Hesitation under acceleration, UPDATE, FIXED!!!!!!!

[mellow65]

Ok I have a 5 speed 4x4 93 Loyale, it runs absolutely great except for one thing. There is a hesitation when accelerating. It feels just like when the AC pump flips on but i know its not that because it happens when that is turned off. It's not like a cylinder it cutting out and runs rough, it just losses power. I just did a full tune up plugs, wires, cap, rotor, fuel filter, air filter, the whole shebang. And its still there.

 

I have ran into this exact same problem, but was on my mazda miata. Crappy plug wire would cause hesitation under acceleration. I swapped out for some quality plug wires and it went away. I just wonder if any one has ran into this in the Loyales.

 

thanks

[Syonyk]

Check your timing. If it's retarded from spec (~20deg BTDC), it will hesitate. Mine had a nasty hesitation & was generally gutless, it was somehow set at ~10deg BTDC.

 

Also, I believe a bad TPS (Throttle Position Sensor) can cause issues.

 

Is it only when cold, or always?

 

-=Russ=-

[GeneralDisorder]

Do the normal stuff - plugs, wires, cap and rotor, pcv valve.

 

Clean your MAF, check the TPS for proper operation, and check the CTS for proper readout when cold and hot.

 

If that doesn't cure it, replace the oxygen sensor.

 

If it's still there, run a D-Check and check for codes from the ECU

 

GD

[mellow65]

Check your timing. If it's retarded from spec (~20deg BTDC), it will hesitate. Mine had a nasty hesitation & was generally gutless, it was somehow set at ~10deg BTDC.

 

Also, I believe a bad TPS (Throttle Position Sensor) can cause issues.

 

Is it only when cold, or always?

 

-=Russ=-

 

 

I timming was dead on. I'll check the TPS when the rain lets up here in the next day or so. And it's all the time, but not all the time. Sometimes it runs great and strong then others it runs like a dog, either way I can still drive it just a little slower.

[mellow65]

Do the normal stuff - plugs, wires, cap and rotor, pcv valve.

 

Clean your MAF, check the TPS for proper operation, and check the CTS for proper readout when cold and hot.

 

If that doesn't cure it, replace the oxygen sensor.

 

If it's still there, run a D-Check and check for codes from the ECU

 

GD

 

Done all the normal stuff except the pcv

 

Is there a way to clean the MAF sensor, I think I remember reading about some product that was a MAF cleaner or use something like brake cleaner.

 

What's a CTS?

 

And it has no codes right now, that is from just blinking them out, not hooking it up to anything.

[GeneralDisorder]

CTS - coolant temp sensor. The one for the ECU, not the one for the guage. It will have a green connector, and it's below and behind the thermostat housing.

 

Clean that MAF with some brake cleaner - works great for me.

 

GD

[86subaru]

idle air control ,might help also , helped mine

[mellow65]

idle air control ,might help also , helped mine

 

 

I thought that only did something at idle

[azsubaru]

Another possibility - fuel pump could be going bad. The one on my Loyale had other problems, so I replaced it last night and discovered that it fixed a similar hesitation problem that had been on-going for quite some time.

[mellow65]

Another possibility - fuel pump could be going bad. The one on my Loyale had other problems, so I replaced it last night and discovered that it fixed a similar hesitation problem that had been on-going for quite some time.

 

 

Hmmm that's a good thought too, well I really can't do much checking till this damn rain lets up. Been crazy out here. I am going to check all that stuff as soon as I get a chance.

[mellow65]

OK with the little trouble shooting that I can do right now, you know with all the floods going on right now, I did a little here and there checking. I unplugged the AC pump to be completely sure that it wasn't that. And I have now noticed that it does it more cold then warm, or it's more abrupt when cold then warm. It's still there when it's warm just not as bad. Also as an in the car way of checking the TPS I would put it in a higher gear and slowly move the throttle from closed to full open and there isn't one place in throttle position that makes it happen, it seems to be more of a combo of throttle and rpm when it does it.

 

As soon and this blasted rain lets up I will get under the hood and start checking more out.

[daeron]

And it's all the time, but not all the time. Sometimes it runs great and strong then others it runs like a dog, either way I can still drive it just a little slower.

 

that makes it sound (to me) exactly like my problem, when my issue was the TPS. Its a nice, easy procedure to test..PM me with your real email address, or post it up here, and I will email you a page out of the FSM that outlines the procedure. All you have to do is, with engine off, check for various resistance values between different pairs of pins on the switch, (at certain throttle positions) and also check the resistance increase as you slowly open the throttle.. the resistance should smoothly, slowly increase.... That second part is what you want to check to eliminate it as your problem, the first step I explained is part of ensuring that it is properly calibrated..

 

Of course, as I said, your statement makes it sound like your having the exact same problem I was. I may be wrong but its an easy check, and not a difficult replacement either. its a part that IS often sourced from a junkyard though.. not too cheap to buy new.. and not too difficult to replace again, if the first JY component goes south. they arent THAT failure prone, either.

[mellow65]

that makes it sound (to me) exactly like my problem, when my issue was the TPS. Its a nice, easy procedure to test..PM me with your real email address, or post it up here, and I will email you a page out of the FSM that outlines the procedure. All you have to do is, with engine off, check for various resistance values between different pairs of pins on the switch, (at certain throttle positions) and also check the resistance increase as you slowly open the throttle.. the resistance should smoothly, slowly increase.... That second part is what you want to check to eliminate it as your problem, the first step I explained is part of ensuring that it is properly calibrated..

 

Of course, as I said, your statement makes it sound like your having the exact same problem I was. I may be wrong but its an easy check, and not a difficult replacement either. its a part that IS often sourced from a junkyard though.. not too cheap to buy new.. and not too difficult to replace again, if the first JY component goes south. they arent THAT failure prone, either.

 

I PMed you

[daeron]

I PMed you

 

I e-mailed you.

[mellow65]

I e-mailed you.

 

 

I got it thanks

[mellow65]

UPDATE UPDATE

 

ok spent the better part of the day tinkering with the roo and this is what I found. I went to the JY and got like 4 temp sensors 3 TPSs some other random crap. I tested all the temp sensor and put the one in that was closest to what the service manual said i tested all the TPSs and the one that was in my car was a tad odd so I replaced it with one that read good. Oh and to anyone that says they are easy to replace doesn't have AC. I cleaned and tested my air flow sensor. hell I even tested my idle air control valve like the one guy said. and last but not least replaced my completely dead O2 sensor. Ok here is where I am at. when the car is cold it still has the hesitation pretty bad but only when you try to get on it. if you accerlerate slowly there is no bogging. now when it gets warm it for the most part disappear, but then will come back at the worst time like when trying to pass someone.

 

So whats left. Some one recommended a new fuel pump. But dang at $160 that is what I am hoping to avoid. My next thing is to try some better plug wires. I have had problems in the past with the cheap ones causing hesitation.

 

Any more input would be great.

 

Oh and if anyone wonders, i have done plugs, wires, cap, rotor, fuel filter and air filter also.

[mikeshoup]

Dirty Injector maybe? Might have something blocking it from supplying enough fuel at full throttle. Heck if I know though.

[Indrid cold]

Keep us posted on this. I have been chasing a similar problem with my 88, also woundering if possibly a compression check would be in order... possibly a leaking head valve or something? I don't know just a noob thought...

[GeneralDisorder]

Have you cleaned the MAF yet? And especially the MAF housing - there is a small by-pass slot that can get dirty and clogged with gunk - this will not allow enough air over the MAF element. Remove the MAF sensor from it's housing and clean that by spraying the wires with brake cleaner. Then remove the housing from the filter box and intake boot and clean that thing till no more dirty brake cleaner comes out of the hole or the slot. Then remove the intake boot and spray that out for good measure - they get a lot of oil in them as the PCV system isn't well designed (they have a kit for it that came out in 91, but it's only a partial solution really - they still get dirty).

 

GD

[goobaroo]

i know this sounds to obvious to be true, but check all ur spark connections, from coil to disty, to plugs, even the rotor and points. i had a bogging issue a couple weeks back and all it was....2 spark wires that had slipped out of the disty far enough to lose contact but not noticable by just looking at them, i had to replace both wire ends and the disty cap cuz the spark was gapping between the wire and the cap, melted both the cap leads and the wire end. since i fixed that it hasnt happened since.

 

just my 2 cents. hope u figure it out!

[mellow65]

Have you cleaned the MAF yet? And especially the MAF housing - there is a small by-pass slot that can get dirty and clogged with gunk - this will not allow enough air over the MAF element. Remove the MAF sensor from it's housing and clean that by spraying the wires with brake cleaner. Then remove the housing from the filter box and intake boot and clean that thing till no more dirty brake cleaner comes out of the hole or the slot. Then remove the intake boot and spray that out for good measure - they get a lot of oil in them as the PCV system isn't well designed (they have a kit for it that came out in 91, but it's only a partial solution really - they still get dirty).

 

GD

 

I did clean it, squirted it down with some brake cleaner then did it again then did it again to be sure. I also tested the was the manual says to all checks out. I will check and clean out the housing to in the next day or so.

 

 

i know this sounds to obvious to be true, but check all ur spark connections, from coil to disty, to plugs, even the rotor and points. i had a bogging issue a couple weeks back and all it was....2 spark wires that had slipped out of the disty far enough to lose contact but not noticable by just looking at them, i had to replace both wire ends and the disty cap cuz the spark was gapping between the wire and the cap, melted both the cap leads and the wire end. since i fixed that it hasnt happened since.

 

just my 2 cents. hope u figure it out!

 

 

I know this problem all to well I had this happen to me also. From that day forward I have always made sure I heard the "click" when putting the wires on the plug and I pull the boot back before putting the other end onto the cap then pull the boot over it.

 

But it's worth looking at again.

 

my next thing is to get better plug wires. I had this exact thing happen on my miata, I mean exact, would drive fine under low load and as soon as you wanted to get on it bog city and it was the damn plug wires. I think I'm just going to order a set of those magacore wires and see if that helps. if not hell the only things that are left are the fuel pump and the ECU and i really dont want to think about paying for that.

 

I'll keep you updated.

[GeneralDisorder]

The by-pass slot in the housing is very important - the MAF can be new, and if the by-pass isn't clean..... when you cleaned it did you remove the MAF or did you just squirt the brake cleaner into the housing - that will just push the grime futher into the by-pass.

 

Any rattleing in the exhaust? Maybe a peice of the cat is floating around in and blocking the exhuast flow. That's a stab in the dark tho.

 

Fuel pump *could* be slightly intermittant but that's really not too likely. Only way to really check that would be to hook up a fuel pressure guage in the cabin, or just try a junk yard pump. They are about $15 at u-pull-it. The one on Foster has a load of them.

 

Plug wires are extremely unlikely. Just get a set of NGK's to test the theory before buying some expensive wires you don't need. The NGK's run about $18 and are as good as any - plus they are numbered and are always the right length.

 

GD

[hooziewhatsit]

how did you test your IAC valve?

 

I used to have pretty bad bogging when cold. Took off the IAC, cleaned out the valve portion of it with carb cleaner, then sprayed some silicon lubricant into the solenoid portion of it.

 

Haven't had any bogging since

 

(tip: to remove the IAC, use vice grips to break the four screws loose and get them by hand after that)

 

-Dave

[mellow65]

The by-pass slot in the housing is very important - the MAF can be new, and if the by-pass isn't clean..... when you cleaned it did you remove the MAF or did you just squirt the brake cleaner into the housing - that will just push the grime futher into the by-pass.

 

Any rattleing in the exhaust? Maybe a peice of the cat is floating around in and blocking the exhuast flow. That's a stab in the dark tho.

 

Fuel pump *could* be slightly intermittant but that's really not too likely. Only way to really check that would be to hook up a fuel pressure guage in the cabin, or just try a junk yard pump. They are about $15 at u-pull-it. The one on Foster has a load of them.

 

Plug wires are extremely unlikely. Just get a set of NGK's to test the theory before buying some expensive wires you don't need. The NGK's run about $18 and are as good as any - plus they are numbered and are always the right length.

 

GD

 

 

I took the MAF out and cleaned it. I will take the whole housing out in the next day or so and clean that all out.

 

No rattling in the exhaust, but hell with almost 200k miles god only knows how clogged up that cat is.

 

I think I may have a pump from my last project that didn't run. I may try that also in the next day or so.

 

And where do you get NGK plug wires for $18? It seems for the most part no one even carries NGK wires, hell let alone finding anyone that carries more then like 3 plugs for what I need is hard enough. So really tell me who has them for $18. I have always had good luck with NGK so I wouldn't mind giving them a shot.

 

 

 

how did you test your IAC valve?

 

I used to have pretty bad bogging when cold. Took off the IAC, cleaned out the valve portion of it with carb cleaner, then sprayed some silicon lubricant into the solenoid portion of it.

 

Haven't had any bogging since

 

(tip: to remove the IAC, use vice grips to break the four screws loose and get them by hand after that)

 

-Dave

 

the manual says to unplug it and the RPMs should change dramatically if so then it is working. I didn't take it off and clean it, but I will add it to the many things to try.

 

I guess this is how it truly goes, you find the super clean wagon that doesn't break the bank and I am chasing the bog demon

[GeneralDisorder]

And where do you get NGK plug wires for $18? It seems for the most part no one even carries NGK wires, hell let alone finding anyone that carries more then like 3 plugs for what I need is hard enough. So really tell me who has them for $18. I have always had good luck with NGK so I wouldn't mind giving them a shot.

 

Local place called "Discount Import Parts". They have two locations here - Beaverton, and Milwaukie(?). They specialize in VW, but have parts for virtually everything on the import scale. Great prices, lots of Redline and specialty fluids, etc. They had the NGK's (plugs and wires) in stock for the EA82. They also have OEM brand oil pumps for $65!

 

GD