Problems when accelerating

ManoWar · Post by **ManoWar** » November 5th, 2007, 5:03 pm

Alright, here is the deal. I have a 93 MX3 V6 and a 94 MX3 V6.

My 94 is a rust bucket so i moved to this 93 which belonged to my sister.

Now she had some probs with the distributor in the past and she changed it with an aftermarket one that only lasted her for 5 months. The car suddently died and it would not start up again. Checked to see if she has spark and no spark to be found.
Today i bought a japanese original (after checking that the one of my 94 does not work) and slapped it on.

Due to the fact that there where no marks on the disty (obviously it was new) i've installed it and centered it on the 2 bolts. The car started up and i took it for a test drive. The car under heavy acceleration just feels like its chugging (SP) and actually de acelerates for a split second before it starts accelerating again. I manually adjusted the timing figuring that it might be that but i remembered that my sister was also complaining about some acceleration issues prior to this whole ordeal. Anyhow i adjusted the timing by ear until the engine was running the smoothest and i got zapped pretty bad in the process. Now the acceleration issues are still there and my attention is turning towards the spark plug wires. (How else did i get zapped if not due to faulty spark plug wires. But unfortunately the local auto store sells em for 200$, too expensive in my opinion!

PS: SPark plugs have just been changed and gapped accordingly!

What else should i check?
Fuel pump?
Maybe my timing is still off?

Any help will be apreciated!

Kirk95gs · Post by **Kirk95gs** » November 5th, 2007, 5:29 pm

old fuel??? dirty fuel filter??? any idleing issues??

ManoWar · Post by **ManoWar** » November 5th, 2007, 5:59 pm

Kirk95gs wrote:old fuel??? dirty fuel filter??? any idleing issues??

idles perfectly . fuel filter was changed aprox 2000km's ago

Tunes67 · Post by **Tunes67** » November 5th, 2007, 6:05 pm

I'd replace the plug wires. You can get a set off of Ebay for $75-$100 for a Probe GT or a MX-6.

Next I would run a couple of bottles of fuel injector cleaner through the next few tanks of gas you do and see if that seems to help things.. if it does.. I'd get the fuel injectors flow tested and have them rebuilt if neccessary.

Tunes67

Kirk95gs · Post by **Kirk95gs** » November 5th, 2007, 6:30 pm

I'd replace the plug wires. You can get a set off of Ebay for $75-$100 for a Probe GT or a MX-6.

Next I would run a couple of bottles of fuel injector cleaner through the next few tanks of gas you do and see if that seems to help things.. if it does.. I'd get the fuel injectors flow tested and have them rebuilt if neccessary.

Tunes67

x2 .... plug ends could be cracked... dirty injector...

Post by **Mooneggs** » November 6th, 2007, 12:02 pm

Tunes67 wrote:I'd get the fuel injectors flow tested and have them rebuilt if neccessary.

x2 I had this issue once and I replaced everything and finally I swapped in some newer injectors and walahh problem solved.

shameem · Post by **shameem** » November 6th, 2007, 12:58 pm

You have to jump TEN->GND before setting timing...... Otherwise the computer will set it back to where it was originally....

ManoWar · Post by **ManoWar** » November 6th, 2007, 2:36 pm

shameem wrote:You have to jump TEN->GND before setting timing...... Otherwise the computer will set it back to where it was originally....

Ya i noticed that.

i didn't know at first what was up and then i figured i should put it in diagnostic mode!

ManoWar · Post by **ManoWar** » November 6th, 2007, 8:12 pm

Ok i took the wires of my 94 and found that the problems are almost gone.

The issue i have is that from idle if i press the accelerator all the way to the floor the car stumbles a bit then starts accelerating and it barely is able to reach the red line.

Timing?

shameem · Post by **shameem** » November 6th, 2007, 9:25 pm

Here are some keywords to search...

vacuum leak
Clogged injector/fuel filter
TPS adjustment
HEI mod
O2 sensor

etc etc etc

ManoWar · Post by **ManoWar** » November 7th, 2007, 8:24 am

thx shameem

-Vacuum leak - i've checked for leaks and i can safely say that from the throttle body to the filter i have no issues.

-Fuel filter has been changed a month ago
-Injectors have not been checked
-TPS has not been checked will check it soon.
-HEI mod will be done at a later day, i dont think its the disty anymore.
-02 sensor should be fine (ECU shows no codes)

PS: Connected to the stock air box there is a switch with a mitsubishi sign on top of it with a rotating head. It has some hoses connected on it. I could not find what that is. Does anyone here know?

ManoWar · Post by **ManoWar** » November 7th, 2007, 8:27 am

found out what it is

http://www.mx-3.com/phpBB2/viewtopic.ph ... shi#417157

PRC valve , i screwed around with that since i did not know what it was, its still connected but i twisted the head around. Anyone think that might be it?

OldMan · Post by **OldMan** » November 7th, 2007, 11:30 am

You might want to check the screen at the bottom of your fuel pump.

OldMan

shameem · Post by **shameem** » November 7th, 2007, 4:03 pm

For checking invisible vacuum leaks - spray wd-40 or carb cleaner or something like that around the intake tube while the engine is idling - if the idle changes then there is a leak (the carb cleaner is getting pulled through the leak.
Sometimes there might be cracks that will open only when flexed - it will be all normal at idle or low speeds but under heay load (heavy engine flex) the crack opens and allows unmetered air in causing the fuel mixture to lean out.

Also run a few bottles of fuel system cleaner and/or injector cleaners with the next few fillups. (I like seafoam for this job bu regular stuff works too).

One problem that gave me a hard time - some idiot at an oil change place overfilled the oil and it was getting into by TB everytime i accelerated hard causing the fuel mixture to go bad. The funny thing is the dipstick didnt show me that there was excess oil.

Our ECUs are not very good with codes for O2 sensors - unplug the O2 sensors and drive around to see if it will actually give you a code....
The recommended change interval is every 60000 miles i think....

Twisting the PRC valve head shouldnt be a big deal unless there is a leak....

Also there is a FAQ (by tunes i think) on setting your TPS -