one and the car hasnt hesitated yet after a full day of driving it like this.
also, before doing this i realized it has an auto harness and unplugged the second plug on the tps with the 5spd ecu and it made no difference. why is it that the car runs normal with auto ecu but not the 5spd

PacS14 08-28-2014 10:49 PM

ECU is supposed to match the harness that's why... I would say most people that do a 5 SPD swap keep the auto harness and ecu. If your car ran good for a while with those two mismatched that was an accomplishment of its own.

1stock240 08-29-2014 06:34 AM

Maybe your ECU was going bad. I did all the tune up shit, cleaned maf and TB. Feels like it's definitely leaning out under load. Leaning towards fpr or fuel pump not keeping up.


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