V6 Engine Hesitates

Dragonwight · Post by **Dragonwight** » December 22nd, 2005, 11:37 am

Hi im new on the forum however ive had two V6 MX3`s great little cars however the current one I have has developed an annoying problem:

Basically it has started hesistating under load. The idle is steady at approx 600 rpm but the minute i accelerate it starts to bog down away from traffic lights and sometimes at high speed.

If i back off the throttle a little and then reapply it goes fine. Also seems too happen alot less first thing when the choke is open.

In attempt to solve this i have tried the following:

Replaced air intake hose which was split.
Replaced plugs they were quite carbon deposited i believe because the air hose was ripped leading to the wrong mixture?
Replaced air filter as was orrible
Put a new battery in as the other was on its last legs
Checked the disti cap there were some white deposits presumably from the electrical current. I gently removed these although the contacts had a slightly uneven surface dont know if this is the cause as the end of the rotor arm was nice and shiny and not badly worn.
Checked plug leads all sparking ok ( RAC checked these! LOL)
Replaced valve cover gaskets as the front one was leaking slightly.
Replaced fuel filter as the other one had not been changed.

I have checked the ecu for any codes none present. So im at a bit of a loss as when it does accelerate it really shifts.

Its a 95 1.8 MX3 V6 with no mods on 92000 miles.

pseudomarine · Post by **pseudomarine** » December 22nd, 2005, 11:53 am

not sure if this will help, but a couple of years ago my car would dip in revs at traffic lights. it was probably more acute when i pressed the accelerator.

It turned out that the bottom of the fuel tank was clogged up. i got it cleared out and got the fuel pipes cleaned.

Maybe just something to watch out for...

good luck.

vozaday2000 · Post by **vozaday2000** » December 22nd, 2005, 7:57 pm

try retiming your car.

bluemx3 · Post by **bluemx3** » December 24th, 2005, 9:45 am

It sounds like you've checked or replaced just about every major component of the engine. Try Seafoam, it might not solve your problem, but it might be an inexpensive fix and it certainly can't hurt. On several occasions I've run into a deadend in solveing a problem and Seafoam helped or at least it doesn't hurt. I've seen it clear up alot of strange stuff.
Also, after you use it, you'll know your fuel system/injectors are clean and your valves should be cleaner.
If that doesn't work, recheck for air leaks. Start the car and let it idle, spray WD40 or something like that around all the areas of the engine that might be able to leak(gaskets,hoses,etc.) If the idle changes up or down, you may have a small hole or air leak. Good Luck

hgallegos915 · Post by **hgallegos915** » December 24th, 2005, 3:11 pm

Mine was doing this around one month ago, it was a bad distributor. I replaced everything new, dplugs, wires , fuel pumo, injectors and rail, cheked harness all the way, compression test.. last thing was disty and yup it was the ignitor going out. it was the saem as u.. as soon as i would acelerate it would bog but after i would let go of the gas it was doing fine.

jschrauwen · Post by **jschrauwen** » December 24th, 2005, 5:42 pm

bluemx3 wrote: recheck for air leaks. Start the car and let it idle, spray WD40 or something like that around all the areas of the engine that might be able to leak(gaskets,hoses,etc.) If the idle changes up or down, you may have a small hole or air leak. Good Luck

WD40 may not be as good a choice as either water mister or butane vapours. You're looking for a definate change to the running of the engine (higher or lower revs) based on a possible air/vaccum leak when introduced to an accellerant or retardant. Spraying butane vapour very closely to each of your lines and observing a noticeable increase in revs, then you've pinpointed the faulty area. Conversely, using a water mister in the same manner will generate the reverse effects achieving the same results. However, the butane is much more effective and easier to focus with, FWIW.

Dragonwight · Post by **Dragonwight** » December 30th, 2005, 5:45 am

Thanks for all the replies guys weather has been bloody freezing at the moment so not really been under the bonnet too much. I have never tried tried Seafoam although i have used injector cleaner on it. Ill have too look into that one. From what i have read on the subject i would have thought if it was a failing ignitor issue then i would have problems actually starting the car.? I think im going too persue the vacaum leak idea as i can here some hissing under the bonnet not sure if this is normal or not. (just air in the pipe noise) So soon as the weather warms up ill start looking at that. Ironically the cold weather seems to have improved it as it hasnt hesistated at all today.

lakersfan1 · Post by **lakersfan1** » December 30th, 2005, 10:31 am

When my kids hesitate, I hit them with a belt. Try that and let us know how it works.

Dragonwight · Post by **Dragonwight** » December 30th, 2005, 11:01 am

A timing belt by any chance?

lakersfan1 · Post by **lakersfan1** » December 30th, 2005, 11:06 am

Dragonwight wrote:A timing belt by any chance?

No. But I did give my 5 year old a timing belt to bring to show and tell on letter 'T' day.

Dragonwight · Post by **Dragonwight** » December 30th, 2005, 11:41 am

And the "T" stands for?

lakersfan1 · Post by **lakersfan1** » December 30th, 2005, 12:01 pm

Dragonwight wrote:And the "T" stands for?

Timing belt ???????

jschrauwen · Post by **jschrauwen** » December 30th, 2005, 12:19 pm

lakersfan1 wrote:
Dragonwight wrote:A timing belt by any chance?
No. But I did give my 5 year old a timing belt to bring to show and tell on letter 'T' day.

Good thing you didn't give em a transmission.

Dragonwight · Post by **Dragonwight** » December 30th, 2005, 12:24 pm

Right

Fortunately my "TB" day was a while ago so thats been done and checked.

lakersfan1 · Post by **lakersfan1** » December 30th, 2005, 1:23 pm

Dragonwight wrote:Right Fortunately my "TB" day was a while ago so thats been done and checked.

I'm sorry to hear that. I hear Tuberculosis can be hard to get rid of.